JP7381547B2 - Conductive particles, conductive materials and connected structures - Google Patents

Description

The present invention relates to conductive particles that can be used, for example, for electrical connection between electrodes. The present invention also relates to a conductive material, a connected structure, and a method for manufacturing a connected structure using the above-mentioned conductive particles.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In these anisotropic conductive materials, conductive particles are dispersed in a binder resin. Further, as the conductive particles, conductive particles having insulating particles attached to the surface of the conductive particle main body (conductive particles with insulating particles) may be used.

The above-mentioned anisotropic conductive material is used to obtain various connected structures, for example, the connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), the connection between a semiconductor chip and a flexible printed circuit board (COF (Film on Glass)), and the connection between a semiconductor chip and a flexible printed circuit board (COF). It is used for connections between semiconductor chips and glass substrates (COG (Chip on Glass)), connections between flexible printed circuit boards and glass epoxy substrates (FOB (Film on Board)), and the like.

As an example of the above conductive particles, Patent Document 1 below discloses insulated conductive particles (conductive particles with insulating particles) in which resin particles are present on at least a part of the surface of the conductive particles. There is. The resin particles are a copolymer of a polymerizable component, and the polymerizable component includes at least an alkyl (meth)acrylate and a polyvalent (meth)acrylate. The above-mentioned polyvalent (meth)acrylate is a compound in which each (meth)acryloyl group is bonded to each other via three or more carbon atoms. Moreover, Patent Document 1 describes that the glass transition temperature of the resin particles may be 180° C. or lower. The Examples and Comparative Examples of Patent Document 1 describe resin particles having glass transition temperatures of 108°C, 113°C, 115°C, 134°C, and 200°C or higher.

Patent Document 2 listed below discloses insulation-coated conductive particles (conductive particles with insulating particles) that include conductive particles and a plurality of insulating particles attached to the outside of the conductive particles. The average particle size of the conductive particles is 1 to 10 μm. The insulating particles include first insulating particles and second insulating particles having a lower glass transition temperature than the first insulating particles. Patent Document 2 describes that the glass transition temperature of the second insulating particles may be 80 to 120°C.

JP2012-72324A Japanese Patent Application Publication No. 2014-17213

For example, when electrically connecting an electrode of a semiconductor chip and an electrode of a glass substrate using the anisotropic conductive material, the anisotropic conductive material containing conductive particles is placed on the glass substrate. Next, the semiconductor chips are stacked and heated and pressurized. Thereby, the anisotropic conductive material is cured, the electrodes are electrically connected via the conductive particles, and a connected structure is obtained.

In the production of this bonded structure, there is an increasing demand for thermocompression bonding at low temperatures. However, with conventional conductive particles (conductive particles with insulating particles), when thermocompression bonding is performed at low temperatures, connection resistance may increase and continuity reliability may decrease.

An object of the present invention is to provide conductive particles that can make a conductive connection at a relatively low temperature and can improve continuity reliability even if the conductive connection is made at a relatively low temperature.

Another object of the present invention is to provide a conductive material, a connected structure, and a method for manufacturing a connected structure using the above-mentioned conductive particles.

According to a broad aspect of the present invention, the present invention includes a conductive particle body having a conductive part, and insulating particles arranged on the surface of the conductive particle body, and the conductive particle body is arranged outside the conductive part. At least one of the insulating particles has a plurality of protrusions on its surface, the glass transition temperature of the insulating particles is less than 100° C., and the insulating particles satisfy compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa. When compressed under compression conditions, the maximum particle diameter of the insulating particles in the compression direction after compression relative to the maximum particle diameter in the direction orthogonal to the compression direction of the insulating particles after compression Conductive particles are provided that are deformable such that the ratio is 0.7 or less.

In a particular aspect of the conductive particle according to the present invention, a plurality of the insulating particles are arranged on the surface of the conductive particle main body.

In a particular aspect of the conductive particles according to the present invention, the ratio of the average particle diameter of the insulating particles to the average height of the protrusions exceeds 0.5.

In a particular aspect of the conductive particle according to the present invention, when the insulating particle is compressed at a temperature of 100° C. and a pressure of 60 MPa, a maximum particle diameter in the compression direction of the insulating particle after compression. can be deformed so that the ratio of the particle diameter of the insulating particles after compression to the maximum value in the direction orthogonal to the compression direction becomes 0.7 or less.

In a particular aspect of the conductive particles according to the present invention, when the insulating particles are compressed under at least one compression condition satisfying compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa, The insulating particles can be deformed so that the maximum particle diameter in the direction of compression of the insulating particles is equal to or less than the average height of the protrusions before compression.

In a particular aspect of the conductive particle according to the present invention, when the insulating particle is compressed at a temperature of 100° C. and a pressure of 60 MPa, a maximum particle diameter in the compression direction of the insulating particle after compression. can be deformed so that the height is less than or equal to the average height of the protrusions before compression.

In a particular aspect of the conductive particles according to the present invention, the conductive particles are used for conductive connection by thermocompression bonding at 120° C. or lower.

According to a broad aspect of the present invention, a conductive material is provided that includes the above-described conductive particles and a binder resin.

In a particular aspect of the conductive material according to the present invention, the conductive material has a viscosity of 1000 Pa·s or more and 5000 Pa·s or less at 100°C.

According to a broad aspect of the present invention, a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and the first connection target member, a connecting part connecting the second connection target member, the material of the connecting part is the above-mentioned conductive particles, or a conductive material containing the conductive particles and a binder resin, A connected structure is provided in which the first electrode and the second electrode are electrically connected by the conductive particle bodies of the conductive particles.

According to a broad aspect of the present invention, the above-mentioned conductive particles are provided between a first connection target member having a first electrode on its surface and a second connection target member having a second electrode on its surface. or a step of arranging a conductive material containing the conductive particles and a binder resin, and a step of making a conductive connection by thermocompression bonding at a temperature above the glass transition temperature of the insulating particles and below 160° C. , a method of manufacturing a connected structure is provided.

In a particular aspect of the method for manufacturing a bonded structure according to the present invention, thermocompression bonding is performed at a temperature higher than the glass transition temperature of the insulating particles and lower than 120°C.

The conductive particle according to the present invention includes a conductive particle main body having a conductive part, and insulating particles arranged on the surface of the conductive particle main body, and the conductive particle main body has an electrically conductive part outside the conductive part. At least one of the insulating particles has a plurality of protrusions on its surface, the glass transition temperature of the insulating particles is less than 100° C., and the insulating particles satisfy compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa. When compressed under compression conditions, the maximum particle diameter in the compression direction of the insulating particles after compression relative to the maximum particle diameter in the direction perpendicular to the compression direction of the insulating particles after compression Since the ratio can be changed to 0.7 or less, conductive connection can be made at a relatively low temperature, and even if conductive connection is made at a relatively low temperature, continuity reliability can be improved.

FIG. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles when the insulating part is an insulating layer. FIG. 5 is a cross-sectional view schematically showing a connected structure using conductive particles shown in FIG.

The present invention will be explained in detail below.

(conductive particles)
The conductive particle according to the present invention includes a conductive particle main body and an insulating part. The conductive particle main body has a conductive part. The insulating section is arranged on the surface of the conductive particle main body. In the conductive particle according to the present invention, the conductive particle main body has a plurality of protrusions on the outer surface of the conductive part. In the conductive particles according to the present invention, the insulating portion has a glass transition temperature of less than 100°C. In the conductive particle according to the present invention, the insulating part is an insulating particle. In the conductive particles according to the present invention, when the insulating particles are compressed under at least one compression condition satisfying compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa, the insulating particles after compression The ratio of the maximum particle diameter in the compression direction of the particles to the maximum particle diameter in the direction orthogonal to the compression direction of the insulating particles after compression can be changed to 0.7 or less. In the present invention, when a conductive particle main body is referred to as a conductive particle, a conductive particle provided with an insulating part can be referred to as a conductive particle with an insulating part. Since the insulating part is an insulating particle, the conductive particle with an insulating part is a conductive particle with an insulating part.

In the present invention, since the above configuration is provided, the continuity reliability can be improved even if the conductive connection is made at a relatively low temperature.

In the present invention, in order to eliminate the insulating part located between the conductive particle body and the electrode during conductive connection, it is possible to effectively eliminate the insulating part even if thermocompression bonding is performed at 120° C. or lower, for example. can. As a result, the electrode and the conductive particle main body can be brought into good contact, and the connection resistance between the electrodes can be lowered. According to the present invention, the reliability of conduction between electrodes can be improved.

In the present invention, it is important not only to lower the glass transition temperature of the insulating part, but also to have the conductive particle body have a plurality of protrusions on the outer surface of the conductive part. For example, even if the glass transition temperature of the insulating part is less than 100°C, it is difficult to sufficiently increase the continuity reliability unless the conductive particle body has a plurality of protrusions on the outer surface of the conductive part. . The reason for this is thought to be that when the temperature during thermocompression bonding is lower than the glass transition temperature of the insulating part, the insulating part is less likely to become soft and therefore less likely to separate from the conductive particle main body. On the other hand, if the conductive particle main body has a plurality of protrusions on the outer surface of the conductive part, the protrusions can eliminate the insulating part and make it possible to make good contact between the electrode and the conductive particle main body. Therefore, it is considered that the conduction reliability can be sufficiently improved. In the present invention, it has been found that it is extremely important to combine a configuration that lowers the glass transition temperature of the insulating part with a configuration in which the conductive particle body has a plurality of protrusions on the outer surface of the conductive part.

From the viewpoint of further improving conduction reliability by thermocompression bonding at low temperatures, the glass transition temperature of the insulating portion is preferably less than 95°C, more preferably less than 90°C, even more preferably less than 85°C, and even more preferably is less than 80°C, even more preferably less than 75°C, particularly preferably less than 70°C.

From the viewpoint of effectively suppressing excessive detachment and excessive deformation of the insulating part before conductive connection, the glass transition temperature of the insulating part is preferably 30°C or higher, more preferably 35°C or higher, and even more preferably The temperature is 40°C or higher, more preferably 45°C or higher, even more preferably 50°C or higher, particularly preferably 55°C or higher.

In this specification, the glass transition temperature can be measured using dynamic viscoelasticity measurement ("ARES-G2" manufactured by TA Instruments) or the like.

In the conductive particle according to the present invention, the insulating part is an insulating particle. The insulating portion may be an insulating layer or may be insulating particles. The surface of the conductive particle body may be covered with the insulating layer. The insulating particles may be attached to the surface of the conductive particle main body. From the viewpoint of further increasing the exclusion property of the insulating part during conductive connection and further increasing the continuity reliability, it is preferable that the insulating part is an insulating particle. From the viewpoint of further improving conduction reliability, it is preferable that a plurality of the insulating particles are arranged on the surface of the conductive particle main body.

Further, on the surface of the conductive particle main body, the above-mentioned insulating part may be a single layer or a multilayer, and the insulating part may be formed on the outside of the insulating particles arranged on the surface of the insulating particle main body. of insulating particles may be arranged.

The average height of the projections is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average height of the protrusions is equal to or greater than the lower limit and equal to or less than the upper limit, the connection resistance is effectively reduced.

The height of the above protrusion is the virtual line of the conductive part (as shown in Figure 1) on the line connecting the center of the conductive particle body and the tip of the protrusion (broken line L1 in Figure 1), assuming that there is no protrusion. The distance from the broken line L2) (on the outer surface of the spherical conductive particle main body assuming there is no protrusion) to the tip of the protrusion is shown. That is, FIG. 1 shows the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion.

From the viewpoint of further improving conduction reliability, the ratio of the average particle diameter of the insulating particles to the average height of the protrusions (average particle diameter of insulating particles/average height of protrusions) is preferably 0.5. more than 2.0, more preferably more than 2.0. From the viewpoint of suppressing unintended detachment of the insulating particles and further improving insulation reliability, the above ratio (average particle diameter of insulating particles/average height of protrusions) is preferably 4.0 or less, more preferably It is 3.0 or less.

The average particle diameter of the above-mentioned insulating particles indicates the number average particle diameter. The average particle diameter of the insulating particles is determined by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope and calculating the average value.

In the conductive particles according to the present invention, the insulating particles satisfy at least one compression condition of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa (preferably a temperature of 100° C. to 120° C. and a pressure of 60 MPa to 80 MPa). The maximum value (L1) of the particle diameter in the compression direction (e.g. vertical direction) of the insulating particles after compression when compressed under at least one compression condition satisfying the compression condition of 80 MPa) The insulating particles can be deformed so that the ratio (L1/L2) of the particle diameter in a direction perpendicular to the compression direction (for example, horizontal direction) to the maximum value (L2) is 0.7 or less. From the viewpoint of further improving conduction reliability, the insulating particles satisfy at least one compression condition of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa (preferably a temperature of 100° C. to 120° C. and a pressure of 60 MPa to 80 MPa). Compression of the maximum particle diameter (L1) in the compression direction (for example, vertical direction) of the insulating particles after compression when compressed under at least one compression condition satisfying the compression conditions of 60 MPa to 80 MPa) It is possible to deform the insulating particles so that the ratio (L1/L2) to the maximum value (L2) of the particle diameter in a direction perpendicular to the compression direction (for example, horizontal direction) of the insulating particles is 0.5 or less. Preferably, it is more preferably deformable to 0.3 or less. The maximum value of the particle diameter is the particle diameter of the portion where the particle diameter is maximum.

In the present invention, it is not necessary that the ratio (L1/L2) be deformable so as to be equal to or less than the upper limit under the entire compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa. However, it is preferable that the above ratio (L1/L2) can be deformed so that it is below the above upper limit under the entire compression conditions of a temperature of 100°C to 120°C and a pressure of 60MPa to 80MPa; It is more preferable that the ratio (L1/L2) can be deformed to be equal to or less than the upper limit under the entire compression condition of pressures of 60 MPa to 80 MPa. Moreover, it is preferable that it is deformable so that the ratio (L1/L2) is equal to or less than the upper limit when compressed under compression conditions of a temperature of 100° C. and a pressure of 60 MPa.

In addition, in this specification, the said "deformation|transformation" also includes collapse of an insulating particle.

From the viewpoint of further improving conduction reliability, the insulating particles satisfy at least one compression condition of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa (preferably a temperature of 100° C. to 120° C. and a pressure of 60 MPa to 80 MPa). When compressed under at least one compression condition satisfying the compression conditions of 60 MPa to 80 MPa), the maximum particle diameter of the insulating particles after compression in the compression direction (for example, the vertical direction) is the same as that before compression. It is preferable that the insulating particles can be deformed so as to be equal to or less than the average height of the protrusions, and the maximum particle diameter of the insulating particles after compression in the compression direction (e.g., vertical direction) is equal to the average height of the protrusions before compression. It is more preferable that the shape can be deformed to 1.0 times the height or less.

In the present invention, under the entire compression conditions of temperature 100°C to 160°C and pressure 60MPa to 80MPa, the insulating particles can be deformed so that the maximum particle diameter in the compression direction after the compression is equal to or less than the upper limit. It doesn't have to be. However, under the entire compression conditions of a temperature of 100° C. to 120° C. and a pressure of 60 MPa to 80 MPa, the insulating particles can be deformed so that the maximum particle diameter in the compression direction after the compression is equal to or less than the upper limit. Preferably, the insulating particles can be deformed so that the maximum particle diameter in the compression direction after the compression is equal to or less than the upper limit under the entire compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa. It is more preferable that Further, when compressed under compression conditions of a temperature of 100° C. and a pressure of 60 MPa, the insulating particles may be deformed so that the maximum particle diameter in the compression direction after the compression is equal to or less than the upper limit. preferable.

The temperature when compressing the insulating particles is preferably 100°C or higher, preferably 160°C or lower, more preferably 150°C or lower, still more preferably 140°C or lower, particularly preferably 120°C or lower. The pressure when compressing the insulating particles is preferably 60 MPa or more, preferably 80 MPa or less, and more preferably 70 MPa or less.

From the viewpoint of further increasing insulation reliability, the coverage ratio, which is the area of the portion covered by the insulating portion (insulating layer or insulating particles) to the entire surface area of the conductive particle body, is preferably 65%. More preferably, it is 70% or more, still more preferably more than 70%, particularly preferably 75% or more, and most preferably 80% or more. From the viewpoint of further increasing conduction reliability, the coverage is preferably 99% or less, more preferably 98% or less, and still more preferably 95% or less. The coverage rate may be 100% or less.

The coverage ratio, which is the area of the portion covered by the insulating particles occupying the entire surface area of the conductive particle body, is determined as follows.

For example, 20 conductive particles are observed using a scanning electron microscope (SEM), and the coverage (%) of the conductive particle main bodies in the conductive particles (also referred to as adhesion rate (%)) is determined. The coverage ratio is the total area (projected area) of the portion covered by the insulating portion in the surface area of the conductive particle main body.

Specifically, when the insulating part is an insulating particle, the above-mentioned coverage is the coverage of the surface of the conductive particle main body in the observed image when the conductive particle is observed from one direction with a scanning electron microscope (SEM). It means the total area of the insulating parts within the circle of the outer peripheral edge portion of the surface of the conductive particle main body, which occupies the entire area within the circle of the outer peripheral edge portion.

The average particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 3 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and particularly preferably is 20 μm or less. When the average particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, when the conductive particles are used to connect the electrodes, the contact area between the conductive particle body and the electrode is sufficiently large, and Agglomerated conductive particles are less likely to be formed when forming a conductive part. Moreover, the distance between the electrodes connected via the conductive particle main body does not become too large, and the conductive part becomes difficult to peel off from the surface of the base particle. Furthermore, when the average particle diameter of the conductive particles is large (more than 10 μm and 50 μm or less), the pressure is lower than when the average particle diameter of the conductive particles is small (1 μm or more and 10 μm or less). And since it can be mounted at low temperature, the conductive particles can be suitably used in semiconductor device modules such as camera modules.

The average particle diameter of the above-mentioned conductive particles indicates a number average particle diameter. The average particle diameter of the conductive particles is determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value.

The above-mentioned conductive particles are preferably used to make conductive connections by thermocompression bonding at 160°C or less, more preferably used to make conductive connections by thermocompression bonding at 120°C or less, and more preferably used to make conductive connections by thermocompression bonding at 120°C or less. By thermocompression bonding, it is more suitably used for electrically conductive connection, and by thermocompression bonding at 100° C. or less, it is particularly suitably used for electrically conductive connection.

The above-mentioned conductive particles are dispersed in a binder resin and suitably used to obtain a conductive material.

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

FIG. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention.

The conductive particle 1 shown in FIG. 1 includes a conductive particle main body 2 and a plurality of insulating particles 3.

The conductive particle body 2 includes a base particle 11 , a conductive part 12 arranged on the surface of the base particle 11 , and a plurality of core substances 13 . The conductive part 12 is a conductive layer. The conductive portion 12 is in contact with the base particle 11 . The conductive part 12 covers the surface of the base particle 11. The conductive particle body 2 is a coated particle in which the surface of a base particle 11 is coated with a conductive part 12. The conductive particle main body 2 has a conductive part 12 on the surface.

The conductive particle main body 2 has a plurality of protrusions on the outer surface of the conductive part 12. The conductive portion 12 has a plurality of protrusions on its outer surface. A plurality of core substances 13 are arranged on the surface of the base particle 12. A plurality of core materials 13 are embedded within the conductive portion 12 . The core material 13 is arranged inside the protrusion. The conductive portion 12 covers a plurality of core substances 13 . The outer surface of the conductive portion 12 is raised by the plurality of core substances 13 to form protrusions.

The insulating particles 3 are arranged on the surface of the conductive particle body 2. The plurality of insulating particles 3 are in contact with and adhere to the surface of the conductive particle body 2 . The plurality of insulating particles 3 are in contact with and adhere to the outer surface of the conductive part 12 in the conductive particle main body 2 .

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

The conductive particle 1A shown in FIG. 2 includes a conductive particle main body 2A and a plurality of insulating particles 3.

The conductive particle body 2 and the conductive particle body 2A are different between the conductive particle 1 and the conductive particle 1A.

The conductive particle body 2A includes a base particle 11, a conductive portion 12A disposed on the surface of the base particle 11, and a plurality of core substances 13.

The conductive part 12 and the conductive part 12A are different between the conductive particle 1 and the conductive particle 1A. The conductive part 12A as a whole includes a first conductive part 12AA on the base particle 11 side and a second conductive part 12AB on the opposite side to the base particle 11 side. In the conductive particle 1, a conductive part 12 with a single layer structure is formed, whereas in the conductive particle 1A, a conductive part 12A with a two-layer structure having a first conductive part 12AA and a second conductive part 12AB is formed. is formed. The first conductive part 12AA and the second conductive part 12AB are formed as separate conductive parts.

The first conductive part 12AA is arranged on the surface of the base particle 11. The first conductive part 12AA is arranged between the base material particle 11 and the second conductive part 12AB. The first conductive portion 12AA is in contact with the base particle 11. The second conductive part 12AB is in contact with the first conductive part 12AA. Therefore, the first conductive part 12AA is arranged on the surface of the base particle 11, and the second conductive part 12AB is arranged on the outer surface of the first conductive part 12AA.

The conductive particle main body 2A has a plurality of protrusions on the outer surface of the conductive part 12A. The conductive portion 12A has a plurality of protrusions on its outer surface. A plurality of core substances 13 are arranged on the surface of the base particle 12. The plurality of core substances 13 are embedded within the conductive portion 12A and the first conductive portion 12AA. The conductive portion 12A and the first conductive portion 12AA cover the plurality of core substances 13. The outer surfaces of the conductive portion 12A, the first conductive portion 12AA, and the second conductive portion 12AB are raised by the plurality of core substances 13 to form protrusions.

The insulating particles 3 are arranged on the surface of the conductive particle main body 2A.

The core material does not need to be in contact with the base particles. The core material may be disposed on the outer surface of the first conductive portion. The outer surface of the first conductive portion may have a spherical shape.

FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

The conductive particles 1B shown in FIG. 3 include a conductive particle main body 2B and a plurality of insulating particles 3.

The conductive particle body 2 and the conductive particle body 2B are different between the conductive particle 1 and the conductive particle 1B.

The conductive particle main body 2B includes a base particle 11 and a conductive part 12B arranged on the surface of the base particle 11. The conductive particle main body 2B does not have a core substance.

The conductive particle body 2 and the conductive particle body 2B differ in the presence or absence of a core substance, and as a result, have different conductive parts. In the conductive particle 1, a core substance 13 is used and the conductive part 12 is formed to cover the core substance 13, whereas in the conductive particle 1B, a core substance is not used and the conductive part 12 is formed so as to cover the core substance 13. A portion 12B is formed.

The conductive portion 12B has a first portion and a second portion thicker than the first portion. The conductive particle main body 2B has a plurality of protrusions on the outer surface of the conductive part 12B. The conductive portion 12B has a plurality of protrusions on its outer surface. The portion excluding the plurality of protrusions is the first portion of the conductive portion 12B. The plurality of protrusions are the second thick portion of the conductive portion 12B.

The insulating particles 3 are arranged on the surface of the conductive particle main body 2B.

FIG. 4 is a cross-sectional view showing conductive particles when the insulating part is an insulating layer.

The conductive particles 1C shown in FIG. 4 include a conductive particle main body 2 and an insulating layer 3C.

The conductive particles 1 and the conductive particles 1C have different insulating particles 3 and an insulating layer 3C.

In the conductive particle 1C, the insulating layer 3C is arranged on the surface of the conductive particle main body 2. The insulating layer 3C is in contact with the surface of the conductive particle body 2 and covers the surface of the conductive particle body 2. The plurality of insulating layers 3C are in contact with the outer surface of the conductive part 12 in the conductive particle main body 2, and cover the outer surface of the conductive part 12. An insulating layer 3C is disposed on the surface of the portion of the conductive portion 12 where the protrusion is present. An insulating layer 3C is also arranged on the surface of the portion of the conductive portion 12 where there are no protrusions. The insulating layer 3C disposed on the surface of the portion of the conductive portion 12 with the protrusion and the insulating layer 3C disposed on the surface of the portion of the conductive portion 12 without the protrusion are continuous.

The conductive particles 1C tend to have lower continuity reliability than the conductive particles 1, 1A, and 1B.

Preferably, the insulating portion is an insulating particle or an insulating layer. From the viewpoint of further improving conduction reliability, the insulating portion is preferably insulating particles. From the viewpoint of further improving insulation reliability, the insulating section is preferably an insulating layer. In the conductive particles according to the present invention, the insulating portion is an insulating particle.

Other details of the conductive particles, insulating particles, etc. will be explained below. In addition, in the following explanation, "(meth)acrylic" means one or both of "acrylic" and "methacrylic", and "(meth)acrylate" means one or both of "acrylate" and "methacrylate". do.

[Conductive particle body]
The conductive particle main body has protrusions on the outer surface of the conductive part. Preferably, the number of the protrusions is plural. An oxide film is often formed on the surface of the electrode connected by the conductive particle body. By using conductive particles having protrusions on the outer surface of the conductive part, the oxide film can be effectively removed by the protrusions by disposing and pressing the conductive particles between the electrodes. For this reason, the electrode and the conductive part come into contact with each other more reliably, and the connection resistance between the electrodes becomes even lower. Furthermore, when connecting the electrodes, the protrusions of the conductive particle body can effectively eliminate the insulating portion between the conductive particle body and the electrode. Further, in the present invention, since the glass transition temperature of the insulating part is low, the insulating part can be effectively eliminated.

The conductive particle main body has a conductive part. The conductive portion is preferably a conductive layer. The conductive particle body may be a conductive particle having a base particle and a conductive part disposed on the surface of the base particle, or it may be a metal particle whose entire body is a conductive part. From the viewpoint of reducing costs and increasing the flexibility of the conductive particle body to further improve the reliability of conduction between the electrodes, it is necessary to Preferably, the conductive particle body has a portion.

Base material particles:
Examples of the base particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The base particles are preferably base particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particles may be core-shell particles.

The base particles are preferably resin particles made of resin. When connecting electrodes using conductive particles, the conductive particles are placed between the electrodes and then compressed by pressure bonding. When the base particles are resin particles, the conductive particle bodies are easily deformed during the pressure bonding, and the contact area between the conductive particle bodies and the electrode becomes large. Therefore, the reliability of conduction between the electrodes is further increased.

Various resins are suitably used as materials for the resin particles. Examples of materials for the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate, and polycarbonate. , polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, polyacetal, Examples include polyimide, polyamideimide, polyetheretherketone, polyethersulfone, and polymers obtained by polymerizing one or more of various polymerizable monomers having ethylenically unsaturated groups.

It is possible to design and synthesize resin particles having arbitrary compression properties suitable for conductive materials, and the hardness of the base particles can be easily controlled within a suitable range. It is preferably a polymer obtained by polymerizing one or more types of polymerizable monomers having a plurality of unsaturated groups.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer. Examples include crosslinkable monomers.

Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; methyl ( meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, lauryl(meth)acrylate, cetyl(meth)acrylate, stearyl(meth)acrylate, cyclohexyl( Alkyl (meth)acrylate compounds such as meth)acrylate and isobornyl (meth)acrylate; oxygen atoms such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate Containing (meth)acrylate compounds; Nitrile-containing monomers such as (meth)acrylonitrile; Vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; Acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, etc. Compounds; unsaturated hydrocarbons such as ethylene, propylene, isoprene, butadiene; halogen-containing monomers such as trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, chlorostyrene, etc. Can be mentioned.

Examples of the crosslinkable monomer include tetramethylolmethanetetra(meth)acrylate, tetramethylolmethanetri(meth)acrylate, tetramethylolmethanedi(meth)acrylate, trimethylolpropanetri(meth)acrylate, dipenta Erythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate Polyfunctional (meth)acrylate compounds such as acrylate, (poly)tetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate; triallyl(iso)cyanurate, triallyl trimellitate, divinylbenzene, Examples include silane-containing monomers such as diallyl phthalate, diallylacrylamide, diallyl ether, γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane.

The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method in which suspension polymerization is carried out in the presence of a radical polymerization initiator, and a method in which monomers are swollen and polymerized together with a radical polymerization initiator using non-crosslinked seed particles.

When the base particles are inorganic particles other than metal particles or organic-inorganic hybrid particles, examples of the inorganic material of the base particles include silica, alumina, barium titanate, zirconia, and carbon black. Preferably, the inorganic substance is not a metal. The particles formed from the above-mentioned silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, baking may be performed as necessary. Examples include particles obtained by Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed from a crosslinked alkoxysilyl polymer and an acrylic resin.

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

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

Examples of the material for the inorganic shell include the inorganic substances mentioned above as the material for the base particle. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed by forming a metal alkoxide into a shell-like material by a sol-gel method on the surface of the core, and then firing the shell-like material. Preferably, the metal alkoxide is a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

When the base particles are metal particles, examples of the metal that is the material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, it is preferable that the base material particles are not metal particles.

Conductive part:
The metal that is the material of the conductive part is not particularly limited. When the conductive particles are metal particles whose entirety is a conductive part, the metal that is the material of the metal particles is not particularly limited. Examples of the above metals include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, and Examples include alloys of Furthermore, examples of the metal include tin-doped indium oxide (ITO) and solder. An alloy containing tin, nickel, palladium, copper, or gold is preferable, and nickel or palladium is preferable, since the connection resistance between the electrodes becomes even lower.

In addition, the conductive portion and the outer surface portion of the conductive portion preferably contain nickel, since the conduction reliability can be effectively improved. The content of nickel in 100% by weight of the conductive part containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, still more preferably 70% by weight or more, particularly preferably It is 90% by weight or more. The content of nickel in 100% by weight of the conductive portion containing nickel may be 97% by weight or more, 97.5% by weight or more, or 98% by weight or more.

Note that hydroxyl groups often exist on the surface of the conductive part due to oxidation. Generally, hydroxyl groups are present on the surface of a conductive part made of nickel due to oxidation. An insulating part can be arranged on the surface of the conductive part having such a hydroxyl group (the surface of the conductive particle main body) via a chemical bond.

The conductive part may be formed of one layer. The conductive part may be formed of multiple layers. That is, the conductive part may have a laminated structure of two or more layers. When the conductive part is formed of multiple layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, and is a gold layer. is more preferable. When the outermost layer is these preferred conductive parts, the connection resistance between the electrodes becomes even lower. Moreover, when the outermost layer is a gold layer, corrosion resistance becomes even higher.

The method for forming the conductive portion on the surface of the base particle is not particularly limited. Examples of methods for forming the conductive part include electroless plating, electroplating, physical vapor deposition, and coating the surface of base particles with metal powder or a paste containing metal powder and a binder. etc. A method using electroless plating is preferred because the conductive portion can be easily formed. Examples of the physical vapor deposition method include vacuum vapor deposition, ion plating, and ion sputtering.

The thickness of the conductive part is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. When the thickness of the conductive part is at least the above lower limit and below the above upper limit, sufficient conductivity can be obtained, and the conductive particles can be sufficiently deformed during connection between the electrodes without becoming too hard. .

When the conductive part is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, more preferably is 0.1 μm or less. When the thickness of the outermost conductive layer is greater than or equal to the lower limit and less than the upper limit, the outermost conductive layer will be uniformly coated, the corrosion resistance will be sufficiently high, and the connection resistance between the electrodes will be sufficiently high. It gets lower.

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

Core material:
The above protrusions can be formed by attaching a core substance to the surface of the base particle and then forming a conductive part by electroless plating, or by forming a conductive part by electroless plating on the surface of the base particle. After that, a method of attaching a core material and further forming a conductive part by electroless plating can be mentioned. Another method for forming the protrusions is to form a first conductive part on the surface of a base particle, place a core material on the first conductive part, and then form a second conductive part. and a method of adding a core substance during the formation of a conductive part (first conductive part, second conductive part, etc.) on the surface of the base particle. In addition, in order to form protrusions, a conductive part is formed on the base material particle by electroless plating without using the above-mentioned core material, and then plating is deposited in the shape of a protrusion on the surface of the conductive part, and then electroless plating is performed. Alternatively, a method of forming a conductive portion using the above method may be used.

As a method for arranging the core substance on the outer surface of the base particle, for example, the core substance is added to a dispersion of the base particle, and the core substance is placed on the surface of the base particle, for example, by van der Waals. Examples include a method of accumulating and adhering by force, and a method of adding a core substance to a container containing base particles and attaching the core substance to the surface of the base particles by mechanical action such as rotation of the container. It will be done. Since it is easy to control the amount of the core substance to be deposited, a method of accumulating and depositing the core substance on the surface of the base particles in the dispersion is preferred.

The material of the core substance is not particularly limited. It is preferable that the material of the core substance has a high Mohs hardness.

Specific examples of the materials for the core substance include barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6-7), titanium oxide (Mohs hardness 7), zirconia (Mohs hardness: 8 to 9), alumina (Mohs hardness: 9), tungsten carbide (Mohs hardness: 9), and diamond (Mohs hardness: 10). The inorganic particles are preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide, or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide, or diamond, and titanium oxide, zirconia , alumina, tungsten carbide or diamond are more preferred, and zirconia, alumina, tungsten carbide or diamond are particularly preferred. The Mohs hardness of the material of the core substance is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, still more preferably 7 or more, particularly preferably 7.5 or more.

The shape of the core material is not particularly limited. The shape of the core material is preferably a block. Examples of the core substance include particulate lumps, aggregates of a plurality of microparticles, and irregularly shaped lumps.

The average diameter (average particle diameter) of the core material is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

The "average diameter (average particle diameter)" of the core material indicates the number average diameter (number average particle diameter). The average diameter of the core material is determined by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating the average value.

(insulation part)
In the conductive particle according to the present invention, the insulating part is an insulating particle. Examples of the materials for the insulation part include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, thermosetting resins, and water-soluble resins. Can be mentioned. Only one type of material for the above-mentioned insulating part may be used, or two or more types may be used in combination.

Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, and the like. Examples of the (meth)acrylate polymer include polymethyl (meth)acrylate, polydodecyl (meth)acrylate, and polystearyl (meth)acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include epoxy resin, phenol resin, and melamine resin. Examples of crosslinking of the thermoplastic resin include introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate, and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and methylcellulose. Furthermore, a chain transfer agent may be used to adjust the degree of polymerization. Examples of chain transfer agents include thiol and carbon tetrachloride.

The material of the insulating part is appropriately selected so that the glass transition temperature of the insulating part is less than 100°C.

The surface of the conductive part and the surface of the insulating part may each be coated with a compound having a reactive functional group. The surface of the conductive part and the surface of the insulating part may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing a carboxyl group to the outer surface of the conductive part, the carboxyl group may be chemically bonded to a functional group on the surface of the insulating part via a polymer electrolyte such as polyethyleneimine.

(conductive material)
The electrically conductive material according to the present invention includes the above-mentioned electrically conductive particles and a binder resin. The conductive particles are preferably used as a conductive material by being dispersed in a binder resin, and preferably used as a conductive material by being dispersed in a binder resin. Preferably, the conductive material is an anisotropic conductive material. The conductive material is preferably used for electrical connection between electrodes. Preferably, the conductive material is a conductive material for circuit connection.

The above binder resin is not particularly limited. As the binder resin, a known insulating resin is used. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include a photocurable component and a thermosetting component. The photocurable component preferably includes a photocurable compound and a photopolymerization initiator. The thermosetting component preferably includes a thermosetting compound and a thermosetting agent.

Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one type of the binder resin may be used, or two or more types may be used in combination.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. Note that the curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The above-mentioned curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrogenated products of styrene-butadiene-styrene block copolymers, and styrene-isoprene block copolymers. - Examples include hydrogenated products of styrene block copolymers. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

In addition to the conductive particles and the binder resin, the conductive materials include, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, and light stabilizers. It may contain various additives such as a UV absorber, a lubricant, an antistatic agent, and a flame retardant.

From the viewpoint of further improving conduction reliability, the viscosity of the conductive material at 100° C. is preferably 1000 Pa·s or more, more preferably 2000 Pa·s or more. From the viewpoint of further improving insulation reliability, the viscosity of the conductive material at 100° C. is preferably 5000 Pa·s or less, more preferably 4000 Pa·s or less.

The above viscosity can be measured, for example, using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) under conditions of 100° C. and 5 rpm.

The conductive material according to the present invention can be used as a conductive paste, a conductive film, and the like. When the conductive material according to the present invention is a conductive film, a film not containing conductive particles may be laminated on a conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

The content of the binder resin in 100% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, particularly preferably 70% by weight or more, and preferably It is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is more than the above lower limit and less than the above upper limit, the conductive particle bodies are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material is further increased. .

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 80% by weight or less, more preferably 60% by weight. The content is more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the conductive particles is at least the above lower limit and at most the above upper limit, the reliability of conduction between the electrodes becomes even higher.

(connected structure)
A connected structure can be obtained by connecting members to be connected using the conductive particles or using a conductive material containing the conductive particles and a binder resin.

The connection structure includes a first connection target member, a second connection target member, and a connection part connecting the first and second connection target members, and the connection part is made of a material as described above. It is preferable that the conductive material is a conductive material containing the above-described conductive particles and a binder resin. It is preferable that the connecting portion is formed of the above-mentioned conductive particles or of a conductive material containing the above-mentioned conductive particles and a binder resin. If conductive particles are used, the connection itself is the conductive particle.

Preferably, the first connection target member has a first electrode on its surface. Preferably, the second connection target member has a second electrode on its surface. It is preferable that the first electrode and the second electrode are electrically connected by the conductive particle main body of the conductive particles.

The connection structure is obtained by arranging the conductive particles or the conductive material between the first connection target member and the second connection target member, and thermocompression bonding. , and the process of making a conductive connection. During the thermocompression bonding, it is preferable to heat the insulating portion to a temperature higher than the glass transition temperature.

FIG. 5 is a cross-sectional view schematically showing a connected structure using conductive particles shown in FIG.

The connection structure 51 shown in FIG. 5 connects a first connection target member 52, a second connection target member 53, and a connection part 54 connecting the first and second connection target members 52 and 53. Be prepared. The connecting portion 54 is formed of a conductive material containing the conductive particles 1. It is preferable that the conductive material has thermosetting properties, and the connecting portion 54 is formed by thermosetting the conductive material. Note that in FIG. 5, the conductive particles 1 are shown schematically for convenience of illustration. In place of the conductive particles 1, conductive particles 1A and 1B may be used.

The first connection target member 52 has a plurality of first electrodes 52a on its surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the front surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected by a conductive particle main body 2 (not shown in the figure) of one or more conductive particles 1. Therefore, the first and second connection target members 52 and 53 are electrically connected by the conductive particle body 2.

The method for manufacturing the above-mentioned connected structure is not particularly limited. As an example of a method for manufacturing a connected structure, the conductive material is placed between a first member to be connected and a second member to be connected, a laminate is obtained, and then the laminate is heated and pressurized. Examples include methods. The pressure of the thermocompression bonding is preferably 40 MPa or more, more preferably 60 MPa or more, and preferably 90 MPa or less, more preferably 70 MPa or less. The heating temperature for the thermocompression bonding is preferably 80°C or higher, more preferably 100°C or higher, and preferably 140°C or lower, more preferably 120°C or lower.

Specifically, the above-mentioned connection target members include electronic components such as semiconductor chips, electronic components such as capacitors and diodes, and circuit boards such as printed circuit boards, flexible printed circuit boards, glass epoxy boards, and glass substrates. It is preferable that the member to be connected is an electronic component. The conductive particles are preferably used for electrical connection of electrodes in electronic components.

Examples of the electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, silver electrodes, SUS electrodes, copper electrodes, molybdenum electrodes, and tungsten electrodes. When the member to be connected is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, it may be an electrode formed only with aluminum, and the electrode may be an electrode in which an aluminum layer is laminated|stacked on the surface of a metal oxide layer. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal elements include Sn, Al, and Ga.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples. The invention is not limited only to the following examples.

(Example 1)
(1) Preparation of conductive particles Divinylbenzene copolymer resin particles having a particle size of 3.0 μm (base particle A, “Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared. After dispersing 10 parts by weight of the above base material particles A in 100 parts by weight of an alkaline solution containing 5% by weight of palladium catalyst liquid using an ultrasonic disperser, the base material particles A were taken out by filtering the solution. . Next, the base particles A were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surfaces of the base particles A. After thoroughly washing the surface-activated base material particles A with water, the particles were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion liquid. Next, 1 g of alumina particle slurry (average particle size: 152 nm) was added to the above dispersion over 3 minutes to obtain a suspension containing base particles to which the core material was attached.

In addition, a nickel plating solution (pH 8.5) containing 0.35 mol/L of nickel sulfate, 1.38 mol/L of dimethylamine borane, and 0.5 mol/L of sodium citrate was prepared.

While stirring the resulting suspension at 60° C., the above nickel plating solution was gradually dropped into the suspension to perform electroless nickel plating. Thereafter, the particles are taken out by filtering the suspension, washed with water, and dried to form a nickel-boron conductive layer (thickness 0.15 μm) on the surface of the base particle A, so that the surface becomes a conductive layer. Conductive particles A were obtained. Of the total surface area of the outer surface of the conductive part (100%), the surface area of the portion with the protrusions was 70%.

(2) Preparation of insulating particles In a 5000 mL separable flask equipped with a 4-necked separable cover, a stirring blade, a three-way cock, a cooling tube, and a temperature probe, add 4000 ml of distilled water, 900 ml of ethanol, 3.3 mol of methyl methacrylate, and methacrylate. After adding a monomer composition containing 4.1 mol of tridecyl acid, 0.5 mmol of acid phosphooxypolyoxyethylene glycol methacrylate, and 0.3 mmol of 2,2'-azobis(2,4-dimethylvaleronitrile), the mixture was stirred at 250 rpm. Then, polymerization was carried out at 60° C. for 5 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was freeze-dried to obtain insulating particles (average particle size: 374 nm) having P-OH groups derived from acid phosphooxypolyoxyethylene glycol methacrylate on their surfaces.

(3) Preparation of conductive particles with insulating particles The insulating particles obtained above were each dispersed in distilled water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of insulating particles. 10 g of the obtained conductive particles A were dispersed in 500 mL of distilled water, 1 g of a 10% by weight aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 8 hours. After filtering through a 3 μm mesh filter, the mixture was further washed with methanol and dried to obtain conductive particles (conductive particles with insulating particles).

(4) Preparation of conductive material (anisotropic conductive paste) 7 parts by weight of the obtained conductive particles (conductive particles with insulating particles), 25 parts by weight of bisphenol A type phenoxy resin, and 4 parts by weight of fluorene type epoxy resin 1 part by weight, 30 parts by weight of a phenol novolac type epoxy resin, and SI-60L (manufactured by Sanshin Kagaku Kogyo Co., Ltd.), and defoamed and stirred for 3 minutes to obtain an anisotropic conductive paste.

(5) Preparation of connected structure A transparent glass substrate was prepared on which an IZO electrode pattern (first electrode, Vickers hardness of metal on the electrode surface: 100 Hv) with L/S of 10 μm/20 μm was formed. Further, a semiconductor chip was prepared in which an Au electrode pattern (second electrode, Vickers hardness of the metal on the electrode surface: 50 Hv) with L/S of 10 μm/20 μm was formed on the lower surface.

The obtained anisotropic conductive paste was applied onto the transparent glass substrate to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chips were stacked on the anisotropic conductive paste layer so that the electrodes faced each other. After that, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 100°C, a pressure heating head is placed on the top surface of the semiconductor chip, and a pressure of 60 MPa is applied to the anisotropic conductive paste layer. It was cured at 100°C to obtain a connected structure. Further, the temperature and pressure during the production of the connected structure were changed as shown in Table 1 below to obtain the connected structure.

(Example 2)
The procedure was the same as in Example 1, except that the tridecyl methacrylate used when producing the insulating particles was changed to stearyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 1 below. , conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained.

(Example 3)
The procedure was the same as in Example 1, except that the tridecyl methacrylate used when producing the insulating particles was changed to dodecyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 1 below. , conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained.

(Example 4)
The procedure was the same as in Example 1, except that the tridecyl methacrylate used when producing the insulating particles was changed to octyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 1 below. , conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained.

( Reference example 5)
The procedure was the same as in Example 1, except that the tridecyl methacrylate used when producing the insulating particles was changed to amyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 1 below. , conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained.

(Example 6)
Conductive particles (conductive particles with insulating particles), anisotropic conductive paste and A connected structure was obtained.

(Example 7)
Conductive particles (conductive particles with insulating particles), anisotropic conductive paste and A connected structure was obtained.

(Example 8)
Conductive particles (conductive particles with insulating particles), anisotropic A conductive paste and a connected structure were obtained.

(Example 9)
Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except that the average particle diameter of the insulating particles was changed to 156 nm.

(Example 10)
Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except that the average particle diameter of the insulating particles was changed to 511 nm.

(Example 11)
The conductive particles were prepared in the same manner as in Example 1, except that the average particle diameter of the base material particles A was changed to 10 μm, and the average particle diameter of the insulating particles was set as shown in Table 2 below. (Conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained.

(Example 12)
The average particle diameter of the base material particles A was changed to 10 μm, the alumina particle slurry used when producing the conductive particles was changed to a nickel particle slurry (average particle diameter 154 nm), and the average particle diameter of the insulating particles. Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1, except that they were set as shown in Table 2 below.

(Example 13)
The average particle diameter of the base material particles A was changed to 20 μm, the average particle diameter of the alumina particle slurry used in the preparation of the conductive particles was changed to 457 nm, and the average particle diameter of the insulating particles was determined from the table below. Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1, except that the settings were as shown in 2.

(Example 14)
The average particle diameter of the base material particles A was changed to 20 μm, the alumina particle slurry used when producing the conductive particles was changed to the average particle diameter of the nickel particle slurry of 461 nm, and the average particle diameter of the insulating particles was changed to 461 nm. Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except for the settings shown in Table 2 below.

(Comparative example 1)
The procedure was the same as in Example 1, except that all the methacrylic esters used during the production of the insulating particles were changed to methyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 2 below. Thus, conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained.

(Comparative example 2)
The procedure was the same as in Example 1, except that the tridecyl methacrylate used when producing the insulating particles was changed to butyl methacrylate, and the average particle diameter of the insulating particles was set as shown in Table 2 below. , conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained.

(Comparative example 3)
Conductive particles (conductive particles with insulating particles), anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1, except that the alumina particle slurry was not used when producing the conductive particles. .

(Comparative example 4)
The average particle diameter of the base material particles A was changed to 10 μm, the alumina particle slurry was not used when producing the conductive particles, and the average particle diameter of the insulating particles was set as shown in Table 2 below. Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except for the above.

(Comparative example 5)
The average particle diameter of the base material particles A was changed to 20 μm, the alumina particle slurry was not used when producing the conductive particles, and the average particle diameter of the insulating particles was set as shown in Table 2 below. Conductive particles (conductive particles with insulating particles), an anisotropic conductive paste, and a connected structure were obtained in the same manner as in Example 1 except for the above.

(evaluation)
(1) Viscosity of conductive material (anisotropic conductive paste) The viscosity of the anisotropic conductive paste was measured at 100°C and 5 rpm using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.). .

(2) Amount of deformation of insulating particles during compression A SEM image of a thin film section of the obtained connected structure was observed using a FIB-SEM composite device. In the obtained connected structure, the amount of deformation (ratio L1/L2 described above) of 10 insulating particles sandwiched between the conductive particles and the transparent glass substrate was measured, and the average value of the measured values was determined.

(3) Continuity reliability (between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of 20 connected structures produced in the same manner as in Example 1 was measured by a four-probe method. Note that from the relationship of voltage=current×resistance, the connection resistance can be determined by measuring the voltage when a constant current is passed. Continuity reliability was determined based on the following criteria.

[Criteria for determining continuity reliability]
○○: Connection resistance is 2.0Ω or less ○: Connection resistance exceeds 2.0Ω and 3.0Ω or less △: Connection resistance exceeds 3.0Ω and 5.0Ω or less ×: Connection resistance exceeds 5.0Ω

(4) Insulation reliability (between horizontally adjacent electrodes)
In the 20 connected structures obtained in the above (3) evaluation of continuity reliability, the presence or absence of leakage between adjacent electrodes was evaluated by measuring the resistance with a tester. Insulation properties were evaluated using the following criteria.

[Judgment criteria for insulation reliability]
○○: The ratio of the number of connected structures with a resistance value of 10 ⁸ Ω or more is 80% or more. ○: The ratio of the number of connected structures with a resistance value of 10 ⁸ Ω or more is 70% or more but less than 80%. △: Resistance The ratio of the number of connected structures with a resistance value of 10 ⁸ Ω or more is 60% or more and less than 70% ×: The ratio of the number of connected structures with a resistance value of 10 ⁸ Ω or more is less than 60%

The results are shown in Tables 1 and 2 below.

1, 1A, 1B, 1C... Conductive particles 2, 2A, 2B... Conductive particle main body 3... Insulating particles 3C... Insulating layer 11... Base material particles 12, 12A, 12B... Conductive part 12AA... First conductive part 12AB... Second conductive part 13... Core substance 51... Connection structure 52... First connection target member 52a... First electrode 53... Second connection target member 53a... Second electrode 54... Connection part

Claims (9)

A conductive particle comprising a conductive particle body having a conductive part and an insulating particle disposed on the surface of the conductive particle body,
The conductive particle main body has a plurality of protrusions on the outer surface of the conductive part,
the insulating particles have a glass transition temperature of less than 80 °C;
When the insulating particles are compressed under at least one compression condition satisfying the compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa, the particle diameter in the compression direction of the insulating particles after compression is deformable so that the ratio of the maximum value to the maximum value of the particle diameter in the direction orthogonal to the compression direction of the insulating particles after compression is 0.7 or less ,
The conductive particles are conductive particles used for conductive connection by thermocompression bonding at 120° C. or lower . The conductive particle according to claim 1, wherein a plurality of the insulating particles are arranged on the surface of the conductive particle main body. The conductive particles according to claim 2, wherein the ratio of the average particle diameter of the insulating particles to the average height of the protrusions exceeds 0.5. When the insulating particles are compressed at a temperature of 100° C. and a pressure of 60 MPa, the maximum particle diameter in the compression direction of the insulating particles after compression is perpendicular to the compression direction of the insulating particles after compression. The conductive particles according to any one of claims 1 to 3, which are deformable so that the ratio of the particle diameter to the maximum value in the direction of the conductive particle is 0.7 or less. When the insulating particles are compressed under at least one compression condition satisfying the compression conditions of a temperature of 100° C. to 160° C. and a pressure of 60 MPa to 80 MPa, the particle diameter in the compression direction of the insulating particles after compression is The conductive particles according to any one of claims 1 to 4, which are deformable so that a maximum value is equal to or less than the average height of the protrusions before compression. When the insulating particles are compressed under compression conditions of a temperature of 100° C. and a pressure of 60 MPa, the maximum particle diameter in the compression direction of the insulating particles after compression is the average height of the protrusions before compression. The conductive particle according to claim 5, which is deformable as follows. A conductive material comprising the conductive particles according to any one of claims 1 to 6 and a binder resin. a first connection target member having a first electrode on its surface;
a second connection target member having a second electrode on its surface;
comprising a connection part connecting the first connection target member and the second connection target member,
The material of the connecting portion is the conductive particles according to any one of claims 1 to 6 , or a conductive material containing the conductive particles and a binder resin,
A connected structure in which the first electrode and the second electrode are electrically connected by the conductive particle main body of the conductive particles. The electrical conductivity according to any one of claims 1 to 6 , between the first connection target member having the first electrode on the surface and the second connection target member having the second electrode on the surface. arranging particles or a conductive material containing the conductive particles and a binder resin;
A method for manufacturing a connected structure, comprising the step of conducting conductive connection by thermocompression bonding at a temperature above the glass transition temperature of the insulating particles and below 120 °C.

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