WO2018079365A1

WO2018079365A1 - Anisotropic conductive film

Info

Publication number: WO2018079365A1
Application number: PCT/JP2017/037664
Authority: WO
Inventors: 三宅　健; 怜司塚尾; 達朗深谷
Original assignee: デクセリアルズ株式会社
Priority date: 2016-10-24
Filing date: 2017-10-18
Publication date: 2018-05-03
Also published as: CN113078486B; JP7248923B2; CN113078486A; JP2021193670A

Abstract

This anisotropic conductive film, which is capable of reliably inhibiting the occurrence of a short circuit, while reducing the conduction resistance of a connection structure that is anisotropically conductively connected, has a structure wherein conductive particles 3 with insulating particles, each of which is obtained by having insulating particles 2 adhere to the surface of a conductive particle 1, are dispersed in an insulating resin layer 5. With respect to the conductive particles 3 with insulating particles in this anisotropic conductive film, the number of insulating particles 2 in contact with a conductive particle 1 in the film thickness direction is smaller than the number of insulating particles 2 in contact with the conductive particle 1 in the film surface direction. The number of insulating particles overlapping conductive particles in a plan view of one of the front and back surfaces of this anisotropic conductive film is preferably smaller than the number of insulating particles overlapping conductive particles in a plan view of the other surface.

Description

Anisotropic conductive film

The present invention relates to an anisotropic conductive film.

Anisotropic conductive films are widely used for mounting electronic components such as IC chips. From the viewpoint of making an anisotropic conductive film correspond to a high mounting density, in an anisotropic conductive film, conductive particles are dispersed in the insulating resin layer at a high density. However, increasing the density of the conductive particles is a cause of short circuit.

In contrast, it has been proposed to use conductive particles with insulating particles in which insulating particles are attached to the surface of the conductive particles instead of the conventional conductive particles (Patent Document 1). An anisotropic conductive film can be obtained by kneading the conductive particles with insulating particles in a binder resin using a mixer and forming a film.

JP 2014-132567 A

However, as described in Patent Document 1, when the conductive particles with insulating particles are kneaded using a binder resin and a mixer, the insulating particles are isolated from the conductive particles, and the original insulating properties of the conductive particles with insulating particles are obtained. It may not be possible. Therefore, there is a possibility that a short circuit may occur in a connection structure of an electronic component that is anisotropically conductively connected using an anisotropic conductive film in which conductive particles with insulating particles are dispersed in a binder resin at high density.

Further, in the anisotropic conductive connection using this anisotropic conductive film, when the conductive particles with insulating particles are pressed against the terminals of the electronic component, not only the conductive particles but also the insulating particles are pressed against the terminals. There is also a problem that the conduction resistance of the connection structure tends to be high.

In contrast, the present invention is an anisotropic conductive film using conductive particles with insulating particles, which reduces the conduction resistance of the connection structure that is anisotropically conductively connected and reliably suppresses the occurrence of short circuits. An object of the present invention is to provide an anisotropic conductive film that can be used.

In producing an anisotropic conductive film using conductive particles with insulating particles in which the insulating particles are adhered substantially evenly to the entire surface of the conductive particles, the present inventor made a film surface of the conductive particles in the conductive particles with insulating particles. The number of insulating particles adhering in the direction is maintained, but if the number of insulating particles adhering in the film thickness direction of the conductive particles is reduced, an anisotropic conductive connection using an anisotropic conductive film is used. In this case, the conductive particles are easily pressed against the terminal surface without using the insulating particles, so that the conduction resistance of the connection structure can be reduced, and the presence of the insulating particles between adjacent terminals is less likely to cause a short circuit. The inventor came up with the present invention.

That is, the present invention is an anisotropic conductive film in which conductive particles with insulating particles attached to the surface of conductive particles are dispersed in an insulating resin layer. Provided is an anisotropic conductive film in which the number of insulating particles in contact with the particles in the film thickness direction is smaller than the number of insulating particles in contact with the conductive particles in the film surface direction.

Also, the present invention provides a method for manufacturing a connection structure in which electronic components are anisotropically conductively connected using the above-described anisotropic conductive film, and a connection structure obtained thereby.

According to the anisotropic conductive film of the present invention, the conductive particles with the initial insulating particles in which the insulating particles adhere substantially uniformly on the entire surface of the conductive particles are in contact with the conductive particles in the film thickness direction. The number of insulating particles is smaller than the number of insulating particles in contact with the conductive particles in the film surface direction. Therefore, when the anisotropic conductive film is used to anisotropically connect the terminals of the electronic component, the direct connection between the terminals and the conductive particles can be achieved as compared with the case where the initial state of the conductive particles with insulating particles is maintained. Since the contact area increases, the conduction resistance can be reduced in the connection structure. Further, according to this anisotropic conductive film, the number of insulating particles in contact with the conductive particles in the film surface direction is maintained at the initial state of the conductive particles with insulating particles. A short circuit between them can be suppressed.

FIG. 1A is a plan view showing the arrangement of conductive particles of an anisotropic conductive film 10A of an example. FIG. 1B is a cross-sectional view of the anisotropic conductive film 10A of the example. FIG. 2 is an explanatory diagram of a method for measuring the number of insulating particles in contact with the surface of the conductive particles in the film thickness direction or the film surface direction. FIG. 3A is an explanatory diagram of a dent in the insulating resin layer around the conductive particles with insulating particles. FIG. 3B is an explanatory diagram of a dent in the insulating resin layer on the conductive particles with insulating particles. FIG. 4A is a cross-sectional view illustrating a method for manufacturing the anisotropic conductive film 10A of the example. FIG. 4B is a cross-sectional view illustrating the method for manufacturing the anisotropic conductive film 10A of the example. FIG. 4C is a cross-sectional view illustrating the method for manufacturing the anisotropic conductive film 10A of the example. FIG. 4D is a cross-sectional view illustrating the method for manufacturing the anisotropic conductive film 10A of the example. Drawing 4E is a sectional view explaining the manufacturing method of anisotropic conductive film 10A of an example. FIG. 4F is a cross-sectional view illustrating the method for manufacturing the anisotropic conductive film 10A of the example. FIG. 5 is a cross-sectional view of the anisotropic conductive film 10B of the example. FIG. 6 is a cross-sectional view of the anisotropic conductive film 10C of the example. FIG. 7 is a cross-sectional view of the anisotropic conductive film 10D of the example.

Hereinafter, an example of 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 component.

<Overall structure of anisotropic conductive film>
FIG. 1A is a plan view for explaining the arrangement of conductive particles of an anisotropic conductive film 10A according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX.

This anisotropic conductive film 10 </ b> A has a structure in which conductive particles 3 with insulating particles in which insulating particles 2 are in contact with or attached to the surface of conductive particles 1 are embedded on one surface of insulating resin layer 5. Yes. In the plan view of the film, the conductive particles 3 with insulating particles are dispersed without contacting each other, and the conductive particles 3 with insulating particles are also dispersed without overlapping each other in the film thickness direction. Further, the positions of the conductive particles 3 with insulating particles in the film thickness direction (the vertical direction of the paper surface of FIG. 1B) are aligned, and the conductive particles 3 with insulating particles are single-layered in the film surface direction (the horizontal direction of the paper surface of FIG. 1B). I am doing.

In the anisotropic conductive film 10A of the present invention, the arrangement of the insulating particles 2 in the conductive particles 3 with insulating particles is characteristic, and is in contact with the conductive particles 1 in the film thickness direction as described in detail below. The number of insulating particles 2 is smaller than the number of insulating particles 2 in contact with the conductive particles 1 in the film surface direction.

<Conductive particles with insulating particles>
In the anisotropic conductive film 10A of the present invention, the number of the conductive particles 1 in the film thickness direction of the conductive particles 1 in the conductive particles 3 with insulating particles is smaller than the number of the conductive particles 1 in the film surface direction. However, as the conductive particles 3 with insulating particles used as the raw material for producing the anisotropic conductive film 10A of the present invention, it is possible to use the conductive particles 1 having the insulating particles 2 attached substantially uniformly to the entire surface of the conductive particles 1. it can.

As such conductive particles with insulating particles, those described in JP2009-280790A, JP2014-132567A, and the like can be used.

The particle diameter of the conductive particles 1 is preferably 1 μm or more and 30 μm or less, more preferably 2.5 μm or more and 13 μm from the viewpoint of suppressing an increase in conduction resistance when there is a variation in wiring height and suppressing the occurrence of short circuits. Hereinafter, it is more preferably 3 μm or more and 10 μm or less.

The particle diameter of the insulating particles 2 is smaller than the particle diameter of the conductive particles 1. The specific particle diameter of the insulating particles 2 can be determined according to the particle diameter of the conductive particles 1, the use of the anisotropic conductive film, etc., but is usually preferably 0.005 μm or more and 5 μm or less, 0.01 μm The thickness is more preferably 2.5 μm or less, further preferably 1 μm or less, and particularly preferably 0.5 μm or less. This eliminates the need for excessively increasing the pressure and temperature required for anisotropic conductive connection. As an example, if the particle diameter of the insulating particles is too small relative to the particle diameter of the conductive particles, it is difficult to impart insulation, so the lower limit is preferably 0.4% or more, and 0.6% More preferably, it is more preferably 0.8% or more. If the upper limit is too large, adhesion to the conductive particles and the necessary number may be insufficient. Therefore, the upper limit is preferably 18% or less, more preferably 12% or less, and even more preferably 6% or less.

The particle diameters of the conductive particles 1, the insulating particles 2, and the conductive particles 3 with insulating particles are measured by spreading these particles on glass, and using an optical microscope, a metal microscope, a transmission electron microscope (TEM), or a scanning electron microscope. It can be determined by observing with (SEM) or the like. These particle sizes in the film can also be obtained from observation with a scanning electron microscope or the like. In the measurement of the particle diameter, it is desirable that the number of samples to be measured is 300 or more. The transmission electron microscope can accurately measure the particle diameter of a relatively small insulating particle, and the scanning electron microscope is particularly suitable for obtaining the particle diameter of the conductive particles 3 with insulating particles.

The average particle diameter of single conductive particles can be measured by a general particle size distribution measuring apparatus. It may be an image type or a laser type. As an example of the image type measuring apparatus, a wet flow type particle diameter / shape analyzer FPIA-3000 (Malvern) can be mentioned. The number of samples (number of conductive particles) for measuring the particle diameter D of the conductive particles with insulating particles is preferably 1000 or more. The particle diameter D of the conductive particles with insulating particles in the anisotropic conductive film can be determined from observation with an electron microscope such as SEM. In this case, it is desirable that the number of samples (number of conductive particles) for measuring the particle diameter D of the conductive particles with insulating particles be 300 or more.

In the conductive particles with insulating particles 3 used as a raw material for manufacturing the anisotropic conductive film 10A, the ratio (coverage) covered with the insulating particles 2 in the entire surface of the conductive particles 1 is preferably 20 to 97%. ~ 95% is more preferred. If the coverage is too small, short-circuiting is likely to occur, and if it is too large, there is a concern that capturing of the conductive particles by the bumps is hindered.

The coverage is the ratio of the covering area (projected area) of insulating particles to the entire surface of the conductive particles with insulating particles. As a specific method for obtaining this, it is obtained by observing 100 conductive particles 3 with insulating particles using a scanning electron microscope and averaging the coverage in each observation image. As a simple method for obtaining the coverage, the number of insulating particles per one conductive particle with insulating particles is measured in each observation image, the numerical value, the projected area of one conductive particle with insulating particles, and one insulating particle. The coverage may be calculated from the projected area. Here, when the observation image of the insulating particles partially overlaps with the circular observation image of the conductive particles, the number of the partially overlapping insulating particles may be calculated as 0.5.

On the other hand, in the conductive particles with insulating particles 3 that actually constitute the anisotropic conductive film 10A, the number of the insulating particles 2 in contact with the conductive particles 1 in the film thickness direction is the number of the insulating particles 2 in contact with the conductive particles 1 in the film surface direction. Less than the number. Here, the number of insulating particles 2 in contact with the conductive particles 1 in the film thickness direction means that the conductive particles with insulating particles in the cross section in the film thickness direction of the conductive particles 3 with insulating particles in the anisotropic conductive film 10A shown in FIG. When the particle 3 is divided into four regions A1, A2, A3, and A4 along a straight line that passes through the center of the conductive particle 1 and is inclined by + 45 ° with respect to the film thickness direction and a straight line that is inclined by minus 45 °, the conductive particle 1 refers to the number of insulating particles 2 existing in regions (regions along the film surface) A1 and A2 above and below 1. In addition, the number of insulating particles 2 in contact with the conductive particles 1 in the film surface direction is a region (region along the film thickness direction) on the left and right of the conductive particles 1 in the four regions A1, A2, A3, and A4 described above. This refers to the number of insulating particles 2 present in A3 and A4. Accordingly, if the number of insulating particles 2 existing in the regions A1, A2, A3, A4 is N _A1 , N _A2 , N _A3 , N _A4 , in the present invention, (N _A3 + N _A4 )> (N _A1 + N _A2 ). In addition, it is preferable that the cross section of a film thickness direction has a several different direction with the same film (confirm the cross-sectional view of a different direction), and it is more preferable that two cross sections which are 90 degrees are included. .

In obtaining the number of insulating particles 2 present in the regions A1, A2, A3, A4, the insulating particles 2 straddling both the upper and lower regions A1, A2 and the left and right regions A3, A4 of the conductive particles 1, The attribution is determined depending on which region it belongs to.

In the present invention, it is not necessary that all the conductive particles with insulating particles 3 satisfy the above inequality. The number of insulating particles 2 present in the regions A1, A2, A3, and A4 in the individual conductive particles 3 with insulating particles may vary, and there are conductive particles 3 with insulating particles that do not satisfy the above inequality. However, when all the conductive particles 3 with insulating particles contained in the anisotropic conductive film are averaged, the above inequality is established, and N _A3 and N _A4 are larger than N _A1 and N _A2 .

In addition, it is not realistic to confirm that the above-mentioned inequality holds for all the conductive particles with insulating particles 3 included in the anisotropic conductive film. Therefore, when the above inequality is satisfied by measuring the number of insulating particles 2 present in the regions A1, A2, A3, and A4 as shown below, the above inequality is obtained in the average of all the conductive particles with insulating particles. It may be considered that the relationship is established.

That is, by observing the cross section of the anisotropic conductive film 10A using a scanning electron microscope, the number of the insulating particles 2 present in the regions A1, A2, A3, and A4 is measured for each conductive particle 3 with insulating particles. In measurement, rectangular measurement areas each having a side of 100 μm or more are separated from each other and set at a plurality of locations (preferably 5 or more, more preferably 10 or more) so that the total area is 1 mm ² or more. The extracted conductive particles 3 with insulating particles 3 were observed, and the number of insulating particles 2 existing in the regions A1 and A2 and the number of insulating particles 2 existing in the regions A3 and A4 for each conductive particle 3 with insulating particles. As the average of 100 conductive particles with insulating particles, the number (N _A1 + N _A2 ) of insulating particles 2 in contact with the conductive particles 1 in the film thickness direction and the conductive particles 1 with the film The number (N _A3 + N _A4 ) of the insulating particles 2 in contact in the plane direction is obtained, and the existence of the above inequality is examined. What is necessary is just to adjust a measurement area | region suitably with the magnitude | size of an electrically-conductive particle.

In addition, the number of insulating particles 2 in contact with the conductive particles 1 in the film thickness direction (N _A1 + N _A2 ) is less than the number of insulating particles 2 in contact with the conductive particles 1 in the film surface direction (N _A3 + N _A4 ). As a method for confirming, the number of the insulating particles 2 overlapping the conductive particles 1 in the plan view of either one of the front and back surfaces of the anisotropic conductive film in the measurement region having an area of 1 mm ² or more is It may be confirmed that the number is smaller than the number of insulating particles 2 overlapping the conductive particles 1 in a plan view of the other film surface. As will be described later, when conductive particles with insulating particles are pressed into the insulating resin layer in the manufacturing process of the anisotropic conductive film of the present invention, N _A3 , N _A4 ≧ N _A2 > N _A1
Therefore, by confirming N _A2 > N _A1 , the number of insulating particles 2 in contact with the conductive particles 1 in the film thickness direction (N _A1 + N _A2 ) is _{equal to} the number of insulating particles 2 in contact with the conductive particles 1 in the film surface direction. It can be confirmed that the number is smaller than the number (N _A3 + N _A4 ).

The difference in the number of insulating particles 2 due to such regions A1, A2, A3, and A4 is that the conductive particles 3 with insulating particles are arranged in a predetermined arrangement in the method of manufacturing the anisotropic conductive film 10A, as will be described later. This occurs when a transfer mold is used. That is, the difference in the number of the insulating particles 2 is that the insulating particles 2 that contact the conductive particles 1 in the film thickness direction (insulation in the region A1) when the conductive particles 3 with insulating particles are transferred from the transfer mold to the insulating resin layer. Insulating that the particles 2) are easily detached from the conductive particles 1 due to friction with the transfer mold or friction with the pressure member and remain in the transfer mold, and also in contact with the conductive particles 1 in the film thickness direction. The particles 2 may move to a position in contact with the conductive particles 1 in the film surface direction, but the insulating particles 2 in contact with the conductive particles 1 in the film surface direction are transferred from the transfer type conductive particles 3 with insulating particles to the insulating resin layer. This is caused by the fact that even when transferred onto the conductive particles 1, detachment or movement from the conductive particles 1 hardly occurs.

<Dispersed state of conductive particles with insulating particles>
The dispersed state of the conductive particles with insulating particles in the present invention includes a state in which the conductive particles with insulating particles 3 are dispersed randomly and a state in which the conductive particles with insulating particles are dispersed in a regular arrangement. In this dispersed state, it is preferable that the conductive particles with insulating particles are arranged in non-contact with each other, and the number ratio is preferably 95% or more, more preferably 98% or more, and further preferably 99.5% or more. . Regarding this number ratio, the conductive particles with insulating particles that are intentionally contacted in a regular arrangement in a dispersed state are counted as one. Similar to the method of obtaining the occupation area ratio of the conductive particles with insulating particles in the film plan view described later, it can be obtained at N = 200 or more. In either case, it is preferable from the viewpoint of capture stability that the positions in the film thickness direction are aligned. Here, the fact that the positions of the conductive particles 1 in the film thickness direction are aligned is not limited to being aligned at a single depth in the film thickness direction, but the front and back interfaces of the insulating resin layer 5 or the vicinity thereof. Each of which includes conductive particles.

In the present invention, as described above, the conductive particles with insulating particles 3 are preferably arranged regularly in a plan view of the film, and can be, for example, a square lattice arrangement as shown in FIG. 1A. . In addition, examples of the regular arrangement of the conductive particles with insulating particles include a lattice arrangement such as a rectangular lattice, an oblique lattice, and a hexagonal lattice. The regular arrangement is not limited to the lattice arrangement, and for example, a row of particles in which conductive particles with insulating particles are arranged in a straight line at a predetermined interval may be arranged in parallel at a predetermined interval. By arranging the conductive particles with insulating particles 3 in a non-contact manner and in a regular arrangement such as a lattice, pressure is applied evenly to the conductive particles with insulating particles 3 during anisotropic conductive connection, Variations can be reduced. The regular arrangement can be confirmed, for example, by repeating a predetermined particle arrangement in the longitudinal direction of the film.

The lattice axis or the array axis of the array of the conductive particles with insulating particles may be parallel to the longitudinal direction of the anisotropic conductive film, may cross the longitudinal direction of the anisotropic conductive film, It can be determined according to the terminal pitch. For example, in the case of an anisotropic conductive film for fine pitch, as shown in FIG. 1A, the lattice axis A of the conductive particles with insulating particles 3 is skewed with respect to the longitudinal direction of the anisotropic conductive film 10A, so The angle θ formed by the longitudinal direction of the terminals 20 connected by the isotropic conductive film 10A (the short direction of the film) and the lattice axis A is preferably 6 ° to 84 °, more preferably 11 ° to 74 °.

The inter-particle distance of the conductive particles 3 with insulating particles is appropriately determined according to the size and terminal pitch of the terminals connected by the anisotropic conductive film. For example, when an anisotropic conductive film is made compatible with fine pitch COG (Chip On Glass), the distance between the conductive particles 1 of the closest conductive particles 3 with insulating particles from the point of preventing the occurrence of short-circuiting is provided. It is preferably larger than 0.5 times the particle diameter of the particles, more preferably larger than 0.7 times. On the other hand, from the viewpoint of capturing properties of the conductive particles 3 with insulating particles, the distance between the conductive particles 1 of the closest conductive particles 3 with insulating particles is preferably 4 times or less the particle diameter of the conductive particles with insulating particles. It is more preferable to set it to double or less.

Further, the area occupation ratio of the conductive particles with insulating particles is determined to be 35% or less, preferably 0.3 to 30%. Here, the area occupancy is
[Number density of conductive particles with insulating particles in plan view] × [average of one planar view area of conductive particles with insulating particles] × 100
Is calculated by

In the formula, the number density measurement region of the conductive particles with insulating particles is arbitrarily a plurality of rectangular regions having a side of 100 μm or more in the anisotropic conductive film 10A (preferably 5 or more, more preferably 10 or more). It is preferable to set the total area of the measurement region to 2 mm ² or more. What is necessary is just to adjust suitably the magnitude | size and number of each area | region according to the state of number density. As an example of a relatively large number density for fine pitch applications, 200 observation points (2 mm ² ) in an area of 100 μm × 100 μm area arbitrarily selected from the anisotropic conductive film 10A are used by using observation images with a metal microscope or the like. By measuring the number density and averaging it, it is possible to obtain the “number density of conductive particles with insulating particles in plan view” of the above formula. A region having an area of 100 μm × 100 μm is a region where one or more bumps exist in a connection object having a space between bumps of 50 μm or less.

The number density is preferably 150 to 70000 pieces / mm ² , particularly in the case of fine pitch use, preferably 6000 to 42000 pieces / mm ² , more preferably 10,000 to 40000 pieces / mm ² , and further preferably 15000 to 35000 pieces / mm ² . In addition, less than 150 pieces / mm ² is not excluded.

The number density of the conductive particles with insulating particles is obtained using a metal microscope as described above, and is measured using image analysis software (for example, WinROOF, Mitani Corporation) on the microscopic image of the conductive particles with insulating particles. May be.

In addition, the average of the film plan view area per one conductive particle with insulating particles can be obtained by measurement from an observation image of the film surface with a metal microscope or the like. Image analysis software may be used as described above. It is preferable that N = 300 or more.

The area occupancy ratio of the conductive particles with insulating particles in a plan view of the film is an index of the thrust required for the pressing jig for thermocompression bonding of the anisotropic conductive film to the electronic component. Conventionally, in order to make an anisotropic conductive film correspond to a fine pitch, the distance between particles of the conductive particles has been reduced and the number density has been increased as long as no short-circuit occurs. The thrust required for the pressing jig for thermocompression bonding the isotropic conductive film to the electronic component becomes excessively large, and there is a problem that the pressing is insufficient with the conventional pressing jig. On the other hand, by setting the area occupancy to the above-described range, the thrust required for the pressing jig for thermocompression bonding of the anisotropic conductive film to the electronic component can be suppressed low.

<Insulating resin layer>
(Minimum melt viscosity of insulating resin layer)
In the anisotropic conductive film of the present invention, the minimum melt viscosity of the insulating resin layer 5 is not particularly limited, and is appropriately determined according to the use object of the anisotropic conductive film, the method for manufacturing the anisotropic conductive film, and the like. be able to. For example, as long as the below-mentioned dents 5b (FIG. 3A) and 5c (FIG. 3B) can be formed, it can be set to about 1000 Pa · s depending on the method for manufacturing the anisotropic conductive film. On the other hand, as a method for producing an anisotropic conductive film, when conducting a method of holding the conductive particles with insulating particles in a predetermined arrangement on the surface of the insulating resin layer and pushing the conductive particles with insulating particles into the insulating resin layer, It is preferable that the minimum melt viscosity of the insulating resin is 1100 Pa · s or higher from the viewpoint that the insulating resin layer enables film forming.

Further, as described in the method for manufacturing an anisotropic conductive film described later, as shown in FIG. 3A, a dent 5b is formed around the exposed portion of the conductive particles with insulating particles 3 pushed into the insulating resin layer 5. 3B, from the point of forming the recess 5c directly above the conductive particles with insulating particles 3 pushed into the insulating resin layer 5, as shown in FIG. 3B, preferably 1500 Pa · s or more, more preferably 2000 Pa · s or more, The pressure is preferably 3000 to 15000 Pa · s, and more preferably 3000 to 10,000 Pa · s. This minimum melt viscosity can be obtained using a rotary rheometer (manufactured by TA Instruments Inc.) as an example, kept constant at a measurement pressure of 5 g, and using a measurement plate having a diameter of 8 mm, and more specifically in the temperature range. At 30 to 200 ° C., it can be obtained by setting the temperature rising rate 10 ° C./min, the measurement frequency 10 Hz, and the load fluctuation 5 g with respect to the measurement plate.

By setting the minimum melt viscosity of the insulating resin layer 5 to a high viscosity of 1500 Pa · s or more, unnecessary movement of the conductive particles can be suppressed for pressure bonding of the anisotropic conductive film to the article. It is possible to prevent the conductive particles to be sandwiched between the terminals sometimes from being caused to flow due to the resin flow.

Further, when the conductive particles with insulating particles 3 are pushed into the insulating resin layer 5, the conductive resin particles with insulating particles 3 are exposed from the insulating resin layer 5 when the conductive particles with insulating particles 3 are pushed. Thus, when the conductive particles 3 with insulating particles are pushed into the insulating resin layer 5, the insulating resin layer 5 is plastically deformed and recessed into the insulating resin layer 5 around the conductive particles 3 with insulating particles (FIG. 3A), or a conductive material with insulating particles so that the conductive particle with insulating particles 3 is buried in the insulating resin layer 5 without being exposed from the insulating resin layer 5. When the 3 is pushed in, a highly viscous viscous material is formed in which a recess 5c (FIG. 3B) is formed on the surface of the insulating resin layer 5 immediately above the conductive particles 3 with insulating particles. Therefore, the viscosity of the insulating resin layer 5 at 60 ° C. is preferably at least 3000 Pa · s, more preferably at least 4000 Pa · s, even more preferably at least 4500 Pa · s, and the upper limit is preferably at most 20000 Pa · s. More preferably, it is 15000 Pa.s or less, More preferably, it is 10000 Pa.s or less. This measurement is performed by the same measurement method as that for the minimum melt viscosity, and can be obtained by extracting a value at a temperature of 60 ° C.

The specific viscosity of the insulating resin layer 5 when the conductive particles 3 with insulating particles are pushed into the insulating resin layer 5 is preferably 3000 Pa depending on the shape and depth of the recesses 5b and 5c to be formed. · 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, more preferably 15000 Pa · s or less, and still more preferably 10000 Pa · s or less. Further, such a viscosity is preferably obtained at 40 to 80 ° C., more preferably 50 to 60 ° C.

As described above, the recesses 5b (FIG. 3A) are formed around the conductive particles 3 with insulating particles exposed from the insulating resin layer 5, and thus the anisotropic conductive film is produced when it is pressed onto the article. The resistance received from the insulating resin against the flattening of the conductive particles 3 with insulating particles is reduced as compared with the case where there is no recess 5b. For this reason, it becomes easy for the conductive particles to be sandwiched between the terminals at the time of anisotropic conductive connection, so that the conduction performance is improved and the trapping property is improved.

Further, since the recess 5c (FIG. 3B) is formed on the surface of the insulating resin layer 5 immediately above the conductive particles 3 with insulating particles buried without being exposed from the insulating resin layer 5, there is no recess 5c. As compared with the case, the pressure at the time of pressure-bonding the anisotropic conductive film to the article tends to concentrate on the conductive particles 3 with insulating particles. For this reason, the trapping property is improved because the conductive particles are easily held between the terminals at the time of anisotropic conductive connection, and the conduction performance is improved.

In the anisotropic conductive film manufacturing method to be described later, the embedding rate when the conductive particles with insulating particles 3 are pushed into the insulating resin layer 5 is 100% or less, and the conductive particles with insulating particles 3 are the insulating resin layer. 5, when the insulating resin layer 5 has a viscosity of 60 ° C. within the above range, the insulating resin layer 5 with the insulating particles is pressed into the insulating resin layer 5 after the insulating particles with the insulating particles 5 are pushed in. A recess 5b (FIG. 3A) may be formed around the conductive particles 3. At this time, only insulating particles may be exposed. When the embedding rate is over 100% and the conductive particles 3 with insulating particles are not exposed from the insulating resin layer 5 and are embedded in the insulating resin layer 5, the conductive particles 3 with insulating particles are directly above the conductive particles 3. A recess 5c (FIG. 3B) may be formed on the surface of the insulating resin layer 5. The meaning of the embedding rate will be described in detail in the description of the embedded state of the conductive particles with insulating particles in the subsequent stage.

Such recesses 5b and 5c are formed according to the viscosity, pressing speed, temperature, and the like of the insulating resin layer 5 when the conductive particles with insulating particles 3 are pressed into the insulating resin layer 5. Although the presence or absence of the recesses 5b and 5c does not particularly affect the effect of the present invention, the recesses 5b and 5c having a large recess depth (for example, the depth of the deepest portion of the recess is the particle diameter D of the conductive particles with insulating particles). If there is a region where 10% or more of the region is locally concentrated, if such a region is bonded to the substrate, depending on the material or surface state of the substrate, the anisotropic conductive connection in that region may occur. Occurrence may occur and the appearance may be inferior even if there is no practical problem. For this, the surface of the anisotropic conductive film having such a region is heated and pressed to such an extent that it does not interfere with the anisotropic conductive connection, or the dent 5b is dispersed by spraying resin. It is preferable to make 5c shallower or flat. In this case, it is preferable that the resin to be dispersed has a lower viscosity than the resin that forms the insulating resin layer 5. The concentration of the resin to be sprayed may be diluted to such an extent that the dent of the insulating resin layer 5 can be confirmed after the spraying.

<"Inclination" or "undulation" instead of dents>
The “dents” 5b and 5c of the anisotropic conductive film as shown in FIGS. 3A and 3B can also be described from the viewpoint of “inclination” or “undulation”. Hereinafter, description will be given with reference to the drawings.

The anisotropic conductive film 10A has a conductive particle dispersion layer, that is, a layer in which the conductive particles with insulating particles 3 are regularly dispersed with one surface of the insulating resin layer 5 exposed (FIGS. 3A and 3B). ). The conductive particles 3 with insulating particles are not in contact with each other in a plan view of the film, and the conductive particles 3 with insulating particles are regularly dispersed in the film thickness direction without overlapping each other. A single-layer conductive particle layer having a uniform position in the thickness direction is formed.

A slope 5b is formed on the surface 5a of the insulating resin layer 5 in the vicinity of each of the conductive particles with insulating particles 3 with respect to the tangential plane 5p of the insulating resin layer 5 at the center between adjacent conductive particles with insulating particles. Has been. As will be described later, in the anisotropic conductive film of the present invention, even when the undulations 5c are formed on the surface of the insulating resin layer 5 immediately above the conductive particles with insulating particles 3 embedded in the insulating resin layer 5. Good (FIG. 3B).

In the present invention, “inclination” means that the flatness of the surface of the insulating resin layer is impaired in the vicinity of the conductive particles 3 with insulating particles, and a part of the insulating resin layer is missing from the tangential plane 5p. This means that the amount is decreasing. In other words, in the inclination, the surface of the insulating resin layer in the vicinity of the conductive particles with insulating particles is missing from the tangent plane. On the other hand, “undulation” means that the surface of the insulating resin layer directly above the conductive particles with insulating particles has undulations, and the resin is reduced due to the presence of a part with a difference in elevation such as undulations. To do. In other words, the resin amount of the insulating resin layer immediately above the conductive particles with insulating particles is smaller than when the surface of the insulating resin layer immediately above the conductive particles with insulating particles is in a tangential plane. Therefore, only the insulating particles may be exposed in the swell. These can be recognized by comparing a portion corresponding to the conductive particles with insulating particles and a flat surface portion (FIGS. 3A and 3B) between the conductive particles. In some cases, the starting point of undulations exists as a slope.

As described above, by forming the slope 5b (FIG. 3A) around the conductive particles 3 with insulating particles exposed from the insulating resin layer 5, the conductive particles 3 with insulating particles at the time of anisotropic conductive connection. Since the resistance received from the insulating resin with respect to the flattening of the conductive particles 3 with insulating particles generated when the particles are sandwiched between the terminals is reduced as compared with the case where there is no inclination 5b, the conductive particles with insulating particles at the terminals As a result, the conduction performance is improved and the trapping property is improved. This inclination is preferably along the outer shape of the conductive particles with insulating particles. This is because, in addition to the effect of connection being more easily manifested, it is easier to recognize the conductive particles with insulating particles, thereby facilitating inspections in the production of anisotropic conductive films. In addition, the inclination and the undulation may be partially lost by heat-pressing the insulating resin layer, and the present invention includes this. In this case, the conductive particles with insulating particles may be exposed at one point on the surface of the insulating resin layer. In addition, the anisotropic conductive film has a variety of electronic parts to be connected, and as long as it is tuned according to these, it is desired that the degree of freedom of design is high enough to satisfy various requirements, so the inclination or undulation is reduced. It can be used even if it disappears or partially disappears.

In addition, since the undulations 5c (FIG. 3B) are formed on the surface of the insulating resin layer 5 directly above the conductive particles 3 with insulating particles buried without being exposed from the insulating resin layer 5, the case of inclination Similarly, a pressing force from the terminal is easily applied to the conductive particles with insulating particles during anisotropic connection. In addition, since the amount of resin immediately above the conductive particles with insulating particles is reduced compared to when the resin is deposited flat due to undulations, the resin directly above the conductive particles with insulating particles at the time of connection is eliminated. This facilitates the contact between the terminal and the conductive particle with insulating particles, so that the trapping property of the conductive particle with insulating particles at the terminal is improved, and the conduction reliability is improved.

(Position of conductive particles with insulating particles in the thickness direction of the insulating resin layer)
The position of the conductive particles 3 with insulating particles in the thickness direction of the insulating resin layer 5 in consideration of the viewpoint of “inclination” or “undulation” is the same as described above. 5 may be exposed or may be embedded in the insulating resin layer 5 without being exposed, but the conductive with insulating particles from the tangential plane 5p in the central portion between the adjacent conductive particles with insulating particles. The ratio (Lb / D) (hereinafter referred to as the embedding rate) of the distance Lb of the deepest part of the particles (hereinafter referred to as the embedding amount) to the particle diameter D of the conductive particles with insulating particles is 30% or more and 105% or less. In order to obtain the effects of the invention, it is more preferable that the ratio be 60% or more and 105% or less.

When the embedding rate (Lb / D) is 30% or more and less than 60%, the ratio of the conductive particles with insulating particles exposed from the relatively high viscosity insulating resin layer holding the conductive particles with insulating particles becomes high. Therefore, lower temperature and low pressure mounting becomes easier. By setting it to 60% or more, the conductive particles 3 with insulating particles can be easily maintained in a predetermined particle dispersion state or a predetermined arrangement by the insulating resin layer 5. Further, since the contact area between the conductive particles with insulating particles and the resin at the time of manufacture (pushing into the film) becomes large, it can be expected that the effects of the invention can be easily obtained. Moreover, by setting it as 105% or less, the resin amount of the insulating resin layer which acts so that the electrically-conductive particle between terminals may flow unnecessarily at the time of anisotropic conductive connection can be reduced.

The value of the embedding rate (Lb / D) is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles with insulating particles contained in the anisotropic conductive film. It means that it is a numerical value of the inclusion rate (Lb / D). Therefore, the embedding rate of 30% or more and 105% or less means that the embedding rate is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles with insulating particles contained in the anisotropic conductive film. The rate is 30% or more and 105% or less. Thus, since the embedding rate (Lb / D) of all the conductive particles with insulating particles is uniform, the pressing load is uniformly applied to the conductive particles with insulating particles, so that the state of trapping the conductive particles with insulating particles at the terminal is captured. Is improved and the stability of conduction is improved.

The embedding rate (Lb / D) was determined by arbitrarily extracting 10 or more regions having an area of 30 mm ² or more from the anisotropic conductive film, observing a part of the film cross section with an SEM image, and totaling 50 or more insulating particles. It can be determined by measuring attached conductive particles. In order to increase the accuracy, 200 or more conductive particles with insulating particles may be measured and obtained.

Further, the measurement of the embedding rate (Lb / D) can be obtained collectively for a certain number by adjusting the focus in the surface field image. Alternatively, a laser discrimination displacement sensor (manufactured by Keyence Co., Ltd.) may be used for measuring the embedding rate (Lb / D).

The point which makes it easy to obtain the effect of the slope 5b (FIG. 3A) of the insulating resin layer 5 around the conductive particles with insulating particles and the undulation 5c (FIG. 3B) of the insulating resin layer immediately above the conductive particles with insulating particles. From the above, the ratio (Le / D) between the maximum depth Le of the inclination 5b and the particle diameter D of the conductive particles 3 with insulating particles is preferably less than 50%, more preferably less than 30%, and even more preferably 20 to 25%. The ratio (Ld / D) between the maximum diameter Ld of the slope 5b or the undulation 5c and the particle diameter D of the conductive particles 3 with insulating particles is preferably 100% or more, more preferably 100 to 150%. The ratio (Lf / D) between the maximum depth Lf of 5c and the particle diameter D of the conductive particles 3 with insulating particles is greater than 0, preferably less than 10%, more preferably 5% or less.

Note that the diameter Lc of the exposed (immediately above) portion of the conductive particles 3 with insulating particles in the slope 5b or the undulation 5c can be equal to or smaller than the particle diameter D of the conductive particles 3 with insulating particles, and preferably 10 to 10 times the particle diameter D. 90%. The conductive particles with insulating particles 3 may be exposed at one point on the top, or the conductive particles with insulating particles 3 are completely buried in the insulating resin layer 5 so that the diameter Lc becomes zero. Good.

In the present invention, the presence of the slopes 5b and undulations 5c on the surface of the insulating resin layer 5 can be confirmed by observing the cross section of the anisotropic conductive film with a scanning electron microscope. Can also be confirmed. The tilt 5b and the undulations 5c can be observed even with an optical microscope or a metal microscope. Moreover, the magnitude | size of the inclination 5b and the undulation 5c can also be confirmed by the focus adjustment at the time of image observation. The same applies even after the inclination or undulation is reduced by heat pressing as described above. This is because traces may remain.

(Composition of insulating resin layer)
The insulating resin layer 5 is preferably formed from a curable resin composition, and can be formed from, for example, a thermopolymerizable composition containing a thermopolymerizable compound and a thermal polymerization initiator. You may make a thermopolymerizable composition contain a photoinitiator as needed.

When a thermal polymerization initiator and a photopolymerization initiator are used in combination, one that also functions as a photopolymerizable compound may be used as the thermopolymerizable compound, and a photopolymerizable compound is contained separately from the thermopolymerizable compound. May be. Preferably, a photopolymerizable compound is contained separately from the thermally polymerizable compound. For example, a cationic curing initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermopolymerizable compound, a photo radical initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound.

As the photopolymerization initiator, a plurality of types that react to light having different wavelengths may be contained. Accordingly, the wavelength 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 bonding the electronic components to each other during the anisotropic conductive connection. Can be used properly.

In photocuring during the production of the anisotropic conductive film, all or part of the photopolymerizable compound contained in the insulating resin layer can be photocured. By this photocuring, the arrangement of the conductive particles with insulating particles 3 in the insulating resin layer 5 is maintained or fixed, and it is expected that the short circuit is suppressed and the conductive particles are captured better. Moreover, you may adjust suitably the viscosity of the insulating resin layer in the manufacturing process of an anisotropic conductive film by this photocuring.

The blending amount of the photopolymerizable compound in the insulating resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. This is because when the amount of the photopolymerizable compound is too large, the thrust applied to the pushing at the time of connection increases.

Examples of the thermally polymerizable composition include a thermal radical polymerizable acrylate composition containing a (meth) acrylate compound and a thermal radical polymerization initiator, and a thermal cationic polymerizable epoxy system containing an epoxy compound and a thermal cationic polymerization initiator. Examples thereof include compositions. Instead of the thermal cationic polymerizable epoxy composition containing a thermal cationic polymerization initiator, a thermal anionic polymerizable epoxy composition containing a thermal anionic polymerization initiator may be used. In addition, a plurality of types of polymerizable compositions may be used in combination as long as there is no particular problem. Examples of the combination include a combination of a cationic polymerizable compound and a radical polymerizable compound.

Here, as the (meth) acrylate compound, a conventionally known thermal polymerization type (meth) acrylate monomer can be used. For example, a monofunctional (meth) acrylate monomer or a bifunctional or higher polyfunctional (meth) acrylate monomer can be used.

Examples of the thermal radical polymerization initiator include organic peroxides and azo compounds. In particular, an organic peroxide that does not generate nitrogen that causes bubbles can be preferably used.

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

Examples of the epoxy compound include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a modified epoxy resin thereof, an alicyclic epoxy resin, and the like. it can. In addition to the epoxy compound, an oxetane compound may be used in combination.

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators for epoxy compounds can be employed. For example, iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc. that generate an acid by heat are used. In particular, an aromatic sulfonium salt showing a good potential with respect to temperature can be preferably used.

If the amount of the thermal cationic polymerization initiator used is too small, curing tends to be poor, and if it is too much, the product life tends to decrease. Therefore, the amount is preferably 2 to 60 mass relative to 100 parts by mass of the epoxy compound. Part, more preferably 5 to 40 parts by weight.

The thermopolymerizable composition preferably contains a film-forming resin and a silane coupling agent. Examples of the film-forming resin include phenoxy resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, and the like. be able to. Among these, a phenoxy resin can be preferably used from the viewpoint of film forming property, workability, and connection reliability. The weight average molecular weight is preferably 10,000 or more. Examples of the silane coupling agent include an epoxy silane coupling agent and an acrylic silane coupling agent. These silane coupling agents are mainly alkoxysilane derivatives.

In order to adjust the melt viscosity, the thermally polymerizable composition may contain an insulating filler separately from the conductive particles with insulating particles 3 described above. Examples of this include silica powder and alumina powder. A fine filler having an insulating filler particle size of 20 to 1000 nm is preferable, and the blending amount is preferably 5 to 50 parts by mass with respect to 100 parts by mass of a thermally polymerizable compound (photopolymerizable compound) such as an epoxy compound. .

The anisotropic conductive film of the present invention contains a filler, softener, accelerator, anti-aging agent, colorant (pigment, dye), organic solvent, ion catcher agent, etc. in addition to the above-mentioned insulating filler. You may let them.

(Insulating resin layer thickness)
In the anisotropic conductive film of the present invention, the ratio (La / D) between the layer thickness La of the insulating resin layer 5 and the particle diameter D of the conductive particles with insulating particles 3 is 0.3 or more because of the reason described later. The upper limit can be made 10 or less. Therefore, the ratio is preferably 0.3 to 10, more preferably 0.6 to 8, and still more preferably 0.6 to 6. Here, the particle diameter D of the conductive particles 3 with insulating particles means the average particle diameter. If the layer thickness La of the insulating resin layer 5 is too large, the conductive particles with insulating particles 3 are likely to be displaced due to resin flow during anisotropic conductive connection, and the trapping property of the conductive particles with insulating particles 3 at the terminals is lowered. Since this tendency is remarkable when this ratio (La / D) exceeds 10, 8 or less is more preferable, and 6 or less is still more preferable. On the contrary, if the layer thickness La of the insulating resin layer 5 is too small and this ratio (La / D) is less than 0.3, the conductive particles 3 with insulating particles are dispersed in a predetermined particle state or a predetermined state by the insulating resin layer 5. Therefore, the ratio (La / D) is preferably 0.3 or more, and the insulating resin layer 5 ensures that the predetermined particle dispersion state or the predetermined arrangement is reliably maintained by 0.6. The above is more preferable. When the terminal to be connected is high density COG, the ratio (La / D) between the layer thickness La of the insulating resin layer 5 and the particle diameter D of the conductive particles 3 with insulating particles is preferably 0.8-2. is there.

<Embedded state of conductive particles with insulating particles in insulating resin layer>
In the embedded state of the conductive particles 3 with insulating particles in the insulating resin layer 5, it is preferable that the burying rate is 30% or more and 105% or less. By setting the embedding rate to 30% or more, preferably 60% or more, the conductive particles 3 with insulating particles can be maintained in a predetermined particle dispersion state or a predetermined arrangement by the insulating resin layer 5. In addition, by setting the embedding rate to 105% or less, it is possible to reduce the amount of resin in the insulating resin layer that acts to cause the conductive particles with insulating particles to flow unnecessarily during anisotropic conductive connection.

Here, the embedding rate is the surface 5a of the insulating resin layer 5 in which the conductive particles 3 with insulating particles are embedded (the surface on which the conductive particles 3 with insulating particles are unevenly distributed in the insulating resin layer 5). ) And the deepest portion of the conductive particles with insulating particles 3 embedded in the insulating resin layer 5 with respect to the surface 5a is the embedded amount Lb, with respect to the particle diameter D of the conductive particles with insulating particles 3 It is the ratio (Lb / D) of the embedding amount Lb (FIG. 1B).

In the present invention, the value of the embedding rate (Lb / D) is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles with insulating particles contained in the anisotropic conductive film. Is the numerical value of the embedding rate (Lb / D). Therefore, the embedding rate of 30% or more and 105% or less means that the embedding rate is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles with insulating particles contained in the anisotropic conductive film. The rate is 30% or more and 105% or less. Thus, since the embedding rate (Lb / D) of the conductive particles with all insulating particles is uniform, the load of pressing is uniformly applied to the conductive particles, so that the state of capturing the conductive particles at the terminals is improved and the conduction is improved. Improves stability.

The embedding rate (Lb / D) was determined by arbitrarily extracting 10 or more regions having an area of 30 mm ² or more from the anisotropic conductive film, observing a part of the film cross section with an SEM image, and totaling 50 or more conductive particles. Can be obtained by measuring In order to increase accuracy, 200 or more conductive particles may be measured and obtained.

<Method for producing anisotropic conductive film>
In an example of the method for manufacturing the anisotropic conductive film 10A shown in FIGS. 1A and 1B, the recesses 31 of the transfer mold 30 are filled with the conductive particles with insulating particles 3 (FIG. 4A). The recesses 31 are formed in the same arrangement as the conductive particles 3 with insulating particles in the anisotropic conductive film.

As such a transfer mold 30, for example, an inorganic material such as silicon, various ceramics, glass, stainless steel, or the like, or an organic material such as various resins may be formed by a known opening forming method such as a photolithographic method. What formed the recessed part 31 can be used. Further, the transfer mold can take a plate shape, a roll shape or the like.

On the other hand, the insulating resin layer 5 is formed in a film shape on the release film 7, and the insulating resin layer 5 is put on the conductive particles 3 with insulating particles filled in the transfer mold 30 (FIG. 4C). Alternatively, before covering the insulating resin layer 5 on the conductive particles with insulating particles 3, the insulating particles 2 are removed from the conductive particles 1 by bringing the flat plate 32 into contact with the conductive particles with insulating particles 3 filled in the transfer mold 30. Then, the insulating resin layer 5 may be covered (FIG. 4C). Next, the insulating resin layer 5 is peeled from the transfer mold 30 to obtain the insulating resin layer 5 to which the conductive particles with insulating particles 3 are transferred (FIG. 4D). In the transfer process of the conductive particles 3 with insulating particles, the transfer mold 30 and the insulating particles 2 are rubbed, so that the insulating particles 2 that are in contact with the bottom surface of the recess 31 of the transfer mold 30 (the ones that become the insulating particles 2 in the region A1). Is easily detached from the conductive particles 3 with insulating particles. Further, when the insulating resin layer 5 is placed on the conductive particles 3 with insulating particles in the transfer mold 30, a large force is applied to the insulating particles 2 that first contact the insulating resin layer 5. The particles 2 (those that become the insulating particles 2 in the region A2) may also be detached. For this reason, the insulating particles 2 may be present (dotted) on the film.

On the other hand, the insulating particles 2 in the film surface direction are maintained on the insulating resin layer 5 without being detached from the insulating resin layer 5 even after the insulating resin layer 5 is peeled off from the transfer mold 30.

Accordingly, the conductive particles 3 with insulating particles after being transferred to the insulating resin layer 5 are in contact with the conductive particles 1 in the film thickness direction among the insulating particles 2 constituting the conductive particles 3 with insulating particles as compared to before the transfer. The number of insulating particles 2 is reduced as compared with the number of insulating particles 2 in contact with the conductive particles 1 in the film surface direction.

Next, if necessary, the conductive particles with insulating particles 3 transferred to the insulating resin layer 5 are pushed in with a flat plate or a roller 33 (FIG. 4E). The insulating particles 2 that have formed the conductive particles 3 with insulating particles at the time of pressing, and the insulating particles 2 (insulating particles 2 to be the region A1) on the flat plate or roller 33 side are in contact with the flat plate or roller 33. Is relatively detached from the conductive particles 1.

The indentation rate (Lb / D) is preferably 30% or more and 105% or less, more preferably 60, when the conductive particles 3 with insulating particles transferred to the insulating resin layer 5 are pressed with a flat plate or roller 33. It is preferable to adjust so that it may become more than% and below 105%, and it is preferable to determine according to the thrust etc. which are required for a pressing jig for pushing.

Thus, an anisotropic conductive film 10A in which the number of insulating particles 2 in contact with the conductive particles 1 in the thickness direction of the anisotropic conductive film among the number of insulating particles 2 in the conductive particles 3 with insulating particles is reduced can be obtained. Yes (FIG. 4F).

Moreover, in the manufacturing method of the anisotropic conductive film 10A described above, the number of the insulating particles 2 detached from the initial conductive particles 3 with insulating particles depends on the temperature and viscosity of the insulating resin layer 5 and the embedding rate (Lb / D) or the like.

<Deformation aspect of anisotropic conductive film>
The anisotropic conductive film of the present invention has an insulating resin layer 5 in which the conductive particles with insulating particles 3 are embedded, as in the anisotropic conductive film 10B shown in FIG. A low viscosity insulating resin layer 6 having a low minimum melt viscosity may be laminated. By laminating the low-viscosity insulating resin layer 6, when an anisotropic conductive film is used to anisotropically connect an electronic component, the space formed by the electrodes and bumps of the electronic component is filled to improve adhesion. Can be made.

The minimum melt viscosity ratio between the insulating resin layer 5 and the low-viscosity insulating resin layer 6 is preferably 2 or more, more preferably 5 or more, still more preferably 8 or more, and practically 15 or less. The more specific minimum melt viscosity of the low-viscosity insulating resin layer 6 is 3000 Pa · s or less, more preferably 2000 Pa · s or less, and particularly preferably 1000 to 2000 Pa · s. By making the low-viscosity insulating resin layer 6 low in this way, the space formed by the electrodes and bumps of the electronic component can be easily filled with the low-viscosity insulating resin layer. The amount is relatively small, and the conductive particles with insulating particles 3 between the terminals are less likely to flow due to resin flow. Therefore, the adhesiveness between the electronic components can be improved without impairing the trapping property of the conductive particles 3 with insulating particles during anisotropic conductive connection.

The minimum melt viscosity of the entire anisotropic conductive film 10B including the insulating resin layer 5 and the low-viscosity insulating resin layer 6 is preferably 200 to 4000 Pa · s.

The low-viscosity insulating resin layer 6 can be formed by adjusting the viscosity in the same resin composition as the insulating resin layer 5.

In the anisotropic conductive film 10B, the layer thickness of the low-viscosity insulating resin layer 6 is preferably 4 to 20 μm. Alternatively, it is preferably 1 to 8 times the particle diameter D of the conductive particles with insulating particles.

In the present invention, the anisotropic conductive film 10C (FIG. 6) may be used as the anisotropic conductive film 10C (FIG. 6) after the insulating resin layer 5 is peeled from the transfer mold 30 and before the conductive particles 3 with insulating particles are pushed. The laminated conductive resin layer 6 may be an anisotropic conductive film 10D (FIG. 7). In this case, the conductive particles with insulating particles may exist between the insulating resin layer and the low-viscosity insulating resin layer. Moreover, it is preferable that the number of insulating particles on the conductive particles in a plan view of the low viscosity insulating resin layer side film surface is smaller than the number of insulating particles on the conductive particles in a plan view of the insulating resin layer side film surface. Furthermore, you may laminate | stack a low-viscosity insulating resin layer further on the insulating resin layer 5 on the opposite side of the low-viscosity insulating resin layer 6 as needed.

Moreover, a plurality of conductive particles 3 with insulating particles may be provided at different positions in the film thickness direction. These deformation modes can be appropriately combined.

<Electronic components connected with anisotropic conductive film>
The anisotropic conductive film of the present invention anisotropically conducts first electronic components such as IC chips, IC modules, and FPCs and second electronic components such as FPCs, glass substrates, plastic substrates, rigid substrates, and ceramic substrates. It can be preferably used when connecting. IC chips and wafers may be stacked to be multilayered. In addition, the electronic component connected with the anisotropic conductive film of this invention is not limited to the above-mentioned electronic component. It can be used for various electronic parts that have been diversified in recent years.

<Connection method and connection structure using anisotropic conductive film>
The present invention provides a method for manufacturing a connection structure for anisotropically conductively connecting electronic components using the anisotropic conductive film of the present invention, and the connection structure obtained by this manufacturing method, that is, facing the connection structure. The terminal of the electronic component is a connection structure in which the conductive particles with insulating particles and the insulating resin layer are anisotropically conductively connected, and the conductive particles with insulating particles that are not sandwiched between opposing terminals are connected to each other. A connection structure including conductive particles with insulating particles having an insulating particle missing region facing in the opposite direction is provided.

In this connection structure, the conductive particles with insulating particles are also included in the conductive particles with insulating particles sandwiched between the opposing terminals and have insulating particle missing regions facing the opposing direction of the terminals. In this connection structure, the opposing direction of the terminals corresponds to the film thickness direction of the anisotropic conductive film of the present invention used for the production of the connection structure, and the connection surface direction of the terminals is the anisotropic conductive film. Corresponds to the film surface direction. In addition, the insulating particle missing region refers to a region where a part of the surface of the conductive particle with insulating particles has a lower surface density of the insulating particles than the outer annular portion. Therefore, in this connection structure, the conductive particles with insulating particles sandwiched between the opposing terminals correspond to the region A1 or A2 in which the number of insulating particles is reduced in the anisotropic conductive film described above. It can be said that the number of insulating particles in contact with the conductive particles in the opposing direction between them is smaller than the number of insulating particles in contact with the conductive particles in the connecting surface direction of the terminals (direction orthogonal to the opposing direction of the terminals). Such conductive particles with insulating particles are held by the insulating resin until the direction of the insulating particle missing region of the conductive particles with insulating particles that are not sandwiched between the opposing terminals is just sandwiched between the terminals. It is presumed that the orientation was maintained even after being pinched. The conductive particles with insulating particles sandwiched between the opposing terminals are preferable in terms of conduction stability because the insulating particle missing region is in contact with at least one of the opposing terminals. More preferably, both are in contact.

Further, in this connection structure, the conductive particles with insulating particles in which the region lacking the insulating particles faces the opposing direction of the terminals, as described above, the region A1 or A2 in which the number of insulating particles is reduced in the anisotropic conductive film. _Therefore , the relationship of (N _A3 + N _A4 )> (N _A1 + N _A2 ) in the anisotropic conductive film is satisfied.

When the conductive particles with insulating particles in the insulating particle missing region in the connection structure are conceptually described, when the conductive particles with insulating particles are spheres, a partial region of the surface of the sphere corresponding to a central angle of 45 ° is This can be said to be a partial region of the surface of the sphere corresponding to the central angle 45 ° when the surface density of the insulating particles is lower than the annular region corresponding to the outer central angle 45 ° to 135 °.

In this connection structure, conductive particles with insulating particles that are not sandwiched between opposing terminals are sandwiched between non-formation regions of the terminal rows in the electronic component, out of the connection surfaces of the opposing electronic component. Including conductive particles with insulating particles in between. The conductive particles with insulating particles in this case are, for example, when the opposing electronic parts are the first electronic part and the second electronic part, the terminal row non-formation region in the first electronic component and the terminal row in the second electronic component It is the electroconductive particle with an insulating particle pinched | interposed by the non-formation area | region of the electronic component in the opposing direction.

Further, in this connection structure, the conductive particles with insulating particles that are not sandwiched between the opposing terminals are the inter-terminal spaces of the opposing electronic components when the terminal rows are formed on the electronic components with the predetermined inter-terminal spaces. Including conductive particles with insulating particles between them.

In other words, the conductive particles with insulating particles that are not sandwiched between opposing terminals mean the majority of conductive particles with insulating particles that do not contribute to connection in the connection structure.

In general, in the connection structure, the conductive particles with insulating particles that are not sandwiched between the opposing terminals are those that have moved relative to the state before the heating and pressurization due to the heating and pressurization during the anisotropic conductive connection. Some are included and have changed orientation. The degree of change in direction varies depending on the position of the conductive particles with insulating particles with respect to the terminals, the viscosity of the insulating resin layer, the heating and pressing conditions, etc. This includes those that maintain their orientation. Therefore, when the anisotropic conductive film used in the manufacture of the connection structure is the anisotropic conductive film of the present invention, at least some of the conductive particles with insulating particles that are not sandwiched between opposing terminals include insulating particles. It can be seen that the missing region includes those facing the opposing direction of the opposing terminals, which is the connection structure of the present invention. In particular, when the conductive particle missing region in the connection structure has the conductive particles with insulating particles facing the opposing direction of the opposing terminals gathered in a certain region, the connection structure is the connection structure of the present invention. It is easy to see that

An anisotropic conductive film may be cut to approximately the same size as one outer shape of an electronic component, but is generally cut to be larger than one outer shape of an electronic component. That is, it may include a region that does not contribute to the connection (separately away from the tool). Therefore, there may be a region lacking insulating particles facing the opposing direction of the terminals in the outer anisotropic conductive film between the opposing electronic components, and from here also confirm the characteristics of the connection structure of the present invention. Can do.

In addition, when the conductive particles with insulating particles are regularly arranged in the anisotropic conductive film used for manufacturing the connection structure, the conductive particles with insulation particles that are not sandwiched between opposing terminals in the connection structure are also arranged. Maintenance of regularity may be found. In this case, in the conductive particles with insulating particles in which the regularity of the arrangement is found, it can be easily confirmed that the insulating particle missing region is facing the facing direction of the terminals. Moreover, ( _NA3 + _NA4 )> ( _NA1 + _NA2 ) can be easily confirmed about the anisotropic conductive film used for the manufacture.

In addition, it is a structure in the manufacturing process of the connection structure of the present invention, and the anisotropic conductive film of the present invention is attached to one electronic component, but the other electronic component is not yet connected The conductive particles with insulating particles in the anisotropic conductive film are the insulating particles in the connection structure described above (the intermediate product in the connection process, in other words, the anisotropic conductive film-attached electronic component). It has the same characteristics as the attached conductive particles.

As a method for connecting an electronic component using an anisotropic conductive film, when the resin layer of the anisotropic conductive film is a single layer of the insulating resin layer 5, it is anisotropic to the second electronic component such as various substrates. The conductive particles with insulating particles 3 of the conductive conductive film are temporarily pressure-bonded from the side embedded in the surface, and the IC chips or the like are provided on the side of the anisotropically conductive film 3 with the insulating particles with insulating particles embedded therein that are not embedded in the surface. These first electronic components can be combined 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 (may be the same as the thermal polymerizable compound), A pressure bonding method using both light and heat may be used. In this way, unnecessary movement of the conductive particles with insulating particles can be minimized. Further, the side on which the conductive particles with insulating particles 3 are not embedded may be temporarily attached to the second electronic component for use. Note that the anisotropic conductive film may be temporarily attached to the first electronic component instead of the second electronic component.

Further, when the resin layer of the anisotropic conductive film is formed of a laminate of the insulating resin layer 5 and the low-viscosity insulating resin layer 6, the insulating resin layer 5 is used as a second electronic component such as various substrates. The first electronic component such as an IC chip is aligned and placed on the low-viscosity insulating resin layer 6 of the anisotropic conductive film that has been temporarily attached and temporarily bonded, and then subjected to thermocompression bonding. The low-viscosity insulating resin layer 6 side of the anisotropic conductive film may be temporarily attached to the first electronic component for use.

Hereinafter, the present invention will be specifically described by way of examples.
Examples 1 to 10
(1) Manufacture of anisotropic conductive film The resin composition which forms an insulating resin layer and a low-viscosity insulating resin layer with the formulation shown in Table 1 was prepared.

The resin composition for forming the insulating resin layer is applied onto a PET film having a film thickness of 50 μm with a bar coater, dried in an oven at 80 ° C. for 5 minutes, and the insulating resin layer having the thickness shown in Table 2 is formed on the PET film. Formed. Similarly, low-viscosity insulating resin layers were formed on PET films with the thicknesses shown in Table 2, respectively.

On the other hand, the conductive particles with insulating particles have a square lattice arrangement shown in FIG. 1A in plan view, and the mold is set so that the distance between particles is equal to the particle diameter of the conductive particles with insulating particles and the number density is 28000 / mm ^2. Produced. That is, the convex pattern of the mold (number density 28000 pieces / mm ² ) is a square lattice arrangement, the pitch of the convex portions on the lattice axis is twice the average particle diameter, and the short of the lattice axis and the anisotropic conductive film. A mold having an angle θ of 15 ° with the hand direction is manufactured, and a known transparent resin pellet is melted and poured into the mold, cooled and solidified, whereby the recesses are arranged as shown in FIG. 1A. A resin mold of the pattern was formed.

Further, the mold of the convex portion pattern (number density 28000 pieces / mm ²⁾ to create a material obtained by randomly recess using the mold to form a resin mold as a random pattern. At this time, the distance between the conductive particles of adjacent conductive particles with insulating particles was set to be 0.5 times or more the average diameter of the conductive particles.

As the conductive particles with insulating particles, insulating fine particles (average particle size of 0) are formed on the surface of metal-coated resin particles (Sekisui Chemical Co., Ltd., AUL703, average particle size of 3 μm) according to the description in JP-A No. 2014-132567. .3 μm) was prepared, and the conductive particles with insulating particles were filled in the resin-shaped recesses, and the above-mentioned insulating resin layer was covered thereon.

In Examples 1 and 2, the insulating resin layer was pressed at 60 ° C. and 0.5 MPa, and the insulating resin layer was peeled off from the resin mold to transfer the conductive particles with insulating particles to the insulating resin layer. . At this time, the embedding rate (Lb / D) of the conductive particles with insulating particles in the insulating resin layer was 30% in cross-sectional observation by SEM. Moreover, there was no dent around the conductive particles with insulating particles on the surface of the insulating resin layer to which the conductive particles with insulating particles were transferred (see FIG. 2). In Examples 7 to 10, the conductive particles with insulating particles were transferred to the insulating resin layer in the same manner as in Examples 1 to 2, but the dents were formed in the insulating resin layer around the conductive particles with insulating particles after transfer. The temperature when pressing the conductive particles with insulating particles against the insulating resin layer was made lower than 60 ° C.

Next, in Examples 3 to 10, the conductive particles with insulating particles were pressed into the insulating resin layer at a pressing rate (Lb / D) of 100% by pressing the conductive particles with insulating particles on the insulating resin layer. The temperature and pressure at the time of pressing were the same as those described above when the conductive particles with insulating particles were transferred from the resin mold to the insulating resin layer. As a result, in Examples 3 to 6, there is no dent in the insulating resin layer around the conductive particles with insulative particles after being pushed in, and in Examples 7 to 10 the insulating resin layer around the conductive particles with insulative particles after being pushed in The dent was formed in (refer FIG. 3A).

In Examples 1 and 2 (embedding rate 30%) and Examples 3 and 4 (embedding rate 100%), a low-viscosity insulating resin layer on the transfer surface of the conductive particles with insulating particles of the insulating resin layer Was laminated to make an anisotropic conductive film (see FIG. 5).

On the other hand, in Examples 5 to 10 (embedding rate 100%), the low-viscosity insulating resin layer was not laminated. Among these, in Examples 7 to 10, a depression was formed in the insulating resin layer around the conductive particles with insulating particles in a state where the conductive particles with insulating particles were pressed into the insulating resin layer. No. 10 eliminated the dent by heating and pressing the insulating resin layer having a dent under the condition that the anisotropic conductive connection was not hindered.

Comparative Examples 1 to 4
In Comparative Examples 1 to 4, insulating coated conductive particles (coated film thickness: 0.1 to 0.5 μm) in which an insulating coating is applied to the entire surface of metal-coated resin particles (Sekisui Chemical Co., Ltd., AUL703, average particle diameter of 3 μm) Is used in place of the conductive particles with insulating particles of the above-mentioned embodiment, the above-mentioned resin mold is filled so that the insulating coated conductive particles are arranged or arranged as shown in Table 2, and the insulating resin layer is insulated with the insulating coated conductive material. The particles were transferred (indentation rate 30%), and in Comparative Examples 3 and 4, the insulating coated conductive particles transferred to the insulating resin layer were pressed into the insulating resin layer so that the indentation rate was 100%. And the low-viscosity insulating resin layer was laminated | stacked on the transfer surface or pushing surface of the insulation coat electrically-conductive particle.

(2) Particle arrangement state
(2-1) Number ratio of independent particles Using a scanning electron microscope (SEM), the front and back film surfaces of the anisotropic conductive films of the examples and comparative examples (for the laminated low viscosity insulating resin layers) 100 conductive particles with insulating particles or insulating coated conductive particles are observed for each of the low-viscosity insulating resin layer side surface and the opposite surface), and the conductive particles with insulating particles or insulating coated conductive particles that are not in contact with each other. The number was measured, and the ratio of the number to the total number (that is, the number ratio of independent particles) was obtained. As a result, in each Example and Comparative Example, the number ratio of independent particles exceeded 99%.

(2-2) Insulating particle coverage The insulating particle coverage of the conductive particles with insulating particles (conductive particles with insulating particles before embedding in the insulating resin layer) used in the production of the anisotropic conductive film of the example was determined. . The insulating particle coverage is measured by observing 100 conductive particles with insulating particles using a scanning electron microscope (SEM) and measuring the number of insulating particles per conductive particle for each conductive particle with insulating particles. The calculated number was calculated from the area in plan view of one conductive particle with insulating particles and the area in plan view of one insulating particle. As a result, the insulating particle coverage in the conductive particles with insulating particles used for the production of the anisotropic conductive film was 67%.

(2-3) Covering state of insulating particles after production of anisotropic conductive film Scanning electron microscope (SEM) shows the covering state of insulating particles in conductive particles with insulating particles dispersed in the anisotropic conductive film of Example It was determined by cross-sectional observation. In this cross-sectional observation, 100 conductive particles with insulating particles were measured, and the number of insulating particles in the regions A1, A2, A3, and A4 shown in FIG. 2 and the magnitude relationship of N _A1 , N _A2 , N _A3 , and N _A4 Examined. As a result, there was no particular difference in the number of insulating particles in the regions A3 and A4 in each example. In Examples 3 to 10, as compared with Example 1, the number of insulating particles in region A1 was significantly reduced compared to the number of insulating particles in region A2.

(3) Evaluation After the anisotropic conductive film of each Example and Comparative Example was cut in an area sufficient for connection and evaluation, the cut anisotropic conductive film was used, as described below (a ) Initial conduction resistance, (b) conduction reliability, (c) short-circuit occurrence rate, and (d) conductive particle trapping property were measured or evaluated. The results are shown in Table 2.

(A) Initial conduction resistance
The anisotropic conductive film of each Example and Comparative Example was sandwiched between an IC for conducting property evaluation and a glass substrate, and heated and pressurized (180 ° C., 60 MPa, 5 seconds) to obtain a connected object for evaluation. The conduction resistance of the obtained connection for evaluation was measured, and the measured initial conduction resistance was evaluated according to the following criteria.
A: 0.3Ω or less B: More than 0.3Ω, 0.4Ω or less C: More than 0.4Ω There is no practical problem if B is evaluated. If it is A evaluation, it is more preferable.

Here, the IC for evaluation and the glass substrate correspond to their terminal patterns, and the sizes are as follows. Further, when connecting the evaluation IC and the glass substrate, the longitudinal direction of the anisotropic conductive film and the short direction of the bump were matched.

IC for evaluating conduction characteristics
Outline 1.8 × 20.0mm
Thickness 0.5mm
Bump specifications Size 30 × 85μm, distance between bumps 50μm, bump height 15μm

Glass substrate Glass material 1737F made by Corning
Outer diameter 30 × 50mm
Thickness 0.5mm
Electrode ITO wiring

(B) Conduction reliability Conductivity after the connected object for evaluation prepared in (a) is placed in a thermostatic chamber at 85 ° C. and humidity 85% RH for 500 hours is measured and measured in the same manner as the initial conduction resistance. The conducted resistance was evaluated according to the following criteria.

S: 3.0Ω or less A: More than 3.0Ω, 4.0Ω or less B: More than 4.0Ω, 6.0Ω or less C: More than 6.0Ω There is no practical problem if it is evaluated as B. If it is more than A evaluation, it is more preferable.

(C) Short-circuit occurrence rate An anisotropic conductive film of each of the examples and comparative examples was obtained by using an insulating test evaluation IC (7.5 μm space comb tooth TEG (test element group)) and a glass substrate corresponding to a terminal pattern. In the same manner as in the initial conduction resistance, the connection object for evaluation is obtained by heating and pressurizing, and the short circuit occurrence rate in the obtained connection object for evaluation is digital multimeter (digital multimeter 7561, Yokogawa meter & instruments ( Co.)). The specification of this insulation test evaluation IC is shown below.

Insulation test evaluation IC
External dimensions 1.5 x 13 mm
Thickness 0.5mm
Bump specifications Gold plating, size 25 × 140μm, distance between bumps 7.5μm, bump height 15μm

The measured incidence of short circuit was evaluated according to the following criteria.
A: Less than 50 ppm
B: 50 ppm or more and 200 ppm or less C: Above 200 ppm, there is no practical problem if it is evaluated as B.

(D) Conductive particle trapping property Using an evaluation IC for conductive particle trapping property, this evaluation IC and the ITO coated substrate corresponding to the terminal pattern are heated and pressurized (180 ° C., 60 MPa, 5 seconds), the number of trapped conductive particles was measured with respect to 100 regions of 6 μm × 66.6 μm where the bumps of the IC for evaluation overlapped with the terminals of the substrate, and the minimum number of traps was determined and evaluated according to the following criteria.

IC for evaluating conductive particle trapping property
Outline 1.6 × 29.8mm
Thickness 0.3mm
Bump specifications Size 12 × 66.6μm, bump pitch 22μm (L / S = 12μm / 10μm), bump height 12μm

Conductive particle scavenging evaluation criteria OK: 3 or more NG: Less than 3

From Table 2, in the anisotropic conductive films of Examples 1 to 10, the number density of the insulating particles in the conductive particles with insulating particles is lower in the regions A2 and A1 than in the regions A3 and A4. In Examples 3 to 10 in which the conductive particles with insulating particles were pushed into the insulating resin layer during production, the number density of the insulating particles was significantly lower in the region A1 than in the region A2. As a result, the number density of the insulating particles 2 in the regions A2 and A1 in contact with the conductive particles in the film thickness direction is further smaller than the number of insulating particles 2 in the regions A3 and A4 in contact with the conductive particles 1 in the film surface direction. It can be seen that Examples 3 and 4 have better conduction reliability than Examples 1 and 2. In contrast, Comparative Examples 1 to 4 using resin-coated conductive particles were inferior in conduction reliability.

Further, in the results of Table 2, the comparison between Examples 1 and 2, the comparison between Examples 3 and 4, the comparison between Examples 5 and 6, the comparison between Examples 7 and 8, the comparison between Examples 9 and 10, and the comparative example According to the comparison between 1 and 2, and the comparison between Comparative Examples 3 and 4, the case where the conductive particles with insulating particles are arranged in a square lattice and the case where the conductive particles with insulating coat are arranged in a square lattice are random. Although there is no difference in conduction resistance, short-circuit occurrence rate, and conductive particle trapping property when arranged in the above, in the evaluation of trapping property, it is better to arrange the conductive particles with insulating particles or insulating coated conductive particles in a square lattice Indentation was easier to check than when placed randomly.

In addition, Examples 5 and 6 in which the insulating resin layer around the conductive particles with insulating particles does not have a dent, and Examples 7 and 8 in which the insulating resin layer around the conductive particles with insulating particles have a dent also have dents. In Examples 9 and 10, which were eliminated by heating and pressing, the initial conduction resistance, conduction reliability, short-circuit occurrence rate, and conductive particle capturing property were also good. From this, it can be seen that in this example, the conductive particles with insulating particles did not move unnecessarily due to the resin flow regardless of the presence or absence of dents.

DESCRIPTION OF SYMBOLS 1 Conductive particle 2 Insulating particle 3 Conductive particle with insulating particle 5 Insulating resin layer 5a Surface of insulating resin layer 5b Recess (inclination)
5c Dent (undulation)
5p Tangent plane 6 Low-viscosity insulating resin layer 7

Release film

10A, 10B, 10C, 10D Anisotropic conductive film 30 Transfer mold 31 Recess 32 Flat plate 33 Flat plate or roller A Grid axis A1, A2, A3, A4 Region D Insulating particle Particle diameter of conductive particles La Layer thickness of insulating resin layer Lb Distance from surface close to conductive particles with insulating particles to deepest part of conductive particles with insulating particles Lc Exposure of conductive particles with insulating particles in inclination or undulation (Directly above) Diameter of the portion Ld Maximum diameter of the inclination or undulation of the insulating resin layer around or directly above the conductive particles with insulating particles Le Maximum depth of inclination in the insulating resin layer around the conductive particles with insulating particles Lf Insulating particles It the longitudinal and the lattice axis of the undulations of the maximum depth _{_{_{N A1, N A2, N A3}}} , the number of insulating particles present in N _A4 region θ terminal in the insulating resin layer just above the Tsukeshirubeden particles Angle

Claims

An anisotropic conductive film in which conductive particles with insulating particles attached to the surface of the conductive particles are dispersed in an insulating resin layer, wherein the conductive particles with insulating particles An anisotropic conductive film in which the number of insulating particles in contact is smaller than the number of insulating particles in contact with conductive particles in the film surface direction.
The number of insulating particles overlapping with the conductive particles in plan view of one film surface on the front and back of the anisotropic conductive film is less than the number of insulating particles overlapping with the conductive particles in plan view of the other film surface Item 10. An anisotropic conductive film according to Item 1.
The anisotropic conductive film according to claim 1 or 2, wherein the conductive particles with insulating particles are arranged in non-contact with each other.
The anisotropic conductive film according to any one of claims 1 to 3, wherein a low-viscosity insulating resin layer having a minimum melt viscosity lower than that of the insulating resin layer is laminated on the insulating resin layer.
The anisotropic conductive film according to claim 4, wherein the conductive particles with insulating particles are present between the insulating resin layer and the low-viscosity insulating resin layer.
The anisotropic structure according to claim 5, wherein the number of insulating particles on the conductive particles in a plan view of the low viscosity insulating resin layer side film surface is smaller than the number of insulating particles on the conductive particles in a plan view of the insulating resin layer side film surface. Conductive film.
Of the front and back surfaces of the insulating resin layer, the ratio of the distance Lb from the surface where the conductive particles with insulating particles are close to the deepest part of the conductive particles with insulating particles to the particle diameter D of the conductive particles with insulating particles (Lb 7. The anisotropic conductive film according to claim 1, wherein / D) is 30 to 105%.
The surface of the insulating resin layer in the vicinity of the conductive particles with insulating particles has an inclination or undulation with respect to the tangential plane of the insulating resin layer at the center between adjacent conductive particles with insulating particles. An anisotropic conductive film as described in 1.
In the inclination, the surface of the insulating resin layer in the vicinity of the conductive particles with insulating particles is chipped with respect to the tangential plane, and in the undulation, the resin amount of the insulating resin layer immediately above the conductive particles with insulating particles is The anisotropic conductive film according to claim 8, wherein the anisotropic conductive film is less than when the surface of the insulating resin layer immediately above the conductive particles with insulating particles is on the tangent plane.
A method for producing a connection structure in which electronic parts are anisotropically conductively connected using the anisotropic conductive film according to any one of claims 1 to 9.
A connection structure in which electronic components are anisotropically conductively connected by the anisotropic conductive film according to any one of claims 1 to 9.
Terminals of opposing electronic components are connected to each other in an anisotropic conductive connection with conductive particles with insulating particles and an insulating resin layer, and the conductive particles with insulating particles that are not sandwiched between the opposing terminals, A connection structure including conductive particles with insulating particles having an insulating particle missing region facing the opposing direction of the terminals.