TW201840418A - Resin composition, method for producing resin composition, and structure - Google Patents

Abstract

Provided are: an anisotropic conductive adhesive in which conductive particles are able to be dispersed by a simple method, and which is capable of suppressing short-circuit between electrode terminals of an electronic component; a method for producing an anisotropic conductive adhesive; and a connection structure. An anisotropic conductive adhesive according to the present invention contains: covered conductive particles, each of which is obtained by covering a part of the surface of a conductive particle with an insulating filler; an insulating filler; and an insulating binder. The covered conductive particles are dispersed in the insulating binder; each one of the conductive particles has a particle diameter of 7 [mu]m or more; the particle diameter of the insulating filler is 0.02-0.143% of the particle diameters of the conductive particles; and the amount of the insulating filler relative to the conductive particles is 0.78-77% by volume.

Description

   Resin composition, method for producing resin composition, and structure   

The present technology relates to a resin composition, a method for manufacturing the resin composition, and a structure. This case is based on the patent application number filed in Japan on March 6, 2017: Japanese Patent Application No. 2017-042220, which claims priority, and refers to this application for reference in this case.

In a resin composition containing particles, high dispersibility is required for the particles due to various factors such as a decrease in performance due to aggregation (for example, refer to Patent Document 1). This requirement is particularly strong for resin components for electronic parts, adhesives for electronic parts, and the like. This is because when the dispersibility of the particles is low, it is difficult to maintain the quality stability of the resin composition.

As an example of an adhesive for electronic parts, there is a circuit connection material, and the anisotropic conductive adhesive is generally one in which conductive particles are dispersed in an insulating adhesive (for example, refer to Patent Documents 2 to 4). However, the conductive particles in the anisotropic conductive adhesive may agglomerate even when they are in a dispersed state immediately after production. Condensation of conductive particles causes a reduction in the capture efficiency of conductive particles, and a short circuit between electrode terminals of electronic parts. Therefore, an insulating film may be formed in advance on the surface of the conductive particles (for example, refer to Patent Document 2).

However, if an insulating coating is formed on the surface of the conductive particles, the manufacturing cost tends to increase. In particular, the larger the particle size of the conductive particles is, the larger the surface area of the conductive particles is, and the difficulty of the technology for forming an insulating coating on the surface of the conductive particles is also increased, and the manufacturing cost tends to increase. Therefore, even when the particle size of the conductive particles is large, it is required to disperse the conductive particles uniformly by a simple method, and to suppress short circuits between the electrode terminals of electronic parts.

Moreover, even when the particle diameter of the particles dispersed in the insulating adhesive is small, it is required that the particles can be uniformly dispersed.

[Prior technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-134887

[Patent Document 2] Japanese Patent Laid-Open No. 2015-133301

[Patent Document 3] Japanese Patent Laid-Open No. 2014-241281

[Patent Document 4] Japanese Unexamined Patent Publication No. 11-148063

In addition, the present technology has been proposed in view of such a past actual situation, and provides a resin composition, a method for producing a resin composition, and a structure which can uniformly disperse particles by a simple method.

In the case of an anisotropic conductive adhesive, even if the particle size of the conductive particles is large, a simple method can be used to uniformly disperse the conductive particles, and the short circuit between the electrode terminals of electronic parts can be suppressed. Anisotropic conductive adhesive, manufacturing method of anisotropic conductive adhesive, and connection structure.

The resin composition of the present technology includes a coated large-diameter particle, a small-diameter filler, and an insulating adhesive partly covered with a small-diameter filler on the surface of the large-diameter particle. The coated large-diameter particle is dispersed. The particle diameter is 2 μm or more, the particle diameter of the small-sized filler is 0.02 to 5.0% of the particle diameter of the large-diameter particles, and the amount of the small-sized filler relative to the large-diameter particles is less than 156% by volume.

The method for producing a resin composition of the present technology has the following steps: Step (A): a large diameter particle having an average particle diameter of 2 μm or more and a small particle diameter of 0.02 to 5.0% of the particle diameter of the large diameter particle The filler is agitated to obtain the first coated particles in which the large-diameter particles are coated with the small-diameter filler. Step (B): The first coated particles and an insulating adhesive are stirred to obtain the insulation. A resin composition in which a part of the surface of the large-diameter particle is partially coated with the second-coated particle of the small-diameter filler, and in the step (A), the resin composition with the small-diameter filler of the large-diameter particle The above-mentioned large-diameter particles and the above-mentioned small-diameter fillers are blended in an amount of less than 156% by volume. In the present invention, the expressions of particles and fillers are used separately in order to make it easier to understand the difference in size.

The anisotropic conductive adhesive of the present technology contains coated conductive particles, insulating fillers, and insulating adhesives that are partially covered with an insulating filler on the surface of the conductive particles. The coated conductive particles are dispersed in the insulating adhesive, and the conductive The particle diameter of the particles is 7 μm or more, the particle diameter of the insulating filler is 0.02 to 0.143% of the particle diameter of the conductive particles, and the amount of the insulating filler relative to the conductive particles is 0.78 to 77% by volume.

The method for producing an anisotropic conductive adhesive of the present technology includes the following steps: Step (A): Insulation of conductive particles having an average particle diameter of 7 μm or more and insulation having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles The first filler conductive particles coated with the conductive filler and the insulating filler are obtained by stirring the conductive filler. Step (B): The first coated conductive particles and the insulating adhesive are stirred to obtain the above. In the insulating adhesive, an anisotropic conductive adhesive having a part of the surface of the conductive particles covered by the insulating filler and anisotropic conductive adhesive of the second coated conductive particles is used in the step (A) to provide the insulating property with respect to the conductive particles. The conductive particles and the insulating filler are blended so that the amount of the filler becomes 0.78 to 77% by volume.

The connection structure of the present technology connects a first electronic component and a second electronic component through an anisotropic conductive film composed of the anisotropic conductive adhesive.

According to the present technology, by forming a "partially coated particle" in which a part of the surface of the large-diameter particle is covered with a small-size filler, the large-diameter particle can be uniformly dispersed.

According to this technology, even when the particle size of the conductive particles is large, the conductive particles (coated conductive particles that are part of the surface of the conductive particles covered with an insulating filler) can be uniformly dispersed in a simple manner, and the electronic components can be suppressed. Short circuit between electrode terminals.

1‧‧‧ connect structure

2‧‧‧Anisotropic conductive film

3‧‧‧ conductive particles

4‧‧‧The first terminal row

5‧‧‧The first electronic part

6‧‧‧ 2nd terminal row

7‧‧‧ 2nd electronic part

10‧‧‧ 1st coated conductive particle

11‧‧‧ 2nd coated conductive particle

12‧‧‧ conductive particles

13‧‧‧ coated conductive particles

20‧‧‧ partially covered particles

21‧‧‧large diameter particles

22‧‧‧ Covered Department

23‧‧‧ exposed

FIG. 1 is a cross-sectional view showing an example of a connection structure according to this embodiment.

FIG. 2 is a diagram showing an example of a mixture obtained by stirring conductive particles and an insulating filler.

FIG. 3 is a diagram showing an example of an anisotropic conductive adhesive obtained by stirring the coated conductive particles coated with an insulating filler and an insulating adhesive.

Fig. 4 is a view showing conductive particles not covered with an insulating filler.

FIG. 5 is a diagram showing an example of an anisotropic conductive adhesive obtained by stirring conductive particles and an insulating adhesive that are not covered with an insulating filler.

FIG. 6 is a diagram showing an example of a mixture obtained by stirring conductive particles and an insulating filler.

FIG. 7 is a cross-sectional view schematically showing a first example of partially coated particles to which the present technology is applied.

FIG. 8 is a cross-sectional view schematically showing a second example of partially coated particles to which the present technology is applied.

FIG. 9 is a cross-sectional view schematically showing a third example of partially coated particles to which the present technology is applied.

This technology improves the dispersibility of large-diameter particles in an insulating adhesive by forming partially-coated particles whose surface is partially covered with a small-diameter filler. On the other hand, when the surface of the large-diameter particles is entirely covered with a small-diameter filler, the amount of the small-diameter filler relative to the large-diameter particles becomes excessive, and there is a risk of large-diameter particles in the insulating adhesive. Dispersion tends to decrease.

Partially coated particles can be obtained by mixing large-diameter particles with powder of small-size filler (preferably only mixing these), and coating the surface of large-diameter particles with small-size filler, This mixture is mixed (kneaded) with the resin composition, thereby peeling off the small-sized filler that covers a part of the surface of the large-diameter particles. In other words, if the partially coated particles are formed, the amount of the small-diameter filler relative to the large-diameter particles is an appropriate amount, and the large-diameter particles in the insulating adhesive have high dispersibility. This can be performed, for example, by using a planetary stirring device and applying high shear (shearing force), thereby efficiently coating and partially peeling the small-diameter filler on the surface of large-diameter particles.

The first embodiment will be described below.

[First Embodiment]

<Resin composition>

The resin composition of this embodiment contains a part of the surface of a large-diameter particle partially covered with a small-sized filler, a partially-coated particle, a small-sized filler, and an insulating adhesive. The partially-coated particle is dispersed and has a large diameter. The particle diameter of the particles is 2 μm or more, the particle diameter of the small particle filler is 0.02 to 5.0% of the particle diameter of the large diameter particle, and the amount of the small particle filler relative to the large diameter particle is less than 155% by volume. In addition, such a description of 0.02 to 5.0% means 0.02% to 5.0% unless otherwise specified.

In this specification, the particle diameter of the large-diameter particles may be a value measured by an image-type particle size analyzer (for example, FPIA-3000: manufactured by malvern). The number is preferably 1,000 or more, and more preferably 2000 or more. In addition, the particle diameter of the small-particle-size filler can be observed with an electron microscope, for example, and the particle diameter can be an average value of any 100 particles, and can also be 200 or more, thereby further improving accuracy.

The amount (vol%) of the small-diameter filler relative to the large-diameter particles can be a value obtained by the following formula.

Amount of small-diameter filler (B) relative to large-diameter particles (A) (volume%) = ((Bw / Bd) / (Aw / Ad)) × 100

Aw: Mass composition (mass%) of large diameter particles (A)

Bw: mass composition of small particle size filler (B) (mass%)

Ad: Specific gravity of large diameter particles (A)

Bd: Specific gravity of small particle size filler (B)

7 to 9 are cross-sectional views schematically showing the first to third examples of partially coated particles to which the present technology is applied, respectively. As shown in FIG. 7 to FIG. 9, a part of the surface of the partially-coated particles 20 is covered with a small-diameter filler. In other words, the partially-coated particle 20 has a coating portion 22 covered with a small-diameter filler on its surface and an exposed portion 23 exposing the surface of the large-diameter particle. The partially-coated particles 20 may be, for example, as shown in FIG. 7, and the exposed portion 23 is located on the surface in a mottled shape as a whole, or as shown in FIG. 8, the exposed portion 23 is located on a part, or may be exposed as shown in FIG. 9. The part 23 accounts for more than one half of the whole. The reason is that it is for the purpose of "easily obtaining the dispersibility of the large-diameter particles partially covered by this method" as a first purpose, rather than to give priority to the performance of large-diameter particles in the coating state.

After the partially-coated particles 20 are formed into a film form in the resin composition, they may be partially covered when they are observed through a surface viewing area such as an electron microscope. In this regard, it is preferable that the same result can be obtained by changing the observation site multiple times. In the case of confirming in detail, it can be confirmed that at least a part of the outermost surface is covered in the cross section of the partially covered particles 20. In addition, by observing the same part on the front and back surfaces of the film body to be observed, it is possible to confirm more precisely and easily. If this is the method, it can be distinguished only by judging whether or not a part of the large-diameter particles is covered. The judgment when the peeled small-size filler overlaps with the large-diameter particles can also be judged individually by adjusting the focal distance.

The proportion of the coating portion 22 in the partially-coated particles 20 can be confirmed by, for example, observing the surface of an area using an electron microscope after the resin composition is formed into a film. Alternatively, the resin composition can be hardened or frozen, and the outermost surface of the cross section of any 100 partially coated particles can be observed with an electron microscope to make it the average value of the proportions of the coated portions of any 100 partially coated particles. The average value of the proportion of the coated part of such partially coated particles may be, for example, 15% or more and less than 100%, and may also be 30 to 95%.

In addition, the proportion of the number of partially-coated particles 20 is 70% or more, preferably 80% or more, and more preferably 95% or more, relative to the entirety of the completely-coated particles and the partially-coated particles. The proportion of the number of partially-coated particles 20 can, for example, harden or freeze the resin composition. Observe any 100 fully-coated particles and partially-coated particles with an electron microscope. Number of coated particles and partially coated particles.

The large-diameter particles are not particularly limited, and the material can be appropriately selected according to the function of the resin composition. For example, when the resin composition is provided with conductivity, for example, conductive particles and metal particles may be selected, and when the resin composition is provided with a spacer function, for example, acrylic rubber, styrene rubber, and benzene may be selected. Ethylene-olefin rubber, silicone rubber, etc. If it can be coated and partially coated with a combination of a filler with a small particle size, it is not particularly limited, and may be an organic substance, an inorganic substance, or a combination of an organic substance and an inorganic substance like metal-plated resin particles. They can be used alone or in combination of two or more. If it is a single type, the evaluation of dispersibility will become easy. In the case of two or more kinds, for the same reason, it is preferable that the appearance is significantly different.

The particle diameter of the large-diameter particles is 2 μm or more. The upper limit of the particle diameter of the large-diameter particles is not particularly limited. For example, when the large-diameter particles are conductive particles, from the viewpoint of the capture efficiency of the conductive particles in the connection structure, it is preferably 50 μm or less, for example. It is preferably 20 μm or less.

The number density of large-diameter particles in the resin composition can be appropriately adjusted according to the purpose, but the lower limit is preferably 20 particles / mm ² or more, more preferably 100 particles / mm ² or more, and even more preferably 150 particles / mm. ² or more. The reason is that when there is too little, the margin for adjusting the ratio to the filler with a small particle diameter becomes small, and reproducibility becomes difficult. The upper limit is preferably 80,000 pieces / mm ² or less, more preferably 70,000 pieces / mm ² or less, and even more preferably 65,000 pieces / mm ² or less. If the number density of large-diameter particles becomes too large, it becomes difficult to "coat a small-size filler" or "mix with a resin composition". The number density can be formed into a film on the smooth surface of the support, and can be obtained from the observation of the surface view. The thickness at this time may be 1.3 times or more than 10 μm of the large diameter particles, and the upper limit may be 4 times or less (preferably 2 times) or 40 μm or less of the large diameter particles. Since this thickness is derived from the resin composition, it is difficult to clearly define the thickness, so the range is set in this manner. Observation of the surface area can be performed using an electron microscope such as a metallographic microscope and an SEM. It can be obtained by measuring each large-diameter particle from the observation image, or it can be calculated by using a well-known image analysis software (for example, WinROOF (Mitani Corporation)). In the case of a resin composition, the thickness may vary depending on the thickness of the film. Therefore, it can be specified by the density of the surface viewing area, which is 1.3 times or 4 times the thickness of a large-diameter particle. When a solvent is contained, the thickness is after drying.

Most of the small-diameter fillers are dispersed in the insulating adhesive, and part of them cover a part of the surface of the large-diameter particles. As the small particle diameter filler, an insulating filler can be used. Examples of the insulating filler include oxides such as titanium oxide, aluminum oxide, silicon dioxide, calcium oxide, and magnesium oxide, hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide, calcium carbonate, magnesium carbonate, Carbonates such as zinc carbonate and barium carbonate, sulfates such as calcium sulfate and barium sulfate, silicates such as calcium silicate, nitrides such as aluminum nitride, boron nitride, and silicon nitride. The insulating fillers may be used singly or in combination of two or more kinds.

The upper limit of the particle size of the small-diameter filler may be 14% or less of the large-diameter particles, and preferably 0.3% or less. Or it is preferably 100 nm or less, and more preferably 50 nm or less. By making the small-diameter filler not too large by the surface area with respect to the large-diameter particles, it is possible to suppress the occurrence of defects such as damage to the surface of the large-diameter particles. The lower limit of the particle size of the small-particle-size filler is preferably 10 nm or more. By making the small-diameter filler not too small by the surface area relative to the large-diameter particles, the aggregation of the large-diameter particles can be more effectively suppressed. When the viscosity is too small, the viscosity of the resin composition may be excessively increased, and thus the effect on the dispersibility may be worried.

From the relationship between the size of the large-diameter particles and the small-diameter filler described above, the ratio of the particle diameter of the large-diameter particles to the small-diameter filler (the particle diameter of the small-diameter filler / the diameter of the large-diameter particles) is 0.02 to 5.0 %, Preferably 0.02 to 2.5%.

In addition, the volume ratio of the small-diameter filler that satisfies the above-mentioned particle diameter ratio to the large-diameter particles is less than 156% by volume. If it exceeds 156% by volume, it will be difficult to uniformly disperse in the resin. In addition, the lower limit value naturally exceeds 0%. However, in addition to the ratio of the sizes of the large-diameter particles and the small-diameter filler, these shapes and the like are also related, so it is difficult to clearly define them. However, if it is 0.78% or more, there is no particular problem, if it is 3.9% or more, it is preferable, and if it is 7.8% or more, it is more preferable. The upper limit value is preferably 78% by volume or less, and more preferably 39% or less. In addition, these values can be appropriately selected from the relationship between large-diameter particles and small-diameter fillers. By satisfying such conditions, the dispersibility of large-diameter particles can be made good.

As the insulating adhesive (insulating resin), a known insulating adhesive can be used. Examples of the curing type include a thermosetting type, a photocuring type, and a photothermal combination curing type. Examples include a photo radical polymerization type resin containing a (meth) acrylate compound and a photo radical polymerization initiator, and a thermal radical polymerization containing a (meth) acrylate compound and a thermal radical polymerization initiator. Type resin, thermal cationic polymerization type resin containing an epoxy compound and a thermal cationic polymerization initiator, thermal anionic polymerization type resin containing an epoxy compound and a thermal anionic polymerization initiator, and the like. Moreover, a well-known adhesive composition can also be used.

The resin composition may further contain components other than the partially-coated particles, a small-particle-size filler, and an insulating adhesive, as necessary. Examples of the other components include a solvent (such as methyl ethyl ketone, toluene, propylene glycol monomethyl ether acetate, etc.), a stress relaxation agent, and a silane coupling agent.

As mentioned above, the resin composition has a particle diameter of large diameter particles of 2 μm or more, and the particle diameter of the small particle filler is 0.02 to 5.0% of the particle diameter of the large diameter particle. It has a high dispersibility of 156% by volume.

In addition, for example, when the resin composition is made to function as a spacer between the first member and the second member, the amount of the small-diameter filler adhered to the large-diameter particles is small, so that they can be formed into large-diameter particles. Spacer of about diameter. In addition, for example, when the resin composition is made of an anisotropic conductive adhesive in which large-diameter particles are conductive particles and small-diameter fillers are insulating fillers, the amount of the insulating fillers attached to the conductive particles is small. Therefore, excellent continuity can be obtained.

In addition, for example, when a resin composition is made into an anisotropic conductive film composed of an anisotropic conductive adhesive and large-diameter particles are conductive particles, and a small-diameter filler is an insulating filler, the dispersibility of the conductive particles Very high, so "the number density of conductive particles in the anisotropic conductive film as a whole (number / mm ² )" and "the conductive particles in the 0.2 mm × 0.2 mm area arbitrarily selected from the anisotropic conductive film" The difference between the number density (number / mm ² ) "is 15% or less. Here, the difference in the number density is the difference between the maximum value and the minimum value of the number density of the conductive particles in the arbitrarily selected predetermined area.

<Manufacturing method of resin composition>

The method for producing a resin composition according to this embodiment includes the following steps (A) and (B).

[Step (A)]

In step (A), the first coated particles are obtained by agitating the large-diameter particles and the small-diameter fillers having small diameter particles. In step (A), in order to suppress aggregation of the second coated particles obtained in step (B), large-diameter particles are coated with a small-diameter filler. In step (A), as described above, the large-diameter particles and the small-diameter filler are blended in such a manner that the amount of the small-diameter filler relative to the large-diameter particles does not reach 156% by volume. By satisfying such conditions, the small-diameter filler can be easily coated on the surface of the large-diameter particles in step (A), and the small-diameter filler in the first coated particles can be easily separated in step (B). .

The method for stirring the large-diameter particles and the small-diameter filler may be a dry method or a wet method, and a dry method is preferred. The reason for this is that a well-known method such as toner is applicable. The device for stirring the large-diameter particles and the small-diameter filler may include, for example, a planetary stirring device, an oscillator, a laboratory mixer, a stirring propeller, and the like. In particular, from the viewpoint of coating large-diameter particles having a relatively large average particle diameter with an insulating filler, a planetary agitating device applying high shear is preferred. Although the method of using a medium such as a ball mill or a beads mill is not excluded, it is not good. The reason for this is that if there are those to be removed in addition to the large-diameter particles and the small-diameter filler, it is less desirable in terms of productivity. In addition, if such a medium (spherical or bead) is used, factors that affect the surface state of large-diameter particles or small-diameter fillers will be increased, making product design difficult. Planetary stirring device refers to a stirring device that rotates a container containing a material (a mixture of large-diameter particles and small-size fillers) and orbits it at the same time. In the case of batch production in each container, quality control is easy, and it is also preferable from this point of view. That is, a resin composition in which large-diameter particles and small-diameter fillers are dispersed can be easily obtained with high accuracy.

The preferable ranges of the large-diameter particles and the small-diameter filler are the same as those of the large-diameter particles and the small-diameter filler described in the above-mentioned anisotropic conductive adhesive. Especially from the viewpoint of coating large-diameter particles with a small-diameter filler in step (A), it is preferable to use large-diameter particles in a dry powder state.

[Step (B)]

In step (B), by stirring the first coated particles and the insulating adhesive, the second coated particles and the small-sized filler separated from the large-diameter particles in the first coated particles are dispersed in the insulating adhesive. Resin composition.

In step (B), by stirring the first coated particles in the insulating adhesive, the small-sized filler in the first coated particles is subjected to friction or high shear with the large-diameter particles, thereby making the small-sized particles smaller. The filler is separated from the large-diameter particle, and a part of the surface of the large-diameter particle that is partially covered with the small-diameter filler is covered with particles (second coated particles). In addition, since the small-diameter filler separated from the large-diameter particles in the first coated particles is interposed between the second coated particles, aggregation of the second coated particles can be suppressed. In this way, by performing step (B), aggregation of the second coated particles can be suppressed, and the second coated particles can be dispersed in the insulating adhesive. At this time, the small particle size filler is also dispersed at the same time. That is, in the present invention, the mixing step only needs to be performed a minimum number of times. For example, although it is possible to add a filler with a small particle size every time in order to adjust the viscosity as in the past, it can be easily expected that it will be difficult to obtain the reproducibility of the dispersed state. However, by adjusting the powder (large-diameter particles and small-diameter fillers) in advance and blending the resin composition with it, the required amount can be adjusted. Therefore, from the aspect of material cost or manufacturing cost, More ideal. In addition, because batches with decentralized bad conditions are also easy to compare, analysis of bad factors will also become easy, as described above, which has advantages even in terms of quality management. In addition, in the case of a batch system, there are advantages such as fewer factors to be examined when transferring from a small amount of development research to a large number of manufacturing. For the same reason, it is also preferable to perform steps (A) and (B) using the same container and the same planetary stirring device in terms of productivity or quality control. It is expected that the effects of pollution will also be suppressed. In the case of mass production, it is sufficient to add the same device. That is, it can respond to a small number of varieties, and it can also respond to scale up. Therefore, the adjustment of production management will become easier.

In addition, regarding "covering the surface of a large-diameter filler with a sufficiently small-diameter filler", as described later, anisotropic conductive connection, when the terminals are sandwiched by conductive particles of large-diameter particles, the surface of the conductive particles is maintained The quality of the state is preferable. That is, a function that covers the irregularity of the surface state generated by the large-diameter particles in contact with each other by covering the small-diameter filler therebetween can be expected. In addition, because the degree of coating can be eliminated by mixing (kneading), it is considered that if direct force such as being held between terminals is applied to large-diameter particles, the partial coating does not hinder conduction. In addition, the insulation between the terminal arrays is also considered to be a state in which large-diameter particles maintain high dispersibility, but at the same time maintain partial coverage, so short circuits (caused by the connection of large-diameter particles) can be easily avoided. If specific effects are exemplified, when the large-diameter particles are conductive particles of metal-plated resin particles, the thickness and material of metal plating, the hardness of resin particles, and the like can be expected to be selected from a wider range than in the past. The same effect can be obtained when the user is clamped like a spacer.

The method for stirring the first coated particles and the insulating adhesive is not particularly limited, and the stirring method in the step (A) described above can be adopted. In particular, from the viewpoint of separating the small-size filler constituting the first coated particles when the first coated particles and the insulating adhesive are stirred, a stirring method using high shear is preferred, such as a stirring method using a planetary stirring device. By using a planetary agitation device, in the insulating adhesive, the small-size filler is caused on the first-coated particles due to friction or application of high shear between the large-diameter particles and the small-size filler in the first-coated particles. Moderate separation from large diameter particles.

According to the production method having the above steps (A) and (B), a resin composition in which the second coating particles are dispersed in the insulating adhesive can be obtained by a simple method. In addition, the manufacturing method may further include steps other than the above-mentioned steps (A) and (B), if necessary. In addition, as described above, from the viewpoint of productivity or quality, it is preferable to perform steps (A) and (B) using the same container and the same device (planetary stirring type mixing device).

<Structure>

The structure of this embodiment is a structure in which the first member and the second member are connected through the resin composition. If the resin composition is a curable resin, it can be hardened and fixed, and if it is an adhesive, it can be stuck only. This is an example. For example, a mold can be filled with a resin composition and hardened to obtain a molded body. For example, when the resin composition functions as a spacer between the first member and the second member, the amount of the small-diameter filler adhered to the large-diameter particles is small, so that it can be formed as approximately the same as the large-diameter particles. Diameter spacers. In addition, for example, when the resin composition is made into a conductive adhesive with large-diameter particles as conductive particles and a small-sized filler as an insulating filler, the amount of the insulating filler adhered to the conductive particles is small, so it can be obtained. Excellent continuity. When an anisotropic conductive adhesive is made, the effect of the terminal and the arrangement of the terminals is more complicated, so this effect can be exerted more. In addition, these can also be made into a membrane body in advance.

The present invention also includes a structure in which a first article and a second article are connected using a resin composition as an adhesive or a film, and a method for producing the same. These articles may be electronic parts, and may be provided with a conductive portion and need not be anisotropic, but are not limited thereto. Regardless of the presence or absence of adhesiveness of the resin composition, a person who adheres the first article to the second article or a method for attaching the same is also included in the present invention. That is, it is the bonding body of the 1st article and the 2nd article, or the bonding method which pressurized these. Moreover, it is also included in this invention that the resin composition or its film | membrane is provided only in the 1st article. This can be applied or bonded to the first article in the form of a film. If the resin composition is an adhesive body, an adhesive layer is formed. An adhesive film can also be formed by being formed on a support.

The second embodiment will be described below.

[Second Embodiment]

<Anisotropic conductive adhesive>

The anisotropic conductive adhesive according to this embodiment includes a coated conductive particle (a second coated conductive particle described later), a conductive filler and an insulating adhesive, which are partially covered with a conductive filler on the surface of the conductive particle. The coated conductive particle is dispersed In an insulating adhesive. In addition, in the following description, a coated conductive particle covered with a conductive filler and obtained by stirring conductive particles having an average particle diameter of 7 μm or more and an insulating filler is referred to as a “first coated conductive particle”. In addition, a coated conductive particle whose part of the surface of the conductive particle obtained by stirring the first coated conductive particle and the insulating adhesive is covered with an insulating filler is referred to as a "second coated conductive particle".

The anisotropic conductive adhesive may be any of a film-shaped anisotropic conductive film (ACF: Anisotropic Conductive Film) or a paste-shaped anisotropic conductive paste (ACP: Anisotropic Conductive Paste). In terms of ease of handling, an anisotropic conductive film is preferred, and in terms of cost, an anisotropic conductive paste is preferred.

Hereinafter, the second coated conductive particles (conductive particles, insulating filler), the insulating adhesive, and other components that may be included in the anisotropic conductive adhesive are described.

[Conductive particles]

The material of the conductive particles is not particularly limited. Examples thereof include metal particles such as nickel, copper, gold, silver, and palladium, and metal-coated resin particles whose surfaces are coated with metal. As the resin particles in the metal-coated resin particles, for example, epoxy resin, phenol resin, acrylic resin, acrylonitrile-styrene resin, and benzoguanidine can be used. Particles of (benzoguanamine) resin, divinylbenzene resin, and styrene resin. The conductive particles may be used alone or in combination of two or more.

The particle diameter of the conductive particles is 7 μm or more. The upper limit of the particle diameter of the conductive particles is not particularly limited, but from the viewpoint of the capture efficiency of the conductive particles in the connection structure, it is preferably, for example, 50 μm or less. The particle size of the conductive particles can be measured by an image-type particle size analyzer (for example, FPIA-3000: manufactured by malvern). Should be measured more than 1,000 (preferably more than 2000) to obtain.

[Insulating filler]

As the insulating filler, insulating inorganic particles can be used. Examples include oxides such as titanium oxide, aluminum oxide, silicon dioxide, calcium oxide, and magnesium oxide; hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; calcium carbonate, magnesium carbonate, zinc carbonate, and barium carbonate Other carbonates, sulfates such as calcium sulfate and barium sulfate, silicates such as calcium silicate, nitrides such as aluminum nitride, boron nitride, and silicon nitride. The insulating fillers may be used singly or in combination of two or more kinds.

Regarding the size (particle diameter) relationship between the conductive particles and the insulating filler, by making the insulating filler significantly smaller than the surface area of the conductive particles, coating and separation of the conductive filler on the surface of the conductive particles can be easily performed. Therefore, if the first coated conductive particles are stirred in the insulating adhesive, the insulating filler separated from the conductive particles in the first coated conductive particles will be interposed between the second coated conductive particles, so that the second coating can be suppressed. Conductive particles condense. Therefore, the second coated conductive particles can be uniformly dispersed in the insulating adhesive.

Specifically, the upper limit of the particle diameter of the insulating filler is preferably 1,000 nm or less, and more preferably 50 nm or less. By making the surface area of the insulating filler with respect to the conductive particles not too large, it is possible to suppress defects such as damage to the surface of the conductive particles. The lower limit of the particle size of the insulating filler is preferably 10 nm or more. When the surface area of the insulating filler with respect to the conductive particles is not too small, it is possible to more effectively suppress the aggregation of the conductive particles. The particle diameter of the insulating filler can be obtained from the observation results of an electron microscope and the like.

From the size relationship between the conductive particles and the insulating filler described above, the ratio of the particle diameter of the conductive particles to the insulating filler (particle diameter of the insulating filler / particle diameter of the conductive particles) is preferably 0.02 to 0.143%, 0.02 to 0.10 %.

In addition, the ratio of the number of the insulating fillers to the conductive particles satisfying the particle size ratio, that is, the amount of the insulating fillers to one conductive particle is 0.78 to 77% by volume, and preferably 3.9 to 38.7% by volume. , More preferably 7.7 to 15.5 vol%. By satisfying such conditions, the dispersibility of the conductive particles can be made good.

[Insulating adhesive]

As the insulating adhesive (insulating resin), an insulating adhesive used for a well-known anisotropic conductive adhesive can be used. Examples of the curing type include a thermosetting type, a photocuring type, and a photothermal combination curing type. Examples include a photoradical polymerization type resin containing a (meth) acrylate compound and a photoradical polymerization initiator, and a thermal radical polymerization type containing a (meth) acrylate compound and a thermal radical polymerization initiator. Resin, thermal cationic polymerization type resin containing an epoxy compound and a thermal cationic polymerization initiator, thermal anionic polymerization type resin containing an epoxy compound and a thermal anionic polymerization initiator, and the like.

Hereinafter, a thermal anionic polymerizable insulating adhesive containing a film-forming resin, an epoxy resin, and a latent curing agent will be described as a specific example.

The film-forming resin is preferably a resin having an average molecular weight of about 10,000 to 80,000. Examples of the film-forming resin include various resins such as epoxy resin, modified epoxy resin, urethane resin, and phenoxy resin. Among these, a phenoxy resin is preferable from a viewpoint of a film formation state, connection reliability, and the like. The film-forming resin may be used singly or in combination of two or more kinds.

The epoxy resin is not particularly limited, and examples thereof include a naphthalene-type epoxy resin, a biphenyl-type epoxy resin, a phenol novolac-type epoxy resin, a bisphenol-type epoxy resin, a fluorene-type epoxy resin, and triphenol methane. (triphenolmethane) type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, sesquicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, and the like. An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

Examples of the latent curing agent include imidazole-based, hydrazine-based, amine imide, dicyandiamide, antimony-based, phosphorus-based, and fluorine-based acid generators. These can be used alone or in combination of two or more. Among these, a microcapsule type in which the surface of the imidazole compound particles is coated with a polymer-based polymer such as a polyurethane system or a polyester system is suitable. Further, a masterbatch-type curing agent in which a microcapsule-type curing agent is dispersed in a liquid epoxy resin may be used.

[Other ingredients]

The anisotropic conductive adhesive may further contain components other than the second-coated conductive particles and the insulating adhesive, if necessary. Examples of the other components include solvents (such as methyl ethyl ketone, toluene, and propylene glycol monomethyl ether acetate), stress relieving agents, and silane coupling agents. The anisotropic conductive adhesive may further contain an insulating filler separated from the conductive particles in the first coated conductive particles.

As described above, the particle size of the conductive particles of the anisotropic conductive adhesive is 7 μm or more, the particle size of the insulating filler is 0.02 to 0.143% of the particle size of the conductive particles, and the amount of the insulating filler relative to the conductive particles is 0.78. ~ 77% by volume. When the first coated conductive particles are stirred in the insulating adhesive, they are separated from the conductive particles in the first coated conductive particles. Therefore, the second coated conductive particles in which the coated insulating filler remains on the particle surface may be obtained. Such a remaining state can be confirmed by a well-known observation method (SEM, TEM or other electron microscope). The existence of such an insulating filler and the dispersed state of the conductive particles can be used to confirm whether they are obtained by the method of the present invention.

The anisotropic conductive adhesive is capable of suppressing the aggregation of the second coated conductive particles because the insulating filler separated from the conductive particles in the first coated conductive particles is interposed between the second coated conductive particles. Therefore, the second coated conductive particles can be dispersed in the insulating adhesive, and a short circuit between the electrode terminals of the electronic component can be suppressed. In addition, the anisotropic conductive adhesive is uniformly present in the vicinity of the second coated conductive particles in the insulating adhesive at a certain ratio, and the electric conduction from the first coated conductive particles is caused by stirring the first coated conductive particles and the insulating adhesive. Particle-separated insulating filler. In such an anisotropic conductive adhesive, the "dispersed state of the second coated conductive particles" and the "region where the insulating filler exists" show a high correlation, and the capture rate of the conductive particles can be stabilized.

Furthermore, in the present technology, a relatively large conductive particle having a thickness of 7 μm or more is simply coated with an insulating filler, and then separated while being kneaded with an insulating adhesive, so that the surface of the conductive particle (conductive Layer) by applying an insulation treatment, a sufficient short-circuit suppression effect can also be obtained. That is, traces of the insulation treatment will disappear except for the insulating filler which remains in the conductive layer of the conductive particles in a small amount without separation. Therefore, the conductive particles are excellent in rationality and advantageous in cost. Also when designing anisotropic conductive adhesives, there are also advantages in development due to fewer parameters. In addition, it is also possible to use conductive particles which have been subjected to insulation treatment in a known manner in advance, thereby improving performance or increasing design freedom by using conductive particles having more excellent insulation properties. Therefore, the present technology does not exclude the use of "a person who has previously applied an insulating treatment to the surface of a conductive particle (conductive layer)".

<Manufacturing method of anisotropic conductive adhesive>

The method for producing an anisotropic conductive adhesive according to this embodiment includes the following steps (A) and (B).

[Step (A)]

In step (A), the first coated conductive particles are obtained by stirring conductive particles having an average particle diameter of 7 μm or more and an insulating filler having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles. In step (A), in order to suppress the aggregation of the second coated conductive particles obtained in step (B), the conductive particles are coated with an insulating filler. In step (A), as described above, the conductive particles and the insulating filler are blended so that the amount of the insulating filler relative to the conductive particles becomes 0.78 to 77% by volume. By satisfying such conditions, the insulating filler can be easily coated on the surface of the conductive particles in step (A), and the insulating filler in the first coated conductive particles can be easily separated in step (B).

The method for stirring the conductive particles and the insulating filler may be either a dry method or a wet method, and a dry method is preferred. Devices for stirring conductive particles and insulating fillers include, for example, planetary stirring devices, oscillators, laboratory mixers, stirring propellers, and the like. In particular, from the viewpoint of coating conductive particles with a relatively large average particle diameter with an insulating filler, a planetary stirring device that applies high shear is preferred. Planetary stirring device refers to a stirring device that rotates a container containing a material (a mixture of conductive particles and an insulating filler) and revolves it at the same time.

The preferable ranges of the conductive particles and the insulating filler are the same as those of the conductive particles and the insulating filler described in the anisotropic conductive adhesive. Especially from the viewpoint of covering the conductive particles with an insulating filler in the step (A), it is preferable to use the conductive particles in a dry powder state.

[Step (B)]

In step (B), by stirring the first coated conductive particles and the insulating adhesive, the second coated conductive particles and the insulating filler separated from the conductive particles in the first coated conductive particles are dispersed in the insulating adhesive. Anisotropic conductive adhesive.

In step (B), the insulating filler in the first coated conductive particles is applied with friction or high shear to the insulating filler in the first coated conductive particles by stirring the first coated conductive particles in the insulating adhesive. The filler is separated from the conductive particles, and coated conductive particles (second coated conductive particles) having a part of the surface of the conductive particles covered with an insulating filler can be obtained. In addition, since the insulating filler separated from the conductive particles in the first coated conductive particles is interposed between the second coated conductive particles, it is possible to suppress the second coated conductive particles from agglomerating. In this way, by performing step (B), aggregation of the second coated conductive particles can be suppressed, and the second coated conductive particles can be dispersed in the insulating adhesive.

The method for stirring the first coated conductive particles and the insulating adhesive is not particularly limited, and the stirring method in the step (A) described above can be adopted. In particular, from the viewpoint of separating the insulating filler constituting the first coated conductive particles when the first coated conductive particles and the insulating adhesive are stirred, a stirring method that applies high shear is preferred, for example, stirring using a planetary stirring device method. By using a planetary stirring device, the conductive filler in the first coated conductive particles may be separated from the conductive particles in the first coated conductive particles due to friction or high shear applied to the insulating filler.

With the manufacturing method having the above steps (A) and (B), an anisotropic conductive adhesive in which the second coated conductive particles are dispersed in the insulating adhesive can be obtained by a simple method. By using this anisotropic conductive adhesive, short circuits between electrode terminals of electronic parts can be suppressed. In addition, if steps (A) and (B) are performed in the same container and the same device (planetary mixing type mixing device), both from the aspect of manufacturing man-hours and from the aspect of quality management to prevent contamination and the like Better.

In addition, the manufacturing method may further include steps other than the above-mentioned steps (A) and (B), if necessary.

<Anisotropic conductive film>

The anisotropic conductive film of this embodiment is composed of the above-mentioned anisotropic conductive adhesive, and the above-mentioned second coated conductive particles are dispersed in an adhesive layer composed of an insulating adhesive. For example, "the number density (seconds / mm ² ) of the second coated conductive particles of the entire anisotropic conductive film (for example, 1.0 mm x 1.0 mm)" and "a narrowly selected region (for example, an anisotropic conductive film) (for example, The difference between the number density of the second coated conductive particles (0.2mm × 0.2mm) (number / mm ² ) ”is preferably 15% or less, more preferably 10% or less, and still more preferably substantially the same (as (For example, within 5%). When an anisotropic conductive paste is used for connection, as an example, the same dispersibility as described above is preferably obtained. This can be confirmed by forming a layer on a smooth surface such as a support.

In this way, it was confirmed that by "the number density of the second coated conductive particles of the entire anisotropic conductive film" and "the number density of the second coated conductive particles in a narrowly selected narrow region of the anisotropic conductive film" The difference is small, and the second coated conductive particles are uniformly dispersed throughout the film. Therefore, the capture rate of the conductive particles is stable, and it is possible to suppress poor conduction or short circuit. When the second coated conductive particles are uniformly dispersed throughout the film, it has the effect of reducing the number of man-hours required for inspecting the quality of the anisotropic conductive film. The reason is that when uniformly dispersed, if there is irregular agglomeration, it will be easy to find. Therefore, especially when it is formed in a length of 10 m or more, the effect is further enhanced. In addition, if the anisotropic conductive film has a long dimension of 10 m or more (preferably 50 m or more), since the connection can be performed continuously, it also has the effect of reducing the cost of the manufacturing method of the connection structure. The upper limit of the long dimension is not particularly limited, but from the viewpoint of minimizing or improving the connection device, it is preferably 5,000 m or less, more preferably 1000 m or less, and even more preferably 600 m or less.

In addition, when the conductive particle diameter is relatively larger than 7 μm as in the present invention, the electronic parts to be connected are suitable for connection where the surface such as a ceramic substrate or the like is less smooth than the glass (the surface has undulations). In addition, relatively large conductive particles are uniformly dispersed as described above, and even if the electronic parts to be connected have undulations, the resin flow during connection is not easily affected by the capture. The reason is that when the conductive particles are agglomerated, the terminal surface that captures the conductive particles is not fixed due to the undulation, so there is a concern that the capture state of each terminal cannot be kept fixed.

The particle density of the second-coated conductive particles in the anisotropic conductive film is not particularly limited as long as it can provide both on-state reliability and short-circuit suppression. It is preferably 20 pieces / mm ² or more, and more preferably 100 pieces / mm ² or more. If the upper limit is too large, the risk of short-circuiting becomes high. As an example, it is preferably 3,000 pieces / mm ² or less, more preferably 2,000 pieces / mm ² or less, and even more preferably 1,000 pieces / mm ² or less. . These can be appropriately adjusted according to the conductive particle size and the size of the terminals to be connected. When an anisotropic conductive paste is used, it is also taken as an example, and is preferably the same as the above. This can be confirmed by forming a layer on a smooth surface such as a support.

The upper limit of the area occupancy when the second coated conductive particles in the anisotropic conductive film are viewed from the top is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less. Such a high area occupancy ratio is because the thickness of the anisotropic conductive film also depends on the ratio of the thickness to the particle diameter of the anisotropic conductive film, but the second coated conductive particles are kneaded to the insulating resin and have high uniformity. Sake. "Even with such a high area occupancy rate, the risk of a short circuit can be avoided" is one of the features of the present invention. When an anisotropic conductive paste is used for connection, as an example, the same dispersibility as described above is preferably obtained. This can be confirmed by forming a layer on a smooth surface such as a support.

The lower limit of the area occupancy of the second coated conductive particles in the anisotropic conductive film when viewed from the top depends on the ratio of the thickness and the particle diameter of the anisotropic conductive film. As an example, if it is greater than 0.2%, It can ensure the minimum continuity performance, more than 5% is better in practical use, more preferably more than 10%. When an anisotropic conductive paste is used, it is also an example, and it is preferably the same as the above. This can be confirmed by forming a layer on a smooth surface such as a support.

The area occupancy of the second coated conductive particles in the anisotropic conductive film when viewed from above can be calculated from observations using an optical microscope, a metallographic microscope, or an electron microscope such as an SEM. It can also be calculated using a well-known image analysis software (for example, WinROOF (Mitani Corporation)). The calculated area of the area occupancy ratio may be the same as an example of the area where the number density is obtained, or a larger area (for example, 2 mm × 2 mm, or 5 mm × 5 mm) may be used. When the connection is used in the form of an anisotropic conductive paste, the same dispersibility as described above is preferably obtained as an example. This can be confirmed by forming a layer on a smooth surface such as a support.

As a method of forming the anisotropic conductive film, for example, a method of forming an anisotropic conductive adhesive into a film by a coating method and drying it. For example, the lower limit of the thickness of the anisotropic conductive film may be the same as the particle diameter, and it may be preferably 1.3 times or more than 10 μm or more. For example, the upper limit may be 40 μm or less or twice the particle size. An anisotropic conductive film may be formed on the release film.

<Connection structure>

The connection structure of this embodiment connects the first electronic component and the second electronic component through the anisotropic conductive film described above. For example, as shown in FIG. 1, the connection structure 1 passes through the conductive particles (second coated conductive particles) 3 in the anisotropic conductive film 2 and is connected to a first electron having a first terminal row 4 composed of a plurality of terminals 4 a. The component 5 is a second electronic component 7 including a second terminal row 6 which is opposite to the first terminal row 4 and is composed of a plurality of terminals 6a.

The first electronic component and the second electronic component are not particularly limited, and can be appropriately selected according to the purpose. Examples of the first electronic component include flexible substrates (FPC: Flexible Printed Circuits) and transparent substrates. The transparent substrate is not particularly limited as long as it has high transparency, and examples thereof include glass substrates and plastic substrates. Examples of the second electronic component include a camera module, an integrated circuit (IC) module, and an IC chip. The second electronic component may be a functional module equipped with a sensor. For camera modules, ceramic substrates are sometimes used from the viewpoint of excellent electrical and thermal insulation properties. A ceramic substrate or a functional module has advantages such as excellent dimensional stability in a miniaturization (for example, 1 cm ² or less).

<Manufacturing method of connection structure>

The manufacturing method of the connection structure of this embodiment includes the following steps: a first electronic component 5 provided with a first terminal row 4 and a second electronic component provided with a second terminal row 6 opposed to the first terminal row 4 7 crimping through the anisotropic conductive film. Thereby, the first terminal row 4 and the second terminal row 6 can be connected through the conductive particles 3.

The first electronic component 5 and the second electronic component 7 are the same as the first electronic component 5 and the second electronic component 7 in the connection structure. The anisotropic conductive adhesive is also the same as the anisotropic conductive adhesive.

[Example]

Hereinafter, a first embodiment of the present technology will be described.

[Experimental Example 1]

[Production of anisotropic conductive adhesive (resin composition)]

1 g of conductive particles (large diameter particles, Ni-plated (thickness 115 nm), resin core, specific gravity 3.44 g / cm ³ ) with an average particle diameter of 3 μm and a silica filler with an average particle diameter of 10 nm as an insulating filler (Small particle size filler, product name: YA010C, specific gravity 2.2g / cm ³ ) 0.5g (78.2% by volume relative to conductive particles) is placed in a planetary agitator (product name: defoaming Taro, manufactured by Shinji Corporation) ), And stirred for 5 minutes to prepare a mixture of conductive particles and insulating filler.

The number of insulating fillers was evaluated using any of "appropriate amount", "excess", and "insufficient". Specifically, the ratio of the number of silicon dioxide fillers to the conductive particles, that is, the amount of the silicon dioxide fillers to the conductive particles is in the range of more than 1.56% by volume but less than 156% by volume as " The right amount. " In addition, the case where the amount of the silica filler relative to the conductive particles exceeded 156% by volume was evaluated as "excess". In addition, a case where the amount of the silica filler relative to the conductive particles was less than 1.56% by volume was evaluated as "insufficient."

Put the "mixture of conductive particles and insulating filler" and "insulating adhesive composed of the following components" into a planetary stirring device (product name: defoaming Taro, manufactured by Shinji Corporation), and stir for 1 minute, An anisotropic conductive adhesive was prepared.

As the insulating adhesive, 20 g of epoxy resin (EP828: manufactured by Mitsubishi Chemical Corporation), 30 g of phenoxy resin (YP-50: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and 50 g of hardener (Novacure 3941HP, manufactured by Asahi Kasei Corporation) were used. Toluene diluted and mixed.

[Production of anisotropic conductive film (film body)]

The anisotropic conductive adhesive was coated on a PET film, and dried in an oven at 80 ° C. for 5 minutes, and an adhesive layer composed of the anisotropic conductive adhesive was formed on the PET film. Thereby, an anisotropic conductive film having a thickness of 12 μm (4 times the particle diameter of the large-diameter particles) was obtained. The number density of the conductive particles in the anisotropic conductive film was adjusted to approximately 5000 particles / mm ² .

[Experimental Example 2]

The anisotropic conductive film was produced in the same manner as in Experimental Example 1 except that the amount of the insulating filler was changed to 0.15 g (23.5% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[Experimental Example 3]

The anisotropic conductive film was produced in the same manner as in Experimental Example 1 except that the amount of the insulating filler was changed to 0.05 g (7.8% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[Experimental Example 4]

An anisotropic conductive film was produced and evaluated in the same manner as in Experimental Example 1 except that an anisotropic conductive adhesive was prepared without blending an insulating filler.

[Experimental Example 5]

The anisotropic conductive film was produced in the same manner as in Experimental Example 1 except that the amount of the insulating filler was changed to 1 g (156% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive, and Evaluate.

[Experimental Example 6]

The anisotropic conductive film was produced in the same manner as in Experimental Example 1 except that the amount of the insulating filler was changed to 0.01 g (1.56 vol% with respect to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[With or without insulating fillers]

The cross section of the conductive particles in the anisotropic conductive film was observed with a scanning electron microscope, and it was confirmed whether an insulating filler was attached to the surface of the conductive particles. The case where an insulating filler was attached to the surface of the conductive particles was evaluated as "yes", and the case where it was not adhered was evaluated as "none". The results are shown in Table 1.

[Difference in number density of conductive particles]

Evaluation of "the density of the number of conductive particles in the entire anisotropic conductive film (1.0 mm × 1.0 mm (number / mm ² )") and "in the 0.2 mm × 0.2 mm area randomly selected from 10 places of this anisotropic conductive film" The difference in the number density (number / mm ² ) of conductive particles. The evaluation criteria are shown below. It is preferably A or B. The results are shown in Table 1. In addition, the difference in number density is the difference between the maximum value and the minimum value of the number density of conductive particles in a arbitrarily selected predetermined area.

A: Number density difference is below 10%

B: Number density difference is greater than 10 but less than 15%

C: Number density difference exceeds 15% (greater than)

[Making Connection Structure]

Using the produced anisotropic conductive film, a flexible substrate (copper wiring: wire / gap (L / S) = 25 μm / 25 μm, terminal height: 8 μm, polyimide thickness: 25 μm) and Glass (thickness: 0.7 mm) provided with ITO on one side was heated and pressed (180 ° C, 2 MPa, 20 seconds) to obtain a connection structure.

[Starting resistance value]

A digital multimeter (manufactured by Yokogawa Electric Corporation) was used to measure the on-resistance value of the connection structure when a current of 1 mA was passed through the 4-terminal method. An evaluation that the on-resistance value of the connection structure was less than 2.0 Ω was "OK", and an evaluation that the on-resistance value was 2.0 Ω or more was "NG". In Experimental Examples 1 to 3, all were OK.

[Resistance after connection reliable test]

After placing the connection structure in an environment of 60 ° C and a relative humidity of 95% for 1,000 hours, the on-resistance value of the connection structure was measured in the same manner as the initial resistance value. The evaluation criteria were "OK" and "Evaluation with an on-resistance value of 5.0 Ω or more" as "OK". In Experimental Examples 1 to 3, all were OK.

[Number of conductive particles captured]

For the connection structure sample, it was confirmed in Experimental Examples 1 to 3 that a sufficient number of conductive particles were captured at the opposite terminals. In addition, if the capture states of Experimental Examples 1 to 3 and Experimental Examples 4 to 6 are compared, the number of captures in each bump of Experimental Examples 1 to 3 shows a more uniform tendency.

[Short circuit]

The same connection structure as that used for the evaluation of the initial resistance value was produced, and the presence or absence of a short circuit between adjacent terminals was evaluated. The "evaluation when the short-circuit occurrence rate is 50 ppm or less" is "OK", and the "evaluation when the short-circuit occurrence rate exceeds 50 ppm" is "NG". In Experimental Examples 1 to 3, all were OK.

In Experimental Examples 1 to 3, the amount of the insulating filler (the particle diameter is 0.02% or more and 5.0% or less) of the conductive particles was more than 1.56% by volume and less than 156% by volume, and the conductive particles were stirred with The insulating filler can reduce the difference in the number density of the conductive particles (second coated conductive particles) in the anisotropic conductive film. In particular, from Experimental Examples 1 to 3, it can be seen that a good state can be obtained if it is 7.8 to 78.2% by volume. That is, it turns out that the dispersibility of a conductive particle is favorable.

In Experimental Examples 1 to 3, observation of SEM images of the conductive particles in the film cross section revealed that the coating state of the insulating filler was confirmed. In addition, in the second-coated conductive particles in the insulating adhesive obtained in this way, a part of the insulating filler coating may remain. The coating of the remaining insulating filler on the surface of the conductive particles can be confirmed by observation of the second coated conductive particles of Experimental Examples 1 to 3 with an electron microscope (SEM).

Further, in Experimental Examples 1 to 3, it was found that short circuits between electrode terminals of electronic components can be suppressed. In addition, in Experimental Examples 1 to 3, it was found that the capture rate of the conductive particles was good, and the evaluation of the initial resistance value and the resistance value after the reliability test was also good. In addition, in Experimental Examples 1 and 2, it was found that the dispersibility of the conductive particles was more favorable.

In Experimental Example 4 in which an insulating filler having a particle diameter of 0.02 to 5.0% of the particle diameter of the conductive particles was not blended, it was found that the difference in the number density of the conductive particles cannot be reduced. That is, in Experimental Example 4, it can be seen that the dispersibility of the conductive particles is not good. Further, in Experimental Example 4, it was impossible to suppress a short circuit between electrode terminals of an electronic component, and it was found that the capture rate of conductive particles was not good. In addition, in Experimental Example 4, if compared with Examples 1 to 3, it can be seen that the initial resistance value and the evaluation of the resistance value after the reliability test were not good.

In Experimental Example 5 in which the amount of the insulating filler (the particle diameter is 0.02 to 0.5% of the particle diameter of the conductive particles) relative to the conductive particles was 156% by volume, it was found that the difference in the number density of the conductive particles cannot be made small. That is, in Experimental Example 5, it can be seen that the insulating filler having a particle diameter of 0.02 to 0.5% of the particle diameter of the conductive particles has an excessive number ratio, so the dispersibility of the conductive particles is not good. In addition, in Experimental Example 5, it was found that the short circuit between the electrode terminals of the electronic component could not be suppressed, and the capture rate of the conductive particles was not good. Moreover, in Experimental Example 5, if compared with Examples 1 to 3, it can be seen that the initial resistance value and the evaluation of the resistance value after the reliability test were not good.

In Experimental Example 6 in which the amount of the insulating filler (the particle diameter is 0.02 to 0.5% of the particle diameter of the conductive particles) with respect to the conductive particles was 1.57% by volume, it was found that the difference in the number density of the conductive particles cannot be made small. That is, in Experimental Example 6, it can be seen that the insulating filler having a particle diameter of 0.02 to 0.5% of the particle diameter of the conductive particles is insufficient in number ratio, so the dispersibility of the conductive particles is not good. Moreover, in Experimental Example 6, when compared with Examples 1 to 3, it can be seen that the short circuit between the electrode terminals of the electronic component cannot be suppressed, and the capture rate of the conductive particles is not good.

Hereinafter, a second embodiment of the present technology will be described.

[Example 1]

[Production of anisotropic conductive adhesive]

1 g of conductive particles (Au (outer layer, thickness 34 nm) / Ni (inner layer, thickness 200 nm), resin core, specific gravity 1.4 g / cm ³ ) with an average particle diameter of 20 μm and an average particle diameter of 10 nm as an insulating filler Silicon dioxide filler (product name: YA010C, specific gravity 2.2g / cm ³ ) 0.5g (38.7% by volume relative to conductive particles) was placed in a planetary agitator (product name: defoaming Taro, manufactured by Shinji Corporation) , Stir for 5 minutes to prepare a mixture of conductive particles and insulating filler.

The ratio of the number of insulating fillers is evaluated by any of "appropriate amount", "excess" and "insufficient". Specifically, the "proper amount" is evaluated as the ratio of the number of silicon dioxide fillers to the conductive particles, that is, the case where the amount of the silicon dioxide filler to the conductive particles is in the range of 0.78 to 77% by volume. In addition, a case where the amount of the silica filler relative to the conductive particles exceeded 77% by volume was evaluated as "excess". In addition, a case where the amount of the silicon dioxide filler relative to the conductive particles was less than 0.78% by volume was evaluated as "insufficient."

Put "mixture of conductive particles and insulating filler" and "insulating adhesive consisting of the following components" into a planetary stirring device (product name: defoaming Taro, manufactured by Shinji Co., Ltd.), and stir for 1 minute, An anisotropic conductive adhesive was prepared.

As the insulating adhesive, 20 g of epoxy resin (EP828: manufactured by Mitsubishi Chemical Corporation), 30 g of phenoxy resin (YP-50: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and 50 g of hardener (Novacure 3941HP, manufactured by Asahi Kasei Corporation) were used. Toluene is diluted and mixed.

[Fabrication of anisotropic conductive film]

The anisotropic conductive adhesive was coated on a PET film, and dried in an oven at 80 ° C. for 5 minutes, and an adhesive layer composed of the anisotropic conductive adhesive was formed on the PET film. Thereby, an anisotropic conductive film having a thickness of 25 μm was obtained. The number density of conductive particles in the anisotropic conductive film was adjusted to about 300 particles / mm ² .

[With or without insulating fillers]

The cross section of the conductive particles in the anisotropic conductive film was observed with a scanning electron microscope, and it was confirmed whether an insulating filler was attached to the surface of the conductive particles. The case where an insulating filler was attached to the surface of the conductive particles was evaluated as "yes", and the case where it was not adhered was evaluated as "none". The results are shown in Table 2.

[Difference in number density of conductive particles]

Evaluation of "the density of the number of conductive particles in the entire anisotropic conductive film (1.0 mm × 1.0 mm (number / mm ² )") and "in the 0.2 mm × 0.2 mm area randomly selected from 10 places of this anisotropic conductive film" The difference in the number density (number / mm ² ) of conductive particles. The evaluation criteria are shown below. It is preferably A or B. In addition, the difference in number density is the difference between the maximum value and the minimum value of the number density of conductive particles in a arbitrarily selected predetermined area. The results are shown in Table 2.

A: The number density difference is less than 10%

B: Number density difference is greater than 10 but less than 15%

C: Number density difference exceeds 15% (greater than)

[Making Connection Structure]

Using the produced anisotropic conductive film, a flexible substrate (copper wiring: wire / gap (L / S) = 100 μm / 100 μm, terminal height: 12 μm, polyimide thickness: 25 μm) was pressed against the substrate by heating and pressing the member. Alumina ceramic substrate (gold / tungsten wiring: wire / gap (L / S) = 100μm / 100μm, wiring height: 10μm, substrate thickness: 0.4mm), heating and pressing (180 ° C, 1MPa, 20 seconds), Get the connection structure.

[Starting resistance value]

A digital multimeter (manufactured by Yokogawa Electric Corporation) was used to measure the on-resistance value of the connection structure when a current of 1 mA was passed through the 4-terminal method. The "evaluation of the on-resistance value of the connection structure less than 1.0Ω" was "OK", and the "evaluation of the on-resistance value of 1.0Ω or more" was "NG". The results are shown in Table 2.

[Resistance after connection reliable test]

After the connection structure was placed in an environment of 60 ° C and a relative humidity of 95% for 1,000 hours, the on-resistance value of the connection structure was measured by the same method as the initial resistance value. The evaluation criteria were made the same as the initial resistance value. The results are shown in Table 2.

[Number of conductive particles captured]

For the connection structure sample, the number of conductive particles captured by the opposite terminals was counted, and an average value of the number of captured conductive particles of 150 terminals was calculated. The average value was evaluated using the following criteria. The evaluation criteria are shown below. It is preferably A or B. The results are shown in Table 2.

A: 5 or more

B: 3 ~ 4

C: less than 2

[Short circuit]

The same connection structure as that used for the evaluation of the initial resistance value was produced, and the presence or absence of a short circuit between adjacent terminals was evaluated. The "evaluation when the short-circuit occurrence rate is 50 ppm or less" is "OK", and the "evaluation when the short-circuit occurrence rate exceeds 50 ppm" is "NG". The results are shown in Table 2.

[Example 2]

The anisotropic conductive film was produced in the same manner as in Example 1 except that the blending amount of the insulating filler was changed to 0.15 g (11.6% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[Example 3]

The anisotropic conductive film was produced in the same manner as in Example 1, except that the amount of the insulating filler was changed to 0.05 g (3.9% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[Comparative Example 1]

An anisotropic conductive film was produced and evaluated in the same manner as in Example 1 except that an anisotropic conductive adhesive was produced without blending an insulating filler.

[Comparative Example 2]

The anisotropic conductive film was produced in the same manner as in Example 1 except that the amount of the insulating filler was changed to 1.0 g (77.3% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

[Comparative Example 2]

The anisotropic conductive film was produced in the same manner as in Example 1 except that the blending amount of the insulating filler was changed to 0.01 g (0.77% by volume relative to the conductive particles) to produce an anisotropic conductive adhesive. And evaluate.

In the examples, it can be seen that the amount of the insulating filler (the particle diameter is 0.02 to 0.143% of the particle diameter of the conductive particles) relative to the conductive particles is 0.78 to 77% by volume, and the conductive particles and the insulating filler are stirred, thereby making it possible to The difference in the number density of conductive particles (second coated conductive particles) in the anisotropic conductive film becomes smaller. In particular, it can be seen from the examples that a good state can be obtained if it is 3.9 to 38.7% by volume. That is, it turns out that the dispersibility of a conductive particle is favorable. In addition, it was found in the examples that short circuits between electrode terminals of electronic components can be suppressed. In addition, it can be seen from the examples that the capture rate of the conductive particles is good, and the evaluation of the initial resistance value and the resistance value after the reliability test is also good. In particular, in Examples 1 and 2, it is found that the dispersibility of the conductive particles is better.

In the embodiment, by stirring the conductive particles and the insulating filler, as shown in FIG. 2, the first coated conductive particles 10 can be obtained. Then, by stirring the first coated conductive particles 10 in the insulating adhesive, the silica filler is separated from the conductive particles in the first coated conductive particles 10, and as shown in FIG. 3, the second coated conductive particles can be obtained. 11. The separated silica filler is interposed between the second coated conductive particles 11. Accordingly, aggregation of the second coated conductive particles 11 can be suppressed, and the second coated conductive particles 11 can be uniformly dispersed in the insulating adhesive. In addition, a part of the insulating filler coating may remain in the second coated conductive particles 11 in the insulating adhesive obtained in this way. The coating of the insulating filler remaining on the surface of the conductive particles can be confirmed by observation with an electron microscope (SEM) from the second coated conductive particles 11 in Experimental Examples 1 to 3.

In Comparative Example 1 in which an insulating filler having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles was not blended, it was found that the difference in the number density of the conductive particles cannot be made small. That is, in Comparative Example 1, it was found that the dispersibility of the conductive particles was not good. Moreover, in Comparative Example 1, it was found that the short circuit between the electrode terminals of the electronic component could not be suppressed, and the capture rate of the conductive particles was not good. In Comparative Example 1, as shown in FIG. 4, conductive particles (raw particles) 12 not coated with silica filler were used, and as shown in FIG. 5, a plurality of conductive particles 12 were caused in the insulating adhesive. Connect and unite.

In Comparative Example 2 in which the amount of the insulating filler (the particle diameter is 0.02 to 0.143% of the particle diameter of the conductive particles) with respect to the conductive particles exceeds 77.3% by volume (more than 77%), it can be seen that the number density of the conductive particles cannot be reduced. The difference becomes smaller. That is, in Comparative Example 2, it was found that the dispersibility of the conductive particles was not good because the insulating filler having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles was excessive. Moreover, in Comparative Example 2, it was found that the short circuit between the electrode terminals of the electronic component could not be suppressed, and the capture rate of the conductive particles was not good. Moreover, in Comparative Example 2, it was found that the evaluation of the initial resistance value and the resistance value after the reliability test were not good. In Comparative Example 2, it was found that, after mixing the conductive particles with the silica filler, for example, as shown in FIG. 6, a part of the two conductive particles was coated with the silica filler and the coated conductive particles 13 were formed.

In Comparative Example 3 in which the amount of the insulating filler (the particle diameter is 0.02 to 0.143% of the particle diameter of the conductive particles) relative to the conductive particles was 0.77% by volume (less than 0.78% by volume), it was found that the number of conductive particles could not be made. The difference in density becomes smaller. That is, in Comparative Example 3, it can be seen that the dispersibility of the conductive particles is not good because the insulating filler having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles is insufficient. Further, in Comparative Example 3, it was found that the short circuit between the electrode terminals of the electronic component could not be suppressed, and the capture rate of the conductive particles was not good.

Claims (23)

    A resin composition comprising a coated large-diameter particle, a small-diameter filler, and an insulating adhesive partly covered with a small-diameter filler on the surface of the large-diameter particle. The coated large-diameter particle is dispersed, and the large-diameter particle is granular. The diameter is 2 μm or more, the particle size of the small-diameter filler is 0.02% to 5.0% of the large-diameter particle, and the amount of the small-diameter filler relative to the large-diameter particle is less than 155% by volume.         The resin composition according to claim 1, wherein the large-diameter particles are conductive particles.         The resin composition according to claim 1 or 2, wherein the small particle size filler is a silica filler.         The resin composition according to any one of claims 1 to 3, wherein the particle diameter of the large-diameter particles is less than 50 μm.         A method for producing a resin composition includes the following steps: Step (A): stirring large diameter particles having an average particle diameter of 2 μm or more and small particle diameters having a particle diameter of 0.02% to 5.0% of the large diameter particles A filler to obtain the first coated particles covered with the large-diameter particles by the small-sized filler, and step (B): stirring the first coated particles and the insulating adhesive to obtain the first adhesive particles in the insulating adhesive In the step (A), the resin composition in which a part of the surface of the large-diameter particles is dispersed with the second-coated particles coated with the small-diameter filler is less than the amount of the small-diameter filler relative to the large-diameter particles. The 156% by volume blended the large diameter particles and the small particle size filler.         An adhesive is composed of the resin composition according to any one of claims 1 to 4.         An adhesive film which consists of the adhesive agent of Claim 6.     The adhesive film according to claim 7, wherein the number density of the large-diameter particles (units / mm ² ) of the entire adhesive film and the large diameter in an area of 0.2 mm × 0.2 mm arbitrarily selected from the adhesive film The difference in the number density of particles (number / mm ² ) is 15% or less.     An anisotropic conductive adhesive is composed of the resin composition according to any one of claims 1 to 4, and the large-diameter particles are conductive particles.         An anisotropic conductive film comprising the anisotropic conductive adhesive according to claim 9.         A structure in which a first member and a second member are connected through the adhesive according to claim 6 or the adhesive film according to claim 7.         A connection structure that is anisotropically connected to a first electronic component and a second electronic component through the anisotropic conductive adhesive described in claim 9 or the anisotropic conductive film described in claim 10.         A method for manufacturing a structure, wherein the first member and the second member are connected through the adhesive described in claim 6 or the adhesive film described in claim 7.         A method of manufacturing a connection structure is to anisotropically connect a first electronic component and a second electronic component through the anisotropic conductive adhesive described in claim 9 or the anisotropic conductive film described in claim 10.         An anisotropic conductive adhesive, which includes coated conductive particles, insulating fillers, and an insulating adhesive partly covered with an insulating filler on the surface of the conductive particles. The coated conductive particles are dispersed in the insulating adhesive, and the conductive particles are dispersed in the insulating adhesive. The particle diameter is 7 μm or more, the particle diameter of the insulating filler is 0.02 to 0.143% of the particle diameter of the conductive particles, and the amount of the insulating filler relative to the conductive particles is 0.78 to 77% by volume.         The anisotropic conductive adhesive according to claim 15, wherein the insulating filler is a silicon dioxide filler.         The anisotropic conductive adhesive according to claim 15 or 16, wherein a particle diameter of the conductive particles is 50 μm or less.         An anisotropic conductive film is composed of the anisotropic conductive adhesive according to any one of claims 15 to 17.     The anisotropic conductive film according to claim 18, wherein the number density of the coated conductive particles (pieces / mm ² ) of the entire anisotropic conductive film and 0.2 mm arbitrarily selected from the anisotropic conductive film The difference in the number density (number / mm ² ) of the coated conductive particles in the × 0.2 mm region is 15% or less.     A method for producing an anisotropic conductive adhesive has the following steps: step (A): stirring conductive particles having an average particle diameter of 7 μm or more and insulating fillers having a particle diameter of 0.02 to 0.143% of the particle diameter of the conductive particles, Thereby, the first coated conductive particles covered with the conductive particles and the insulating filler are obtained, and step (B): the first coated conductive particles and the insulating adhesive are stirred, thereby obtaining a dispersion in the insulating adhesive. The anisotropic conductive adhesive of the second coated conductive particle whose part of the surface of the conductive particle is covered with the insulating filler, in this step (A), the amount of the insulating filler relative to the conductive particle becomes 0.78 to 77 The conductive particles and the insulating filler are blended in a volume% manner.         A connection structure in which the first electronic component and the second electronic component are anisotropically connected through the anisotropic conductive adhesive according to any one of claims 15 to 17 or the anisotropic conductive film according to claim 18 .         The connection structure according to claim 21, wherein the first electronic component or the second electronic component is a ceramic substrate.         A method for manufacturing a connection structure, wherein the first electronic component and the second electronic component are passed through the anisotropic conductive adhesive described in any one of claims 15 to 17 or the anisotropic conductive film described in claim 18 Anisotropic connection.