TW201934703A - Solder particles, electroconductive material, solder particle storage method, electroconductive material storage method, electroconductive material production method, connection structure, and connection structure production method - Google Patents

Abstract

Provided are solder particles capable of effectively increasing the coalescence of solder when forming electroconductive connections. The solder particles according to the present invention comprise a solder particle body and an oxide film disposed on the outer surface of the solder particle body. The particle size of the solder particles is at least 0.01 [mu]m and less than 1 [mu]m. The average thickness of the oxide film is 5 nm or less.

Description

Solder particles, conductive materials, storage methods of solder particles, storage methods of conductive materials, methods of manufacturing conductive materials, connection structures, and methods of manufacturing connection structures

The present invention relates to, for example, a solder particle and a method for storing solder particles that can be used for electrical connection between electrodes. The present invention also relates to a conductive material containing the solder particles, a method for storing the conductive material, and a method for manufacturing the conductive material. The present invention also relates to a method of manufacturing a connection structure and a connection structure using the solder particles or the conductive material.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. The anisotropic conductive material has conductive particles dispersed in a binder. As the conductive particles, solder particles are widely used.

The above-mentioned anisotropic conductive material is used to obtain various connection structures. Examples of the connection through 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 wafer and a flexible printed circuit board (COF (Chip on Film) , Film-on-chip)), the connection of semiconductor wafers and glass substrates (COG (Chip on Glass, glass-on-chip)), and the connection of flexible printed substrates and glass epoxy substrates (FOB (Film on Board)) )Wait.

When the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Then, the flexible printed circuit board is laminated, and heated and pressurized. Thereby, the anisotropic conductive material is hardened, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

As an example of the above-mentioned anisotropic conductive material, the following Patent Document 1 describes an anisotropic conductive material containing conductive particles and a resin component whose curing is not completed at the melting point of the conductive particles. Specific examples of the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd). ), Gallium (Ga) and thorium (Tl) and other metals, or alloys of these metals.

Patent Document 1 describes a resin heating step of heating an anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and the curing of the resin component is not completed, and a resin component curing step of curing the resin component. Electrically connect the electrodes. In addition, Patent Document 1 describes mounting using a temperature profile shown in FIG. 8 of Patent Document 1. In Patent Document 1, at the heating temperature of the anisotropic conductive resin, the conductive particles are melted in the resin component whose curing is not completed.

The following Patent Document 2 discloses a solder material including a solder layer and a coating layer covering the surface of the solder layer. The solder layer includes a metal material containing an alloy having a Sn content of 40% or more or a metal material having a Sn content of 100%. The coating layer includes a SnO film and a SnO ₂ film. The SnO film is formed on the outer surface side of the solder layer. The SnO ₂ film is formed on the outer surface side of the SnO film. The thickness of the coating layer is greater than 0 nm and less than 4.5 nm.
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-260131
[Patent Document 2] WO2016 / 031067A1

[Problems to be solved by the invention]

In recent years, the industry is promoting finer pitch of wiring such as printed wiring boards. As a result, for conductive materials including solder particles or conductive particles having solder on the surface, miniaturization and reduction in size of the solder particles or conductive particles having solder on the surface are being promoted.

When the particle size of the solder particles and the like is reduced, there is a case where it is difficult to efficiently aggregate the solder particles and the like between the upper and lower electrodes to be connected when a conductive connection using a conductive material is used. In particular, when the conductive material is heated and hardened, the viscosity of the conductive material increases before the solder particles and the like are sufficiently moved to the electrode, and the solder particles and the like remain in the electrodeless area. As a result, there are cases in which the conduction reliability between electrodes to be connected and the insulation reliability between adjacent electrodes that cannot be connected cannot be sufficiently improved.

In addition, as the particle diameter of the solder particles and the like becomes smaller, the surface area of the solder particles and the like increases, so the content of the oxide film on the surface of the solder particles and the like also increases. If an oxide film is present on the surface of the solder particles, the solder particles and the like cannot be efficiently agglomerated on the electrode. Therefore, the conventional conductive materials require measures such as increasing the content of flux in the conductive materials. However, if the content of the flux in the conductive material is increased, there are cases in which the flux reacts with the thermosetting component in the conductive material, the storage stability of the conductive material decreases, or the heat resistance of the hardened material of the conductive material decreases. . In addition, if the content of the flux in the conductive material is increased, there may be cases where voids are generated in the hardened material of the conductive material, or poor curing of the conductive material may occur.

The previous conductive materials are difficult to meet all the requirements of improving solder agglutination during conductive connection, improving the storage stability of conductive materials, and improving the heat resistance of hardened materials of conductive materials.

An object of the present invention is to provide a solder particle and a method for storing the solder particle, which are capable of effectively improving solder cohesiveness at the time of conductive connection. Another object of the present invention is to provide a conductive material containing the solder particles, a method for storing the conductive material, and a method for manufacturing the conductive material. Another object of the present invention is to provide a connection structure and a method of manufacturing the connection structure using the solder particles or the conductive material.
[Technical means to solve the problem]

According to a broad aspect of the present invention, it is possible to provide a solder particle having a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and the particle diameter of the solder particle is 0.01 μm or more. The thickness is less than 1 μm, and the average thickness of the oxide film is 5 nm or less.

In a specific aspect of the solder particles of the present invention, when the solder particles are heated at 120 ° C. for 10 hours in an air environment, the average thickness of the oxide film before heating is relative to the average thickness of the oxide film after heating. The ratio is below 2/3.

In a specific aspect of the solder particles of the present invention, the absolute value of the heat generation at 200 ° C or higher is 100 mJ / mg or more.

According to a wider aspect of the present invention, a conductive material can be provided, which includes a thermosetting component and a plurality of solder particles, and the solder particles have a solder particle body, and a solder particle body disposed on an outer surface of the solder particle body. The oxide film has a particle diameter of the solder particles of 0.01 μm or more and less than 1 μm, and the average thickness of the oxide film is 5 nm or less.

In a specific aspect of the conductive material of the present invention, when the solder particles are heated at 120 ° C. for 10 hours in an air environment, the average thickness of the oxide film before heating is relative to the average thickness of the oxide film after heating. The ratio is below 2/3.

In a specific aspect of the conductive material of the present invention, the viscosity at 25 ° C is 10 Pa · s or more and 1000 Pa · s or less.

In a specific aspect of the conductive material of the present invention, the viscosity measured using an E-type viscometer at 25 ° C and 0.5 rpm is divided by the value measured using an E-type viscometer at 25 ° C and 5 rpm. The thixotropic index obtained from the viscosity is 1 or more and 10 or less.

In a specific aspect of the conductive material of the present invention, the absolute value of the exothermic heat of the solder particles at 200 ° C or higher is 100 mJ / mg or more.

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

According to a wider aspect of the present invention, a method for storing solder particles can be provided, which is the method for storing the solder particles described above, and the solder particles are placed in a storage container and stored in an inert gas environment, or The solder particles are placed in a storage container and stored in a vacuum under a condition of 1 × 10 ² Pa or less.

According to a broad aspect of the present invention, a method for storing a conductive material can be provided, which is the method for storing the above-mentioned conductive material, and the method is to place the above-mentioned conductive material in a storage container and keep it at -40 ° C or higher and 10 ° C Storage is performed under the following conditions, or the solder particles are placed in a storage container and stored in an inert gas environment.

According to a wider aspect of the present invention, a method for manufacturing a conductive material may be provided, which includes a mixing step of mixing a thermosetting component and a plurality of solder particles to obtain a conductive material. The method for manufacturing the conductive material is obtained as follows Conductive material: The solder particles have a solder particle body and an oxide film disposed on the outer surface of the solder particle body. The particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. The average thickness of the oxide film is 5 nm or less.

In a specific aspect of the method for manufacturing a conductive material of the present invention, the method further includes a storage step of storing the solder particles, and the storage step is a step of placing the solder particles in a storage container and storing the solder particles in an inert gas environment. Or, it is a step of putting the solder particles into a storage container and storing them in a vacuum under 1 × 10 ² Pa. The solder particles are solder particles that have been stored in the storage step.

According to a broad aspect of the present invention, there can be provided a connection structure including a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, and the above-mentioned first connection target. A connection portion between the member and the second connection object member, and the material of the connection portion includes the solder particles, and the first electrode and the second electrode are electrically connected by the solder portion of the connection portion.

According to a broad aspect of the present invention, there can be provided a connection structure including a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, and the above-mentioned first connection target. A connection portion between the member and the second connection object member, and a material of the connection portion is the conductive material, and the first electrode and the second electrode are electrically connected by a solder portion of the connection portion.

According to a broad aspect of the present invention, a method for manufacturing a connection structure can be provided, which includes the following steps: using a conductive material containing the above-mentioned solder particles, disposing on the surface of a first connection target member having a first electrode on the surface The conductive material; a second connection target member having a second electrode on the surface is arranged on the surface of the conductive material opposite to the first connection target member side so that the first electrode and the second electrode face each other; and The conductive material is heated to a temperature above the melting point of the solder particles to form a connection portion connecting the first connection target member and the second connection target member from the conductive material. The first electrode is electrically connected to the second electrode.

According to a broad aspect of the present invention, a method for manufacturing a connection structure can be provided, which includes the steps of: disposing the conductive material on a surface of a first connection target member having a first electrode on the surface of the conductive material; The second connection target member having the second electrode is disposed on the surface of the conductive material opposite to the first connection target member side so that the first electrode and the second electrode face each other; and It is heated above the melting point of the solder particles to form a connection portion connecting the first connection target member and the second connection target member from the conductive material, and the first electrode and the above are connected by a solder portion of the connection portion. The second electrode is electrically connected.
[Effect of the invention]

The solder particles of the present invention include a solder particle body and an oxide film disposed on an outer surface of the solder particle body. In the solder particles of the present invention, the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. In the solder particles of the present invention, the average thickness of the oxide film is 5 nm or less. Since the solder particle of this invention has the said structure, it can effectively improve the solder agglutination property at the time of a conductive connection.

The conductive material of the present invention includes a thermosetting component and a plurality of solder particles. In the conductive material of the present invention, the solder particles include a solder particle body and an oxide film disposed on an outer surface of the solder particle body. In the conductive material of the present invention, the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. In the conductive material of the present invention, the average thickness of the oxide film existing on the surface of the solder particles is 5 nm or less. Since the conductive material of the present invention has the above-mentioned structure, it is possible to effectively improve solder agglutinability during conductive connection.

The method for producing a conductive material of the present invention includes a mixing step of obtaining a conductive material by mixing a thermosetting component and a plurality of solder particles. In the conductive material manufacturing method of the present invention, a conductive material is obtained in which the solder particles have a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and a particle diameter of the solder particles is 0.01 μm or more and Up to 1 μm, the average thickness of the oxide film is 5 nm or less. Since the manufacturing method of the conductive material of this invention is provided with the said structure, the solder agglutination property at the time of a conductive connection can be improved effectively.

Hereinafter, details of the present invention will be described.

(Solder particles)
The solder particles of the present invention include a solder particle body and an oxide film disposed on an outer surface of the solder particle body. In the solder particles of the present invention, the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. In the solder particles of the present invention, the average thickness of the oxide film is 5 nm or less.

Since the solder particle of this invention has the said structure, it can effectively improve the solder agglutination property at the time of a conductive connection.

Compared with previous conductive materials containing solder particles with a particle size of about 35 μm, conductive materials containing solder particles with a particle size of 10 μm or less have the following problems: when conducting a conductive connection, solder cannot be made Particles efficiently aggregate between the upper and lower electrodes that should be connected. The present inventors made diligent research in order to solve the above-mentioned problems, and found that the reason for the above problems is that as the particle diameter of the solder particles becomes smaller, the oxide film existing on the surface of the solder particles becomes relatively thicker; The increase in the surface area increases the content of the oxide film existing on the surface of the solder particles. The present inventors have found that this problem occurs remarkably when the particle diameter of the solder particles is less than 1 μm. Furthermore, the present inventors have made intensive studies in order to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by controlling the oxide film existing on the surface of the solder particles to a specific thickness. In the present invention, although the solder particles are made smaller in size, the above-mentioned movement of the solder particles onto the electrodes is sufficiently performed, so that the solder can be efficiently aggregated between the electrodes to be connected, and the conduction reliability and insulation reliability can be improved.

5 and 6 are diagrams for explaining the agglomeration property of solder particles. Figures 5 and 6 are diagrams when the solder particles under various conditions (three particle sizes and the presence or absence of control of the thickness of the oxide film) are heated and the solder particles are aggregated.

Regarding the solder particles in which the thickness of the oxide film is not controlled in FIGS. 5 and 6, it can be understood that the smaller the particle diameter of the solder particles, the less the solder particles will aggregate. The reason is that as the particle diameter of the solder particles becomes smaller, the oxide film existing on the surface of the solder particles becomes relatively thicker; and because the surface area of the solder particles increases, the content of the oxide film existing on the surface of the solder particles is increased. increase.

Regarding the solder particles of which the thickness of the oxide film is not controlled as shown in Figs. 5 and 6, for the solder particles having a particle diameter of 10 μm, although the solder particles aggregate and form solder aggregates, they can be located around the solder aggregate Unagglomerated solder particles were confirmed. For solder particles having a particle diameter of 0.05 μm, 0.1 μm, 0.5 μm, 2 μm, and 5 μm, it was confirmed that the solder particles were not aggregated at all, and solder aggregates were not formed.

On the other hand, regarding the solder particles controlling the thickness of the oxide film in FIGS. 5 and 6, it was confirmed that regardless of the particle diameter of the solder particles, the solder particles aggregated to form a large solder aggregate. It can be understood that, in order to improve the cohesiveness of the solder particles, it is important to control the oxide film existing on the surface of the solder particles to a specific thickness.

In addition, in the present invention, by controlling the oxide film existing on the surface of the solder particles to a specific thickness, the solder particles can be efficiently aggregated on the electrodes, so there is no need to excessively increase the content of the flux in the conductive material. . As a result, the reaction between the thermosetting component and the flux in the conductive material can be effectively suppressed, and the storage stability of the conductive material can be effectively improved.

In addition, the melting point (active temperature) of the flux in the conductive material is often lower than the Tg of the thermosetting component in the conductive material. The more the content of the flux in the conductive material becomes, the more the conductive material is hardened. The heat resistance of a material tends to decrease. Since the present invention does not need to excessively increase the content of the flux in the conductive material, it can effectively improve the heat resistance of the hardened material of the conductive material. In addition, the present invention does not need to increase the content of the flux in the conductive material excessively, so it can effectively suppress the generation of voids in the hardened material of the conductive material, and can effectively suppress the occurrence of poor hardening of the conductive material.

Since the present invention has the above-mentioned configuration, it can satisfy all the requirements of improving solder agglutination during conductive connection, improving storage stability of conductive materials, and improving heat resistance of hardened materials of conductive materials.

In the present invention, in order to obtain the effects as described above, it is useful to control the oxide film existing on the surface of the solder particles to a specific thickness.

The solder particles include a solder particle body and an oxide film disposed on an outer surface of the solder particle body. Both the central portion and the outer surface of the solder particle body are formed of solder. The above solder particles are the particles of solder in the central part and the outer surface of the system. The oxide film is formed by subjecting the outer surface of the solder particle body to oxygen oxidation in the air. The oxide film includes tin oxide and the like. Generally speaking, commercially available solder particles are oxidized on the outer surface by oxygen in the air and have an oxide film.

In the case where conductive particles including substrate particles made of a material other than solder and solder portions arranged on the surface of the substrate particles are used instead of the solder particles, it is difficult for the conductive particles to collect on the electrode. In addition, the conductive particles described above have a low solder bonding property with each other. Therefore, the conductive particles tend to move to the outside of the electrode, and the effect of suppressing the positional shift between the electrodes is also low. The tendency.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Moreover, in the following drawings, the size, thickness, shape, etc. may be different from the actual size, thickness, shape, etc. for convenience of illustration.

Fig. 4 is a sectional view showing an example of solder particles that can be used for a conductive material.

The solder particle 21 shown in FIG. 4 includes a solder particle body 22 and an oxide film 23 disposed on an outer surface of the solder particle body 22. The solder particle body 22 is in contact with the oxide film 23. The entire solder particle body 22 is formed of solder. The solder particle body 22 does not have substrate particles in the core, and is not a core-shell particle. Both the central portion and the outer surface of the solder particle body 22 are formed of 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 refers to 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, and more preferably 160 ° C or lower. The solder particles are preferably low-melting-point solders having a melting point of less than 150 ° C.

The melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) device include "EXSTAR DSC7020" manufactured by SII.

The solder particles preferably contain tin. The content of tin in 100% by weight of the metal contained in the solder particles is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and even more preferably 90% by weight or more. When the content of tin in the solder particles is greater than or equal to the above lower limit, the connection reliability between the solder portion and the electrode is further increased.

Furthermore, the above-mentioned tin content can be measured using a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS" manufactured by Shimadzu, Ltd.). ) And so on.

By using the above-mentioned solder particles, the solder is melted and bonded to the electrode, and the solder is solidified to form a solder portion, and the solder portion conducts between the electrodes. For example, since the solder portion and the electrode are easily in surface contact rather than point contact, the connection resistance becomes low. In addition, by using the above-mentioned solder particles, the bonding strength between the solder portion and the electrode becomes high, and as a result, peeling of the solder portion and the electrode is less likely to occur, and continuity reliability and connection reliability are further increased.

The metal constituting the solder particles is not particularly limited. The metal is preferably tin or an alloy containing tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, and tin-indium alloy. In terms of excellent wettability to the electrode, the above-mentioned metal is preferably tin, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, and tin-indium alloy. More preferred are tin-bismuth alloys and tin-indium alloys.

Regarding the solder particles described above, based on JIS Z3001: welding term, a filler material having a liquidus of 450 ° C. or lower is preferred. Examples of the composition of the solder particles include metal compositions including zinc, gold, silver, lead, copper, tin, bismuth, and indium. A low melting point and lead-free tin-indium system (117 ° C eutectic) or tin-bismuth system (139 ° C eutectic) is preferred. That is, it is preferable that the said solder particle does not contain lead, and it contains tin and indium, or tin and bismuth.

In order to further improve the bonding strength between the solder portion and the electrode, the solder particles may further include nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum, and palladium. And other metals. From the viewpoint of further improving 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 improving the bonding strength between the solder portion and the electrode, the content of these metals to increase the bonding strength is preferably 0.0001% by weight or more and preferably 1% by weight or less based on 100% by weight of the solder particles.

In the solder particles of the present invention, the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. The particle diameter of the solder particles is preferably 0.02 μm or more, more preferably 0.05 μm or more, and more preferably 0.5 μm or less, more preferably 0.2 μm or less, and still more preferably 0.1 μm or less. When the particle diameter of the said solder particle is more than the said lower limit and below the said upper limit, the solder agglutination property at the time of a conductive connection can be improved more effectively. The particle diameter of the solder particles is particularly preferably 0.05 μm or more and 0.1 μm or less.

The particle diameter of the solder particles is preferably an average particle diameter, and more preferably a number average particle diameter. The particle diameter of the solder particles is determined, for example, by observing arbitrary 50 solder particles with an electron microscope or an optical microscope, and calculating an average value of the particle diameters of the respective solder particles, or by performing a laser diffraction type particle size distribution measurement. In observation with an electron microscope or an optical microscope, the particle diameter of each solder particle was determined by setting the particle diameter in terms of a circle equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter in terms of circular equivalent diameter and the average particle diameter in terms of spherical equivalent diameter of any 50 solder particles are approximately equal. In the laser diffraction type particle size distribution measurement, the particle diameter of each solder particle is determined by setting the particle diameter in terms of spherical equivalent diameter. The average particle diameter of the solder particles is preferably calculated by laser diffraction particle size distribution measurement.

The coefficient of variation (CV value) of the particle diameter of the solder particles is preferably 5% or more, more preferably 10% or more, and preferably 40% or less, and more preferably 30% or less. If the variation coefficient of the particle diameter of the said solder particle is more than the said lower limit and below the said upper limit, a solder can be arrange | positioned more uniformly on an electrode. However, the CV value of the particle diameter of the solder particles may be less than 5%.

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

CV value (%) = (ρ / Dn) × 100
ρ: standard deviation of the particle diameter of the solder particles
Dn: average value of particle diameter of solder particles

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

In the solder particles of the present invention, the average thickness of the oxide film is 5 nm or less. The average thickness of the oxide film is preferably 0.5 nm or more, more preferably 1 nm or more, and more preferably 4 nm or less, and even more preferably 3 nm or less. When the average thickness of the oxide film is equal to or more than the lower limit and equal to or less than the upper limit, the solder agglomeration property at the time of conductive connection can be more effectively improved. Moreover, if the average thickness of the said oxide film is more than the said lower limit and below the said upper limit, the storage stability of a conductive material can be improved more effectively, and the heat resistance of the hardened | cured material of a conductive material can be improved more effectively. Moreover, if the average thickness of the said oxide film is more than the said minimum, it can be used suitably for the use of a conductive material. Moreover, if the average thickness of the said oxide film is more than the said lower limit, the handleability of the conductive material containing the said solder particle can be improved more effectively. In addition, by setting the thickness of the oxide film to be greater than or equal to the above lower limit and less than or equal to the above upper limit, it is possible to appropriately control the melting property of the surface of the solder particles during heating. Therefore, it is considered that the solder agglomeration during conductive connection is more effective Becomes high.

The average thickness of the said oxide film can be calculated | required by observing the cross section of a solder particle using a transmission electron microscope, for example. The average thickness of the oxide film can be calculated, for example, based on the average value of the thickness of the oxide film at 10 locations arbitrarily selected.

When the solder particles are heated at 120 ° C for 10 hours in the air, the ratio of the average thickness of the oxide film before heating to the average thickness of the oxide film after heating (average thickness of the oxide film before heating / heating) The average thickness of the subsequent oxide film) is preferably 2/3 or less, and more preferably 1/2 or less. The lower limit of the above ratio (average thickness of the oxide film before heating / average thickness of the oxide film after heating) is not particularly limited. The above ratio (average thickness of the oxide film before heating / average thickness of the oxide film after heating) may be 1/100 or more, may be 1/50 or more, and may be 1/10 or more. If the above ratio (average thickness of the oxide film before heating / average thickness of the oxide film after heating) is equal to or less than the above upper limit, solder cohesiveness at the time of conductive connection can be more effectively improved. If the above ratio (average thickness of the oxide film before heating / average thickness of the oxide film after heating) is below the above upper limit, the storage stability of the conductive material can be more effectively improved, and furthermore, the conductive material can be more effectively improved. Heat resistance of hardened material. Moreover, if the said ratio (average thickness of the oxide film before heating / average thickness of the oxide film after heating) is below the said upper limit, it can be used suitably for the use of a conductive material.

Since the solder particles of the present invention control the oxide film before heating to a specific thickness (the oxide film is relatively thin), the thickness of the oxide film can be increased by heating at 120 ° C for 10 hours in an air environment, which can satisfy the above ratio. (Average thickness of oxide film before heating / Average thickness of oxide film after heating). The previous solder particles had a relatively thick oxide film before heating, so there was insufficient room for oxidation. Even if heated at 120 ° C for 10 hours in an air environment, the thickness of the oxide film will not increase so much, which does not meet the above ratio (heating The average thickness of the previous oxide film / the average thickness of the oxide film after heating).

The average thickness of the oxide film before heating and the average thickness of the oxide film after heating can be determined by, for example, observing the cross section of the solder particles before and after heating using a transmission electron microscope. The average thickness of the above-mentioned oxide film before heating and the average thickness of the above-mentioned oxide film after heating can be calculated, for example, from the average value of the thicknesses of the oxide films at 10 locations arbitrarily selected.

The ratio of the average thickness of the oxide film to the particle diameter of the solder particles (average thickness of the oxide film / particle diameter of the solder particles) is preferably 0.001 or more, more preferably 0.002 or more, and more preferably 0.5 or less, and more preferably It is 0.4 or less. When the above ratio (average thickness of the oxide film / particle diameter of the solder particles) is equal to or more than the above lower limit and equal to or less than the above upper limit, the solder agglutinability at the time of conductive connection can be more effectively improved. In addition, if the ratio (average thickness of the oxide film / particle diameter of the solder particles) is greater than or equal to the lower limit and less than the upper limit, the storage stability of the conductive material can be more effectively improved, and furthermore, the conductive material can be more effectively improved. Heat resistance of hardened material.

The content of the oxide film in 100% by volume of the solder particles is preferably 1% by volume or more, more preferably 2% by volume or more, and more preferably 70% by volume or less, and more preferably 60% by volume or less. When the content of the oxide film is greater than or equal to the above lower limit and less than or equal to the above upper limit, solder cohesiveness at the time of conductive connection can be more effectively improved. In addition, if the content of the oxide film is at least the above lower limit and below the above upper limit, the storage stability of the conductive material can be more effectively improved, and furthermore, the heat resistance of the cured material of the conductive material can be more effectively improved.

The content of the oxide film can be calculated based on the weight of the solder particles before and after the oxide film is removed.

The absolute value of the exothermic heat of the solder particles at 200 ° C or higher is preferably 100 mJ / mg or more, more preferably 200 mJ / mg or more, and preferably 400 mJ / mg or less, and more preferably 300 mJ / mg or less. It is considered that the absolute value of the exothermic heat of the solder particles at 200 ° C. or more changes depending on the thickness of the oxide film on the surface of the solder particles and the like. If the absolute value of the heat radiation above 200 ° C. is above the lower limit and below the upper limit, the solder cohesiveness at the time of conductive connection can be more effectively improved.

The exothermic amount of the solder particles at 200 ° C or higher can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) device include "EXSTAR DSC7020" manufactured by SII.

The said solder particle can be obtained by acid-treating a commercially available solder particle, for example. It is preferable to control the thickness of the oxide film existing on the surface of the solder particles by the acid treatment. Examples of the acid used in the acid treatment include organic acids.

(Storage method of solder particles)
The method for storing solder particles of the present invention is preferably a method for storing the solder particles. It is preferable that the said solder particle is stored by the storage method of the solder particle of this invention. The solder particles are preferably placed in a storage container and stored under an inert gas atmosphere, or the solder particles are placed in a storage container and vacuum stored under a condition of 1 × 10 ² Pa or less.

From the viewpoint of more effectively improving the solder cohesiveness at the time of conductive connection, the storage method of the solder particles may be refrigerated storage or frozen storage.

However, the solder particles of the present invention may be stored in a storage container at a temperature of 10 ° C or higher and 50 ° C or lower, for example. The solder particles of the present invention can be stored at 10 ° C or higher and 45 ° C or lower, or can be stored at 20 ° C or higher, can be stored at 25 ° C or higher, and can be stored at 40 ° C or lower, or 30 ° C or lower. Keep it. The storage method of the solder particles is preferably storage below room temperature, and more preferably storage below room temperature.

In order to store the said solder particle under the said temperature conditions, a constant temperature bath etc. can be used. It is preferable that the storage container containing the solder particles is stored in a thermostatic bath set to the above-mentioned preferable temperature conditions.

From the viewpoint of more effectively improving solder agglutination at the time of conductive connection, as for the method for storing the solder particles, it is preferable that the solder particles are stored in a storage container and stored in an inert gas environment.

Examples of the inert gas include argon and nitrogen.

From the viewpoint of more effectively improving the solder agglutination property during the conductive connection, as for the method for storing the solder particles, it is preferable that the solder particles are placed in a storage container and vacuumed under a condition of 0.8 × 10 ² Pa or less. For storage, it is more preferable to perform vacuum storage under the conditions of 0.5 × 10 ² Pa or less.

In order to store the said solder particle under the said vacuum condition, it is preferable to store under reduced pressure in the said storage container using a vacuum pump etc.

The storage container is not particularly limited as long as it is a container capable of withstanding refrigerated storage, refrigerated storage, and vacuum storage. From the viewpoint of more effectively improving the solder agglutination property during the conductive connection, the storage container is preferably a container capable of preventing penetration of oxygen, and more preferably a container having good airtightness. Examples of the storage container include aluminum bags.

From the viewpoint of more effectively improving the solder agglutination property during conductive connection, it is preferable to control the oxygen concentration in the storage container. From the viewpoint of more effectively improving solder agglutination during conductive connection, the oxygen concentration in the storage container is preferably 200 ppm or less, and more preferably 100 ppm or less. Examples of a method for controlling the oxygen concentration in the storage container include a method of performing nitrogen substitution in the storage container.

The oxygen concentration in the storage container can be determined using an oxygen concentration meter. Examples of the oxygen concentration meter include "XO-326IIsA" manufactured by New Cosmos Electric.

(Conductive material and manufacturing method of conductive material)
The conductive material of the present invention includes a thermosetting component and a plurality of solder particles. In the conductive material of the present invention, the solder particles include a solder particle body and an oxide film disposed on an outer surface of the solder particle body. In the conductive material of the present invention, the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. In the conductive material of the present invention, the average thickness of the oxide film existing on the surface of the solder particles is 5 nm or less.

The method for producing a conductive material of the present invention includes a mixing step of obtaining a conductive material by mixing a thermosetting component and a plurality of solder particles. In the conductive material manufacturing method of the present invention, a conductive material is obtained in which the solder particles have a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and a particle diameter of the solder particles is 0.01 μm or more and Up to 1 μm, the average thickness of the oxide film is 5 nm or less.

In the conductive material of the present invention and the method of manufacturing the conductive material of the present invention, solder particles are used. The solder particles are preferably the solder particles. The conductive material of the present invention and the method of manufacturing the conductive material of the present invention preferably use the solder particles described above.

Since the conductive material of the present invention and the method of manufacturing the conductive material of the present invention have the above-mentioned configuration, it is possible to effectively improve the solder agglutinability during conductive connection.

Compared with previous conductive materials containing solder particles with a particle size of about 35 μm, conductive materials containing solder particles with a particle size of 10 μm or less have the following problems: when conducting a conductive connection, solder cannot be made Particles efficiently aggregate between the upper and lower electrodes that should be connected. The present inventors made diligent research in order to solve the above-mentioned problems, and found that the reason for the above problems is that as the particle diameter of the solder particles becomes smaller, the oxide film existing on the surface of the solder particles becomes relatively thicker; The increase in the surface area increases the content of the oxide film existing on the surface of the solder particles. Furthermore, the present inventors have made intensive studies in order to solve the above problems, and as a result, they have found that the above problems can be solved by controlling the oxide film existing on the surface of the solder particles to a specific thickness. In the present invention, although the solder particles are reduced in size, the above-mentioned movement of the solder particles toward the electrodes is sufficiently performed, and the solder can be efficiently aggregated between the electrodes to be connected, thereby improving the conduction reliability and the insulation reliability. .

In addition, in the present invention, since the oxide film existing on the surface of the solder particles is controlled to a specific thickness, the solder particles can be efficiently aggregated on the electrodes, so it is not necessary to excessively increase the content of the flux in the conductive material. . As a result, the reaction between the thermosetting component and the flux in the conductive material can be effectively suppressed, and the storage stability of the conductive material can be effectively improved.

In addition, the melting point (active temperature) of the flux in the conductive material tends to be lower than the Tg of the thermosetting component in the conductive material, and the more the content of the flux in the conductive material becomes, The lower the heat resistance of the hardened material of the conductive material. Since the present invention does not need to excessively increase the content of the flux in the conductive material, it can effectively improve the heat resistance of the hardened material of the conductive material. In addition, the present invention does not need to increase the content of the flux in the conductive material excessively, so it can effectively suppress the generation of voids in the hardened material of the conductive material, and can effectively suppress the occurrence of poor hardening of the conductive material.

Since the present invention has the above-mentioned configuration, it can satisfy all the requirements of improving solder agglutination during conductive connection, improving storage stability of conductive materials, and improving heat resistance of hardened materials of conductive materials.

In the present invention, in order to obtain the effects as described above, it is useful to control the oxide film existing on the surface of the solder particles to a specific thickness.

Furthermore, the present invention can prevent the positional shift between the electrodes. In the present invention, when the second connection target member is superimposed on the first connection target member on which the conductive material is disposed on the upper surface, the alignment of the electrode of the first connection target member and the electrode of the second connection target member is shifted. In this state, the offset can be corrected to connect the electrodes to each other (self-aligning effect).

From the viewpoint of more effectively improving the solder cohesiveness at the time of the conductive connection, the conductive material is preferably liquid at 25 ° C, and more preferably a conductive paste.

From the viewpoint of more effectively improving solder agglutination during conductive connection, the viscosity (η25 (5 rpm)) of the above-mentioned conductive material at 25 ° C and 5 rpm is preferably 10 Pa · s or more, and more preferably 30 Pa · s or more, more preferably 50 Pa · s or more, and even more preferably 100 Pa · s or more. From the viewpoint of more effectively improving solder agglutination during conductive connection, the viscosity (η25 (5 rpm)) of the above-mentioned conductive material at 25 ° C and 5 rpm is preferably 1,000 Pa · s or less, and more preferably 400 Pa · s or less, more preferably 300 Pa · s or less, and particularly preferably 200 Pa · s or less. The above viscosity (η25 (5 rpm)) can be appropriately adjusted according to the type and amount of the compounding ingredients.

The viscosity (η25 (5 rpm)) 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.

From the viewpoint of more effectively improving the solder agglutination during conductive connection, the viscosity (η20 (5 rpm)) of the above-mentioned conductive material under the conditions of 20 ° C and 5 rpm is preferably 10 Pa · s or more, more preferably 30 Pa · s or more, preferably 600 Pa · s or less, and more preferably 400 Pa · s or less. The above-mentioned viscosity (η20 (5 rpm)) can be appropriately adjusted according to the type and amount of the ingredients to be blended.

The viscosity (η20 (5 rpm)) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) and the like at 20 ° C and 5 rpm.

From the viewpoint of more effectively improving the solder agglutination during conductive connection, the viscosity (η25 (0.5 rpm)) of the above-mentioned conductive material measured using an E-type viscometer at 25 ° C and 0.5 rpm is preferably 50. Pa · s or more, more preferably 100 Pa · s or more, more preferably 400 Pa · s or less, and even more preferably 300 Pa · s or less. The above viscosity (η25 (0.5 rpm) can be appropriately adjusted according to the type and amount of the blended ingredients.

From the viewpoint of more effectively improving the solder agglutination at the time of conductive connection, the viscosity (η25 (5 rpm)) of the above-mentioned conductive material measured using an E-type viscometer at 25 ° C and 5 rpm is preferably 50. Pa · s or more, more preferably 100 Pa · s or more, more preferably 300 Pa · s or less, and even more preferably 200 Pa · s or less. The above viscosity (η25 (5 rpm)) can be appropriately adjusted according to the type and amount of the compounding ingredients.

Examples of the E-type viscosity meter include "TVE22L" manufactured by Toki Sangyo.

Thixotropy obtained by dividing the viscosity of the above-mentioned conductive material using an E-type viscometer at 25 ° C and 0.5 rpm divided by the viscosity of the above-mentioned conductive material using an E-type viscometer at 25 ° C and 5 rpm The index (η25 (0.5 rpm) / η25 (5 rpm)) is preferably 1 or more, more preferably 1.1 or more, and even more preferably 1.5 or more. Thixotropy obtained by dividing the viscosity of the above-mentioned conductive material using an E-type viscometer at 25 ° C and 0.5 rpm divided by the viscosity of the above-mentioned conductive material using an E-type viscometer at 25 ° C and 5 rpm The index (η25 (0.5 rpm) / η25 (5 rpm)) is preferably 10 or less, more preferably 5 or less, and even more preferably 4 or less. If the thixotropic index (η25 (0.5 rpm) / η25 (5 rpm)) is equal to or greater than the lower limit and equal to or lower than the upper limit, solder agglutination at the time of conductive connection can be more effectively improved.

The above conductive materials can be used as a conductive paste, a conductive film, and the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. From the viewpoint of more effectively improving the solder agglutination property during the conductive connection, the conductive material is preferably a conductive paste. The above conductive material can be suitably used for the electrical connection of the electrodes. The conductive material is preferably a circuit connection material.

The method for producing a conductive material of the present invention includes a mixing step of obtaining a conductive material by mixing a thermosetting component and a plurality of solder particles. In the conductive material manufacturing method of the present invention, a conductive material is obtained in which the solder particles have a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and a particle diameter of the solder particles is 0.01 μm or more and Up to 1 μm, the average thickness of the oxide film is 5 nm or less.

The method for producing a conductive material according to the present invention preferably further includes a storage step for storing the solder particles. In the manufacturing method of the conductive material of the present invention, the storage step is preferably a step of storing the solder particles in a storage container and storing the solder particles in an inert gas environment. In the method for producing a conductive material according to the present invention, the storage step is preferably a step of storing the solder particles in a storage container and performing vacuum storage under a condition of 1 × 10 ² Pa or less. In the method for producing a conductive material according to the present invention, the solder particles are preferably solder particles that have been stored in the storage step.

From the viewpoint of more effectively improving the solder cohesiveness at the time of conductive connection, the storage method of the solder particles may be refrigerated storage or frozen storage.

However, the solder particles of the present invention may be stored in a storage container at a temperature of 10 ° C or higher and 50 ° C or lower, for example. The solder particles of the present invention can be stored at 10 ° C or higher and 45 ° C or lower, or can be stored at 20 ° C or higher, can be stored at 25 ° C or higher, and can be stored at 40 ° C or lower, or 30 ° C or lower. Keep it. The storage method of the solder particles is preferably storage below room temperature, and more preferably storage below room temperature.

In the manufacturing method of the conductive material of this invention, it is preferable that the said solder particle is the said solder particle. In the method for producing a conductive material according to the present invention, the solder particles may be solder particles that have been stored by the storage method of the solder particles.

In the mixing step, the method of mixing the thermosetting component and the solder particles may be a conventionally known dispersion method, and is not particularly limited. As a method of dispersing the said solder particle in the said thermosetting component, the following method is mentioned. The method of adding the said solder particle to the said thermosetting component, and kneading | dispersing it using a planetary mixer etc., and dispersing. A method of uniformly dispersing the solder particles in water or an organic solvent using a homogenizer or the like, adding the solder particles to the thermosetting component, and kneading and dispersing the particles with a planetary mixer or the like. The method of diluting the said thermosetting component with water, an organic solvent, etc., adding the said solder particle, and kneading | dispersing by a planetary mixer etc. and dispersing.

From the viewpoint of more effectively improving solder agglutination during conductive connection, in the mixing step, it is preferable to control the oxygen concentration so that the solder particles are not excessively oxidized. Examples of the method for controlling the above-mentioned oxygen concentration include a method for performing the above-mentioned mixing step in a nitrogen environment, and the like. From the viewpoint of more effectively improving solder agglutination during conductive connection, the oxygen concentration in the mixing step is preferably 200 ppm or less, and more preferably 100 ppm or less.

The oxygen concentration in the mixing step can be determined using an oxygen concentration meter. Examples of the oxygen concentration meter include "XO-326IIsA" manufactured by New Cosmos Electric.

In 100% by weight of the conductive material, the content of the solder particles is preferably 10% by weight or more, more preferably 20% by weight or more, and preferably 80% by weight or less, and more preferably 70% by weight or less. When the content of the solder particles is equal to or more than the lower limit and equal to or less than the upper limit, it is easy to more efficiently dispose the solder on the electrode, and the conduction reliability is more efficiently increased. From the viewpoint of more effectively improving the conduction reliability, it is preferable that the content of the solder particles is large.

(Storage method of conductive materials)
The method for storing the conductive material of the present invention is preferably a method for storing the above-mentioned conductive material. The conductive material is preferably stored by the storage method of the conductive material of the present invention.

From the viewpoint of more effectively improving the solder agglutination property during conductive connection, it is preferable that the conductive material is stored in a storage container at a temperature of -40 ° C or higher and 10 ° C or lower in the storage method of the conductive material. Storage or storage of the conductive material in a storage container under an inert gas environment.

From the viewpoint of more effectively improving the solder agglutination property during conductive connection, the storage method of the conductive material may be refrigerated storage or frozen storage.

However, the conductive material of the present invention can be stored at 10 ° C or higher and 45 ° C or lower, can be stored at 20 ° C or higher, can be stored at 25 ° C or higher, and can be stored at 40 ° C or lower, or 30 ° C. Store it as follows. The conductive material of the present invention can be stored at -20 ° C or higher, or at -10 ° C or higher, and can be stored at 50 ° C or lower, or 10 ° C or lower. The above-mentioned storage method of the conductive material is preferably storage below normal temperature, and more preferably storage below normal temperature.

In order to store the conductive material under the above-mentioned temperature conditions, a refrigerator, a freezer, a constant temperature bath, or the like can be used. Preferably, the storage container containing the conductive material is stored in a thermostatic bath set to the above-mentioned preferable temperature conditions.

From the viewpoint of more effectively improving the solder cohesiveness at the time of conductive connection, as for the storage method of the conductive material, it is preferable that the conductive material is placed in a storage container and stored under an inert gas environment.

Examples of the inert gas include argon and nitrogen.

From the viewpoint of more effectively improving the solder agglutination property during conductive connection, it is preferable that the storage method of the conductive material is that the conductive material is placed in a storage container and vacuum stored under a condition of 0.8 × 10 ² Pa or less. More preferably, vacuum storage is performed under the conditions of 0.5 × 10 ² Pa or less.

In order to store the conductive material under the vacuum condition, it is preferable to store the inside of the storage container under reduced pressure using a vacuum pump or the like.

The storage container is not particularly limited as long as it is a container capable of withstanding refrigerated storage and refrigerated storage. From the viewpoint of more effectively improving the solder agglutination property during the conductive connection, the storage container is preferably a container capable of preventing penetration of oxygen, and more preferably a container having good airtightness. Examples of the storage container include aluminum bags.

From the viewpoint of more effectively improving the solder agglutination property during conductive connection, it is preferable to control the oxygen concentration in the storage container. From the viewpoint of more effectively improving solder agglutination during conductive connection, the oxygen concentration in the storage container is preferably 200 ppm or less, and more preferably 100 ppm or less. Examples of a method for controlling the oxygen concentration in the storage container include a method of performing nitrogen substitution in the storage container.

The oxygen concentration in the storage container can be determined using an oxygen concentration meter. Examples of the oxygen concentration meter include "XO-326IIsA" manufactured by New Cosmos Electric.

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

(Thermosetting component)
The said thermosetting component is not specifically limited. The thermosetting component may include a thermosetting compound that can be hardened by heating, and a thermosetting agent.

(Thermosetting component: thermosetting compound)
Examples of the thermosetting compound include an oxetane compound, an epoxy compound, an episulfide compound, a (meth) acrylic compound, a phenol compound, an amine compound, an unsaturated polyester compound, and a polyurethane. Ester compounds, polysiloxanes, and polyimide compounds. From the viewpoint of making the hardening and viscosity of the conductive material better, the viewpoint of more effectively improving the conduction reliability, and the viewpoint of more effectively improving the insulation reliability, an epoxy compound or an episulfide compound is more preferable, It is preferably an epoxy compound. It is preferable that the said thermosetting component contains an epoxy compound. It is preferable that the said thermosetting component contains an epoxy compound and a hardening | curing agent. These thermosetting components may be used alone or in combination of two or more.

The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compound include a bisphenol A epoxy compound, a bisphenol F epoxy compound, a bisphenol S epoxy compound, a phenol novolac epoxy compound, a biphenyl epoxy compound, and a biphenyl compound. Novolak type epoxy compound, biphenol type epoxy compound, resorcinol type epoxy compound, naphthalene type epoxy compound, fluorene type epoxy compound, benzophenone type epoxy compound, phenol aralkyl type Epoxy compounds, naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, anthracene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, A naphthyl ether type epoxy compound, an epoxy compound having a triple core in the skeleton, and the like. These epoxy compounds may be used alone or in combination of two or more.

As said epoxy compound, aromatics, such as a resorcinol type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound, a benzophenone type epoxy compound, and a phenol novolak type epoxy compound, are preferable. Group of epoxy compounds. The melting temperature of the epoxy compound is preferably below the melting point of the solder. The melting temperature of the epoxy compound is preferably 100 ° C or lower, more preferably 80 ° C or lower, and even more preferably 40 ° C or lower. By using the above-mentioned preferred epoxy compound, the viscosity is high at the stage of attaching the connection target member, and when acceleration is applied due to the impact of transportation or the like, the positions of the first connection target member and the second connection target member can be suppressed. Offset. Furthermore, the heat at the time of hardening may cause a significant decrease in viscosity, and it is possible to more effectively improve the solder agglutinability during conductive connection.

From the viewpoint of more effectively improving the heat resistance of the cured product, the thermosetting component preferably contains a thermosetting compound having an isocyanuric acid skeleton.

Examples of the above-mentioned thermosetting compound having an isocyanuric acid skeleton include a triisocyanurate-type epoxy compound, and a TEPIC series (TEPIC-G, TEPIC-S, TEPIC- SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC), etc.

The content of the thermosetting compound in 100% by weight of the conductive material is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and more preferably 99% by weight or less, and more preferably It is 98% by weight or less, more preferably 90% by weight or less, and particularly preferably 80% by weight or less. When the content of the thermosetting compound is equal to or more than the lower limit and equal to or less than the upper limit, the solder cohesiveness at the time of conductive connection can be more effectively improved, and the heat resistance of the hardened material of the conductive material can be more effectively improved. From the viewpoint of improving the impact resistance more effectively, it is preferable that the content of the thermosetting compound is large.

The content of the epoxy compound in 100% by weight of the conductive material is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, and preferably 99% by weight or less, and more preferably 98% by weight or less, more preferably 90% by weight or less, and particularly preferably 80% by weight or less. When the content of the epoxy compound is greater than or equal to the above lower limit and less than or equal to the above upper limit, it is possible to more effectively improve solder agglutination at the time of conductive connection, and it is possible to more effectively improve heat resistance of the hardened material of the conductive material. From the viewpoint of further improving 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 thermally hardens the thermosetting compound. Examples of the thermal hardener include thiol hardeners such as imidazole hardeners, amine hardeners, phenol hardeners, and polythiol hardeners, sulfonium salts, acid anhydride hardeners, thermal cationic initiators (thermal cationic hardeners), and Thermal free radical generators, etc. These thermosetting agents may be used alone or in combination of two or more.

From the standpoint that the conductive material can be hardened more quickly at a low temperature, the thermal curing agent is preferably an imidazole curing agent, a thiol curing agent, or an amine curing agent. From the viewpoint of improving storage stability when the thermosetting compound is mixed with the thermosetting agent, 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. The thermosetting agent may be coated with a polymer material 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, and 1-cyanoethyl-2-phenylimidazolium. Trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethylhexamide and 2,4-diamino-6- [2'-methyl -Imidazolyl- (1 ')]-ethyl-tristriisocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5- Dihydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-p-tolyl-4-methyl-5-hydroxymethylimidazole, 2-m-tolyl-4 -Methyl-5-hydroxymethyl imidazole, 2-m-tolyl-4,5-dimethylol imidazole, 2-p-tolyl-4,5-dimethylol imidazole, etc. An imidazole compound in which the hydrogen at the 5-position of imidazole is substituted with a hydroxymethyl group, and the hydrogen at the 2-position is substituted with a phenyl group or a tolyl group.

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

The amine hardener is not particularly limited. Examples of the amine hardener include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8, 10-tetraspiro [5.5] undecane, bis (4-aminocyclohexyl) methane, m-phenylenediamine and diaminodiphenylphosphonium.

The aforementioned sulfonium salt is not particularly limited. Examples of the phosphonium salt include tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium OO diethyl dithiophosphate, methyltributylphosphonium dimethyl phosphate, and tetra-n-butylphosphonium benzo. Triazole, tetra-n-butylphosphonium tetrafluoroborate, and tetra-n-butylphosphonium tetraphenylborate, and the like.

The said acid anhydride hardening | curing agent is not specifically limited, If it is an acid anhydride used as a hardening | curing agent of thermosetting compounds, such as an epoxy compound, it can use widely. Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic acid. Acid anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, anhydride of phthalic acid derivatives, maleic anhydride, dianhydride, methyl dianhydride, Glutaric anhydride, succinic anhydride, glyceryl bistrimellitic anhydride monoacetate, and ethylene glycol bistrimellitic anhydride, bifunctional anhydride hardeners, trifunctional anhydride hardeners, such as trimellitic anhydride, and homobenzene Tetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, methylcyclohexene tetracarboxylic anhydride, and polyazeptic anhydride hardeners such as polyazeptic anhydride.

The thermal cationic initiator (thermal cationic hardener) is not particularly limited. Examples of the thermal cationic initiator (thermal cationic curing agent) include a fluorene-based cationic curing agent, Based cationic hardeners and fluorene based cationic hardeners. Examples of the fluorene-based cationic hardener include bis (4-thirdbutylphenyl) fluorene hexafluorophosphate and the like. As above Cation hardener, trimethyl Tetrafluoroborate, etc. Examples of the fluorene-based cationic hardener include tri-p-tolyl fluorene hexafluorophosphate and the like.

The thermal radical generator is not particularly limited. Examples of the thermal radical generator include an azo compound and an organic peroxide. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-third butyl peroxide and methyl ethyl ketone peroxide.

The reaction starting temperature of the above-mentioned thermosetting agent is preferably 50 ° C or higher, more preferably 70 ° C or higher, even more preferably 80 ° C or higher, and more preferably 250 ° C or lower, more preferably 200 ° C or lower, and even more preferably Below 150 ° C, particularly preferably below 140 ° C. If the reaction initiation temperature of the thermosetting agent is above the above lower limit and below the above upper limit, the solder can be more efficiently disposed on the electrode. The reaction starting temperature of the above-mentioned thermosetting agent is particularly preferably 80 ° C or higher and 140 ° C or lower.

From the viewpoint of more efficiently disposing the solder on the electrode, the reaction starting temperature of the thermal hardener is preferably higher than the melting point of the solder in the solder particles, more preferably 5 ° C or higher, and more preferably It is higher than 10 ° C.

The reaction start temperature of the above-mentioned thermosetting agent means the temperature at which the rise of the exothermic wave peak in DSC starts.

The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 part by weight or more, more preferably 1 part by weight or more, and more preferably 200 parts by weight or less, and more preferably 100 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. It is more preferably 75 parts by weight or less. When the content of the thermosetting agent is at least the above-mentioned lower limit, it is easy to sufficiently harden the conductive material. If the content of the heat curing agent is equal to or less than the above-mentioned upper limit, the remaining heat curing agent that does not participate in hardening does not easily remain after hardening, and the heat resistance of the hardened material is further increased.

(Flux)
The conductive material may include a flux. By using a flux, a solder can be arrange | positioned on an electrode more efficiently. The above-mentioned flux is not particularly limited. As the above-mentioned flux, a flux generally used in solder bonding or the like can be used.

Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, a hydrazine, an amine compound, and an organic compound. Acid and turpentine. These fluxes may be used alone or in combination of two or more.

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 turpentine include activated turpentine and non-activated turpentine. The above-mentioned flux is preferably an organic acid or rosin having two or more carboxyl groups. The flux may be an organic acid having two or more carboxyl groups, or may be turpentine. By using an organic acid or rosin having two or more carboxyl groups, the reliability of conduction between the electrodes is further increased.

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, benzophenamine, imidazole, benzimidazole, phenylimidazole, carboxybenzimidazole, benzotriazole, and carboxybenzotriazole. Azole and so on.

The rosin is a rosin containing rosin acid as a main component. Examples of the rosins include rosin acid and acrylic-modified rosin. The flux is preferably rosin, and more preferably rosin acid. With the use of the preferred flux, the conduction reliability between the electrodes is further increased.

The activity temperature (melting point) of the above-mentioned flux is preferably 50 ° C or higher, more preferably 70 ° C or higher, further preferably 80 ° C or higher, and more preferably 200 ° C or lower, more preferably 190 ° C or lower, even more preferably 160 ° C or lower, more preferably 150 ° C or lower, even more preferably 140 ° C or lower. If the active temperature of the above-mentioned flux is above the above-mentioned lower limit and below the above-mentioned upper limit, the effect of the flux can be exerted more effectively, and the solder can be more uniformly arranged on the electrode. The activity temperature (melting point) of the flux is preferably 80 ° C or higher and 190 ° C or lower. The activity temperature (melting point) of the above-mentioned flux is particularly preferably 80 ° C or higher and 140 ° C or lower.

Examples of the flux whose activity temperature (melting point) of the flux is 80 ° C. to 190 ° C. include succinic acid (melting point 186 ° C), glutaric acid (melting point 96 ° C), and adipic acid (melting point 152 ° C). , Dicarboxylic acids such as pimelic acid (melting point: 104 ° C), 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 disposing the solder on the electrode, the melting point of the flux is preferably higher than the melting point of the solder in the solder particles, more preferably 5 ° C or higher, and further preferably 10 ° C or higher. the above.

From the viewpoint of more efficiently disposing the solder on the electrode, the melting point of the above-mentioned flux is preferably higher than the reaction starting temperature of the above-mentioned thermosetting agent, more preferably 5 ° C or higher, and further preferably 10 ° C or higher. Above ℃.

The flux may be dispersed in a conductive material or may be adhered to the surface of the solder particles.

Since the melting point of the flux is higher than the melting point of the solder, the solder particles can be efficiently aggregated on the electrode portion. The reason is that when heat is applied during bonding, if 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 higher than that of the connection target around the electrode. The thermal conductivity of the component part causes the electrode part to heat up faster. At the stage where the melting point of the solder particles is exceeded, the inside of the solder particles will dissolve, but the oxide film formed on the surface does not reach the melting point (active temperature) of the flux, so it will not be removed. In this state, the temperature of the electrode portion first reaches the melting point (active temperature) of the flux, so the oxide film on the surface of the solder particles moving to the electrode is preferentially removed, and the solder particles can be wetted and diffused on the surface of the electrode. Thereby, solder particles can be efficiently aggregated on the electrode.

The above-mentioned flux is preferably a flux which releases cations by heating. By using a flux that releases cations by heating, the solder can be more efficiently disposed on the electrode.

Examples of the flux that releases cations by heating include the above-mentioned thermal cation initiator (thermal cation hardener).

From the viewpoint of more efficiently disposing the solder on the electrode, the viewpoint of more effectively improving the insulation reliability, and the viewpoint of more effectively improving the conduction reliability, the above-mentioned flux is preferably a salt of an acid compound and an alkali compound .

The acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, and malic acid as aliphatic carboxylic acids. , Cyclohexylcarboxylic acid as cyclic aliphatic carboxylic acid, 1,4-cyclohexyldicarboxylic acid, isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediamine tetra as aromatic carboxylic acids Acetic acid, etc. From the viewpoint of more efficiently disposing the solder on the electrodes, the viewpoint of more effectively improving the insulation reliability, and the viewpoint of more effectively improving the conduction reliability, the acid compound is preferably glutaric acid or cyclohexyl carboxylate. Acid, or adipic acid.

The base compound is preferably an organic compound having an amine group. Examples of the base compound include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzylamine, 2-methylbenzylamine, 3- Methyl benzylamine, 4-tert-butylbenzylamine, N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzyl Amine, N, N-dimethylbenzylamine, imidazole compound, and triazole compound. From the viewpoint of more efficiently disposing the solder on the electrode, the viewpoint of more effectively improving the insulation reliability, and the viewpoint of more effectively improving the conduction reliability, the above-mentioned alkali compound is preferably benzylamine.

In 100% by weight of the conductive material, the content of the above-mentioned flux is preferably 0.5% by weight or more, and preferably 30% by weight or less, and more preferably 25% by weight or less. The conductive material may include a flux. If the content of the flux is greater than or equal to the above lower limit and less than or equal to the above upper limit, it is more difficult to form an oxide film on the surface of the solder and the electrode, and the oxide film formed on the surface of the solder and the electrode can be more effectively removed.

(filler)
The conductive material of the present invention may include a filler. The filler may be an organic filler or an inorganic filler. Since the conductive material contains a filler, the solder can be uniformly aggregated on the entire electrode of the substrate.

The conductive material preferably does not contain the filler, or contains the filler in an amount of 5% by weight or less. When the above-mentioned thermosetting compound is used, the smaller the content of the filler, the easier it is for the solder to move to the electrode.

The content of the filler in 100% by weight of the conductive material is preferably 0% by weight (not contained), more preferably 5% by weight or less, more preferably 2% by weight or less, and even more preferably 1% by weight or less. If the content of the filler is above the lower limit and below the upper limit, the solder can be more efficiently disposed on the electrode.

(Other ingredients)
The above conductive materials may also include fillers, extenders, softeners, plasticizers, thixotropic agents, leveling agents, polymerization catalysts, hardening catalysts, colorants, antioxidants, heat stabilizers, and light stabilizers as required Additives, UV absorbers, lubricants, antistatic agents and flame retardants.

(Connection structure and manufacturing method of connection structure)
The connection structure of 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, and a connection portion connecting the first connection target member and the second connection target member. . In the connection structure of the present invention, the material of the connection portion includes the solder particles. In the connection structure of the present invention, the material of the connection portion is the conductive material. In the connection structure of the present invention, the first electrode and the second electrode are electrically connected by a solder portion of the connection portion.

The method for manufacturing a connection structure of the present invention includes the steps of using the conductive material containing the solder particles or the conductive material, and disposing the conductive material on a surface of a first connection target member having a first electrode on the surface. The method for manufacturing a connection structure according to the present invention includes the following steps: arranging a second connection target member having a second electrode on the surface, the first electrode and the second electrode being opposed to each other on the conductive material and the first connection; On the opposite side of the object member side. The manufacturing method of the connection structure of the present invention includes the steps of forming a connection portion connecting the first connection target member and the second connection target member from the conductive material by heating the conductive material to a melting point of the solder particles or more. In addition, the first electrode and the second electrode are electrically connected by a solder portion of the connection portion.

In the connection structure and the manufacturing method of the connection structure of the present invention, since specific solder particles or specific conductive materials are used, the solder particles can be efficiently disposed on the electrodes, and the first particles and the second electrodes are easily gathered. In this way, the solder particles can be efficiently aggregated on the electrode (wire). In addition, it is difficult to dispose a part of the solder particles in a region (void) where no electrode is formed, and the amount of solder particles disposed in a region where no electrode is formed can be greatly reduced. Therefore, it is possible to improve the conduction reliability between the first electrode and the second electrode. In addition, it is possible to prevent the electrical connection between the electrodes that are not connected laterally adjacent to each other, and to improve the insulation reliability.

In addition, in order to efficiently dispose the solder on the electrode and greatly reduce the amount of solder disposed in the region where the electrode is not formed, it is preferable that the conductive material uses a conductive paste instead of a conductive film.

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, and more preferably 80 μm or less. The wet area of solder on the surface of the electrode (the 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 manufacturing method of the connection structure of the present invention, it is preferable that the second connection target member is not subjected to pressure in the step of disposing the second connection target member and the step of forming the connection portion, and the conductive material is applied with the second connection target member. weight. In the manufacturing method of the connection structure of the present invention, it is preferable that in the step of disposing the second connection target member and the step of forming the connection portion, the conductive material is not applied with a force exceeding the weight of the second connection target member. Pressurizing pressure. In these cases, the uniformity of the solder amount can be further improved in the plurality of solder portions. Furthermore, the thickness of the solder portion can be made more effective, a plurality of solder particles can be easily gathered between the electrodes, and the plurality of solder particles can be more efficiently disposed on the electrode (wire). In addition, it is difficult to dispose a part of the plurality of solder particles in a region (void) where no electrode is formed, and it is possible to further reduce the amount of solder in the solder particles disposed in a region where no electrode is formed. Therefore, it is possible to further improve the conduction reliability between the electrodes. In addition, it is possible to prevent the electrical connection between the electrodes that are not connected laterally adjacent to each other, and to further improve the insulation reliability.

In addition, if a conductive paste is used instead of a conductive film, it is easy to adjust the thickness of the connection portion and the solder portion by the application amount of the conductive paste. On the other hand, the conductive film has the following problems: In order to change or adjust the thickness of the connection portion, it is necessary to prepare a conductive film of a different thickness or a conductive film of a specific thickness. Moreover, compared with a conductive paste, a conductive film tends to be unable to sufficiently reduce the melt viscosity of the conductive film at the melting temperature of the solder, and tends to hinder the aggregation of the solder particles.

Hereinafter, a specific embodiment 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 by using a conductive material according to an embodiment of the present invention.

The connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 3, and a connection portion 4 that connects the first connection target member 2 and the second connection target member 3. The connection portion 4 is formed of the aforementioned conductive material. In this embodiment, the conductive material includes a thermosetting compound, a thermosetting agent, and solder particles. In this embodiment, a conductive paste is used as a conductive material.

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

The first connection target member 2 has a plurality of first electrodes 2a on a 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 a 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. Furthermore, solder particles are not present in the connection portion 4 in a region (a portion of the hardened portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a. In a region different from the solder portion 4A (the portion of the hardened portion 4B), there are no solder particles separated from the solder portion 4A. Furthermore, if it is a small amount, solder particles may be present in a region (a portion of the hardened portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

As shown in FIG. 1, in the connection structure 1, between the first electrode 2a and the second electrode 3a, a plurality of solder particles are aggregated, and after the plurality of solder particles are melted, the molten material of the solder particles is wet on the surface of the electrode. Diffusion, followed by curing, forms a solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a become larger. That is, by using solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a are compared with a case where conductive particles having a conductive outer surface of a metal such as nickel, gold, or copper are used. The contact area becomes larger. In this case, the connection reliability and connection reliability of the connection structure 1 are also improved. Furthermore, when a flux is contained in a conductive material, the flux is usually gradually deactivated by heating.

Further, in the connection structure 1 shown in FIG. 1, all of the solder portions 4A are located in regions facing each other between the first and second electrodes 2 a and 3 a. Regarding the connection structure 1X of the modification shown in FIG. 3, only the connection portion 4X is different from the connection structure 1 shown in FIG. 1. The connection portion 4X includes a solder portion 4XA and a hardened portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in a region facing the first and second electrodes 2a and 3a and a part of the solder portion 4XA is located in a region facing the first and second electrodes 2a and 3a. Spill to the side. The solder portion 4XA overflowing to the side from the areas facing the first and second electrodes 2a and 3a is a part of the solder portion 4XA, and is not solder particles separated from the solder portion 4XA. Furthermore, in this embodiment, the amount of solder particles separated from the solder portion can be reduced, and the solder particles separated from the solder portion can also be present in the hardened portion.

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

Among the connection structures 1 and 1X, it is preferable that only the mutually opposing portions of the first electrode 2a and the second electrode 3a are observed in the laminated direction of the first electrode 2a, the connection portions 4, 4X, and the second electrode 3a. Solder portions 4A and 4XA of the connection portions 4 and 4X are arranged at 50% or more of 100% of the area of the first electrode 2a and the second electrode 3a facing each other. Since the solder portions 4A and 4XA of the connection portions 4 and 4X satisfy the above-mentioned preferred aspect, the conduction reliability can be further improved.

In a case where only a portion where the first electrode and the second electrode oppose each other is observed in a lamination direction of the first electrode and the connection portion and the second electrode, it is preferable that the first electrode and the second electrode face each other. The solder portion of the connection portion is arranged at 50% or more of 100% of the area of the electrodes facing each other. When only the mutually opposing portions of the first electrode and the second electrode are observed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable that the first electrode and the second electrode face each other. At least 60% of 100% of the area of the electrodes facing each other is provided with the solder portion of the connection portion. When only the mutually opposing portions of the first electrode and the second electrode are observed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable that the first electrode and the second electrode face each other. The solder portion of the connection portion is disposed at 70% or more of 100% of the area of the two electrodes facing each other. When only the mutually opposing portions of the first electrode and the second electrode are observed in the stacked direction of the first electrode, the connection portion, and the second electrode, it is particularly preferable that the first electrode and the second electrode face each other. At least 80% of 100% of the area of the electrodes facing each other is provided with the solder portion of the connection portion. When only the mutually opposing portions of the first electrode and the second electrode are observed in the stacked direction of the first electrode, the connection portion, and the second electrode, it is preferable that the first electrode and the second electrode face each other. 90% or more of 100% of the areas of the electrodes facing each other are provided with the solder portion of the connection portion. By satisfying the above-mentioned preferred aspect of the solder portion in the connection portion, the conduction reliability can be further improved.

When only the mutually opposing portions of the first electrode and the second electrode are observed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is preferable that the first electrode and the second electrode face each other. 60% or more of the solder part in the said connection part is arrange | positioned in the mutually opposing part of an electrode and the said 2nd electrode. When only the mutually opposing portions of the first electrode and the second electrode are observed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable to the first electrode 70% or more of the solder part in the said connection part is arrange | positioned in the mutually opposing part of an electrode and the said 2nd electrode. When only the mutually opposing portions of the first electrode and the second electrode are observed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable that 90% or more of the solder part in the said connection part is arrange | positioned in the mutually opposing part of the 1 electrode and the said 2nd electrode. It is particularly preferable to observe only the portion where the first electrode and the second electrode oppose each other in a direction orthogonal to the laminated direction of the first electrode, the connection portion, and the second electrode. 95% or more of the solder part in the said connection part is arrange | positioned in the mutually opposing part of an electrode and the said 2nd electrode. When only a portion where the first electrode and the second electrode oppose each other is observed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is preferably the first electrode At least 99% of the solder portion of the connection portion is disposed between the electrode and the second electrode facing each other. By satisfying the above-mentioned preferred aspect of the solder portion in the connection portion, the conduction reliability can be further improved.

Next, an example of a method of manufacturing the connection structure 1 using the conductive material according to an embodiment of the present invention will be described in FIG. 2.

First, the first connection target member 2 having the first electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2 (a), a conductive material 11 including a thermosetting component 11B and a plurality of solder particles 11A is disposed on the surface of the first connection target member 2 (first step). The conductive material 11 used includes a thermosetting compound and a thermosetting agent as the thermosetting component 11B.

A conductive material 11 is disposed on a surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive material 11 is disposed, the solder particles 11A are disposed on the first electrode 2a (line) and the area (void) where the first electrode 2a is not formed.

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

In addition, a second connection target member 3 having a second electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2 (b), among the conductive material 11 on the surface of the first connection target member 2, a second connection is arranged on the surface of the conductive material 11 on the side opposite to the first connection target member 2 side. Object component 3 (second step). On the surface of the conductive material 11, a second connection target member 3 is arranged from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

Then, the conductive material 11 is heated to a temperature higher than the melting point of the solder particles 11A (third step). The conductive material 11 is preferably heated to a temperature higher than the curing temperature of the thermosetting component 11B (thermosetting compound). During this heating, the solder particles 11A existing in the area where the electrode is not formed are collected between the first electrode 2a and the second electrode 3a (self-aggregation effect). When a conductive paste is used instead of a conductive film, the solder particles 11A are more effectively collected between the first electrode 2a and the second electrode 3a. In addition, the solder particles 11A are melted and bonded to each other. The thermosetting component 11B is thermoset. As a result, as shown in FIG. 2 (c), the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. The connecting portion 4 is formed of the conductive material 11, a plurality of solder particles 11A are joined to form a solder portion 4A, and a thermosetting component 11B is thermally cured to form a hardened portion 4B. If the solder particles 11A move sufficiently, the movement of the solder particles 11A not located between the first electrode 2a and the second electrode 3a is completed until the movement of the solder particles 11A to the first electrode 2a and the second electrode 3a is completed, It is not necessary to keep the temperature fixed.

In this 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 applied to the conductive material 11. Therefore, when the connection portion 4 is formed, the solder particles 11A are more effectively collected between the first electrode 2a and the second electrode 3a. Furthermore, if pressure is applied in at least one of the second step and the third step described above, the tendency of the solder particles 11A to collect between the first electrode 2a and the second electrode 3a is hindered. high.

In this embodiment, since no pressure is applied, the first connection target member 2 and the second connection target member 3 are overlapped even when the alignment of the first electrode 2a and the second electrode 3a is shifted. In this case, the offset can be corrected to connect the first electrode 2a and the second electrode 3a (self-alignment effect). The reason is that when the area where the molten solder self-aggregated between the first electrode 2a and the second electrode 3a contacts with other components such as the solder and the conductive material between the first electrode 2a and the second electrode 3a is minimized, Since the energy is stable, the force applied to the connection structure that is the smallest area, that is, the connection structure that achieves alignment, acts. At this time, it is desirable that the conductive material is not hardened and the viscosity of components other than the solder particles of the conductive material is sufficiently low under the conditions of the temperature and time.

The viscosity (ηmp) 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, even more preferably 1 Pa · s or less, and more preferably 0.1 Pa · s or more , More preferably 0.2 Pa · s or more. When the viscosity (ηmp) is equal to or less than the upper limit described above, the solder particles can be efficiently aggregated. When the viscosity (ηmp) is equal to or more than the lower limit, the voids in the connection portion can be suppressed, and the conductive material can be prevented from overflowing outside the connection portion.

The viscosity (ηmp) of the above-mentioned conductive material at the melting point of the solder particles can be controlled by strain such as STRESSTECH (manufactured by REOLOGICA), etc. with a strain of 1 rad, a frequency of 1 Hz, a heating rate of 20 ° C / min, and a measurement temperature range of 25 to 200 ° C (wherein, When the melting point of the solder particles exceeds 200 ° C., the measurement is performed under the condition that the upper limit of the temperature is the melting point of the solder particles). Based on the measurement results, the viscosity at the melting point (° C) of the solder particles was 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. Alternatively, after performing the second step described above, the obtained laminated body of the first connection target member 2 and the conductive material 11 and the second connection target member 3 may be moved to the heating section to perform the third step. In order to perform the heating, the laminated body may be arranged on a heating member, or the laminated body may be arranged in a heated space.

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

Examples of the heating method in the third step include a method of using a reflow furnace or an oven to heat the entire connection structure to a temperature above the melting point of the solder particles and a temperature higher than the curing temperature of the thermosetting component, or to heat only the connection structure. Method for locally heating the connecting portion.

Examples of the device used for the local heating method include a hot plate, a hot air gun for imparting hot air, a soldering iron, and an infrared heater.

In addition, when the heating plate is used for local heating, it is preferable that the surface of the heating plate is formed with a metal having high thermal conductivity directly below the connection portion, and the heating plate is formed with a material having low thermal conductivity such as fluororesin in other parts that are not suitable for heating. On the surface.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include semiconductor wafers, semiconductor packages, LED (Light Emitting Diode) chips, LED packages, electronic components such as capacitors and diodes, and resins. Films, printed substrates, flexible printed substrates, flexible flat cables, rigid and flexible substrates, glass epoxy substrates, and glass substrates and other electronic components. The first and second connection target members are preferably electronic components.

Preferably, at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid-flexible substrate. The second connection target member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid-flexible substrate. Resin films, flexible printed substrates, flexible flat cables, and rigid-flexible substrates have high flexibility and are relatively lightweight. When a conductive film is used for the connection of such a connection target member, there is a tendency that the solder particles do not easily accumulate on the 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 substrate is used, the solder particles can be efficiently collected on the electrodes, thereby sufficiently improving the conduction between the electrodes. reliability. When a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid-flexible substrate is used, it is possible to obtain conduction between electrodes more effectively without applying pressure than when using other connection target members such as semiconductor wafers. Improved reliability.

Examples of the electrodes provided on the connection target member include metals such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS (Steel Use Stainless) electrodes, and tungsten electrodes. electrode. When the connection target member is a flexible printed circuit 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. When the above-mentioned electrode is an aluminum electrode, it may be an electrode formed of only aluminum, or an electrode formed of an aluminum layer on the surface area of the metal oxide layer. Examples of the material of 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 of the present invention, the first electrode and the second electrode are preferably arranged in a surface array or a peripheral device. When the first electrode and the second electrode are arranged in a surface array or a peripheral device, the effects of the present invention can be exerted more effectively. The so-called surface array has a structure in which electrodes are arranged in a lattice pattern on a surface where electrodes of a connection target member are arranged. The so-called peripheral device has a structure in which electrodes are arranged on the outer periphery of the connection target member. In the case of a structure in which the electrodes are arranged in a comb shape, the solder particles may be aggregated in a direction perpendicular to the comb. In contrast, the above-mentioned surface array or peripheral structure needs to be in the surface where the electrodes are arranged, so that the solder particles are distributed throughout The noodles are agglomerated evenly. Therefore, in the previous method, the amount of solder tends to become uneven. In contrast, the method of the present invention can more effectively exert the effect of the present invention.

Hereinafter, the present invention will be specifically described using examples and comparative examples. The present invention is not limited to the following examples.

Thermosetting component (thermosetting compound):
Thermosetting compound 1: "DEN-431" manufactured by The Dow Chemical Company, epoxy resin thermosetting compound 2: "JER152" manufactured by Mitsubishi Chemical Corporation, epoxy resin

Thermosetting component (thermosetting agent):
Thermal hardener 1: "BF3-MEA" manufactured by Tokyo Chemical Industry Co., Ltd., boron trifluoride-monoethylamine complex thermal hardener 2: "2PZ-CN", 1-cyanide manufactured by Shikoku Chemical Industry Co., Ltd. Ethyl-2-phenylimidazole

Solder particles:
Solder particle 1: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.5 μm, average thickness of oxide film: 4.5 nm
Solder particle 2: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.1 μm, average thickness of oxide film: 4.8 nm
Solder particle 3: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.05 μm, average thickness of oxide film: 5 nm
Solder particle 4: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.5 μm, average thickness of oxide film: 4.5 nm
Solder particle 5: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.1 μm, average thickness of oxide film: 5 nm
Solder particle 6: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.05 μm, average thickness of oxide film: 5 nm
Solder particle 7: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.5 μm, average thickness of oxide film: 10 nm
Solder particle 8: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.1 μm, average thickness of oxide film: 10 nm
Solder particle 9: Sn96.5Ag3Cu0.5 solder particle, melting point 220 ° C, particle size: 0.05 μm, average thickness of oxide film: 10 nm
Solder particle 10: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.5 μm, average thickness of oxide film: 12 nm
Solder particle 11: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.1 μm, average thickness of oxide film: 12 nm
Solder particle 12: Sn42Bi58 solder particle, melting point 138 ° C, particle size: 0.05 μm, average thickness of oxide film: 12 nm

Flux:
Flux 1: "benzyl glutarate", melting point 108 ° C

Production 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 at room temperature until uniform. 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. Put the obtained mixed liquid in a refrigerator at 5-10 ° C and leave it overnight. The precipitated crystal was separated by filtration, washed with water, and vacuum-dried to obtain a flux 1.

(Examples 1 to 6 and Comparative Examples 1 to 6)
(1) Production of conductive material (anisotropic conductive paste) The components shown in Tables 1 and 2 were blended at the blending amounts shown in Tables 1 and 2 below to obtain a conductive material (anisotropic conductive paste).

(2) Production of connection structure (L / S = 100 μm / 100 μm) A connection structure was produced as follows using a conductive material (anisotropic conductive paste) just produced.

Prepare a glass epoxy substrate (FR-4 substrate) with a L / S of 100 μm / 100 μm and a copper electrode pattern with an electrode length of 3 mm (the thickness of the copper electrode is 12 μm) (first connection target member) . A flexible printed circuit board (second connection target member) having a L / S of 100 μm / 100 μm and a copper electrode pattern (a copper electrode thickness of 12 μm) having an electrode length of 3 mm on the lower surface was prepared.

The overlapping area of the glass epoxy substrate and the flexible printed substrate is set to 1.5 cm × 3 mm, and the number of connected electrodes is set to 75 pairs.

On the upper surface of the above glass epoxy substrate, a conductive mask (anisotropic conductive paste) just coated with a metal mask is applied on the electrode of the glass epoxy substrate so as to have a thickness of 100 μm by screen printing. A conductive material (anisotropic conductive paste) layer is formed. Then, on the upper surface of the conductive material (anisotropic conductive paste) layer, the flexible printed circuit board is laminated so that the electrodes face each other. At this time, no pressure is applied. The weight of the flexible printed circuit board is applied to the conductive material (anisotropic conductive paste) layer. From this state, heating is performed such that the temperature of the conductive material (anisotropic conductive paste) layer becomes the melting point of the solder 5 seconds after the start of the temperature rise. Further, the conductive material (anisotropic conductive paste) layer was heated so that the temperature of the conductive material (anisotropic conductive paste) layer became 160 ° C. 15 seconds after the start of the heating, and the conductive material (anisotropic conductive paste) layer was hardened to obtain a connection structure. During heating, no pressure was applied.

(Evaluation)
(1) The particle diameter of the solder particles and the average thickness of the oxide film of the solder particles The particle diameter of the solder particles was measured using a laser diffraction particle size distribution measuring device ("LA-920" manufactured by HORIBA, Ltd.).

Furthermore, the cross section of the solder particles was observed using a transmission electron microscope, and the average thickness of the oxide film of the solder particles (the oxide film of the solder particles before heating was calculated from the average value of the thickness of the oxide film at 10 locations arbitrarily selected). Average thickness).

Based on the measurement results of the particle diameter of the solder particles and the average thickness of the oxide film of the solder particles, the ratio of the average thickness of the oxide film of the solder particles to the diameter of the solder particles (average thickness of the oxide film of the solder particles / the ratio of the solder particles) Particle size).

The solder particles were heated at 120 ° C for 10 hours in an air environment. The cross section of the solder particles after heating was observed using a transmission electron microscope, and the average thickness of the oxide film after heating was calculated based on the average value of the thickness of the oxide film at arbitrarily selected 10 locations.

Based on the measurement results of the average thickness of the oxide film of the solder particles before and after heating, calculate the ratio of the average thickness of the oxide film of the solder particles before heating to the average thickness of the oxide film of the solder particles after heating (the ratio of the solder particles before heating Average thickness of oxide film / average thickness of oxide film of solder particles after heating).

(2) The content of the oxide film in 100% by volume of the solder particles The content of the oxide film in 100% by volume of the solder particles is calculated based on the weight of the solder particles before and after the oxide film is removed.

(3) Absolute value of heat generation of solder particles above 200 ° C. The heat generation of solder particles above 200 ° C. was measured using a differential scanning calorimetry (DSC) device (“EXSTAR DSC7020” manufactured by SII Corporation).

(4) Viscosity of conductive material at 25 ° C (η25 (5 rpm))
For the obtained conductive material (anisotropic conductive paste), the viscosity (η25 (5 rpm)) of the conductive material at 25 ° C was measured using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co.) at 25 ° C and 5 ° C. The measurement was performed under the conditions of rpm.

(5) The thixotropic index of the obtained conductive material (anisotropic conductive paste) viscosity (η25 (0.5 rpm)) using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25 ° C and 0.5 rpm The conditions are measured. The viscosity (η25 (5 rpm)) of the obtained conductive material (anisotropic conductive paste) was measured using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25 ° C and 5 rpm.

Based on the measurement results, calculate the viscosity of the conductive material (anisotropic conductive paste) measured at 25 ° C and 0.5 rpm using an E-type viscometer divided by 25 ° C and 5 rpm using an E-type viscometer. The thixotropic index (η25 (0.5 rpm) / η25 (5 rpm)) of the viscosity of the obtained conductive material (anisotropic conductive paste).

(6) Placement accuracy of solder on electrodes (solder agglutination)
In the obtained connection structure, when only the mutually opposing portions of the first electrode and the second electrode were observed in the laminated direction of the first electrode and the connection portion and the second electrode, the first electrode and the second electrode were observed. The ratio X of the area in which the solder portion is disposed in the connection portion in the area where the opposing portions are 100% is evaluated. The accuracy of solder placement on the electrodes (solder agglutination) was determined on the basis of the following criteria.

[Criteria for judging the placement accuracy (solder agglutination) of solder on electrodes]
○○: Ratio X is 70% or more ○: Ratio X is 60% or more and less than 70%
△: Ratio X is 50% or more and less than 60%
×: Ratio X is less than 50%

(7) Continuity reliability between the upper and lower electrodes In the obtained connection structure (n = 15), the connection resistance of each connection part between the upper and lower electrodes was measured by the four-terminal method, respectively. Calculate the average connection resistance. In addition, the connection resistance can be obtained by measuring the voltage when a fixed current flows based on the relationship of voltage = current × resistance. The following criteria were used to determine the conduction reliability.

[Judgment Criteria for Continuity Reliability]
○○: The average value of the connection resistance is 50 mΩ or less ○: The average value of the connection resistance exceeds 50 mΩ and 70 mΩ or less △: The average value of the connection resistance exceeds 70 mΩ and 100 mΩ or less ×: The average value of the connection resistance exceeds 100 mΩ or poor connection

(8) Insulation reliability between horizontally adjacent electrodes In the obtained connection structure (n = 15), place it in an environment of 85 ° C and 85% humidity for 100 hours, and then place it between the horizontally adjacent electrodes. 5 V was applied, and resistance values were measured at 25 locations. Insulation reliability was judged by the following criteria.

[Judgment Criteria for Insulation Reliability]
○○: The average value of the connection resistance is 10 ⁷ Ω or more ○: The average value of the connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω
△: The average value of the connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω
×: The average value of the connection resistance does not reach 10 ⁵ Ω

The results are shown in Tables 1 and 2 below.

[Table 1]

[Table 2]

The same tendency can be seen when using a flexible printed circuit board, a resin film, a flexible flat cable, and a rigid-flexible substrate.

1‧‧‧ connect structure

1X‧‧‧ Connected Structure

2‧‧‧The first connection target component

2a‧‧‧The first electrode

3‧‧‧ 2nd connection target component

3a‧‧‧Second electrode

4‧‧‧ Connection Department

4A‧‧‧Solder Department

4B‧‧‧Hardened Materials Division

4X‧‧‧Connecting section

4XA‧‧‧Solder Department

4XB‧‧‧Hardened material department

11‧‧‧ conductive material

11A‧‧‧Solder particles

11B‧‧‧thermosetting ingredients

21‧‧‧Solder particles

22‧‧‧Solder particle body

23‧‧‧oxide film

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

2 (a) to (c) are cross-sectional views for explaining each step of an example of a method of 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 modified example of the connection structure.

Fig. 4 is a sectional view showing an example of solder particles that can be used for a conductive material.

FIG. 5 is a diagram for explaining the cohesiveness of solder particles.

FIG. 6 is a diagram for explaining the cohesiveness of solder particles.

Claims (17)

A solder particle comprising a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and The particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. The average thickness of the oxide film is 5 nm or less. For example, the solder particles of claim 1, wherein when the solder particles are heated at 120 ° C for 10 hours in the air, the ratio of the average thickness of the oxide film before heating to the average thickness of the oxide film after heating is 2 / 3 or less. For example, the solder particles of claim 1 or 2 have an absolute value of exothermic heat at 200 ° C or higher of 100 mJ / mg or more. A conductive material including a thermosetting component and a plurality of solder particles, and The solder particle has a solder particle body and an oxide film disposed on an outer surface of the solder particle body, The particle diameter of the solder particles is 0.01 μm or more and less than 1 μm. The average thickness of the oxide film is 5 nm or less. The conductive material according to claim 4, wherein when the solder particles are heated at 120 ° C. for 10 hours in the air, the ratio of the average thickness of the oxide film before heating to the average thickness of the oxide film after heating is 2 / 3 or less. For example, the conductive material of claim 4 or 5 has a viscosity at 25 ° C of 10 Pa · s or more and 1000 Pa · s or less. For the conductive material of claim 4 or 5, wherein the viscosity measured using the E-type viscometer at 25 ° C and 0.5 rpm is divided by the viscosity measured using the E-type viscometer at 25 ° C and 5 rpm. The obtained thixotropic index is 1 or more and 10 or less. For example, the conductive material of claim 4 or 5, wherein the absolute value of the exothermic heat of the solder particles above 200 ° C is 100 mJ / mg or more. The conductive material of claim 4 or 5 is a conductive paste. A method for storing solder particles, which is the method for storing solder particles according to any one of claims 1 to 3, and the method is to put the solder particles in a storage container and store them in an inert gas environment, or The solder particles are placed in a storage container and stored in a vacuum under a condition of 1 × 10 ² Pa or less. A method for storing a conductive material, which is the method for storing a conductive material according to any one of claims 4 to 9, and In this method, the conductive material is placed in a storage container and stored at a temperature of -40 ° C to 10 ° C, or the solder particles are placed in a storage container and stored in an inert gas environment. A method for manufacturing a conductive material, comprising a mixing step of mixing a thermosetting component and a plurality of solder particles to obtain a conductive material, and The manufacturing method of the conductive material obtains the following conductive material: the solder particles have a solder particle body and an oxide film disposed on an outer surface of the solder particle body, and the particle diameter of the solder particles is 0.01 μm or more and less than 1 μm, The average thickness of the oxide film is 5 nm or less. The method for manufacturing a conductive material according to claim 12, further comprising a storage step of storing the solder particles, and the storage step is a step of placing the solder particles in a storage container and storing the solder particles in an inert gas environment, or The solder particles are put into a storage container and vacuum stored under a condition of 1 × 10 ² Pa or less. The solder particles are solder particles stored after the storage step. A connection structure having: A first connection target member having a first electrode on the surface, A second connection target member having a second electrode on the surface, and A connection portion that connects the first connection target member and the second connection target member, and The material of the connection part includes solder particles as in any one of claims 1 to 3, The first electrode and the second electrode are electrically connected by a solder portion of the connection portion. A connection structure including a first connection target member having a first electrode on a surface, A second connection target member having a second electrode on the surface, and A connection portion that connects the first connection target member and the second connection target member, and The material of the connection part is a conductive material as in any one of claims 4 to 9, The first electrode and the second electrode are electrically connected by a solder portion of the connection portion. A method for manufacturing a connection structure includes the following steps: Using a conductive material containing solder particles as in any one of claims 1 to 3, disposing the above-mentioned conductive material on the surface of a first connection target member having a first electrode on the surface; Arranging a second connection target member having a second electrode on the surface on a surface of the conductive material opposite to the first connection target member side so that the first electrode and the second electrode face each other; and The conductive material is heated to a temperature above the melting point of the solder particles to form a connection portion connecting the first connection target member and the second connection target member from the conductive material. The first electrode is electrically connected to the second electrode. A method for manufacturing a connection structure, comprising the steps of: using the conductive material according to any one of claims 4 to 9, disposing the conductive material on a surface of a first connection target member having a first electrode on the surface; Arranging a second connection target member having a second electrode on the surface on a surface of the conductive material opposite to the first connection target member side so that the first electrode and the second electrode face each other; and The conductive material is heated to a temperature above the melting point of the solder particles to form a connection portion connecting the first connection target member and the second connection target member from the conductive material. The first electrode is electrically connected to the second electrode.