TWI806494B - Anisotropic conductive film, connection structure, method for producing the connection structure and wound roll - Google Patents

Abstract

The anisotropic conductive film of the present invention has the following structure: conductive particles 1A having a high hardness of 20% compressive elastic modulus of 8000~28000N/ ^mm2 and low 20% compressive elastic modulus are dispersed in the insulating resin layer 2 The low-hardness conductive particle 1B in the high-hardness conductive particle 1A. The number density of the conductive particles as a whole is above 6000/mm ² , and the number density of the low-hardness conductive particles 1B is above 10% of the total conductive particles.

Description

Anisotropic conductive film, connection structure, manufacturing method of connection structure, and package

The invention relates to an anisotropic conductive film.

For the mounting of electronic components such as IC chips, anisotropic conductive films in which conductive particles are dispersed in insulating resin layers are widely used. However, when an oxide film is formed on the surface of a terminal of an electronic component connected by an anisotropic conductive film, connection resistance becomes high. In this regard, it has been proposed to use conductive particles with different particle sizes to pierce the oxide film to achieve low resistance (Patent Document 1), or to use harder conductive particles to sink the conductive particles into the wiring, increasing the Realize low resistance by reducing the connection area (Patent Document 2) and the like.

prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2013-182823

Patent Document 2: Japanese Patent Laid-Open No. 2012-164454

If conductive particles with different particle diameters are used as described in Patent Document 1, particles smaller than particles with larger particle diameters will sink into the terminals, making it difficult to achieve a sufficient low resistance. In addition, if hard conductive particles are used as described in Patent Document 2, it is necessary to press under high pressure during anisotropic conductive connection, and there is a connection structure between the substrate and the IC chip obtained by anisotropic conductive connection Body deformed or cracked.

In order to prevent deformation or cracks, there is a method of reducing conductive particles, but if the conductive particles are reduced, the number of conductive particles caught in the terminal will decrease, which will instead increase the resistance, or cause an increase in the on-resistance after connection.

In view of this, the purpose of the present invention is to use high-hardness conductive particles in a manner that can be connected even to terminals on which an oxide film is formed, and to realize crimping under low-voltage conditions, and to easily confirm the capture of conductive particles of the terminals, Realize low resistance reliably.

The inventors of the present invention conceived of the present invention by finding that, if conductive particles with different hardness are mixed and used, the connection pressure will concentrate on the high-hardness conductive particles during anisotropic conductive connection, and the high-hardness conductive particles will pierce the oxidized particles. film; low-hardness conductive particles use the "cracks formed by high-hardness conductive particles in the oxide film" to facilitate conduction; therefore, even if the particle density of high-hardness conductive particles is reduced, both high-hardness conductive particles and low-hardness conductive particles are also Contributes to the conduction of the terminal, so it can reduce the on-resistance; in addition, it can reduce the particle density of high-hardness conductive particles, so there is no need for crimping under high pressure during anisotropic conductive connection, which can eliminate deformation or cracking of the connection structure problems; and by mixing high-hardness conductive particles and low-hardness conductive particles, it is easy to observe the indentation of conductive particles.

That is, the present invention provides an anisotropic conductive film, which is dispersed in an insulating resin layer, as conductive particles, high-hardness conductive particles with a 20% compressive modulus of 8000 to 28000 N/mm ² and 20% compressive modulus of less than The high-hardness conductive particles are low-hardness conductive particles, and the number density of the whole conductive particles is more than 6000 pieces/mm ² , and the number density of the low-hardness conductive particles is more than 10% of the whole conductive particles.

According to the anisotropic conductive film of the present invention, even if an oxide film is formed on the surface of the terminal of an electronic component, the high-hardness conductive particles will be immersed in the oxide film. In addition, the cracks formed in the oxide film by the high-hardness conductive particles are utilized , Low-hardness conductive particles also contribute to the conduction of the terminal, so it can reduce the on-resistance.

In addition, by mixing low-hardness conductive particles with high-hardness conductive particles, compared with the case where the conductive particles are only composed of high-hardness conductive particles, the crimping force required for anisotropic conductive connection can be reduced. Therefore, it is possible to prevent deformation or cracking of the connection structure of the anisotropic conductive connection.

Furthermore, in the connection structure connected by anisotropic conduction, the indentation of high-hardness conductive particles and the indentation of low-hardness conductive particles can be observed, especially the indentation of high-hardness conductive particles can be clearly observed, so it can be Accurately evaluate the capture number of conductive particles in the terminal. Therefore, low resistance can be reliably achieved.

1A: High hardness conductive particles

1B: Low hardness conductive particles

2: Insulating resin layer

2b: sunken (tilted)

2c: depression (undulation)

3: Conductive particle dispersion layer

4: The second insulating resin layer

10A, 10B, 10C, 10D, 10E, 10F, 10G: Anisotropic conductive film

D: Average particle size of conductive particles

La: layer thickness of insulating resin layer

Lb: the distance between the tangent plane of the central part of the adjacent conductive particles and the deepest part of the conductive particles

Lc: The diameter of the exposed (directly above) part of the conductive particles in the slope or undulation

Ld: the maximum diameter of the inclination or undulation of the insulating resin layer around or directly above the conductive particles

Le: The maximum depth of the inclination in the insulating resin layer around the conductive particles

Lf: Maximum depth of undulations in the insulating resin layer directly above the conductive particles

[FIG. 1A] It is a top view which shows the arrangement|positioning of the conductive particle of the anisotropic conductive film 10A which is one Example of this invention.

[ FIG. 1B ] is a cross-sectional view of an anisotropic conductive film 10A of an embodiment.

[FIG. 2A] It is a top view which shows the arrangement|positioning of the conductive particle of the anisotropic conductive film 10B which is one Example of this invention.

[ FIG. 2B ] is a cross-sectional view of the anisotropic conductive film 10B of the embodiment.

[ Fig. 3 ] is a cross-sectional view of an anisotropic conductive film 10C of an embodiment.

[FIG. 4] It is a sectional view of the anisotropic conductive film 10D of an Example.

[ Fig. 5 ] is a cross-sectional view of an anisotropic conductive film 10E of an embodiment.

[ Fig. 6] Fig. 6 is a cross-sectional view of an anisotropic conductive film 10F of an embodiment.

[ Fig. 7 ] is a cross-sectional view of an anisotropic conductive film 10G of an embodiment.

[ Fig. 8] Fig. 8 is a cross-sectional view of an anisotropic conductive film 100A of an embodiment.

[ Fig. 9 ] is a cross-sectional view of an anisotropic conductive film 100B of an embodiment.

[ FIG. 10A ] is a cross-sectional view of an anisotropic conductive film 100C of an embodiment.

[ FIG. 10B ] is a cross-sectional view of the anisotropic conductive film 100C' of the embodiment.

[ Fig. 11 ] is a cross-sectional view of an anisotropic conductive film 100D of an embodiment.

[ Fig. 12 ] is a cross-sectional view of an anisotropic conductive film 100E of an embodiment.

[ Fig. 13 ] is a cross-sectional view of an anisotropic conductive film 100F of an embodiment.

[ Fig. 14 ] is a cross-sectional view of an anisotropic conductive film 100G of an embodiment.

[ Fig. 15 ] is a cross-sectional view of an anisotropic conductive film 100X for comparison.

Hereinafter, the anisotropic conductive film of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code|symbol represents the same or equivalent structural element.

<The overall structure of the anisotropic conductive film>

FIG. 1A is a plan view illustrating the arrangement of conductive particles 1A, 1B for an anisotropic conductive film 10A according to an embodiment of the present invention. In addition, FIG. 1B is an x-x sectional view of the anisotropic conductive film 10A.

The anisotropic conductive film 10A is formed by a conductive particle dispersion layer 3. The conductive particle dispersion layer 3 is made of high-hardness conductive particles 1A with a 20% compressive elastic modulus of 8000-28000 N/ ^mm2 and a 20% compressive elastic modulus lower than Both the high-hardness conductive particle 1A and the low-hardness conductive particle 1B are dispersed in the insulating resin layer 2 . The total number density of conductive particles combining high-hardness conductive particles 1A and low-hardness conductive particles 1B is above 6000 pieces/mm ² , wherein the number density of low-hardness conductive particles 1B accounts for more than 10% of the total conductive particles. The conductive particles are arranged in a square grid as a whole, but there is no regularity as to which of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B exists at each grid point.

<conductive particle>

Both the high-hardness conductive particle 1A and the low-hardness conductive particle 1B exist as conductive particles in the conductive particle dispersion layer 3 . Among them, the 20% compression elastic rate of the high-hardness conductive particles 1A is 8000-28000 N/mm ² .

Here, the 20% compressive elastic modulus is used to measure the "compression variable of the conductive particles when a compressive load is applied to the conductive particles using a micro compression tester (for example, Fischerscope H-100 manufactured by Fischer Instruments Co., Ltd.), and the value obtained by the following formula is used. Calculated K value: 20% compression modulus (K)(N/mm ² )=(3/2 ^1/2 )‧F‧S ^-3/2 ‧R ^-1/2 .

In the formula,

F: The load value when the conductive particles undergo 20% compression deformation (N)

S: Compression displacement of conductive particles when 20% compression deformation occurs (mm)

R: Radius of conductive particles (mm).

By setting the 20% compressive elastic modulus of the high-hardness conductive particles to 8000N/mm2 ^or more, even if an oxide film is formed on the surface of the terminal of the electronic component, the oxide film can be pierced by the high-hardness conductive particles. In addition, by By setting it below 28000N/mm ² , the crimping force required for anisotropic conductive connection will not become too high, and conventional pressing jigs can be used for anisotropic conductive connection.

The particle size of the high-hardness conductive particles 1A is preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and less than 10 μm, in order to suppress an increase in on-resistance and suppress occurrence of short circuits. The particle diameter of the conductive particles before being dispersed in the insulating resin layer can be measured with a general particle size distribution measuring device, and the average particle diameter can also be obtained using a particle size distribution measuring device. It can be image type or laser type. As an image-type measuring device, a wet-type floating particle size/shape analyzer can be cited as an example. FPIA-3000 (Malvern Corporation). The number of samples (the number of conductive particles) for measuring the average particle diameter D is preferably 1000 or more. The particle size of the conductive particles of the anisotropic conductive film can be determined by observing an electron microscope such as SEM. In this case, it is preferable to set the number of samples for measuring the average particle diameter to 200 or more.

In addition, when using what adhered the insulating fine particle to the surface as a conductive particle, the particle diameter of the conductive particle in this invention means the particle diameter of the insulating fine particle which does not include a surface.

On the other hand, the 20% compressive elastic modulus of the low-hardness conductive particles 1B is lower than that of the high-hardness conductive particles, preferably not less than 10% and not more than 70% of the 20% compressive elastic modulus of the high-hardness conductive particles. If the 20% compressive elastic modulus of the low-hardness conductive particles 1B is too low, it will become difficult to contribute to conduction. On the contrary, if it is too high, the hardness difference with the high-hardness conductive particles will become insufficient, and the effect of the present invention cannot be obtained. .

The particle size of the low-hardness conductive particles 1B is preferably 1 μm or more and 30 μm or less. As long as the particle size of the high-hardness conductive particles is 80% or more, there is no problem in practical use, and it is preferably equal to or more. By setting the particle size of the low-hardness conductive particles to be equal to or greater than the particle size of the high-hardness conductive particles, the low-hardness conductive particles will be easily damaged due to cracks in the oxide film formed on the surface of the terminal by the high-hardness conductive particles. help conduction.

The high-hardness conductive particle 1A and the low-hardness conductive particle 1B having the above-mentioned hardness and particle size can be appropriately selected from conductive particles used in known anisotropic conductive films. Examples thereof include metal particles such as nickel, cobalt, silver, copper, gold, and palladium, alloy particles such as solder, metal-coated resin particles, and metal-coated resin particles with insulating fine particles adhered to the surface. The thickness of the metal layer of the metal-coated resin particles is preferably 50 nm to 250 nm. In addition, the conductive particles may also be provided with protrusions on the surface. In the case of metal-coated resin particles, those listed in JP-A-2016-89153 can also be used.

<Number density of conductive particles>

The number density of the low-hardness conductive particles 1B is more than 10% of the total conductive particles, and can be appropriately adjusted according to the type of terminal to be connected or the connection conditions. As an example, it is preferably 20% or more and 80% or less, more preferably 30% or more and 70% or less. Regardless of the number density of low-hardness conductive particles relative to the overall conductive particles If it is too low or too high, it is difficult to obtain the effect of the present invention produced by mixing conductive particles with high hardness and conductive particles with low hardness.

In addition, the number density of the conductive particles as a whole is not particularly limited, but as an example, when the average particle diameter D of the conductive particles 1A and 1B as a whole is less than 10 μm, it is preferably 6000 pieces/mm ² or more and 42000 pieces/mm ² or less. When the average particle diameter becomes 10 micrometers or more, it is not limited to this range. As an example, it is 20 pieces/mm ² or more and 2000 pieces/mm ² or less.

When the average particle diameter D of the conductive particles 1A and 1B as a whole is less than 10 μm, if the number density of the conductive particles as a whole becomes too high, the area occupancy ratio of the conductive particles calculated according to the following formula also becomes too high .

Area occupancy rate=[number density of conductive particles under top view (pieces/mm ² )]×[average value of top view area of 1 conductive particle (mm ² /piece)]×100

The area occupancy rate is an indicator of the thrust force required for the press jig to thermocompress the anisotropic conductive film to the electronic component. By setting the area occupancy ratio to preferably 35% or less, and more preferably 0.3 to 30%, it is possible to minimize the pressure required for the pressing jig for thermocompression-bonding the anisotropic conductive film to the electronic component. The thrust restraint is lower.

In addition, the number density of conductive particles can be measured using observation images obtained with a metal microscope or the like. In addition, it can also be obtained by measuring the observed image with image analysis software (such as WinROOF, Mitani Trading Co., Ltd., etc.). The measurement area in the case of obtaining the number density of conductive particles is preferably arbitrarily set a plurality of locations (preferably 5 or more locations, more preferably 10 or more locations) in a rectangular area with a side of 100 μm or more. The total area of the measurement area is set to 2 mm ² or more. The size or quantity of each area can be properly adjusted according to the state of the number density. In addition, the average value of the plan view area of one conductive particle can be calculated|required by measuring the observation image of the film surface obtained with the electron microscopes, such as a metal microscope and SEM. Image analysis software can also be used. The observation method or measurement method is not limited to the above-mentioned methods.

In addition, the distance Lg between the particles as a whole of the conductive particles 1A, 1B is appropriately set in accordance with a specific number density and particle arrangement after achieving the area occupancy of the conductive particles 1A, 1B.

<Configuration of Conductive Particles>

In the anisotropic conductive film of the present invention, the arrangement of the entire film of conductive particles including the high-hardness conductive particles 1A and the low-hardness conductive particles 1B in plan view may be regular or random. As an aspect of the regular arrangement, besides the square lattice shown in FIG. 1A , lattice arrangements such as hexagonal lattice, oblique square lattice, and rectangular lattice can also be mentioned. Moreover, as particle arrangement|positioning of the whole electroconductive particle, the particle row which arrange|positioned electroconductive particle 1A or 1B linearly at a predetermined interval may be arranged in parallel at a predetermined interval. In the present invention, the regular arrangement is not particularly limited as long as it is repeated in the longitudinal direction of the film.

On the other hand, each of the high-hardness conductive particle 1A and the low-hardness conductive particle 1B may be regularly arranged. For example, like the anisotropic conductive film 10B shown in Figure 2A and Figure 2B, the number density of the low-hardness conductive particles 1B can be set to 50% of the total conductive particles, and the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are respectively Those are arranged in a square grid. In FIG. 2A , high-hardness conductive particles 1A and low-hardness conductive particles 1B are alternately arranged, but the present invention includes such a strict arrangement as well as other arrangements.

When the particle arrangement as a whole of the conductive particles has a lattice axis or an arrangement axis, the lattice axis or arrangement axis may be parallel to the long side direction of the anisotropic conductive film 10A, or may be parallel to the long side of the anisotropic conductive film. The direction of crossing can be determined according to the width of the terminal to be connected, the distance between the terminals, etc. For example, when making an anisotropic conductive film for fine pitch, it is preferable to make at least one grid axis A of the conductive particles 1A, 1B oblique to the long side direction of the anisotropic conductive film 10A as shown in FIG. 1A. Well, the angle θ formed between the longitudinal direction of the terminals 20 connected by the anisotropic conductive film 10A and the lattice axis A is set to 16° to 74°.

In addition, it is preferable that the conductive particles 1A and 1B exist without contacting each other in a planar view of the film, and that the conductive particles 1A and 1B also exist without overlapping each other in the film thickness direction. Therefore, the ratio of the number of conductive particles 1A and 1B that exist without contact with each other with respect to the entire conductive particles is 95% or more, preferably 98% or less. On, more preferably more than 99.5%. This situation is the same whether it is a regular configuration or a random configuration. When the conductive particles 1A and 1B are regularly arranged using a transfer mold as described below, the ratio of the conductive particles 1A and 1B that do not come into contact with each other can be easily controlled, which is preferable. In the case of random arrangement, it is easy to knead the conductive particles 1A and 1B in the insulating resin to make an anisotropic conductive film, so it is also possible to choose the manufacturing method and utilization of the transfer mold based on the balance between performance and cost Any production method of kneading.

When each conductive particle 1A, 1B exists without contacting each other, it is preferable to align the position of the film thickness direction. For example, when the particle diameters of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are equal, as shown in FIG. 1B , the embedding amounts Lb in the film thickness direction of the conductive particles 1A and 1B can be made the same. That is, since the distance to the interface of the insulating resin layer 2 can be made uniform, the capture property of the conductive particle of a terminal becomes easy to stabilize.

In addition, when the particle diameters of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are different, if the conductive particles 1A, 1B are buried in the insulating resin layer 2 so that the surface of the insulating resin layer 2 If the distance between the conductive particles 1A and 1B is the same, the catchability of the conductive particles of the terminal is likely to be stabilized for the same reason as above. On the other hand, when the conductive particles 1A and 1B are exposed from the insulating resin layer 2 as shown in FIG. The position of the exposed top of layer 2 in the film thickness direction is aligned. In addition, the relationship between the layer thickness La of the insulating resin layer 2 and the ratio (La/D) of the average particle diameter D of conductive particle 1A, 1B is demonstrated below.

When the particle diameters of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are equal or different, if the conductive particles 1A and 1B are exposed from the insulating resin layer 2, the pressure applied during the connection is easily transmitted to the Conductive particles 1A, 1B. Taking the case of metal-coated resin particles as an example to describe in detail, similar to the function of the following recesses 2b and 2c, when the conductive particles 1A and 1B are exposed from the insulating resin layer 2, when the anisotropic conductive connection The resistance of the insulating resin layer 2 to the deformation of the metal-coated resin particles produced by pressing the metal-coated resin particles with a pressing jig is reduced, so the pressure after connection The state of the marks is easy to become uniform. Thereby, it becomes easy to confirm the state after connection.

Here, the embedding amount Lb refers to the distance between the surface of the insulating resin layer 2 in which the conductive particles 1A, 1B are embedded (in the front and back of the insulating resin layer 2, the conductive particles 1A, 1B are exposed. The surface on the side of 1B, or when the conductive particles 1A, 1B are completely embedded in the insulating resin layer 2, the surface that is closer to the conductive particles 1A, 1B) and the central portion between the adjacent conductive particles The distance between the plane 2p and the deepest part of the conductive particles 1A, 1B. When the ratio of the embedding amount Lb of the conductive particles 1A and 1B to the average particle diameter D is the embedding ratio (Lb/D), the embedding ratio is preferably 30% or more and 105% or less.

If the embedding ratio (Lb/D) is set at 30% or more and less than 60%, the ratio of particles exposed from the relatively high-viscosity resin that holds the conductive particles becomes higher, making low-voltage packaging easier. By setting it as 60% or more, it becomes easy to maintain electroconductive particle 1A, 1B in the specific particle dispersion state or specific arrangement|positioning by the insulating resin layer 2. Moreover, by setting it as 105% or less, the resin amount of the insulating resin layer which functions as the conductive particle between terminals flows unnecessarily at the time of anisotropic conductive connection can be reduced. Moreover, conductive particle 1A, 1B may penetrate the insulating resin layer 2, and the embedding rate (Lb/D) in this case becomes 100%.

In addition, in the present invention, the numerical value of the embedding rate (Lb/D) refers to more than 80% of the total number of conductive particles contained in the anisotropic conductive film, preferably more than 90%, more preferably more than 96% It becomes the numerical value of this embedding rate (Lb/D). Therefore, the embedding rate of not less than 30% and not more than 105% refers to an embedding rate of not less than 80%, preferably not less than 90%, more preferably not less than 96%, of the total number of conductive particles contained in the anisotropic conductive film 30% or more and 105% or less. By making the embedding ratio (Lb/D) of all the conductive particles uniform in this way, the pressing load is uniformly applied to the conductive particles, so the capture state of the conductive particles of the terminal becomes good, and conduction reliability can be expected. In order to further improve the accuracy, it can also be obtained by measuring more than 200 conductive particles.

In addition, the embedding rate (Lb/D) can be measured by focusing on the surface field image Adjust to obtain a certain degree of number at a time. Alternatively, a laser-type discrimination displacement sensor (manufactured by KEYENCE Co., Ltd., etc.) may also be used for the measurement of the embedding rate (Lb/D).

<Insulating resin layer>

(Viscosity of insulating resin layer)

In the anisotropic conductive film of the present invention, the minimum melt viscosity of the insulating resin layer 2 is not particularly limited, and can be appropriately determined according to the application object of the anisotropic conductive film, the manufacturing method of the anisotropic conductive film, and the like. For example, as long as the following depressions 2b ( FIG. 4 ) and 2c ( FIG. 5 ) can be formed, it can be set to about 1000 Pa·s depending on the method of manufacturing the anisotropic conductive film. On the other hand, as a method for producing an anisotropic conductive film, a method of holding conductive particles in a specific arrangement on the surface of an insulating resin layer and pressing the conductive particles into the insulating resin layer is performed. Since the insulating resin layer can be formed into a film, it is preferable to set the minimum melt viscosity of the insulating resin layer to 1100 Pa·s or more.

In addition, as described in the following method for producing an anisotropic conductive film, as shown in FIG. As shown, the depression 2c is formed directly above the conductive particles 1A and 1B pressed into the insulating resin layer 2. In this respect, it is preferably 1500 Pa‧s or more, more preferably 2000 Pa‧s or more, and even more preferably 3000~15000Pa‧s, more preferably 3000~10000Pa‧s. As an example, the minimum melt viscosity can be obtained by using a rotational rheometer (manufactured by TA Instruments) under a measuring pressure of 5 g and using a measuring plate with a diameter of 8 mm. From 30°C to 200°C, the rate of temperature rise is 10°C/min, the measurement frequency is 10 Hz, and the load variation with respect to the above-mentioned measuring plate is 5g, and is determined.

By setting the minimum melt viscosity of the insulating resin layer 2 to a high viscosity of 1500 Pa‧s or higher, it is possible to suppress the useless movement of conductive particles in the crimping of the anisotropic conductive film to the article, especially to prevent anisotropic conductive connection The conductive particles that should be clamped between the terminals flow due to the flow of the resin.

In addition, in the case where the conductive particle dispersion layer 3 of the anisotropic conductive film 10A is formed by press-fitting the conductive particles 1A, 1B into the insulating resin layer 2, the insulation at the time of press-fitting the conductive particles 1A, 1B The insulating resin layer 2, when the conductive particles 1A, 1B are pressed into the insulating resin layer 2 in such a manner that the conductive particles 1A, 1B are exposed from the insulating resin layer 2, the insulating resin layer 2 becomes plastically deformed. The insulating resin layer 2 around the conductive particles 1A, 1B forms a high-viscosity viscous body like a depression 2b ( FIG. 4 ), or when the conductive particles 1A, 1B are not exposed from the insulating resin layer 2 and are buried in the insulating When the resin layer 2 is pressed into the conductive particles 1A, 1B, it becomes a high-viscosity viscous body like a depression 2c ( FIG. 5 ) formed on the surface of the insulating resin layer 2 directly above the conductive particles 1A, 1B. Therefore, the lower limit of the viscosity of the insulating resin layer 2 at 60° C. is preferably 3000 Pa‧s or more, more preferably 4000 Pa‧s or more, further preferably 4500 Pa‧s or more, and the upper limit is preferably 20000 Pa‧s or less. It is preferably not more than 15000 Pa‧s, and more preferably not more than 10000 Pa‧s. This measurement can be obtained by the same measurement method as the minimum melt viscosity, and the extraction temperature is 60°C.

Regarding the specific viscosity of the insulating resin layer 2 when the conductive particles 1A, 1B are pressed into the insulating resin layer 2, according to the shape or depth of the depressions 2b, 2c to be formed, the lower limit is preferably 3000 Pa‧s or more. More preferably at least 4000 Pa‧s, further preferably at least 4500 Pa‧s, the upper limit is preferably at most 20000 Pa‧s, more preferably at most 15000 Pa‧s, further preferably at most 10000 Pa‧s. In addition, it is preferable to obtain such a viscosity at 40-80°C, more preferably at 50-60°C.

As described above, by forming the recesses 2b ( FIG. 4 ) around the conductive particles 1A, 1B exposed from the insulating resin layer 2, the conductive particles 1A, 1B generated when the anisotropic conductive film is pressed against the article The flattening of 1B reduces the resistance received from the insulating resin compared to the case of no recess 2b. Therefore, the conductive particles are easily held by the terminals at the time of anisotropic conductive connection, thereby improving the conduction performance and improving the trapping property.

In addition, by forming the recess 2c (FIG. 5) on the surface of the insulating resin layer 2 directly above the conductive particles 1A, 1B buried without being exposed from the insulating resin layer 2, compared with the case without the recess 2c, the effect is different. When the tropic conductive film is crimped to the article, the pressure tends to concentrate on the conductive particles 1A and 1B. Therefore, the conductive particles are easily held by the terminals during the anisotropic conductive connection, thereby improving the catchability and improving the conduction performance. high.

<"Slope" or "Undulation" instead of depression>

The "recesses" 2b, 2c of the anisotropic conductive film shown in Figures 4 and 5 can also be described based on the viewpoint of "inclination" or "undulation". Hereinafter, it demonstrates referring drawings (FIGS. 8-15).

The anisotropic conductive film 100A is composed of a conductive particle dispersion layer 3 ( FIG. 8 ). In the conductive particle dispersion layer 3 , the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are regularly dispersed in a state exposed on one side of the insulating resin layer 2 . Under the top view of the film, the conductive particles 1A and 1B are not in contact with each other, and in the film thickness direction, the conductive particles 1A and 1B are not overlapped with each other but are regularly dispersed, forming a unit with aligned positions of the conductive particles 1A and 1B in the film thickness direction. layer of conductive particles.

Surface 2a of insulating resin layer 2 around each conductive particle 1A, 1B is formed with inclination 2b with respect to tangent plane 2p of insulating resin layer 2 in the center between adjacent conductive particles. In addition, as described below, in the anisotropic conductive film of the present invention, undulations 2c may be formed on the surface of the insulating resin layer immediately above the conductive particles 1A, 1B embedded in the insulating resin layer 2 (FIG. 11 , Figure 13).

In the present invention, "inclination" refers to a state in which the flatness of the surface of the insulating resin layer near the conductive particles 1A, 1B is damaged, and a part of the resin layer is missing with respect to the tangent plane 2p, thereby reducing the amount of resin. In other words, with regard to the inclination, the surface of the insulating resin layer around the conductive particles is notched with respect to the tangent plane. On the other hand, "undulation" refers to a state in which the resin is reduced due to fluctuations in the surface of the insulating resin layer directly above the conductive particles, and there are portions having height differences like fluctuations. In other words, the amount of resin in the insulating resin layer directly above the conductive particles is smaller than that when the surface of the insulating resin layer directly above the conductive particles is located at the tangent plane. These can be identified by comparing the portion directly above the conductive particles with the flat surface portion ( FIG. 11 , 2f of FIG. 13 ) between the conductive particles. In addition, there are cases where the starting point of the ups and downs exists as an inclination.

As mentioned above, by forming the slope 2b ( FIG. 8 ) around the conductive particles 1A, 1B exposed from the insulating resin layer 2 , the conductive particles 1A, 1B are sandwiched between the terminals for anisotropic conductive connection. When the flattening of the conductive particles 1A and 1B occurs, the resistance received from the insulating resin layer is lower than that of the case of no inclination 2b, so it becomes easier to hold the conductive particles in the terminal, thereby improving the conduction performance. In addition, Improved catchability. The slope is preferably along the shape of the conductive particles. This is because, in addition to expressing the effect of connection more easily, it becomes easy to identify the conductive particles, thereby making it easy to perform inspections and the like at the time of manufacturing the anisotropic conductive film. In addition, some of the inclinations and undulations may disappear due to "hot pressing of the insulating resin layer, etc.", and the present invention includes such cases. In this case, conductive particles may be exposed at one point on the surface of the insulating resin layer. In addition, regarding the anisotropic conductive film, in the case where various electronic components are connected and adjusted accordingly, it is desirable to have a high degree of design freedom so as to satisfy various requirements. disappeared, can be used.

In addition, by forming undulations 2c on the surface of the insulating resin layer 2 immediately above the buried conductive particles 1A, 1B that are not exposed from the insulating resin layer 2 (Fig. 11, Fig. 13), similarly to the case of inclination , the pressing force from the terminal is easily applied to the conductive particles during the anisotropic conductive connection. In addition, by having undulations, the amount of resin directly above the conductive particles is reduced compared to the case where the resin is deposited flatly, so it is easy to remove the resin directly above the conductive particles during connection, and the terminal and the conductive particles are easy to contact, so the terminal The catchability of conductive particles is improved, and the conduction reliability is improved.

(Position of conductive particles in the thickness direction of the insulating resin layer)

The positions of the conductive particles 1A and 1B in the thickness direction of the insulating resin layer 2 in consideration of the viewpoint of "inclination" or "undulation" are the same as above, and the conductive particles 1A and 1B can be separated from the insulating resin layer 2. It may be exposed or not exposed but embedded in the insulating resin layer 2. The distance (hereinafter referred to as the embedded amount) Lb from the tangential plane 2p of the central part between adjacent conductive particles to the deepest part of the conductive particles is the same as that of the conductive particles. The ratio (Lb/D) of the average particle diameter D of the particles (hereinafter referred to as embedding rate) is preferably 30% or more and 105% or less.

By setting the embedding rate (Lb/D) to 30% or more, the conductive particles 1A and 1B can be maintained in a specific particle dispersion state or a specific arrangement by the insulating resin layer 2, and by setting the embedding rate (Lb/D) to 105% In the following, it is possible to reduce unnecessary flow of conductive particles between terminals during anisotropic conductive connection The amount of resin in the insulating resin layer that functions.

In addition, the numerical value of the embedding rate (Lb/D) refers to 80% or more of the total number of conductive particles contained in the anisotropic conductive film, preferably 90% or more, more preferably 96% or more to become the embedding rate (Lb/D) value. Therefore, the so-called embedment rate of 30% or more and 105% or less refers to an embedment rate of 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film. 30% or more and 105% or less. By making the embedding rate (Lb/D) of all the conductive particles uniform in this way, the pressing load is applied to the conductive particles evenly, so the state of capturing the conductive particles of the terminal becomes good, and the conduction reliability improves.

The embedding rate (Lb/D) can be obtained by the following method: Randomly extract 10 or more regions with an area of 30mm2 ^or more from the anisotropic conductive film, and observe a part of the film cross section by using a SEM image. Measure a total of 50 or more conductive particles. In order to further improve the accuracy, it can also be obtained by measuring more than 200 conductive particles.

In addition, the measurement of the embedding ratio (Lb/D) can obtain a certain number of objects at a time by adjusting the focus on the surface view image. Alternatively, a laser-type discrimination displacement sensor (manufactured by KEYENCE Co., Ltd., etc.) may also be used for the measurement of the embedding ratio (Lb/D).

(The embedding rate is more than 30% and less than 60%)

As a more specific embedding form of the conductive particles 1A, 1B having an embedding rate (Lb/D) of 30% or more and less than 60%, first, an anisotropic conductive film 100A as shown in FIG. The aspect in which the conductive particles 1A and 1B are embedded so that the embedding ratio is 30% or more and less than 60% so as to be exposed from the insulating resin layer 2 . The anisotropic conductive film 100A has an inclination 2b, and the inclination 2b is a portion of the surface of the insulating resin layer 2 that is in contact with the conductive particles 1A, 1B exposed from the insulating resin layer 2 and its vicinity relative to the adjacent conductive particles. The tangent plane 2p of the surface 2a of the insulating resin layer in the center between the particles is substantially along the ridgeline of the shape of the conductive particle.

This kind of inclination 2b or the following undulation 2c is achieved by pressing the conductive particles 1A, 1B into the insulation. When the insulating resin layer 2 is used to manufacture the anisotropic conductive film 100A, the conductive particles 1A and 1B can be separated by a viscosity of 3000~20000Pa‧s, more preferably 4500~15000Pa‧s at 40~80°C. formed by pressing.

(The embedding rate is more than 60% and less than 100%)

As a more specific embedding form of the conductive particles 1A and 1B with the embedding rate (Lb/D) of 60% or more and less than 100%, firstly, conductive particles such as the anisotropic conductive film 100A shown in FIG. 8 can be cited. 1A and 1B are aspects in which the insulating resin layer 2 is exposed so as to be embedded with an embedding rate of 60% or more and less than 100%. The anisotropic conductive film 100A has an inclination 2b, and the inclination 2b is a portion of the surface of the insulating resin layer 2 that is in contact with the conductive particles 1A, 1B exposed from the insulating resin layer 2 and its vicinity relative to the adjacent conductive particles. The tangent plane 2p of the surface 2a of the insulating resin layer in the center between the particles is substantially along the ridgeline of the shape of the conductive particle.

Regarding such inclination 2b or undulation 2c described below, in the case of manufacturing the anisotropic conductive film 100A by press-fitting the conductive particles 1A, 1B into the insulating resin layer 2, when the conductive particles 1A, 1B are press-fitted The lower limit of the viscosity is preferably above 3000Pa‧s, more preferably above 4000Pa‧s, more preferably above 4500Pa‧s, and the upper limit is preferably below 20000Pa‧s, more preferably below 15000Pa‧s, still more preferably 10000Pa ‧s or less. In addition, it is preferable to obtain such a viscosity at 40-80°C, more preferably at 50-60°C. In addition, part of the inclination 2b or undulation 2c may disappear due to hot pressing of the insulating resin layer, etc., or the inclination 2b may be changed into the undulation 2c. In addition, conductive particles having the undulation 2c may be formed on the top of the conductive particle. The dots are exposed on the insulating resin layer 2 .

(100% embedding rate)

Next, as an aspect of the embedding ratio (Lb/D) of 100% in the anisotropic conductive film of the present invention, it can be enumerated: like the anisotropic conductive film 100B shown in FIG. 9 , between the conductive particles 1A, 1B The periphery has "inclination 2b substantially along the ridge line of the same shape of the conductive particles as that of the anisotropic conductive film 100A shown in Fig. 8", and the exposed diameter Lc of the conductive particles 1A and 1B exposed from the insulating resin layer 2 is smaller than The level of conductive particles The average particle diameter D; like the anisotropic conductive film 100C shown in Figure 10A, the slope 2b around the exposed portion of the conductive particles 1A, 1B appears steeply near the conductive particles 1A, 1B, and the conductive particles 1A, 1B The exposed diameter Lc is approximately equal to the average particle diameter D of the conductive particles; like the anisotropic conductive film 100D shown in Figure 11, there are relatively shallow undulations 2c on the surface of the insulating resin layer 2. One point of its top 1a is exposed from the insulating resin layer 2 .

In addition, the minute protruding portion 2q may be formed adjacent to the inclination 2b of the insulating resin layer 2 around the exposed portion of the conductive particles, or the undulation 2c of the insulating resin layer directly above the conductive particles. This example is shown in FIG. 10B.

These anisotropic conductive films 100B (FIG. 9), 100C (FIG. 10A), and 100D (FIG. 11) have an embedding rate of 100%, so that the top 1a of the conductive particles 1A, 1B and the surface 2a of the insulating resin layer 2 Align to the same side. If the tops 1a of the conductive particles 1A, 1B are aligned on the same plane as the surface 2a of the insulating resin layer 2, the following effects will be achieved: as shown in Figure 8, the conductive particles 1A, 1B protrude from the insulating resin layer 2 Compared with anisotropic conductive connection, the amount of resin in the film thickness direction is less likely to become uneven around each conductive particle, and the movement of conductive particles caused by resin flow can be reduced. In addition, even if the embedding ratio is not strictly 100%, if the tops 1a of the conductive particles 1A and 1B embedded in the insulating resin layer 2 are aligned to the same level as the surface 2a of the insulating resin layer 2, to get that effect. In other words, when the embedding rate (Lb/D) is approximately 80-105%, especially 90-100%, it can be considered that the top 1a of the conductive particles 1A, 1B embedded in the insulating resin layer 2 and the insulating resin The surface 2a of layer 2 is the same plane, which can reduce the movement of conductive particles caused by resin flow.

In these anisotropic conductive films 100B ( FIG. 9 ), 100C ( FIG. 10A ), and 100D ( FIG. 11 ), since the amount of resin around the conductive particles 1A and 1B in 100D is less likely to become uneven, it is possible to eliminate the amount of resin caused by the resin. The movement of the conductive particles caused by the flow is also one point of the top 1a, but the conductive particles 1A, 1B are exposed from the insulating resin layer 2, so the following effect can be expected: the capture of the conductive particles 1A, 1B of the terminal is also Good, and it is not easy to cause slight movement of conductive particles. Therefore, this aspect is especially useful for fine-pitch or Effective when the space between the bumps is narrow.

In addition, the anisotropic conductive films 100B (FIG. 9), 100C (FIG. 10A), and 100D (FIG. 11) with different shapes or depths of inclinations 2b and undulations 2c can be pressed into the conductive particles 1A and 1B by changing as follows The viscosity of the insulating resin layer 2 and the like are manufactured.

(implementation rate exceeds 100%)

In the anisotropic conductive film of the present invention, when the embedding rate exceeds 100%, the conductive particles 1A and 1B are exposed like the anisotropic conductive film 100E shown in FIG. 12 and have the exposed parts. The inclination 2b of the surrounding insulating resin layer 2 relative to the cutting plane 2p or the undulation 2c of the insulating resin layer 2 directly above the conductive particles 1A, 1B relative to the cutting plane 2p ( FIG. 13 ).

In addition, the insulating resin layer 2 around the exposed portion of the conductive particles 1A, 1B has an anisotropic conductive film 100E ( FIG. 12 ) having an inclination 2b, and the insulating resin layer 2 directly above the conductive particles 1A, 1B has a The anisotropic conductive film 100F (FIG. 13) with undulations 2c can be produced by changing the viscosity of the insulating resin layer 2 when the conductive particles 1A and 1B are pressed in isochronously.

In addition, when the anisotropic conductive film 100E shown in FIG. 12 is used for anisotropic conductive connection, since the conductive particles 1A and 1B are directly pressed by the terminals, the capturing properties of the conductive particles of the terminals are improved. In addition, if the anisotropic conductive film 100F shown in FIG. 13 is used for anisotropic conductive connection, the conductive particles 1A, 1B do not directly press the terminals, but press through the insulating resin layer 2, but in the pressing direction The amount of resin present and the state of FIG. 15 (that is, the conductive particles 1A, 1B are embedded with an embedding rate exceeding 100%, the conductive particles 1A, 1B are not exposed from the insulating resin layer 2, and the insulating resin layer 2 The flat surface state) is relatively small, so the pressing force is easily applied to the conductive particles, and it is possible to prevent the conductive particles 1A, 1B between the terminals from moving unnecessarily due to resin flow during anisotropic conductive connection.

It is easy to obtain the inclination 2b (Fig. 8, Fig. 9, Fig. 10A, Fig. 12) of the insulating resin layer 2 around the exposed portion of the above-mentioned conductive particles, or the undulation 2c (Fig. 11. In terms of the effect of FIG. 13 ), the maximum depth Le of the slope 2b and the conductive particles 1A, 1B The ratio (Le/D) of the average particle diameter D is preferably less than 50%, more preferably less than 30%, and more preferably 20-25%. , The ratio (Ld/D) of the average particle diameter D of 1B is preferably more than 100%, more preferably 100~150%, the ratio of the maximum depth Lf of the undulation 2c to the average particle diameter D of the conductive particles 1A, 1B (Lf /D) is greater than 0, preferably less than 10%, more preferably less than 5%.

In addition, the diameter Lc of the exposed (directly above) portion of the conductive particles 1A, 1B on the slope 2b or undulation 2c can be set to be less than the average particle diameter D of the conductive particles 1A, 1B, preferably 10~90% of the average particle diameter D . One point of the top of the conductive particles 1A, 1B may be exposed, or the conductive particles 1A, 1B may be completely buried in the insulating resin layer 2 so that the diameter Lc becomes zero.

In addition, as shown in FIG. 14, in the anisotropic conductive film 100G whose embedding rate (Lb/D) is less than 60%, the conductive particles 1A and 1B are easy to rotate on the insulating resin layer 2, so that the anisotropic conductive film 100G is improved. From the viewpoint of the capture rate at the time of conductive connection, it is preferable to set the embedding rate (Lb/D) to 60% or more.

In addition, in the aspect (Lb/D) in which the embedding rate exceeds 100%, when the surface of the insulating resin layer 2 is flat like the anisotropic conductive film 100X of the comparative example shown in FIG. The amount of resin between the conductive particles 1A, 1B and the terminals becomes too much. In addition, since the conductive particles 1A and 1B do not directly contact the terminals and press the terminals, but press the terminals through the insulating resin layer, the conductive particles also easily flow due to resin flow.

In this invention, the presence of inclinations 2b and undulations 2c on the surface of the insulating resin layer 2 can be confirmed by observing the cross-section of the anisotropic conductive film with a scanning electron microscope, and can also be confirmed in the field of view observation Undergo verification. The inclination 2b and undulation 2c can also be observed with an optical microscope or a metal microscope. In addition, the size of the inclination 2b and the undulation 2c can also be confirmed by focusing adjustment during image observation, etc. It is the same even after the inclination or undulation is reduced by heat pressing as described above. The reason for this is that traces may remain.

(composition of insulating resin layer)

The insulating resin layer 2 is preferably formed of a curable resin composition, for example, may be formed by containing thermally polymerizable Formation of thermally polymerizable composition of compound and thermal polymerization initiator. A photopolymerization initiator may also be contained in a thermally polymerizable composition as needed.

When a thermal polymerization initiator and a photopolymerization initiator are used in combination, one that functions as both a thermally polymerizable compound and a photopolymerizable compound may be used, and a photopolymerizable compound may also be included in addition to the thermally polymerizable compound. polymeric compound. It is preferable to contain a photopolymerizable compound in addition to a thermopolymerizable compound. For example, a thermal cationic polymerization initiator is used as a thermal polymerization initiator, an epoxy compound is used as a thermal polymerizable compound, a photoradical polymerization initiator is used as a photopolymerization initiator, and an acrylate compound is used as a photopolymerizable compound. .

As a photoinitiator, you may contain multiple types which respond to the light of a different wavelength. Thereby, the wavelengths used for the photocuring of the resin constituting the insulating resin layer during the production of the anisotropic conductive film and the photocuring of the resin for adhering electronic components during the anisotropic conductive connection can be used separately.

In the photocuring during production of the anisotropic conductive film, all or part of the photopolymerizable compound contained in the insulating resin layer may be photocured. By this photocuring, the arrangement of the conductive particles 1A and 1B in the insulating resin layer 2 can be maintained or fixed, and the suppression of short circuit and the improvement of trapping are expected. Moreover, the viscosity of the insulating resin layer in the manufacturing process of an anisotropic conductive film can also be adjusted suitably by this photocuring. In particular, this photocuring is preferably performed when the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A, 1B is less than 0.6. The reason is that when the layer thickness of the insulating resin layer 2 is thinner with respect to the diameter of the conductive particles, the arrangement of the conductive particles is more reliably maintained or fixed in the insulating resin layer 2, and the insulating properties are improved. The viscosity adjustment of the resin layer 2 suppresses the reduction of the yield rate in the connection of the electronic parts using an anisotropic conductive film.

The compounding quantity of the photopolymerizable compound in an insulating resin layer becomes like this. Preferably it is 30 mass % or less, More preferably, it is 10 mass % or less, More preferably, it is less than 2 mass %. The reason for this is that when there are too many photopolymerizable compounds, the pushing force applied by the press-fitting at the time of connection increases.

Examples of thermally polymerizable compositions include thermally radically polymerizable acrylate compositions containing (meth)acrylate compounds and thermally radical polymerization initiators, thermally radically polymerizable acrylate compositions containing epoxy compounds and thermally cationic polymerization initiators Thermal cationic polymerizable epoxy-based compositions, etc. Instead of the thermal cation polymerizable epoxy composition containing a thermal cationic polymerization initiator, a thermal anionic polymerizable epoxy composition containing a thermal anionic polymerization initiator may also be used. Moreover, unless there is a hindrance in particular, multiple polymeric compounds can also be used together. Examples of combined use include combined use of a cationically polymerizable compound and a radically polymerizable compound, and the like.

Here, as the (meth)acrylate compound, a conventionally known thermally polymerizable (meth)acrylate monomer can be used. For example, a monofunctional (meth)acrylate monomer and a difunctional or higher polyfunctional (meth)acrylate monomer can be used.

As a thermal radical polymerization initiator, an organic peroxide, an azo compound, etc. are mentioned, for example. In particular, an organic peroxide that does not generate nitrogen gas that causes air bubbles can be preferably used.

Regarding the amount of the thermal radical polymerization initiator used, if it is too small, hardening will be poor, and if it is too large, the life of the product will be shortened. Therefore, it is preferably 2 to 60 parts by mass relative to 100 parts by mass of the (meth)acrylate compound. , more preferably 5 to 40 parts by mass.

Examples of epoxy compounds include bisphenol A epoxy resins, bisphenol F epoxy resins, novolac epoxy resins, modified epoxy resins, and alicyclic epoxy resins. Two or more of these are used in combination. In addition, an epoxy compound may be used in combination other than the oxetane compound.

As the thermal cationic polymerization initiator, known thermal cationic polymerization initiators as epoxy compounds can be used, for example, iodonium salts, permalium salts, phosphonium salts, ferrocenes, etc. that generate acids by heat can be used, especially Aromatic cobaltium salts that exhibit good latency to temperature can be preferably used.

Regarding the amount of the thermal cationic polymerization initiator used, if it is too small, the hardening tends to be poor, and if it is too large, the life of the product tends to be shortened, so it is preferably 2 to 60 parts by mass relative to 100 parts by mass of the epoxy compound , more preferably 5 to 40 parts by mass.

The thermopolymerizable composition preferably contains a film-forming resin or a silane coupling agent. Examples of film-forming resins include phenoxy resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, urethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefin resins. Resin etc. can use these 2 or more types together. Among these, a phenoxy resin can be preferably used from the viewpoint of film-forming properties, processability, and connection reliability. The weight average molecular weight is preferably at least 10,000. Moreover, an epoxy-type silane coupling agent, an acryl-type silane coupling agent, etc. are mentioned as a silane coupling agent. These silane coupling agents are mainly alkoxysilane derivatives.

In addition to the above-mentioned conductive particles 1A and 1B, an insulating filler may be contained in the thermopolymerizable composition in order to adjust the melt viscosity. Silica powder, alumina powder, etc. are mentioned as this insulating filler. It is preferably a fine filler with an insulating filler particle size of 20 to 1000 nm, and the blending amount is preferably 5 to 50 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable compound) such as an epoxy compound. .

The anisotropic conductive film of the present invention may contain fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion scavengers, etc. in addition to the above-mentioned insulating fillers.

(layer thickness of insulating resin layer)

In the anisotropic conductive film of the present invention, the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A, 1B can be set as the following reason. is 0.3 or more, and the upper limit can be made 10 or less. Therefore, the ratio is preferably 0.3-10, more preferably 0.6-8, and still more preferably 0.6-6. Here, the average particle diameter D of conductive particle 1A, 1B means the average particle diameter. If the layer thickness La of the insulating resin layer 2 is too large, the conductive particles 1A, 1B are likely to be misaligned due to resin flow during anisotropic conductive connection, and the catchability of the conductive particles 1A, 1B of the terminal is reduced. Since this tendency becomes remarkable when this ratio (La/D) exceeds 10, it is more preferably 8 or less, and it is still more preferable that it is 6 or less. Conversely, if the layer thickness La of the insulating resin layer 2 is too small and the ratio (La/D) is less than 0.3, it will be difficult to maintain the conductive particles 1A, 1B by the insulating resin layer 2. It is a specific particle dispersion state or a specific arrangement, so the ratio (La/D) is preferably 0.3 or more, and it is more preferable in terms of maintaining a specific particle dispersion state or a specific arrangement by the insulating resin layer 2. 0.6 or more. In addition, when the terminal to be connected is a high-density COG, the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A, 1B is preferably 0.8-2.

On the other hand, when the average particle diameter D is 10 μm or more, the upper limit of La/D is 3.5 or less, preferably 2.5 or less, more preferably 2 or less, and the lower limit is 0.8 or more, preferably 0.8 or less. 1 or more, more preferably greater than 1.3.

Regardless of the size of the average particle diameter D, if the layer thickness La of the insulating resin layer 2 is too large and the ratio becomes too large, it is difficult for the conductive particles 1A and 1B to be pressed against the terminals during anisotropic conductive connection, and the conductive particles are easily Flow due to resin flow. Therefore, the position of the conductive particles tends to shift, and the catchability of the conductive particles of the terminal decreases. In addition, in order to press the conductive particles against the terminal, the thrust required for the pressing jig is also increased, hindering the low-voltage structure. Conversely, when the layer thickness La of the insulating resin layer 2 is too small and the ratio becomes too small, it will be difficult to maintain the conductive particles 1A, 1B in a specific arrangement by the insulating resin layer 2 .

<morph form>

As the anisotropic conductive film of the present invention, the second insulating resin layer 4 having a lower minimum melt viscosity than the resin constituting the insulating resin layer 2 can be laminated on the conductive particle dispersion layer 3 (FIGS. 6 and 7). The second insulating resin layer 4 can fill spaces formed by terminals such as bumps of electronic components during anisotropic conductive connection, thereby improving the adhesion between opposing electronic components. That is, in order to realize low-voltage assembly of electronic parts using anisotropic conductive film, and to suppress resin flow of insulating resin layer 2 during anisotropic conductive connection and improve particle capture properties of conductive particles 1A, 1B, it is more desirable In order to increase the viscosity of the insulating resin layer 2 and reduce the thickness of the insulating resin layer 2 within the range where the position of the conductive particles 1A and 1B does not shift, if the thickness of the insulating resin layer 2 becomes too thin, then Insufficient amount of resin for bonding opposing electronic parts is caused, and thus there is a risk of lowering the adhesiveness. In this regard, by providing the second insulating resin layer 4 with a lower viscosity than the insulating resin layer 2 during anisotropic conductive connection, the adhesion between electronic parts can also be improved, because the second insulating resin The fluidity of the layer 4 is higher than that of the insulating resin layer 2, so it is less likely to hinder the clamping or pressing of the conductive particles 1A, 1B using the terminals.

In the case of laminating the second insulating resin layer 4 on the conductive particle dispersion layer 3, regardless of whether the second insulating resin layer 4 is located on the formation surface of the depression 2b, it is preferable to paste the second insulating resin layer 4 Electronic components that are pressurized using a tool (insulating resin layer 2 is attached to electronic components placed on a stage). Thereby, useless movement of conductive particles can be avoided, and capture performance can be improved.

The greater the difference in the minimum melt viscosity ratio between the insulating resin layer 2 and the second insulating resin layer 4, the easier it is for the space formed by the electrodes or bumps of the electronic component to be filled by the second insulating resin layer 4, and the more electronic components can be improved. The adhesion of parts to each other. In addition, the more this difference exists, the less the amount of movement of the insulating resin layer 2 existing in the conductive particle dispersion layer 3 becomes, the less likely the conductive particles 1A, 1B between the terminals will flow due to the flow of the resin. Particles 1A and 1B are preferable because the capturing properties are improved. In practical applications, the minimum melt viscosity ratio between the insulating resin layer 2 and the second insulating resin layer 4 is preferably 2 or higher, more preferably 5 or higher, and even more preferably 8 or higher. On the other hand, if the ratio is too large, when the long anisotropic conductive film is made into a package, resin overflow or sticking may occur, so it is preferably 15 or less in practical use. More specifically, the preferred minimum melt viscosity of the second insulating resin layer 4 satisfies the above ratio and is 3000 Pa·s or less, preferably 2000 Pa·s or less, especially 100 to 2000 Pa·s.

In addition, the second insulating resin layer 4 can be formed by adjusting the viscosity of the same resin composition as that of the insulating resin layer 2 .

In addition, the layer thickness of the second insulating resin layer 4 is preferably 4 to 20 μm. Alternatively, it is preferably 1 to 8 times the average particle diameter D of the conductive particles 1A and 1B.

In addition, the overall minimum melt viscosity of the anisotropic conductive films 10F and 10G formed by combining the insulating resin layer 2 and the second insulating resin layer 4 is below 8000Pa‧s in practical applications, preferably 200~7000Pa‧ s, more preferably 200~4000Pa‧s.

As a specific form of lamination of the second insulating resin layer 4, for example, as shown in FIG. 6 When the conductive particles 1A, 1B protrude from one side of the insulating resin layer 2 like the directional conductive film 10F, the second insulating resin layer 4 can be layered on the protruding area, and the conductive particles 1A, 1B can be immersed in the second insulating resin layer 2. 2 Insulating resin layer 4. When the embedding rate (Lb/D) of the conductive particles 1A and 1B is 0.95 or less, it is preferable to laminate the second insulating resin layer 4 in this way, and it is more preferable to be 0.9 or less. In addition, when the average particle diameter D is less than 10 μm, it may be more desirable to laminate in this way.

On the other hand, like the anisotropic conductive film 10G shown in FIG. 7, the second insulating resin may be laminated on "the surface opposite to the surface of the insulating resin layer 2 in which the conductive particles 1A, 1B are embedded". Layer 4.

(the third insulating resin layer)

A third insulating resin layer may be provided on the side opposite to the second insulating resin layer 4 via the insulating resin layer 2 . The third insulating resin layer can be made to function as an adhesive layer. Similar to the second insulating resin layer 4 , it may be provided to fill a space formed by electrodes or bumps of electronic components.

The resin composition, viscosity and thickness of the third insulating resin layer may be the same as that of the second insulating resin layer 4 or may be different. The minimum melt viscosity of the anisotropic conductive film formed by combining the insulating resin layer 2, the second insulating resin layer 4 and the third insulating resin layer is not particularly limited. The best is 200~7000Pa‧s, more preferably 200~4000Pa‧s.

<Manufacturing method of anisotropic conductive film>

The anisotropic conductive film of the present invention can be produced, for example, by maintaining the conductive particles 1A, 1B on the surface of the insulating resin layer 2 in an independent specific regular arrangement or in a random dispersion state, and using a flat plate Or a roller press-fits the conductive particles 1A, 1B into the insulating resin layer 2 .

Here, the embedding amount Lb of the conductive particles 1A, 1B in the insulating resin layer 2 can be adjusted by pressing force, temperature, etc. when pressing the conductive particles 1A, 1B. And the depth can be adjusted by the viscosity of the insulating resin layer 2 during pressing, the pressing speed, temperature, etc.

In addition, there is no particular limitation on the method for holding the conductive particles 1A, 1B on the insulating resin layer 2, but when the conductive particles 1A, 1B are arranged regularly, for example, a transfer mold is used. Conductive particles 1A, 1B mixed at a specific ratio are held in insulating resin layer 2 . As the transfer mold, for example, a transfer mold material formed of inorganic materials such as metals such as silicon, various ceramics, glass, and stainless steel, or organic materials such as various resins is formed by known openings such as photolithography. method to form those with openings. In addition, the transfer mold can be in the shape of a plate, a roll, or the like.

As a method of obtaining the conductive particles 1A, 1B of the insulating resin layer 2 in a randomly dispersed state, the insulating resin layer 2 can also be formed by kneading (mixing) the conductive particles 1A, 1B at a specific ratio. and coating it on a release film to obtain an insulating resin layer in which conductive particles 1A, 1B are located at random positions.

In order to economically connect electronic components using the anisotropic conductive film, the anisotropic conductive film is preferably long to some extent. Therefore, the length of the anisotropic conductive film is preferably 5 m or more, more preferably 10 m or more, and more preferably 25 m or more. On the other hand, if the anisotropic conductive film becomes too long, the conventional connecting device cannot be used. The conventional connecting device is used in the manufacture of electronic parts using the anisotropic conductive film, and the operability is also poor. poor. Therefore, the length of the anisotropic conductive film is preferably 5000 m or less, more preferably 1000 m or less, and still more preferably 500 m or less. From the viewpoint of excellent handleability, it is preferable to make such a long body of the anisotropic conductive film into a package wound into a core.

<How to use anisotropic conductive film>

The anisotropic conductive film of the present invention can be used for anisotropic conductive connection of first electronic parts such as IC chips, IC modules, and FPCs with second electronic parts such as FPCs, glass substrates, plastic substrates, rigid substrates, and ceramic substrates. It can be used preferably, especially as a plastic substrate, and it is exemplified that a terminal is formed on a PET substrate that is easily deformed or cracked by crimping under high pressure. In addition, the PET substrate may be one in which a polyimide substrate is laminated via an adhesive. As an example, the total thickness of these can be set to 0.15 mm or less. IC chips or wafers can also be stacked and multilayered using the anisotropic conductive film of the present invention. In addition, electronic components to be connected using the anisotropic conductive film of the present invention are not limited to the above-mentioned electronic components. In recent years, various electric subpart. The present invention also includes a connection structure in which electronic components are anisotropically conductively connected using the anisotropic conductive film of the present invention. Also included is a method for producing a connection structure including the step of arranging the anisotropic conductive film of the present invention between the first electronic component and the second electronic component to perform anisotropic conductive connection between them.

As a method of connecting electronic components using an anisotropic conductive film, in the case where the resin layer of the anisotropic conductive film is composed of a single layer of the conductive particle dispersion layer 3, it can be produced by the following method: For various substrates, etc. Electronic parts, from the side of the surface of the anisotropic conductive film where the conductive particles 1A, 1B are embedded, temporarily attached and temporarily crimped, and the surface of the temporarily crimped anisotropic conductive film is not embedded with conductive particles 1A, 1B On the other side, the first electronic components such as IC chips are aligned and thermocompression bonded. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerizable compound, but also a photopolymerization initiator and a photopolymerizable compound (which may also be the same as the thermal polymerizable compound) In this case, it can also be a crimping method that uses both light and heat. In this way, unintended movement of conductive particles can be suppressed to a minimum. In addition, the side where the conductive particles are not buried can also be temporarily attached to the second electronic component and used. Moreover, you may temporarily attach an anisotropic conductive film to a 1st electronic component instead of a 2nd electronic component.

In addition, when the anisotropic conductive film is formed of a laminate of the conductive particle dispersion layer 3 and the second insulating resin layer 4, the conductive particle dispersion layer 3 is temporarily attached to second electronic components such as various substrates and temporarily pressed. For bonding, the first electronic component such as an IC chip is aligned on "the second insulating resin layer 4 side of the temporary pressure-bonded anisotropic conductive film", and placed and thermocompression-bonded. The second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component. In addition, the conductive particle dispersion layer 3 side may be temporarily attached to the first electronic component and used.

Example

Hereinafter, the present invention will be specifically described based on examples.

Embodiment 1~4, comparative example 1, 2

(1) Manufacture of anisotropic conductive film

The resin composition for forming an insulating resin layer forming the conductive particle dispersion layer and the resin composition for forming a second insulating resin layer were prepared with the compositions shown in Table 1, respectively. The minimum melt viscosity of the insulating resin layer is 3000 Pa‧s or more, and the ratio of the minimum melt viscosity of the insulating resin layer to the minimum melt viscosity of the second insulating resin layer is 2 or more.

On the other hand, prepare high-hardness conductive particles (20% compression elastic modulus 22000N/mm) with about 70 alumina particles (average particle diameter 150nm) on the surface of the resin core particle and a Ni layer (thickness 100nm) on the outermost layer ^2. The average particle size is 3 μm, manufactured by Sekisui Chemical Industry Co., Ltd. (manufactured by the method described in Japanese Patent Laid-Open No. 2006-269296). In addition, prepare low-hardness conductive particles with the same structure as high-hardness conductive particles (20% compression elastic modulus 6000 N/mm ² , average particle diameter 3 μm, manufactured by Sekisui Chemical Co., Ltd.). Moreover, in the following Examples 1-24 and Comparative Examples 1-10, the electroconductive particle by Sekisui Chemical Co., Ltd. manufactured similarly was prepared.

High-hardness conductive particles and low-hardness conductive particles were mixed into the resin composition for forming an insulating resin layer (high-viscosity resin layer) in such a manner that the number density thereof became the ratio shown in Table 2, and the resin composition was mixed with a bar coater. Spread it on a PET film with a film thickness of 50 μm, and dry it in an oven at 80°C for 5 minutes to form a conductive particle dispersion layer with high-hardness conductive particles and low-hardness conductive particles randomly dispersed on the PET film . The thickness of the insulating resin layer of the conductive particle dispersion layer was 6 μm. In addition, the resin composition for forming the second insulating resin layer was coated on a PET film with a film thickness of 50 μm by a bar coater, and dried in an oven at 80° C. for 5 minutes to form on the PET film. The resin layer used as the second insulating resin layer with a thickness of 12 μm. This resin layer was laminated|stacked on the said conductive particle dispersion layer, and it was set as the anisotropic conductive film.

(2) Evaluation of anisotropic conductive film

The anisotropic conductive films of the examples and comparative examples produced in (1) were cut to an area sufficient for connection, and a connection structure of electronic parts was produced using the obtained ones, and (a) capture efficiency was evaluated as follows , (b) indentation, (c) particle flattening rate, (d) resistance value. The results are shown in Table 2.

(a) Capture efficiency

For the evaluation IC shown below and the glass substrate (Ti/Al wiring) with the terminal pattern corresponding to the evaluation IC, pressurize at 200°C for 5 seconds at the pressure described in Table 2 through the anisotropic conductive film. The heat and pressure were applied to obtain a connection structure for evaluation.

Evaluation IC:

Dimensions 1.8×20.0mm

Thickness 0.5mm

Bump specification size 30×85μm, distance between bumps 20μm, surface material of bumps Au

For 100 terminal pairs after heating and pressing, the captured numbers of high-hardness conductive particles and low-hardness conductive particles were measured, and the average value was calculated. In addition, the theoretical value of the high-hardness conductive particles and low-hardness conductive particles existing on the terminals before heating and pressing is calculated in advance based on [terminal area of 100 terminals] × [number density of conductive particles], and the measured conductive The ratio of the number of captured particles to the theoretical value was evaluated based on the following criteria. In practical application, it is better to have a rating of B or above.

Capture Efficiency Evaluation Benchmark

A: More than 30%

B: More than 15% and less than 30%

C: less than 15%

(b) Indentation

Use a metal microscope to observe the indentation of the high-hardness conductive particles and low-hardness conductive particles of the connection structure manufactured in (a), and use the image analysis software WinROOF (Mitani Corporation) for the five terminal pairs after heating and pressing Co., Ltd.) measured the number of indentations (captures) of high-hardness conductive particles and low-hardness conductive particles, and calculated the average value. In addition, the theoretical value of the high-hardness conductive particles and low-hardness conductive particles existing on the terminals before heating and pressing is calculated in advance based on [terminal area of 5 terminals] × [number density of conductive particles], and the measured conductive The ratio of the number of indentation (trapping) of particles to the theoretical value was evaluated based on the following criteria. In addition, in the dispersed anisotropic conductive film in which the conductive particles are randomly arranged, the indentations confirmed are about 100 in total for five bumps, and the following conductive particles are square In the aligned anisotropic conductive film arranged in a grid, the total number of indentations of five bumps is about 200.

Indentation Evaluation Criteria

OK: More than 50% of the theoretical value can be identified as indentation

NG: less than 50% of the theoretical value can be identified as indentation

(c) Particle flattening rate

Immediately after production (initial stage) of the connection structure for evaluation manufactured in (a), and the connection structure for evaluation manufactured in (a) was placed in a constant temperature bath at a temperature of 85°C and a humidity of 85%RH for 500 After one hour (500h), the distance between the facing terminals was measured as the particle size after crimping, and the average particle size was obtained. On the other hand, the average particle diameter before pressure bonding was also obtained in advance, the particle flattening rate was calculated according to the following formula, and the evaluation was performed according to the following criteria. In practical application, it is better to have a rating of B or above.

Particle flattening rate (%)=([average particle size before crimping]-[average particle size after crimping])×100/[average particle size before crimping]

Evaluation criteria of particle flattening rate at initial stage and 500h

A: More than 10%

B: More than 5% and less than 10%

C: less than 5%

(d) resistance value

Immediately after production (initial stage) of the connection structure for evaluation manufactured in (a), and the connection structure for evaluation manufactured in (a) was placed in a constant temperature bath at a temperature of 85°C and a humidity of 85%RH for 500 After one hour (500h), the conduction resistance was measured by the four-probe method, and the evaluation was performed according to the following criteria. The resistance value is preferably above the B evaluation in practical applications.

Evaluation criteria for initial resistance value

A: Less than 3Ω

B: More than 3Ω and less than 5Ω

C: More than 5Ω and less than 10Ω

D: 10Ω or more

Evaluation criteria of resistance value at 500h

A: Less than 3Ω

B: More than 3Ω and less than 5Ω

C: More than 5Ω and less than 10Ω

D: 10Ω or more

Embodiment 5～8, comparative example 3,4

The same conductive particles as in Example 1 were prepared. Among them, by adjusting the 20% compressive elastic modulus of the resin core particles, prepare conductive particles (average particle diameter 3 μm) with a 20% compressive elastic modulus of 14000N/ ^mm2 as high-hardness conductive particles, and prepare a 20% compressive elastic modulus of 6000N /mm ² conductive particles (average particle size 3μm) as low hardness conductive particles.

The high-hardness conductive particles and the low-hardness conductive particles were mixed into the resin composition for forming an insulating resin layer (high-viscosity resin layer) in such a manner that the ratio shown in Table 3 was obtained, except that it was the same as in Example 1. In this way, an anisotropic conductive film in which high-hardness conductive particles and low-hardness conductive particles are randomly dispersed is produced.

In addition, (a) capture efficiency, (b) indentation, (c) particle flattening rate, and (d) resistance value were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Embodiment 9～12, comparative example 5

The same conductive particles as in Example 1 were prepared. Among them, by adjusting the 20% compressive elastic modulus of the resin core particles, prepare conductive particles (average particle diameter 3 μm) with a 20% compressive elastic modulus of 9000N/ ^mm2 as high-hardness conductive particles, and prepare a 20% compressive elastic modulus of 6000N /mm ² conductive particles (average particle size 3μm) as low hardness conductive particles.

The high-hardness conductive particles and the low-hardness conductive particles were mixed into the resin composition for forming an insulating resin layer (high-viscosity resin layer) in such a manner that the ratio shown in Table 4 was obtained, except that it was the same as in Example 1. In this way, an anisotropic conductive film in which high-hardness conductive particles and low-hardness conductive particles are randomly dispersed is produced.

In addition, (a) capture efficiency, (b) indentation, (c) particle flattening rate, and (d) resistance value were evaluated in the same manner as in Example 1. The results are shown in Table 4.

Embodiment 13～16, comparative example 6,7

With the blending composition shown in Table 1, a resin composition for forming an insulating resin layer forming a conductive particle dispersion layer was prepared, which was coated on a PET film with a film thickness of 50 μm by a bar coater, and heated at 80°C. Dry in an oven for 5 minutes to form an insulating resin layer on the PET film. The thickness of the insulating resin layer was 6 μm. In addition, the second insulating resin layer-forming resin composition was prepared with the composition shown in Table 1, and in the same manner A resin layer with a thickness of 12 μm was formed.

In addition, the same high-hardness conductive particles with a 20% compressive modulus of 22000 N/mm ² and low-hard conductive particles with a 20% compressive modulus of 6000 N/mm ² were prepared as in Example 1.

On the other hand, as shown in Figure 1A, the conductive particles are arranged in a square lattice, and the overall number density of the high-hardness conductive particles and the low-hardness conductive particles becomes the value shown in Table 5. The particles of the transparent resin flow into the mold in a molten state, and are cooled and solidified to form a resin mold in which the recesses are arranged in the pattern shown in FIG. 1A.

By mixing high-hardness conductive particles and low-hardness conductive particles in the ratio shown in Table 5 and filling the concave portion of the resin mold, covering the above-mentioned insulating resin layer, pressing at 60°C at 0.5MPa and make it fit. Then, the insulating resin layer was peeled off from the mold, and the conductive particles on the insulating resin layer were pressed into the insulating resin layer under (pressing conditions: 60~70°C, 0.5MPa) to form a conductive particle dispersion layer. In this case, the embedding rate was set to 99.9%. On the surface of the conductive particle dispersion layer embedded with conductive particles, a resin layer formed of the above-mentioned resin composition for forming the second insulating resin layer is laminated, so that the high-hardness conductive particles and the low-hardness conductive particles are arranged in a square lattice as a whole Anisotropic conductive film.

The thus obtained anisotropic conductive film was cut into an area sufficient for connection, and using the cut anisotropic conductive film, an evaluation connection structure was produced in the same manner as in Example 1, and (a) capture efficiency was evaluated. , (b) indentation, (c) particle flattening rate, (d) resistance value. The results are shown in Table 5.

Embodiment 17～20, comparative example 8,9

The same high-hardness conductive particles with a 20% compressive elastic modulus of 14000 N/mm ² and low-hard conductive particles with a 20% compressive elastic modulus of 6000 N/mm ² were prepared as in Example 5.

The high-hardness conductive particles and the low-hardness conductive particles were mixed in the ratio shown in Table 6 and filled into a resin mold. In the same manner as in Example 13, a high-hardness Anisotropic conductive film in which high-strength conductive particles and low-hardness conductive particles are arranged in a square grid.

In addition, similarly to Example 1, it was cut to an area sufficient for connection, and (a) capture efficiency, (b) indentation, (c) particle flattening rate, (d) were evaluated using the cut anisotropic conductive film. )resistance. The results are shown in Table 6.

Embodiment 21～24, comparative example 10

The same high-hardness conductive particles with a 20% compression modulus of 9000 N/mm ² and 20% low-hardness conductive particles with a compression modulus of 6000 N/mm ² were prepared as in Example 9.

The high-hardness conductive particles and low-hardness conductive particles were mixed in the ratio shown in Table 7 and filled into a resin mold. In the same manner as in Example 13, high-hardness conductive particles and low-hardness conductive particles were produced. Anisotropic conductive film with particles arranged in a square lattice as a whole.

In addition, similarly to Example 1, it was cut to an area sufficient for connection, and (a) capture efficiency, (b) indentation, (c) particle flattening rate, (d) were evaluated using the cut anisotropic conductive film. )resistance. The results are shown in Table 7.

It can be seen from Table 2 that, based on the implementation of 20% high-hardness conductive particles with a compressive modulus of 22000N/ ^mm2 and 20% of low-hardness conductive particles with a compressive modulus of 6000N/ ^mm2 , and random arrangement of conductive particles For the anisotropic conductive films of Examples 1 to 4, the indentation evaluation was good, and the conduction characteristics (initial resistance value, 500h resistance value) were also good. In contrast, regarding the anisotropic conductive film of Comparative Example 1 containing only 20% of high-hardness conductive particles with a compressive modulus of 22000N/ ^mm2 , and the anisotropic conductive film containing only 20% of low-hardness conductive particles with a compressive modulus of 6000N/ ^mm2 The anisotropic conductive film of Comparative Example 2 with particles was poor in the evaluation of indentation, and the conduction characteristic (500h) of the anisotropic conductive film of Comparative Example 1 containing only high-hardness conductive particles was poor. It is deduced from this that if the conductive particles are only low-hardness conductive particles, the hardness is insufficient, so it becomes difficult to see the indentation state, and if the conductive particles are only high-hardness conductive particles, the compression of the conductive particles becomes too hard. full, so the indentation is hard to see. In addition, even when the evaluation of the indentation was OK in the case of only the high-hardness conductive particles, the indentation was more likely to be observed in the example in which the high-hardness conductive particles and the low-hardness conductive particles were mixed.

It can be seen from Table 5 that in the implementation of the implementation that contains 20% high-hardness conductive particles with a compression elastic rate of 22000N/ ^mm2 and 20% low-hardness conductive particles with a compressive elastic rate of 6000N/ ^mm2 , and the conductive particles are arranged in a square grid In Examples 13 to 16, similarly to the above-mentioned Examples 1 to 4, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500h resistance value) were also good. In Comparative Examples 6 and 7 containing only either the high-hardness conductive particles or the low-hardness conductive particles, there was a problem in indentation.

As can be seen from Table 3, regarding the implementation of containing 20% of high-hardness conductive particles with a compressive modulus of 14000N/ ^mm2 and 20% of low-hardness conductive particles with a compressive modulus of 6000N/ ^mm2 , and randomly arranging the conductive particles For the anisotropic conductive films of Examples 5-8, the indentation evaluation was good, and the conduction characteristics (initial resistance value, 500h resistance value) were also good. In particular, it is good even when the pressure at the time of anisotropic conductive connection is a low pressure of 60 MPa. In contrast, the evaluation of the indentation of the anisotropic conductive film of Comparative Example 3, which only contains 20% of high-hardness conductive particles with a compressive elastic rate of 14000N/ ^mm2 , is poor, and if the pressure at the time of anisotropic conductive connection is 60MPa , the conduction characteristics (500h) are also poor. In addition, the anisotropic conductive film of Comparative Example 4 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

From Table 6, it can be seen that in the implementation of 20% high-hardness conductive particles with a compressive modulus of 14000N/ ^mm2 and 20% of low-hardness conductive particles with a compressive modulus of 6000N/ ^mm2 , and the conductive particles are arranged in a square grid In Examples 17 to 20, similarly to the aforementioned Examples 5 to 8, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500h resistance value) were also good. In Comparative Examples 8 and 9 containing only either one of the high-hardness conductive particles or the low-hardness conductive particles, there was a problem in indentation.

It can also be seen from Table 4 that the anisotropy of Examples 9 to 12 that contain 20% of the high-hardness conductive particles with a compressive modulus of 9000N/ ^mm2 and 20% of the low-hardness conductive particles with a compressive modulus of 6000N/ ^mm2 The indentation evaluation of the conductive film is good, and the conduction characteristics (initial resistance value, 500h resistance value) are also good, especially when the pressure of anisotropic conductive connection is a low pressure of 60MPa. In addition, the anisotropic conductive film of Comparative Example 5 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

From Table 7, it can be seen that in the implementation of 20% high-hardness conductive particles with a compressive elastic rate of 9000N/ ^mm2 and 20% low-hardness conductive particles with a compressive elastic rate of 6000N/ ^mm2 , and the conductive particles are arranged in a square grid In Examples 21 to 24, similar to the above Examples 9 to 12, the evaluation of the indentation is good, and the conduction characteristics (initial resistance value, 500h resistance value) are also good, especially even if the pressure during anisotropic conductive connection is It is also good at low pressure of 60MPa. In addition, the anisotropic conductive film of Comparative Example 10 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

1A: High hardness conductive particles

1B: Low hardness conductive particles

2: Insulating resin layer

10A: Anisotropic conductive film

20: terminal

A: grid axis

θ: angle

Claims (17)

An anisotropic conductive film, which is dispersed in an insulating resin layer as conductive particles with a 20% compressive elastic modulus of 8,000 to 28,000 N/mm ² of high-hardness conductive particles and a 20% compressive elastic modulus lower than the high-hardness conductive particles Particles are low-hardness conductive particles, and the average particle size of the whole conductive particles is less than 10 μm, the number density of low-hardness conductive particles is more than 10% of the whole conductive particles, and the positions of the conductive particles in the film thickness direction are aligned, including high-hardness The conductive particles of the conductive particles and the low-hardness conductive particles are arranged regularly in plan view, and the surface of the insulating resin layer near the high-hardness conductive particles and the low-hardness conductive particles is opposite to the insulating resin layer in the center between the adjacent conductive particles. The tangent planes of the layers have slopes or undulations. For example, the anisotropic conductive film of claim 1, wherein the overall number density of the conductive particles is not less than 6,000/mm ² and not more than 42,000/mm ² . The anisotropic conductive film according to claim 1 or 2, wherein the ratio (La/D) of the thickness La of the insulating resin layer to the average particle diameter D of the entire conductive particles is 0.3 or more. The anisotropic conductive film as claimed in claim 1 or 2, wherein the embedding rate of conductive particles is not less than 30% and not more than 105%. An anisotropic conductive film, which is dispersed in an insulating resin layer as conductive particles with a 20% compressive elastic modulus of 8,000 to 28,000 N/mm ² of high-hardness conductive particles and a 20% compressive elastic modulus lower than the high-hardness conductive particles Particles are low-hardness conductive particles, and the average particle size of the whole conductive particles is 10 μm or more, the number density of the whole conductive particles is 20 pieces/mm2 ^or more and 2000 pieces/ ^mm2 or less, and the number density of low-hardness conductive particles is It is more than 10% of the whole conductive particles, the positions of the conductive particles in the film thickness direction are aligned, and the conductive particles including high-hardness conductive particles and low-hardness conductive particles are regularly arranged in a top view, and the high-hardness conductive particles and low-hardness conductive particles are arranged The surface of the adjacent insulating resin layer has an inclination or undulation with respect to a tangent plane of the insulating resin layer at the center between adjacent conductive particles. The anisotropic conductive film according to claim 5, wherein the ratio (La/D) of the thickness La of the insulating resin layer to the average particle diameter D of the entire conductive particles is 3.5 or less. For example, the anisotropic conductive film of claim 5 or 6, wherein the embedding rate of conductive particles is not less than 30% and not more than 105%. For example, the anisotropic conductive film of any one of items 1, 2, 5, and 6 in the scope of the patent application, wherein the 20% compressive elastic rate of the low-hardness conductive particles is 10% of the 20% compressive elastic rate of the high-hardness conductive particles Above and below 70%. The anisotropic conductive film according to any one of items 1, 2, 5, and 6 of the scope of application, wherein the number density of the low-hardness conductive particles is more than 20% and less than 80% of the total conductive particles. The anisotropic conductive film as claimed in claim 1 or 5, wherein the number ratio of conductive particles including high-hardness conductive particles and low-hardness conductive particles without contact with each other is 95% or more. The anisotropic conductive film according to any one of items 1, 2, 5, and 6 of the patent claims, wherein the conductive particles with high hardness and conductive particles with low hardness are randomly mixed. The anisotropic conductive film according to claim 1 or 5 of the patent scope, wherein, in the above-mentioned slope, the surface of the insulating resin layer around the high-hardness conductive particles and the low-hardness conductive particles is defective relative to the above-mentioned tangent plane; In the above undulations, when the amount of resin in the insulating resin layer directly above the high-hardness conductive particles and the low-hardness conductive particles is greater than the surface of the insulating resin layer directly above the high-hardness conductive particles and the low-hardness conductive particles on the tangent plane few. A connection structure, which utilizes the anisotropic conductive film of any one of claims 1 to 12 in the scope of the patent application to conduct anisotropic conductive connection between a first electronic component and a second electronic component. In the connection structure according to claim 13 of the patent application, in the first electronic component, terminals are formed on the PET base material. A method for manufacturing a connection structure, which uses the anisotropic conductive film of any one of claims 1 to 12 in the scope of the patent application to conduct anisotropic conductive connection between a first electronic component and a second electronic component. The method for manufacturing a connection structure as claimed in claim 15, wherein, in the first electronic component, terminals are formed on the PET base material. A package body, which is a package body formed by rolling the elongated body of the anisotropic conductive film in any one of the claims 1 to 12 of the patent application into a core.

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