JP2020095815A - Conductive film and connection structure - Google Patents

Abstract

To provide a conductive film capable of effectively enhancing conductive reliability when electrically connected between electrodes and effectively enhancing insulation reliability.SOLUTION: The conductive film includes a plurality of conductive particles and a binder resin. The conductive particle includes a conductive particle body having a conductive part and an insulation part arranged on the surface of the conductive particle body; the conductive film includes a layer including the conductive particles and a layer without including the conductive particles; and the content of the conductive particles is 60 vol.% or more and 80 vol.% or less in 100 vol.% of the layer including the conductive particles.SELECTED DRAWING: Figure 1

Description

The present invention relates to a conductive film containing conductive particles. The present invention also relates to a connection structure using the conductive film.

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin. Further, as the conductive particles, conductive particles whose surface is subjected to an insulation treatment may be used.

The anisotropic conductive material is used to obtain various connection structures. Examples of the connection using the anisotropic conductive material include connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), connection between a semiconductor chip and the flexible printed circuit board (COF (Chip on Film)), Examples include connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

As an example of the anisotropic conductive material, the following Patent Document 1 discloses an anisotropic conductive film including an insulating adhesive layer and conductive particles arranged in the insulating adhesive layer. The anisotropic conductive film has a conductive particle arrangement region formed corresponding to the outer shape of the arrangement region of the terminals of the electronic component connected by the anisotropic conductive film. In the anisotropic conductive film, the conductive particle arrangement regions are periodically formed in the longitudinal direction of the anisotropic conductive film.

JP, 2016-119306, A

By the anisotropic conductive material, for example, when electrically connecting the electrode of the flexible printed board and the electrode of the glass epoxy substrate, the anisotropic conductive material containing conductive particles is arranged on the glass epoxy substrate. To do. Next, the flexible printed boards are laminated, and heated and pressed. As a result, the anisotropic conductive material is cured and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

In the production of this connection structure, when a flexible flexible printed board is used, there is an increasing demand for low-voltage mounting in order to suppress deformation of the flexible printed board. However, in the case of the conventional anisotropic conductive material, when the mounting is performed at a low voltage, the conductive particles and the electrode may not sufficiently contact with each other, resulting in a high connection resistance and a low conduction reliability.

In recent years, electronic devices have become thinner and smaller. Therefore, in the wiring connected by the conductive particles in the electronic component, L/S indicating the width of the line (L) where the wiring is formed and the width of the space (S) where the wiring is not formed becomes small. The narrowing of the pitch is progressing. In such fine wiring, when conducting conductive connection between electrodes using conventional anisotropic conductive material, a sufficient number of conductive particles are not arranged on the line, connection resistance becomes high, and conduction reliability is increased. May become less active.

In addition, when the number of conductive particles is increased in order to arrange a sufficient number of conductive particles on the line, the pressure applied to each conductive particle decreases, so the mounting pressure is increased. It is necessary, and it is difficult to perform mounting at low pressure with the conventional anisotropic conductive material. In addition, when the number of conductive particles arranged on the line is increased, the conductive particles come close to each other, which may cause a short circuit between electrodes that are adjacent to each other and that are not connected to each other in the lateral direction. In the conventional anisotropic conductive material, it may be difficult to sufficiently enhance the conduction reliability between upper and lower electrodes to be connected and the insulation reliability between laterally adjacent electrodes that should not be connected.

Further, in the anisotropic conductive film described in Patent Document 1, the conductive particle arrangement area is limited to a specific area. Therefore, unless the electrodes and the conductive particles are accurately aligned, the conduction reliability may be considerably lowered.

An object of the present invention is to provide a conductive film that can effectively improve conduction reliability and electrically insulation reliability when electrodes are electrically connected. .. Another object of the present invention is to provide a connection structure using the above conductive film.

According to a broad aspect of the present invention, a conductive film containing a plurality of conductive particles and a binder resin, the conductive particles, a conductive particle body having a conductive portion, on the surface of the conductive particle body. And a conductive film having a layer containing the conductive particles and a layer not containing the conductive particles, wherein 100% by volume of the layer containing the conductive particles, Provided is a conductive film having a content of conductive particles of 60% by volume or more and 80% by volume or less.

In one specific aspect of the conductive film according to the present invention, the content of the conductive particles is 5% by volume or more and 80% by volume or less in 100% by volume of the conductive film.

In one specific aspect of the conductive film according to the present invention, the ratio of the distance between the adjacent conductive particle bodies to the particle diameter of the conductive particle body is 1/30 or more and 1/1 or less.

In one specific aspect of the conductive film according to the present invention, when the conductive film is viewed in a plan view, the area of the portion where the conductive particle main body is arranged occupies 100% of the total area of the conductive film is 40% or more. Is.

In a specific aspect of the conductive film according to the present invention, the insulating portion is an insulating layer, and the insulating layer is arranged on the surface of the conductive particle body.

In a specific aspect of the conductive film according to the present invention, the insulating portion is an insulating particle, and the plurality of insulating particles are arranged on the surface of the conductive particle body.

According to a broad aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, 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 film, and the first electrode and the second electrode are the conductive particles. A connection structure is provided that is electrically connected by the conductive portion in.

The conductive film according to the present invention contains a plurality of conductive particles and a binder resin. In the conductive film according to the present invention, the conductive particles include a conductive particle body having a conductive portion and an insulating portion arranged on the surface of the conductive particle body. The conductive film according to the present invention has a layer containing the conductive particles and a layer not containing the conductive particles. In the conductive film according to the present invention, the content of the conductive particles is 60% by volume or more and 80% by volume or less in 100% by volume of the layer containing the conductive particles. In the conductive film according to the present invention, since the above configuration is provided, when electrically connecting between the electrodes, it is possible to effectively enhance the conduction reliability, and effectively the insulation reliability. Can be increased.

1A and 1B are a plan view and a cross-sectional view showing a conductive film according to an embodiment of the present invention. 2A and 2B are a plan view and a cross-sectional view showing a first modified example of the conductive film according to the present invention. FIG. 3 is a cross-sectional view showing conductive particles used in the conductive film according to the present invention. FIG. 4 is a cross-sectional view showing a first modified example of conductive particles. FIG. 5: is sectional drawing which shows the 2nd modification of a conductive particle. FIG. 6 is a sectional view showing a third modified example of the conductive particles. FIG. 7: is sectional drawing which shows the 4th modification of a conductive particle. FIG. 8 is a sectional view showing an example of a connection structure using the conductive film according to the present invention.

Hereinafter, the details of the present invention will be described.

(Conductive film)
The conductive film according to the present invention contains a plurality of conductive particles and a binder resin. In the conductive film according to the present invention, the conductive particles include a conductive particle body having a conductive portion and an insulating portion arranged on the surface of the conductive particle body. The conductive film according to the present invention has a layer containing the conductive particles and a layer not containing the conductive particles. In the conductive film according to the present invention, the content of the conductive particles is 60% by volume or more and 80% by volume or less in 100% by volume of the layer containing the conductive particles. The conductive film according to the present invention contains a large amount of the conductive particles.

In the conductive film according to the present invention, since the above configuration is provided, when electrically connecting between the electrodes, it is possible to effectively enhance the conduction reliability, and effectively the insulation reliability. Can be increased.

A connection structure can be obtained by electrically connecting the electrodes on the substrate using an anisotropic conductive material. In the production of this connection structure, when a flexible flexible printed board is used, there is an increasing demand for low-voltage mounting in order to suppress deformation of the flexible printed board. However, in the conventional anisotropic conductive material, the conductive particles and the electrode may not sufficiently contact each other when mounted at a low pressure. In particular, an insulating material such as insulating particles may be arranged on the surface of the conductive particles, and when a connecting structure is obtained using the conductive particles on which the insulating material is arranged, the conductive connection Sometimes it is necessary to implement at relatively high pressure and high temperature to eliminate the insulating material located between the conductive particles and the electrodes. As a result, the conventional anisotropic conductive material may have high connection resistance and low conduction reliability when mounted at low voltage.

In recent years, electronic devices have become thinner and smaller. Therefore, in the wiring connected by the conductive particles in the electronic component, L/S indicating the width of the line (L) where the wiring is formed and the width of the space (S) where the wiring is not formed becomes small. The narrowing of the pitch is progressing. In such fine wiring, when conducting conductive connection between electrodes using conventional anisotropic conductive material, a sufficient number of conductive particles are not arranged on the line, connection resistance becomes high, and conduction reliability is increased. May become less active.

In addition, when the number of conductive particles is increased in order to arrange a sufficient number of conductive particles on the line, the pressure applied to each conductive particle decreases, so the mounting pressure is increased. It is necessary, and it is difficult to perform mounting at low pressure with the conventional anisotropic conductive material. In addition, when the number of conductive particles arranged on the line is increased, the conductive particles come close to each other, which may cause a short circuit between electrodes that are adjacent to each other and that are not connected to each other in the lateral direction. In the conventional anisotropic conductive material, it may be difficult to considerably increase the reliability of conduction between the upper and lower electrodes to be connected and the reliability of insulation between laterally adjacent electrodes that should not be connected.

The present inventors have found that by using a conductive film containing specific conductive particles, low-voltage mounting can be performed, and further, the conduction reliability and the insulation reliability can be effectively improved. .. In the present invention, since the insulating portion located between the conductive particle body and the electrode can be relatively easily removed during the conductive connection, the mounting can be performed at a relatively low voltage. Further, in the present invention, since the conductive film contains a sufficient amount of conductive particles, a sufficient number of conductive particles can be arranged on a line when conductive connection is performed using the conductive film. Further, in the present invention, since the conductive particles contained in the conductive film are provided with an insulating portion, even if the conductive particles are close to each other, a short circuit occurs between electrodes adjacent in the lateral direction that should not be connected. Can be prevented. As a result, the conduction reliability between the upper and lower electrodes to be connected and the insulation reliability between the laterally adjacent electrodes that should not be connected can be effectively increased.

In the present invention, the use of a conductive film containing specific conductive particles makes a great contribution to obtain the above effects.

The viscosity (η25) at 25° C. of the conductive film is preferably 1000 Pa·s or more, more preferably 5000 Pa·s or more, preferably 100000 Pa·s or less, more preferably 50000 Pa·s or less. When the viscosity (η25) of the conductive material at 25° C. is equal to or higher than the lower limit and equal to or lower than the upper limit, insulation reliability between electrodes can be more effectively enhanced, and conduction reliability between electrodes can be further improved. It can be increased more effectively. The viscosity (η25) can be appropriately adjusted depending on the type and blending amount of blending components.

The viscosity (η80) at 80° C. of the conductive film is preferably 100 Pa·s or more, more preferably 1000 Pa·s or more, preferably 50000 Pa·s or less, more preferably 20000 Pa·s or less. When the viscosity (η80) of the conductive material at 80° C. is not less than the above lower limit and not more than the above upper limit, the insulation reliability between the electrodes can be more effectively enhanced, and the conduction reliability between the electrodes can be further improved. It can be increased more effectively. The above-mentioned viscosity (η80) can be appropriately adjusted depending on the type and amount of compounding ingredients.

The viscosity (η180) at 180° C. of the conductive film is preferably 50 Pa·s or more, more preferably 100 Pa·s or more, preferably 20000 Pa·s or less, more preferably 10000 Pa·s or less. When the viscosity (η180) of the conductive material at 180° C. is equal to or higher than the lower limit and equal to or lower than the upper limit, insulation reliability between electrodes can be more effectively enhanced, and conduction reliability between electrodes can be further improved. It can be increased more effectively. The viscosity (η180) can be appropriately adjusted depending on the type and amount of the compounding ingredients.

The viscosity (η25, η80 and η180) can be measured using STRESSTECH (manufactured by REOLOGICA) under the conditions of strain control 1 rad, frequency 1 Hz, temperature rising rate 20° C./min, and measurement temperature range 25 to 200° C. is there. In this measurement, η25, η80, and η180 are calculated by reading the viscosity at each temperature (25°C, 80°C, and 180°C).

The conductive film is preferably an anisotropic conductive film. The conductive film is preferably used for electrical connection of electrodes. The conductive film is preferably a circuit connecting material.

Hereinafter, the conductive film according to the present invention will be specifically described with reference to the drawings.

1A and 1B are a plan view and a cross-sectional view showing a conductive film according to an embodiment of the present invention. FIG. 1B is a sectional view taken along the line AA in FIG.

The conductive film 21 shown in FIGS. 1A and 1B has a layer (ACF layer) 22 containing the conductive particles 1 and a layer (NCF layer) 23 not containing the conductive particles 1. The layer 22 containing the conductive particles 1 and the layer 23 not containing the conductive particles 1 contain a binder resin. In the conductive film 21, the layer 23 not containing the conductive particles 1 is laminated on one surface of the layer 22 containing the conductive particles 1. The conductive film 21 is a laminated film having a two-layer structure. In addition, in FIGS. 1A and 1B, the conductive particles 1 are schematically illustrated for convenience of illustration.

2A and 2B are a plan view and a cross-sectional view showing a first modified example of the conductive film according to the present invention. FIG. 2B is a sectional view taken along the line BB in FIG.

The conductive film 21A shown in FIGS. 2A and 2B includes a layer (ACF layer) 22 containing the conductive particles 1, a layer (NCF layer) 23 not containing the conductive particles 1, and the conductive particles 1. The layer 24 (NCF layer) which does not contain. The layer 22 containing the conductive particles 1, the layer 23 not containing the conductive particles 1 and the layer 24 not containing the conductive particles 1 contain a binder resin. In the conductive film 21A, the layer 22 containing the conductive particles 1 is disposed between the layer 23 not containing the conductive particles 1 and the layer 24 not containing the conductive particles 1. In the conductive film 21A, the layer 23 not containing the conductive particles 1 is laminated on one surface of the layer 22 containing the conductive particles 1, and the other surface of the layer 22 containing the conductive particles 1 is A layer 24 not containing the conductive particles 1 is laminated. The conductive film 21A is a laminated film having a three-layer structure. 2A and 2B, the conductive particles 1 are schematically shown for convenience of illustration.

In the layer containing the conductive particles (ACF layer), it is preferable that the conductive particles are closest packed. In the ACF layer, the conductive particles are preferably arranged in a single layer so that the conductive particles do not overlap each other. In the ACF layer, it is preferable that the conductive particles are arranged in a single layer and are closest packed. When the ACF layer is viewed in a plan view, the conductive particles are preferably arranged in tetragonal packing, and more preferably in hexagonal packing.

The layer containing no conductive particles (NCF layer) preferably contains no conductive particles, and is preferably formed of only a binder resin. The binder resin contained in the ACF layer and the binder resin contained in the NCF layer may be the same or different.

When electrically connecting the electrodes, the thickness of the ACF layer is preferably 5 μm or more, from the viewpoint of further effectively increasing conduction reliability and further effectively improving insulation reliability. The thickness is more preferably 10 μm or more, preferably 40 μm or less, and more preferably 30 μm or less. The thickness of the ACF layer means one layer when the ACF layer in the conductive film is one layer, and two or more layers when the ACF layer in the conductive film is two or more layers. It means the total thickness.

When electrically connecting the electrodes, the thickness of the NCF layer is preferably 5 μm or more, from the viewpoint of further effectively increasing the conduction reliability and further effectively increasing the insulation reliability. The thickness is more preferably 10 μm or more, preferably 40 μm or less, and more preferably 30 μm or less. The thickness of the NCF layer means one layer when the NCF layer in the conductive film is one layer, and two or more layers when the NCF layer in the conductive film is two or more layers. It means the total thickness.

The thickness of the ACF layer and the thickness of the NCF layer can be calculated by observing the cross section of an arbitrary conductive film with a scanning electron microscope (SEM) or the like. The thickness of the ACF layer and the thickness of the NCF layer are calculated by observing the cross section of an arbitrary conductive film with a scanning electron microscope (SEM) or the like and calculating the thickness of the ACF layer and the thickness of the NCF layer at arbitrary 50 places. It is preferable to calculate on average.

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

(Conductive particles)
The conductive film contains a plurality of conductive particles. The conductive particle includes a conductive particle body having a conductive portion and an insulating portion arranged on the surface of the conductive particle body. The conductive part may have a single-layer structure or a multi-layer structure having two or more layers.

The conductive film has a layer containing the conductive particles (ACF layer) and a layer not containing the conductive particles (NCF layer). The content of the conductive particles in 100% by volume of the ACF layer is 60% by volume or more and 80% by volume or less. The content of the conductive particles in 100% by volume of the ACF layer is preferably 65% by volume or more, more preferably 68% by volume or more, preferably 75% by volume or less, more preferably 72% by volume or less. .. When the content of the conductive particles in 100% by volume of the ACF layer is equal to or more than the lower limit and equal to or less than the upper limit, conduction reliability is further effectively improved when the electrodes are electrically connected. In addition, the insulation reliability can be improved more effectively.

In the ACF layer in which the conductive particles are closest packed, the content of the conductive particles in 100% by volume of the ACF layer is preferably 60% by volume or more and 80% by volume or less.

In 100% by volume of the conductive film, the content of the conductive particles is preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 20% by volume or more, preferably 80% by volume or less, It is preferably 60% by volume or less. When the conductive particles have a true spherical shape or a shape close to a true spherical shape, the content of the conductive particles in 100% by volume of the conductive film is 55% by volume or less, and may be 53% by volume or less. preferable. When the content of the conductive particles is not less than the lower limit and not more than the upper limit, it is possible to further effectively enhance the conduction reliability when electrically connecting the electrodes, and the insulation reliability. Can be increased more effectively.

In the conductive film having the ACF layer in which the conductive particles are most closely packed, the content of the conductive particles in 100% by volume of the conductive film is preferably 5% by volume or more and 80% by volume or less.

In the above ACF layer, the method of closely packing the conductive particles (the method of setting the content of the conductive particles in 100 volume% of the ACF layer to 60 volume% or more and 80 volume% or less) is as follows. Methods and the like. A method of transferring a film layer to aligned conductive particles. A method of aligning conductive particles, which are magnetic materials, by applying a magnetic field with a magnet or the like in the vertical direction in the film. A method in which conductive particles are dispersed in a volatile solvent, coated on a drying base material, and aligned and dried while applying vibration. When electrically connecting the electrodes, from the viewpoint of more effectively increasing the insulation reliability and the conduction reliability, the method of closest packing the conductive particles is a magnet or the like in the vertical direction in the film. A method of aligning the conductive particles that are magnetic bodies by applying a magnetic field is preferable.

In the ACF layer, the distance between the adjacent conductive particle bodies is preferably 0.2 μm or more, more preferably 0.5 μm or more, preferably 4 μm or less, more preferably 1 μm or less. When the distance between the adjacent conductive particle bodies is equal to or more than the lower limit and equal to or less than the upper limit, it is possible to more effectively enhance the conduction reliability when electrically connecting the electrodes, and, The insulation reliability can be improved more effectively. The distance between the conductive particle bodies is larger than the distance between the conductive particles by the thickness of the insulating portion.

In the ACF layer, the ratio of the distance between the adjacent conductive particle bodies to the particle diameter of the conductive particle body (distance between adjacent conductive particle bodies/particle diameter of the conductive particle body) is preferably It is 1/30 or more, more preferably 1/10 or more, preferably 1/1 or less, more preferably 1/3 or less. When the ratio (distance between adjacent conductive particle main bodies/particle diameter of conductive particle main body) is equal to or more than the lower limit and equal to or less than the upper limit, conduction reliability is further improved when electrodes are electrically connected. It is possible to more effectively enhance the insulation reliability.

The distance between the adjacent conductive particle bodies can be calculated by observing an arbitrary conductive film with a scanning electron microscope (SEM) or the like. The distance between the adjacent conductive particle bodies is the surface of the conductive particle body in any one conductive particle in the conductive film, and the surface of the conductive particle body in the conductive particles adjacent to the conductive particles. It is the dimension that minimizes the distance connecting the lines.

The distance between the adjacent conductive particle bodies is determined by observing an arbitrary conductive particle body in the conductive film with a scanning electron microscope (SEM) or the like, and determining an adjacent conductive particle body in 50 arbitrary conductive particle bodies. It is preferable to calculate the distance between them by arithmetic mean.

In the conductive film, when the conductive film is viewed in a plan view, the area (occupancy rate) of the portion where the conductive particles are arranged in 100% of the total area of the conductive film is preferably 10% or more, more preferably Is 40% or more. When the occupancy rate is equal to or higher than the lower limit, it is possible to further effectively improve the conduction reliability and further effectively increase the insulation reliability when the electrodes are electrically connected. You can The portion where the conductive particles are arranged can be obtained by summing the area surrounded by the outer circumference of each conductive particle in the plan view of the conductive particle. The occupancy rate does not include the area of the insulating portion of the conductive particles.

The occupancy rate can be calculated by observing the conductive film with a scanning electron microscope (SEM) or the like.

The area (coverage) of the portion covered with the insulating portion in the entire surface area of the conductive particle body is preferably 65% or more, more preferably 70% or more, further preferably more than 70%, and particularly preferably. Is 75% or more, and most preferably 80% or more. The coverage is preferably 99% or less, more preferably 98% or less, still more preferably 95% or less. The coverage may be 100% or less. When the coverage is equal to or higher than the lower limit and equal to or lower than the upper limit, it is possible to further effectively improve the conduction reliability when electrically connecting the electrodes, and further improve the insulation reliability. Can be increased.

The coverage is obtained by observing the conductive particles with a scanning electron microscope (SEM) or the like, and calculating the total area (projected area) of the portion covered by the insulating portion in the entire surface area of the conductive particle body. It can be obtained by The coverage is preferably calculated by observing 50 arbitrary conductive particles and arithmetically averaging each coverage.

Specifically, when the insulating portion is an insulating particle, the above-mentioned coverage is obtained by observing the conductive particle from one direction with a scanning electron microscope (SEM) and measuring the outside of the surface of the conductive particle main body in the observed image. This means the total area of the insulating particles in the circle of the outer peripheral edge portion of the surface of the conductive particle body, which occupies the entire area of the circle in the peripheral edge portion.

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 60 μm or less, even more preferably 30 μm or less, further preferably 10 μm or less, particularly preferably Is 5 μm or less. The particle size of the conductive particles is not less than the lower limit and not more than the upper limit, when connecting the electrodes using the conductive particles, the contact area between the conductive particles and the electrode is sufficiently large, In addition, it is difficult for the conductive particles that are aggregated to form when forming the conductive portion. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive parts are less likely to peel off from the surface of the base material particles.

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

The coefficient of variation (CV value) of the particle diameter of the conductive particles is preferably 10% or less, more preferably 5% or less. When the variation coefficient of the particle diameter of the conductive particles is equal to or less than the upper limit, it is possible to more effectively enhance the conduction reliability and the insulation reliability between the electrodes.

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

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

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

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

FIG. 3 is a cross-sectional view showing conductive particles used in the conductive film according to the present invention.

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

The conductive particle body 2 has base particles 11 and conductive parts 12 arranged on the surfaces of the base particles 11. In the conductive particle 1, the conductive portion 12 is a conductive layer. The conductive portion 12 is in contact with the base material particles 11. The conductive portion 12 covers the surface of the base particle 11. The conductive particle body 2 is a coated particle in which the surface of the base particle 11 is coated with the conductive portion 12. The conductive particle body 2 has a conductive portion 12 on the surface. In the conductive particle 1, the conductive portion 12 is a single-layer conductive layer.

Unlike the conductive particles 1A and 1B described later, the conductive particles 1 do not have a core substance. The conductive particles 1 do not have protrusions on the conductive surface and do not have protrusions on the outer surface of the conductive portion 12. The conductive particles 1 are spherical.

Thus, the conductive particles used in the conductive film according to the present invention may not have a protrusion on the conductive surface, the outer surface of the conductive portion may not have a protrusion, spherical May be

FIG. 4 is a cross-sectional view showing a first modified example of conductive particles.

The conductive particle 1A shown in FIG. 4 includes a conductive particle body 2A and a plurality of insulating particles 3.

The conductive particle body 2A includes base particles 11, a conductive portion 12A arranged on the surface of the base particles 11, and a plurality of core substances 13. The conductive portion 12A is a conductive layer. The conductive portion 12A is in contact with the base material particles 11. The conductive portion 12A covers the surface of the base particle 11. The conductive particle body 2A is a coated particle in which the surface of the base material particle 11 is coated with the conductive portion 12A. The conductive particle body 2A has a conductive portion 12A on the surface. In the conductive particles 1A, the conductive portion 12A is a single conductive layer.

The conductive particles 1A have a plurality of protrusions 1Aa on the outer surface. In the conductive particle 1A, the conductive portion 12A has a plurality of protrusions 12Aa on the outer surface. The plurality of core substances 13 raise the outer surface of the conductive portion 12A. The protrusion 1Aa and the protrusion 12Aa are formed by the outer surface of the conductive portion 12A being raised by the plurality of core substances 13. The plurality of core substances 13 are embedded in the conductive portion 12A. The core substance 13 is disposed inside the protrusions 1Aa and 12Aa. The conductive portion 12A covers a plurality of core substances 13. In the conductive particle body 2A, the core substance 13 is used to form the protrusions 1Aa and the protrusions 12Aa. In the conductive particle body, a plurality of core materials may not be used to form the protrusion. The conductive particle body may not include the plurality of core substances. The core substance may not be in contact with the base particles. The outer surface of the conductive portion may have a spherical shape.

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

FIG. 5: is sectional drawing which shows the 1st modification of a conductive particle.

The conductive particle 1B shown in FIG. 5 includes a conductive particle body 2B and a plurality of insulating particles 3.

The conductive particle 1A and the conductive particle 1B are different from each other in the conductive particle body 2A and the conductive particle body 2B.

The conductive particle body 2B has base particles 11, a conductive portion 12B arranged on the surface of the base particles 11, and a plurality of core substances 13.

The conductive particles 1A and the conductive particles 1B are different from each other in the conductive portion 12A and the conductive portion 12B. The conductive portion 12B has a first conductive portion 12BA on the base material particle 11 side and a second conductive portion 12BB on the opposite side to the base material particle 11 side as a whole. In the conductive particle 1A, the conductive portion 12A having a one-layer structure is formed, whereas in the conductive particle 1B, the conductive portion 12B having a two-layer structure having the first conductive portion 12BA and the second conductive portion 12BB. Are formed. The first conductive portion 12BA and the second conductive portion 12BB may be formed as different conductive portions, or may be formed as the same conductive portion.

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

The conductive particle 1B has a plurality of protrusions 1Ba on its outer surface. In the conductive particle 1B, the conductive portion 12B has a plurality of protrusions 12Ba on the outer surface. In the conductive particle 1B, the first conductive portion 12BA has a plurality of protrusions 12BAa on the outer surface. In conductive particle 1B, second conductive portion 12BB has a plurality of protrusions 12BBa on the outer surface. The plurality of core substances 13 raise the outer surface of the conductive portion 12B. The protrusion 1Ba, the protrusion 12Ba, the protrusion 12BAa, and the protrusion 12BBa are formed by the outer surface of the conductive portion 12B being raised by the plurality of core substances 13. The plurality of core substances 13 are embedded in the conductive portion 12B. The core substance 13 is arranged inside the protrusion 1Ba, the protrusion 12Ba, the protrusion 12BAa, and the protrusion 12BBa. The conductive portion 12B covers a plurality of core substances 13. In the conductive particle body 2B, the core substance 13 is used to form the protrusion 1Ba, the protrusion 12Ba, the protrusion 12BAa, and the protrusion 12BBa. In the conductive particle body, a plurality of core materials may not be used to form the protrusion. The conductive particle body may not include the plurality of core substances. The core substance may not be in contact with the base particles. The core substance 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.

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

FIG. 6 is a sectional view showing a second modification of the conductive particles.

The conductive particle 1C shown in FIG. 6 includes a conductive particle body 2C and a plurality of insulating particles 3.

The conductive particle 1A and the conductive particle 1C are different from each other in the conductive particle main body 2A and the conductive particle main body 2C.

The conductive particle body 2C includes the base particles 11 and the conductive portions 12C arranged on the surfaces of the base particles 11. The conductive particle body 2C has no core substance.

The conductive particle main body 2A and the conductive particle main body 2C are different in the presence or absence of the core substance, and as a result, the conductive portions are different. In the conductive particles 1A, the core substance 13 is used, and the conductive portion 12A is formed so as to cover the core substance 13, whereas in the conductive particles 1C, the core substance is not used, and The portion 12C is formed.

The conductive portion 12C has a first portion and a second portion that is thicker than the first portion. The conductive particles 1C have a plurality of protrusions 1Ca on the outer surface. The conductive particle 1C has a plurality of protrusions 12Ca on the outer surface of the conductive portion 12C. The portion excluding the protrusion 1Ca and the protrusion 12Ca is the first portion of the conductive portion 12C. The protrusions 1Ca and the protrusions 12Ca are the above-mentioned second portions in which the conductive portion 12C is thick.

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

FIG. 7: is sectional drawing which shows the 3rd modification of a conductive particle.

The conductive particle 1D shown in FIG. 7 includes a conductive particle body 2A and an insulating layer 3D.

The insulating particles 3 and the insulating layer 3D are different between the conductive particles 1A and the conductive particles 1D.

In the conductive particle 1D, the insulating layer 3D is arranged on the surface of the conductive particle main body 2A. The insulating layer 3D is in contact with the surface of the conductive particle main body 2A and covers the surface of the conductive particle main body 2A. The plurality of insulating layers 3D are in contact with the outer surface of the conductive portion 12A in the conductive particle body 2A and cover the outer surface of the conductive portion 12A.

The conductive particle 1D has a plurality of protrusions 1Da on its outer surface. In the conductive particle 1D, the conductive portion 12A has a plurality of protrusions 12Aa on the outer surface. In the conductive particle 1D, the insulating layer 3D has a plurality of protrusions 3Da on the outer surface. The insulating layer 3D is arranged on the surface of the portion where the protrusion 1Da, the protrusion 12Aa, and the protrusion 3Da are present. The insulating layer 3D is also disposed on the surface of the portion where the protrusion 1Da, the protrusion 12Aa, and the protrusion 3Da are not provided. The insulating layer 3D arranged on the surface of the portion having the protrusions 1Da, 12Aa, and 3Da and the insulating layer 3D arranged on the surface of the portion not having the protrusions 1Da, 12Aa, and 3Da are continuous. .. The insulating layer may cover the entire surface of the conductive particle body or may partially cover the surface of the conductive particle body.

The insulating part is preferably an insulating particle or an insulating layer. From the viewpoint of further effectively increasing the conduction reliability, the insulating portion is preferably an insulating particle, and a plurality of the insulating particles are preferably arranged on the surface of the conductive particle body. .. From the viewpoint of further effectively increasing the insulation reliability, the insulating portion is preferably an insulating layer, and the insulating layer is preferably arranged on the surface of the conductive particle body.

Hereinafter, other details of the conductive particles and the like will be described. In the following description, "(meth)acrylic" means one or both of "acrylic" and "methacrylic", and "(meth)acrylate" means one or both of "acrylate" and "methacrylate". To do.

(Main body of conductive particles)
The conductive particle body has a conductive portion. The conductive portion is preferably a conductive layer. The conductive particle body may be a conductive particle having a base particle and a conductive portion arranged on the surface of the base particle, or may be a metal particle having a conductive portion as a whole. From the viewpoint of reducing the cost and increasing the flexibility of the conductive particle main body to further enhance the conduction reliability between the electrodes, the base particles and the conductive particles arranged on the surface of the base particles are used. A conductive particle body having a part is preferred.

Base particle:
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 particle may be a core-shell particle including a core and a shell arranged on the surface of the core. The core may be an organic core and the shell may be an inorganic shell.

Various organic substances are preferably used as the material of the resin particles. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; polycarbonate, polyamide, Phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, Examples thereof include polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene-based copolymer. Examples of the divinylbenzene-based copolymer and the like include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. Is preferred.

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

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, Alkyl (meth)acrylate compounds such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate. Oxygen atom-containing (meth)acrylate compounds such as; nitrile-containing monomers such as (meth)acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate, and stearic acid Acid vinyl ester compounds such as vinyl; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene And the halogen-containing monomer.

Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(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) Polyfunctional (meth)acrylate compounds such as acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene , Diallyl phthalate, diallyl acrylamide, diallyl ether, and silane-containing monomers such as 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 of performing suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles to perform polymerization.

When the base particles are inorganic particles excluding metals or organic-inorganic hybrid particles, examples of the inorganic material for forming the base particles include silica, alumina, barium titanate, zirconia and carbon black. The inorganic substance is preferably not a metal. The particles formed of the above 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, firing is optionally performed. Particles obtained by carrying out are included. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

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

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

Examples of the material of the inorganic shell include the inorganic materials mentioned as the materials of the base particles. 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. The metal alkoxide is preferably silane alkoxide. The inorganic shell is preferably made 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.

The particle size of the base particles is preferably 1 μm or more, more preferably 2 μm or more, preferably 20 μm or less, more preferably 10 μm or less. When the particle size of the base material particles is equal to or more than the above lower limit and equal to or less than the above upper limit, small conductive particles can be obtained even if the distance between the electrodes is small and the thickness of the conductive layer is increased. Furthermore, it becomes difficult for the conductive particles to aggregate when forming the conductive portion on the surface of the substrate particles, and it becomes difficult for the aggregated conductive particles to be formed.

It is particularly preferable that the base particles have a particle size of 3 μm or more and 5 μm or less. When the particle size of the base particles is in the range of 3 μm or more and 5 μm or less, it becomes difficult to aggregate when forming the conductive portion on the surface of the base particles, and it becomes difficult to form the aggregated conductive particles.

The particle size of the base particles indicates the diameter when the base particles are spherical, and indicates the maximum diameter when the base particles are not spherical.

The particle size of the base particles indicates the number average particle size. The particle size of the above-mentioned base particles can be obtained using a particle size distribution measuring device or the like. The particle diameter of the base material particles is preferably obtained by observing 50 arbitrary base material particles with an electron microscope or an optical microscope and calculating an average value. In the case of measuring the particle size of the above-mentioned base particles in the conductive particles, it can be measured as follows, for example.

The conductive particles are added to "Technobit 4000" manufactured by Kulzer Co., Ltd. so that the content of the conductive particles is 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the conductive particles dispersed in the inspection embedded resin. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25,000 times, 50 conductive particles were randomly selected, and the base particles of each conductive particle were observed. To do. The particle diameter of the base material particles in each conductive particle is measured, and they are arithmetically averaged to obtain the particle diameter of the base material particles.

Conductive part:
In the present invention, the conductive particle main body has a conductive portion. The entire conductive particles may be the conductive portion, or only the surface portion of the conductive particles may be the conductive portion. The conductive part preferably contains a metal. The metal forming the conductive portion is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. In addition, tin-doped indium oxide (ITO) may be used as the metal. Only 1 type may be used for the said metal and 2 or more types may be used together. From the viewpoint of further lowering the connection resistance between the electrodes, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable.

Further, from the viewpoint of effectively enhancing the conduction reliability, it is preferable that the conductive portion and the outer surface portion of the conductive portion contain nickel. The content of nickel in 100% by weight of the conductive portion containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, further preferably 70% by weight or more, particularly preferably 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.

In addition, a hydroxyl group is often present on the surface of the conductive portion due to oxidation. Generally, hydroxyl groups are present on the surface of the conductive portion formed of nickel due to oxidation. The insulating portion can be arranged on the surface of the conductive portion having such a hydroxyl group (the surface of the conductive particles) through a chemical bond.

The conductive part may be formed of one layer. The conductive part may be formed of a plurality of layers. That is, the conductive part may have a laminated structure of two or more layers. When the conductive portion is formed of a plurality of layers, the metal forming the outermost layer is preferably gold, nickel, palladium, copper or an alloy containing tin and silver, and is gold. More preferable. When the metal forming the outermost layer is one of these preferable metals, the connection resistance between the electrodes becomes even lower. Further, when the metal forming the outermost layer is gold, the corrosion resistance is further enhanced.

The method for forming the conductive portion on the surface of the base material particles is not particularly limited. As the method of forming the conductive portion, for example, a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and a metal powder or Examples thereof include a method of coating the surface of the base particles with a paste containing a metal powder and a binder. The method of forming the conductive portion is preferably a method by electroless plating, electroplating or physical collision. Examples of the physical vapor deposition method include vacuum vapor deposition, ion plating, and ion sputtering. Further, in the above-mentioned physical collision method, for example, a sheet composer (manufactured by Tokuju Kosakusho Co., Ltd.) is used.

The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, still more preferably 0.3 μm or less. The thickness of the conductive portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles are sufficient when connecting the electrodes. It can be transformed.

When the conductive portion is formed of a plurality of layers, the thickness of the conductive portion of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably Is 0.1 μm or less. When the thickness of the conductive portion of the outermost layer is not less than the lower limit and not more than the upper limit, the conductive portion of the outermost layer is uniform, corrosion resistance is sufficiently high, and the connection resistance between the electrodes is sufficiently low. can do.

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

Core substance:
The conductive particle body preferably has a plurality of protrusions on the outer surface of the conductive portion. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When the conductive particles having protrusions on the surface of the conductive portion are used, the oxide film can be effectively eliminated by the protrusions by disposing the conductive particles between the electrodes and pressing them. For this reason, the electrodes and the conductive portion contact each other more reliably, and the connection resistance between the electrodes becomes even lower. Further, when connecting the electrodes, the insulating particles between the conductive particles and the electrodes can be effectively eliminated by the protrusions of the conductive particles. Therefore, the reliability of conduction between the electrodes is further enhanced.

As the method of forming the protrusions, after attaching the core substance to the surface of the base material particles, a method of forming a conductive portion by electroless plating, and forming a conductive portion by electroless plating on the surface of the base material particles Then, a method of attaching a core substance and then forming a conductive portion by electroless plating, etc. may be mentioned. As another method of forming the protrusions, after forming the first conductive portion on the surface of the base material particle, the core substance is disposed on the first conductive portion, and then the second conductive portion is formed. And a method of adding a core substance in the middle of forming a conductive part (first conductive part, second conductive part or the like) on the surface of the base material particles. Further, in order to form the protrusions, the conductive material is formed on the base particles by electroless plating without using the above core substance, and then plating is deposited in the form of protrusions on the surface of the conductive parts, and further electroless plating is performed. You may use the method of forming a conductive part by.

As a method of attaching the core substance to the surface of the base material particles, for example, in the dispersion liquid of the base material particles, the core substance is added, the core material is accumulated on the surface of the base material particles by Van der Waals force, Examples thereof include a method of attaching the core substance, a method of adding the core substance to a container containing the base particles, and a method of attaching the core substance to the surface of the base particles by a mechanical action such as rotation of the container. From the viewpoint of controlling the amount of the core substance to be attached, the method of attaching the core substance to the surface of the base material particles is a method of accumulating the core substance on the surface of the base material particles in the dispersion and attaching the core substance. preferable.

Examples of the substance forming the core substance include a conductive substance and a non-conductive substance. Examples of the conductive substance include a metal, a metal oxide, a conductive non-metal such as graphite, and a conductive polymer. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive substance include silica, alumina and zirconia. From the viewpoint of further improving the conduction reliability between the electrodes, the core substance is preferably a metal.

The metal is not particularly limited. Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead. Examples of the alloy include alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and tungsten carbide. From the viewpoint of further enhancing the conduction reliability between the electrodes, the metal is preferably nickel, copper, silver or gold. The metal may be the same as or different from the metal forming the conductive part (conductive layer).

The shape of the core substance is not particularly limited. The shape of the core substance is preferably massive. Examples of the core substance include a particulate mass, an agglomerate of a plurality of fine particles, and an amorphous mass.

The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, 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 lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively reduced.

The particle size of the core substance is preferably an average particle size, and more preferably a number average particle size. The particle size of the core substance is, for example, observing 50 arbitrary core substances with an electron microscope or an optical microscope, calculating the average value of the particle size of each core substance, and performing a laser diffraction particle size distribution measurement. Required by.

(Insulation part)
The conductive particles include an insulating portion arranged on the surface of the conductive particle body. In this case, if the conductive particles are used to connect the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating portion exists between the plurality of electrodes, so that a short circuit between adjacent electrodes in the lateral direction can be prevented, not between the upper and lower electrodes. In addition, when connecting the electrodes, the conductive particles are pressed by the two electrodes, whereby the insulating portion between the conductive portion of the conductive particles and the electrode can be easily eliminated. Furthermore, in the case of conductive particles having a plurality of protrusions on the outer surface of the conductive portion, the insulating portion between the conductive portion of the conductive particles and the electrode can be more easily eliminated.

From the viewpoint of further effectively increasing the insulation reliability, the insulating portion is preferably an insulating layer. From the viewpoint of further effectively increasing the insulation reliability, the insulating layer is preferably disposed on the surface of the conductive particle body.

The thickness of the insulating layer can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles, and the like. The thickness of the insulating layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, preferably 2 μm or less, more preferably 1 μm or less. When the thickness of the insulating layer satisfies the above lower limit, it becomes difficult for the conductive portions of the plurality of conductive particles to come into contact with each other when the conductive particles are dispersed in the binder resin. When the thickness of the insulating layer satisfies the above upper limit, it is not necessary to raise the pressure too high in order to eliminate the insulating layer between the electrodes and the conductive particles when the electrodes are connected to each other, and the insulating layer is heated to a high temperature. There is no need to do it. When the thickness of the insulating layer satisfies the lower limit and the upper limit, the insulation reliability can be more effectively improved when the electrodes are electrically connected.

The thickness of the insulating layer is preferably an average thickness. The thickness of the insulating layer is preferably obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value. When the thickness of the insulating layer in the conductive particles is measured, it can be measured as follows, for example.

The conductive particles are added to "Technobit 4000" manufactured by Kulzer Co., Ltd. so as to have a content of 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the dispersed conductive particles in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 50,000 times, 50 conductive particles are randomly selected, and the insulating layer of each conductive particle is observed. . The thickness of the insulating layer in each conductive particle is measured, and they are arithmetically averaged to obtain the thickness of the insulating layer.

The ratio of the particle diameter of the conductive particles to the thickness of the insulating layer (particle diameter of the conductive particles/thickness of the insulating layer) is preferably 1 or more, more preferably 5 or more, and preferably 40 or less. It is preferably 20 or less. When the above ratio (particle diameter of conductive particles/thickness of insulating layer) is not less than the above lower limit and not more than the above upper limit, insulation reliability and conduction reliability are further enhanced when electrodes are electrically connected. Can be increased.

From the viewpoint of further effectively increasing the conduction reliability, the insulating portion is preferably insulating particles. From the viewpoint of more effectively increasing the conduction reliability, it is preferable that the plurality of insulating particles be arranged on the surface of the conductive particle body.

The particle size of the insulating particles can be appropriately selected depending on the particle size of the conductive particles and the use of the conductive particles. The particle diameter of the insulating particles is preferably 0.1 μm or more, more preferably 0.3 μm or more, preferably 2 μm or less, more preferably 1 μm or less. When the particle diameter of the insulating particles satisfies the above lower limit, it becomes difficult for the conductive parts of the plurality of conductive particles to contact each other when the conductive particles are dispersed in the binder resin. When the particle diameter of the insulating particles satisfies the above upper limit, at the time of connection between the electrodes, in order to eliminate the insulating particles between the electrodes and the conductive particles, it is not necessary to increase the pressure too much, There is no need to heat to a high temperature. When the particle diameter of the insulating particles satisfies the lower limit and the upper limit, the insulation reliability can be more effectively improved when the electrodes are electrically connected.

The particle size of the insulating particles is preferably an average particle size, and more preferably a number average particle size. The particle size of the above-mentioned insulating particles can be obtained using a particle size distribution measuring device or the like. The particle size of the insulating particles is preferably obtained by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope and calculating an average value. In the case of measuring the particle size of the insulating particles in the conductive particles, it can be measured as follows, for example.

The conductive particles are added to "Technobit 4000" manufactured by Kulzer Co., Ltd. so as to have a content of 30% by weight, and dispersed to prepare an embedded resin for conductive particle inspection. A cross section of the conductive particles is cut out using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass near the center of the dispersed conductive particles in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification is set to 50,000 times, 50 conductive particles are randomly selected, and the insulating particles of each conductive particle are observed. To do. The particle diameter of the insulating particles in each conductive particle is measured, and they are arithmetically averaged to obtain the particle diameter of the insulating particles.

The ratio of the particle diameter of the conductive particles to the particle diameter of the insulating particles (particle diameter of conductive particles/particle diameter of insulating particles) is preferably 1 or more, more preferably 5 or more, and preferably It is 40 or less, more preferably 20 or less. When the ratio (particle diameter of conductive particles/particle diameter of insulating particles) is not less than the above lower limit and not more than the above upper limit, insulation reliability and conduction reliability are further improved when electrodes are electrically connected. It can be increased more effectively.

Examples of the material of the insulating portion include insulating resin. Examples of the insulating resin include materials of resin particles that can be used as base particles.

Specific examples of the insulating resin that is the material of the insulating portion include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, and thermosetting. Resins and water-soluble resins.

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, polyethyl (meth)acrylate, and polybutyl (meth)acrylate. Examples of the block polymer include polystyrene, a styrene-acrylic acid ester copolymer, an SB type styrene-butadiene block copolymer, an 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 the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide and methyl cellulose. A chain transfer agent may be used to adjust the degree of polymerization. Examples of the chain transfer agent include thiol and carbon tetrachloride.

Examples of the method of disposing the insulating particles on the surface of the conductive portion include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion method, spraying method, dipping method, and vacuum deposition method. When electrically connecting the electrodes, from the viewpoint of further effectively increasing the insulation reliability and conduction reliability, the method of arranging the insulating particles on the surface of the conductive portion is a physical method. Preferably.

The outer surface of the conductive portion and the outer surface of the insulating particles may be coated with a compound having a reactive functional group. The outer surface of the conductive portion and the outer surface of the insulating particles 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 portion, the carboxyl group may be chemically bonded to a functional group on the outer surface of the insulating particle through a polymer electrolyte such as polyethyleneimine.

When the insulating particles are used as the insulating portion, two or more kinds of insulating particles having different particle sizes may be used together. By using two or more kinds of insulating particles having different particle sizes together, the insulating particles having a small particle size enter the gap covered with the insulating particles having a large particle size, and the insulating property is provided on the surface of the conductive particle. The particles can be arranged even more efficiently. When the insulating particles are used as the insulating portion, the insulating particles include first insulating particles having a particle diameter of 0.1 μm or more and 0.3 μm or less and particle diameters of 0.3 μm or more and 3 μm or less. It is preferable to include the second insulating particles. It is preferable that the particle size distribution of the first insulating particles does not overlap with the particle size distribution of the second insulating particles. The average particle size of the first insulating particles and the average particle size of the second insulating particles are preferably different.

The coefficient of variation (CV value) of the particle diameter of the insulating particles is preferably 20% or less. When the coefficient of variation of the particle diameter of the insulating particles is equal to or less than the upper limit, the thickness of the insulating particles of the conductive particles with the obtained insulating particles becomes more uniform, and the pressure during the conductive connection is more uniform. It can be applied more easily, and the connection resistance between the electrodes can be further reduced.

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

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

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

(Binder resin)
The conductive film contains the conductive particles described above and a binder resin. The layer containing the conductive particles (ACF layer) is preferably formed of the conductive particles described above and a binder resin. The layer containing no conductive particles (NCF layer) is preferably formed of only a binder resin. The binder resin used for the ACF layer and the binder resin used for the NCF layer may be the same or different.

The binder resin is not particularly limited. A known insulating resin is used as the binder resin. 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 contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent. In the conductive film, the binder resin is preferably not completely cured. The binder resin may be B-staged by heating or the like.

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

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

The conductive film, in addition to the conductive particles and the binder resin, for example, a filler, a filler, a softening agent, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer. It may contain various additives such as agents, ultraviolet absorbers, lubricants, antistatic agents and flame retardants.

As a method for dispersing the conductive particles in the binder resin, a conventionally known dispersion method can be used and is not particularly limited. Examples of the method of dispersing the conductive particles in the binder resin include the following methods. A method in which the conductive particles are added to the binder resin and then kneaded and dispersed by a planetary mixer or the like. A method in which the above conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the above binder resin, and kneaded and dispersed by a planetary mixer or the like. A method of diluting the binder resin with water, an organic solvent or the like, adding the conductive particles, and kneading and dispersing with a planetary mixer or the like.

The content of the binder resin in 100% by weight of the conductive film is preferably 10% by weight or more, more preferably 30% by weight or more, further preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably Is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is not less than the lower limit and not more than the upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further enhanced. You can

(Connection structure)
A connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, and the first connection target member, And a connecting portion connecting the second connection target member. In the connection structure according to the present invention, the material of the connection portion is the above-mentioned conductive film. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive portion of the conductive particle.

The connection structure is obtained through a step of disposing the conductive film between the first connection target member and the second connection target member and a step of conductive connection by thermocompression bonding. be able to. It is preferable that the insulating portion be detached from the conductive particles during the thermocompression bonding.

FIG. 8 is a sectional view showing an example of a connection structure using the conductive film according to the present invention.

The connection structure 51 shown in FIG. 8 includes a first connection target member 52, a second connection target member 53, and a connection portion that connects the first connection target member 52 and the second connection target member 53. And 54. The connection portion 54 is formed of a conductive film containing the conductive particles 1. It is preferable that the conductive film has a thermosetting property and the connection portion 54 is formed by thermosetting the conductive film. In addition, in FIG. 8, the conductive particles 1 are schematically illustrated for convenience of illustration. Instead of the conductive particles 1, conductive particles 1A, 1B, 1C and 1D may be used.

The first connection target member 52 has a plurality of first electrodes 52a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the front surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected by the conductive portion 12 (not shown in FIG. 8) in the plurality of conductive particles 1. Therefore, the first connection target member 52 and the second connection target member 53 are electrically connected by the conductive portion 12 (not shown in FIG. 8) in the conductive particle 1.

The method for manufacturing the connection structure is not particularly limited. As an example of the method for manufacturing the connection structure, the conductive film is arranged between the first connection target member and the second connection target member to obtain a laminated body, and then the laminated body is heated and pressed. Methods and the like. The pressure at the time of pressurization is preferably 40 MPa or more, more preferably 60 MPa or more, preferably 90 MPa or less, more preferably 70 MPa or less. The temperature at the time of heating is preferably 80°C or higher, more preferably 100°C or higher, preferably 140°C or lower, more preferably 120°C or lower. When the pressure at the time of pressurization and the temperature at the time of heating are not less than the lower limit and not more than the upper limit, the insulating part can be easily detached from the surface of the conductive particle main body at the time of conductive connection, and the conduction reliability between the electrodes can be improved. It can be further enhanced.

When the laminated body is heated and pressed, the insulating portion existing between the conductive particle body and the first electrode and the second electrode can be eliminated. For example, at the time of the heating and pressurization, the insulating portion existing between the conductive particle body and the first electrode and the second electrode is a surface of the conductive particle body. Easily detach from. During the heating and pressurization, some of the insulating parts may be detached from the surface of the conductive particle body, and the surface of the conductive part may be partially exposed. By exposing the surface of the conductive portion to the first electrode and the second electrode, the first electrode and the second electrode are separated from each other via the conductive portion of the conductive particle body. It can be electrically connected.

The first connection target member and the second connection target member are not particularly limited. Specific examples of the first connection target member and the second connection target member include semiconductor chips, semiconductor packages, LED chips, LED packages, electronic components such as capacitors and diodes, and resin films, printed boards, and flexible parts. Examples include electronic components such as printed circuit boards, flexible flat cables, rigid flexible substrates, circuit boards such as glass epoxy substrates and glass substrates. It is preferable that the first connection target member and the second connection target member are 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, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the member to be connected is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the member to be connected 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 electrode is an aluminum electrode, it may be an electrode formed only of aluminum or an electrode in which an aluminum layer is laminated on the surface of a 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.

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

(Example 1)
(1) Preparation of Conductive Particle Main Body Resin particles (base particles) formed of a copolymer resin of tetramethylolmethane tetraacrylate and divinylbenzene having a particle diameter of 3 μm were prepared. After 10 parts by weight of the base particles were dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of the palladium catalyst solution using an ultrasonic disperser, the solution was filtered to take out the base particles. Next, the base particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the base particles. After thoroughly washing the surface-activated substrate particles with water, the dispersion liquid was obtained by adding and dispersing 500 parts by weight of distilled water. Next, 1 g of nickel particle slurry (average particle diameter 0.15 μm) was added to the above dispersion over 3 minutes to obtain a suspension containing base material particles to which the core substance was attached.

Further, 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 obtained suspension at 70° C., the above nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Thereafter, the suspension is filtered to take out the particles, washed with water, and dried to form a conductive particle body having conductive parts (nickel-boron layer, thickness 0.15 μm) formed on the surface of the base material particles. Got

(2) Production of conductive particles 10 g of the obtained conductive particle main body was placed in a 2000 mL separable flask equipped with a 4-neck separable cover, a stirring blade, a three-way cock, and a temperature probe, 1000 mL of isopropyl alcohol, and distilled water. 50 mL was added. Further, titanium alkoxide was added so as to have a concentration of 0.5 mol/L, the mixture was stirred at 250 rpm, and polymerization was performed at 25° C. for 1 hour in a nitrogen atmosphere to obtain conductive particles. In the obtained conductive particles, the insulating layer (thickness 0.1 μm) was arranged on the surface of the conductive particle main body.

(3) Production of conductive film (anisotropic conductive film) 60 parts by weight of the obtained conductive particles, 8 parts by weight of bisphenol A type phenoxy resin, 1 part by weight of fluorene type epoxy resin, and 10 parts of phenol novolac type epoxy resin 10. By weight, SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) was mixed with 0.06 part by weight to obtain a layer (ACF layer) containing conductive particles. Specifically, the above formulation was dissolved in methyl ethyl ketone (MEK) so that the solid content was 40% by weight to obtain a solution. After stirring with a planetary stirrer at 2000 rpm for 5 minutes, the release PET (polyethylene terephthalate) film was coated with a bar coater so that the thickness after drying was 3.5 μm. The layer containing conductive particles (ACF layer) was obtained by removing MEK by vacuum drying at room temperature. The content of the conductive particles in 100% by volume of the obtained layer containing the conductive particles (ACF layer) was 62% by volume.

A layer containing 8 parts by weight of a bisphenol A-type phenoxy resin, 10 parts by weight of a phenol novolac type epoxy resin, and 0.06 part by weight of SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) and containing no conductive particles. (NCF layer) was obtained. Specifically, the above formulation was dissolved in methyl ethyl ketone (MEK) so that the solid content was 40% by weight to obtain a solution. A release PET (polyethylene terephthalate) film was coated using a bar coater so that the thickness after drying was 3.5 μm. MEK was removed by vacuum drying at room temperature to obtain a layer (NCF layer) containing no conductive particles.

A conductive film was obtained by laminating the ACF layer and the NCF layer under conditions of a temperature of 40° C. and a pressure of 5 MPa.

(4) Preparation of Connection Structure A transparent glass substrate having an IZO electrode pattern (first electrode, metal Vickers hardness of 100 Hv on the electrode surface) having an L/S of 10 μm/10 μm was prepared. In addition, a semiconductor chip having an Au electrode pattern (second electrode, metal Vickers hardness of 50 Hv on the electrode surface) having L/S of 10 μm/10 μm formed on the lower surface was prepared.

The obtained conductive film was laminated on the transparent glass substrate. Next, the semiconductor chip was laminated on the upper surface of the conductive film so that the electrodes face each other. After that, while adjusting the temperature of the head so that the temperature of the conductive film becomes 140° C., a pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 60 MPa is applied to the electrode area to keep the conductive film at 140° C. It hardened and the connection structure was obtained.

(Examples 2 to 6, 8 to 18, 20 to 25)
Thickness of insulating layer, content of conductive particles in 100% by volume of layer containing conductive particles (ACF layer), content of conductive particles in 100% by volume of conductive film, thickness of conductive portion, base particle The particle size, the particle size of the core substance, and the material of the core substance were changed as shown in Tables 1 to 4 below. In the same manner as in Example 1 except for the above changes, conductive particle bodies, conductive particles, a conductive film, and a connection structure were obtained.

(Example 7)
(1) Preparation of conductive particle main body In the same manner as in Example 1, a conductive particle main body was obtained.

(2) Preparation of Insulating Particles The following composition was put into a 1000 mL separable flask equipped with a four-neck separable cover, a stirring blade, a three-way cock, a cooling tube and a temperature probe, and then the above composition was solid content. Of distilled water was added so as to be 10% by weight, the mixture was stirred at 200 rpm, and polymerization was carried out at 50° C. for 5 hours in a nitrogen atmosphere. The above composition comprises glycidyl methacrylate 45 mmol, methyl methacrylate 380 mmol, ethylene glycol dimethacrylate 13 mmol, acid phosphooxypolyoxyethylene glycol methacrylate 0.5 mmol, and 2,2′-azobis{2-[N-(2- 1 mmol of carboxyethyl)amidino]propane}. After completion of the reaction, it was freeze-dried to obtain insulating particles (particle diameter 0.36 μm) having P-OH groups derived from acid phosphooxypolyoxyethylene glycol methacrylate on the surface.

(3) Preparation of conductive particles The insulating particles obtained above were 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 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 with a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles. In the obtained conductive particles, the insulating particles were arranged on the surface of the conductive particle body.

(4) Preparation of conductive film (anisotropic conductive film) The obtained conductive particles were used in an amount of 45 parts by weight, and the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) was A conductive film was obtained in the same manner as in Example 1 except that the content was 68% by volume.

(5) Production of connection structure A connection structure was obtained in the same manner as in Example 1 except that the obtained conductive film was used.

(Example 19)
(1) Preparation of conductive particle body A conductive particle body was obtained in the same manner as in Example 1 except that the core substance was not used.

(2) Preparation of Insulating Particles Insulating particles were obtained in the same manner as in Example 7, except that the particle size of the insulating particles was 0.5 μm.

(3) Preparation of conductive particles In the same manner as in Example 7, conductive particles were obtained.

(4) Preparation of conductive film (anisotropic conductive film) In the same manner as in Example 1, a conductive film was obtained.

(5) Production of connection structure A connection structure was obtained in the same manner as in Example 1 except that the obtained conductive film was used.

(Comparative Example 1)
A conductive film was prepared in the same manner as in Example 4 except that the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) was 56% by volume during the production of the conductive film. Obtained.

(Comparative example 2)
A conductive film was prepared in the same manner as in Example 4 except that the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) was 83% by volume during the production of the conductive film. Obtained.

(Comparative example 3)
When the conductive film is produced, the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) is 57% by volume, and the content of the conductive particles in 100% by volume of the conductive film. A conductive film was obtained in the same manner as in Example 4 except that the amount was 3% by volume.

(Comparative example 4)
When the conductive film is produced, the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) is 92% by volume, and the content of the conductive particles in 100% by volume of the conductive film. A conductive film was obtained in the same manner as in Example 4 except that the amount was 82% by volume.

(Comparative example 5)
A conductive film was prepared in the same manner as in Example 4 except that the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) was 49% by volume during the production of the conductive film. Obtained.

(Comparative example 6)
A conductive film was prepared in the same manner as in Example 4 except that the content of the conductive particles in 100% by volume of the layer containing the conductive particles (ACF layer) was 32% by volume during the production of the conductive film. Obtained.

(Evaluation)
(1) Distance between adjacent conductive particle bodies (distance R)
Regarding the distance between the adjacent conductive particle bodies, any conductive particles in the obtained conductive film are observed by a scanning electron microscope (SEM), and the distance R in 50 arbitrary conductive particles is arithmetically averaged. Calculated by

(2) Area (occupancy rate) of a portion where the conductive particle main body is arranged occupying 100% of the total area of the conductive film when the conductive film is viewed in plan
The occupancy rate was calculated by observing an arbitrary place on the obtained conductive film with a scanning electron microscope (SEM) and arithmetically averaging the percentage of the projected area of the conductive particle main body to 100% of the total area of the conductive film.

(3) Conduction reliability (between upper and lower electrodes)
The connection resistances between the upper and lower electrodes of the obtained 20 connection structures were measured by the 4-terminal method. From the relationship of voltage=current×resistance, the connection resistance can be obtained by measuring the voltage when a constant current is applied. The continuity reliability was judged according to the following criteria.

[Criteria for continuity reliability]
○ ○ ○: Connection resistance is 1.5Ω or less ○ ○: Connection resistance is more than 1.5Ω and 2Ω or less ○: Connection resistance is more than 2Ω and 5Ω or less △: Connection resistance is more than 5Ω and 10Ω or less ×: Connection resistance exceeds 10Ω and 15Ω or less XX: Connection resistance exceeds 15Ω

(4) Insulation reliability (between laterally adjacent electrodes)
In the 20 connection structures obtained in the above (3) Evaluation of conduction reliability, the presence or absence of leakage between adjacent electrodes was evaluated by measuring the resistance value with a tester. The insulation reliability was evaluated according to the following criteria.

[Criteria for insulation reliability]
○○○: number of resistance 10 ⁸ Omega more connections structures, 20 ○○: the number of the resistance value is 10 ⁸ Omega more connections structures, less than 20 18 or more ○: resistance the number of 10 ⁸ Omega more connection structure is less than 15 or more 18 △: number of resistance 10 ⁸ Omega more connections structures, 10 or more 15 than ×: resistance 10 ⁸ Omega more Less than 10 connection structures

The results are shown in Tables 1 to 4 below.

1, 1A, 1B, 1C, 1D... Conductive particles 1Aa, 1Ba, 1Ca, 1Da... Protrusions 2, 2A, 2B, 2C... Conductive particle body 3... Insulating particles 3D... Insulating layer 3Da... Protrusion 11... Base material Particles 12, 12A, 12B... Conductive portion 12Aa, 12Ba, 12Ca... Protrusion 12BA... First conductive portion 12BB... Second conductive portion 12BAa, 12BBa... Protrusion 13... Core substance 21, 21A... Conductive film 22... Conductive particle Layers 23, 24 containing layers 23 containing no conductive particles 51 Connection structure 52 First connection target member 52a First electrode 53 Second connection target member 53a Second electrode 54 Connection Department

Claims (7)

A conductive film containing a plurality of conductive particles and a binder resin,
The conductive particles include a conductive particle body having a conductive portion, and an insulating portion arranged on the surface of the conductive particle body,
The conductive film has a layer containing the conductive particles, and a layer not containing the conductive particles,
A conductive film in which the content of the conductive particles is 60% by volume or more and 80% by volume or less in 100% by volume of the layer containing the conductive particles. The conductive film according to claim 1, wherein the content of the conductive particles is 5% by volume or more and 80% by volume or less in 100% by volume of the conductive film. The conductive film according to claim 1, wherein a ratio of a distance between the adjacent conductive particle main bodies to a particle diameter of the conductive particle main body is 1/30 or more and 1/1 or less. The area of the portion in which the conductive particle main body is arranged occupying 100% of the total area of the conductive film when viewed in plan is 40% or more, according to any one of claims 1 to 3. The conductive film described. The insulating portion is an insulating layer,
The conductive film according to claim 1, wherein the insulating layer is arranged on the surface of the conductive particle body. The insulating portion is an insulating particle,
The conductive film according to claim 1, wherein the plurality of insulating particles are arranged on the surface of the conductive particle body. A first connection target member having a first electrode on the surface;
A second connection target member having a second electrode on the surface;
The first connection target member, and a connection portion connecting the second connection target member,
The material of the connecting portion is the conductive film according to any one of claims 1 to 6,
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive portion of the conductive particle.

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