HK1240710B - Anisotropic conductor film - Google Patents

Description

Anisotropic conductive film

Technical Field

The present invention relates to an anisotropic conductive film.

Background Art

Anisotropic conductive films, which are made by dispersing conductive particles in an insulating resin binder, are widely used when mounting electronic components such as IC chips on wiring substrates. However, in such anisotropic conductive films, the conductive particles are present in a linked or aggregated state. Therefore, when anisotropic conductive films are used to connect the terminals of IC chips, which are becoming narrower in pitch due to the lightweight and miniaturization of electronic devices, to the terminals of wiring substrates, short circuits may sometimes occur between adjacent terminals due to the linked or aggregated conductive particles in the anisotropic conductive film.

In the past, anisotropic conductive films have been proposed to address this narrowing of the pitch. For example, an anisotropic conductive film has been proposed in which conductive particles are regularly arranged in the film. For example, an anisotropic conductive film has been proposed in which an adhesive layer is formed on a stretchable film, conductive particles are densely packed in a single layer on the surface of the adhesive layer, and the film is then subjected to a biaxial stretching treatment until the distance between the conductive particles reaches the desired distance, thereby regularly arranging the conductive particles. Subsequently, an insulating adhesive base layer, a component of the anisotropic conductive film, is pressed against the conductive particles to transfer the conductive particles to the insulating adhesive base layer (Patent Document 1). Furthermore, an anisotropic conductive film has been proposed in which conductive particles are scattered on a concave-forming surface of a transfer mold having concave portions, the concave-forming surface is scraped to hold the conductive particles in the concave portions, an adhesive film having a transfer adhesive layer formed thereon is pressed thereon to transfer the conductive particles to the adhesive layer, and then an insulating adhesive base layer, a component of the anisotropic conductive film, is pressed against the conductive particles attached to the adhesive layer to transfer the conductive particles to the insulating adhesive base layer (Patent Document 2). In these anisotropic conductive films, an insulating adhesive cover layer is generally laminated on the surface of the conductive particles to cover the conductive particles.

Prior art literature

Patent Literature

Patent Document 1: WO2005/054388

Patent Document 2: Japanese Patent Application Laid-Open No. 2010-33793

Summary of the Invention

Problems to be solved by the invention

However, conductive particles tend to aggregate due to static electricity and become secondary particles, making it difficult for the conductive particles to always exist independently as primary particles. Therefore, the technologies of Patent Documents 1 and 2 present the following problems. Specifically, in the case of Patent Document 1, there are the following problems: it is difficult to densely fill the entire surface of the stretchable film with conductive particles in a single layer without defects, and the conductive particles are filled in the stretchable film in an aggregated state, causing a short circuit; or unfilled areas (so-called "missing areas") appear, causing poor conduction. In addition, in the case of Patent Document 2, there is the following problem: if the concave portion of the transfer mold is covered with conductive particles with a large particle size, it will be removed by scraping afterwards, resulting in a concave portion that does not hold the conductive particles, and "missing" conductive particles will occur in the anisotropic conductive film, which will become the cause of poor conduction; or conversely, if a plurality of small conductive particles are squeezed into the concave portion, the conductive particles will aggregate when transferred to the insulating adhesive base layer. In addition, the conductive particles located at the bottom side of the concave portion do not contact the insulating adhesive base layer, and are therefore dispersed on the surface of the insulating adhesive base layer, destroying the regular arrangement and causing short circuits and poor conduction.

The purpose of the present invention is to solve the above problems of the prior art and provide an anisotropic conductive film in which the conductive particles that should be arranged in a regular pattern are free from "missing" or "agglomerating" problems and the occurrence of short circuits and poor conduction is greatly suppressed.

Methods for solving problems

The present inventors discovered that, when arranging conductive particles at the lattice points of a planar lattice, the above-mentioned object can be achieved by arranging a conductive particle group consisting of a plurality of conductive particles at the lattice point regions of the planar lattice pattern, thereby completing the present invention. Furthermore, the inventors discovered that such an anisotropic conductive film can be produced by attaching a plurality of conductive particles to the tips of convex portions of a transfer member having convex portions formed on its surface, rather than arranging the conductive particles in the concave portions of the transfer member, thereby completing the production method of the present invention.

That is, the present invention provides an anisotropic conductive film having a structure in which conductive particles are arranged on or near the surface of an insulating adhesive base layer.

Two or more conductive particles gather together to form a conductive particle group.

The conductive particle group is arranged in the lattice point region of the planar lattice pattern.

The present invention also provides an anisotropic conductive film having a structure in which an insulating adhesive base layer and an insulating adhesive cover layer are laminated, and conductive particles are arranged near the interface between the laminated layers.

Two or more conductive particles gather together to form a conductive particle group.

The conductive particle group is arranged in the lattice point region of the planar lattice pattern.

The present invention also provides a method for producing an anisotropic conductive film having a structure in which conductive particles are arranged on or near the surface of the insulating adhesive base layer, comprising the following steps (I) to (IV):

<Step (I)>

a step of preparing a transfer body having a surface formed with protrusions corresponding to the grid point region of a planar grid pattern;

<Step (II)>

forming at least two slightly adhesive portions on the top surface of the convex portion of the transfer body;

<Step (III)>

a step of attaching conductive particles to slightly adhered portions of the convex portions of the transfer member; and

<Step (IV)>

The conductive particles are transferred to the insulating adhesive base layer by overlapping and pressing the insulating adhesive base layer with the surface of the transfer body to which the conductive particles are attached. In this step (IV), the transferred conductive particles can be further squeezed into the insulating adhesive base layer 11.

The present invention also provides a method for producing an anisotropic conductive film having a structure in which the insulating adhesive base layer and the insulating adhesive cover layer are laminated and conductive particles are arranged near the interface between the laminated layers, the method comprising the following steps (I) to (V):

<Step (I)>

a step of preparing a transfer body having a surface formed with protrusions corresponding to the grid point region of a planar grid pattern;

<Step (II)>

forming at least two slightly adhesive portions on the top surface of the convex portion of the transfer body;

<Step (III)>

a step of attaching conductive particles to slightly adhesive portions of the convex portions of the transfer body;

<Step (IV)>

a step of overlapping and pressing an insulating adhesive base layer on the surface of the transfer body on which the conductive particles are attached, thereby transferring the conductive particles to the insulating adhesive base layer; and

＜Process (V)＞

A step of laminating an insulating adhesive cover layer on the insulating adhesive base layer to which the conductive particles have been transferred, from the conductive particle-attached surface side.

Furthermore, the present invention provides a connection structure in which a terminal of a first electronic component and a terminal of a second electronic component are anisotropically conductively connected via the anisotropic conductive film of the present invention.

Effects of the Invention

In the anisotropic conductive film of the present invention, two or more conductive particles aggregate to form conductive particle groups, and many conductive particle groups are arranged at the lattice points of a planar lattice pattern. Therefore, when the anisotropic conductive film of the present invention is used for anisotropic conductive connections, it can achieve excellent initial conductivity and good conductivity reliability after aging, while also suppressing the occurrence of short circuits.

Furthermore, in the method for manufacturing an anisotropic conductive film of the present invention, a transfer member having protrusions formed on its surface corresponding to the lattice regions of a planar lattice pattern is used. At least two or more slightly adhesive portions are formed on the top surfaces of these protrusions. After conductive particles are attached to these slightly adhesive portions, the conductive particles are transferred to an insulating adhesive base layer. Consequently, a conductive particle group consisting of two or more conductive particles is arranged in the lattice regions of the planar lattice pattern. Therefore, the use of the anisotropic conductive film obtained by the manufacturing method of the present invention enables anisotropic conductive connection between narrow-pitch IC chips and wiring substrates while significantly reducing the occurrence of short circuits and poor conduction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1A is a cross-sectional view of an anisotropic conductive film according to the present invention.

FIG1B is a cross-sectional view of the anisotropic conductive film of the present invention.

FIG. 2A is a plan perspective view of an anisotropic conductive film according to the present invention.

FIG. 2B is a plan perspective view of the anisotropic conductive film of the present invention.

FIG. 2C is a plan perspective view of the anisotropic conductive film of the present invention.

FIG. 2D is a plan perspective view of the anisotropic conductive film of the present invention.

FIG. 2E is a plan perspective view of the anisotropic conductive film of the present invention.

FIG. 3A is a process diagram for explaining the manufacturing method of the present invention.

FIG3B is a process diagram for explaining the manufacturing method of the present invention.

FIG3C is a process diagram illustrating the manufacturing method of the present invention.

FIG3D is a process diagram for explaining the manufacturing method of the present invention.

FIG. 3E is a process diagram illustrating the manufacturing method of the present invention.

FIG3F is a diagram illustrating the steps of the manufacturing method of the present invention, and is also a schematic cross-sectional view of the anisotropic conductive film of the present invention.

DETAILED DESCRIPTION

Hereinafter, the anisotropic conductive film of the present invention will be described in detail with reference to the drawings.

<Anisotropic Conductive Film>

The anisotropic conductive film of the present invention is shown in FIG1A (cross-sectional view) or FIG1B (cross-sectional view) and FIG2A (plan perspective view). In the case of FIG1A , the anisotropic conductive film 10 of the present invention has a single-layer structure in which conductive particles 13 are arranged on the surface or near the surface of an insulating adhesive base layer 11. Here, “conductive particles 13 are arranged on the surface of the insulating adhesive base layer 11” means that a part of the conductive particles 13 are squeezed into the insulating adhesive base layer 11 and arranged, and conductive particles are arranged near the surface of the insulating adhesive base layer means that the conductive particles 13 are completely squeezed into the insulating adhesive base layer 11 and embedded. In addition, in the case of FIG1B , the anisotropic conductive film 10 of the present invention has a stacked structure in which an insulating adhesive base layer 11 and an insulating adhesive cover layer 12 are stacked, and conductive particles 13 are arranged near their interface. Here, “conductive particles 13 are arranged near the interface between the insulating adhesive base layer 11 and the insulating adhesive cover layer 12” means that the conductive particles 13 are located at the interface between the two layers, or the conductive particles 13 are completely embedded in either the insulating adhesive base layer 11 or the insulating adhesive cover layer 12.

Furthermore, in the anisotropic conductive film 10 of the present invention, two or more conductive particles 13 are aggregated to form conductive particle groups 14, which are arranged in lattice regions 15 of a planar lattice pattern (dashed lines in FIG2 ). While the planar lattice pattern is assumed to be along the longitudinal direction of the anisotropic conductive film 10 and in a direction perpendicular thereto (the width direction), it can also be assumed to be tilted relative to the longitudinal and width directions. This tilt is expected to improve the ability to capture bumps.

(Flat lattice pattern)

Examples of the planar lattice pattern assumed in the anisotropic conductive film include a rhombus lattice, a hexagonal lattice, a square lattice, a rectangular lattice, and a parallelogram lattice, among which the hexagonal lattice that allows closest packing is preferred.

(Grid area)

The shape of the lattice region 15 of the planar lattice pattern can be various, for example, circular, triangular, quadrilateral, polygonal, or amorphous. However, from the perspective of easily preventing the conductive particles located at the end from falling out by having similarity with the conductive particles in a planar view, the center (center of gravity) of the lattice region is preferably aligned with the lattice point P of the planar lattice pattern, and a circle centered at the lattice point P is particularly preferred.

(Shortest distance between adjacent grid areas)

In addition, the shortest distance between adjacent lattice areas in the planar lattice pattern, that is, the shortest distance between the centers (centers of gravity) of adjacent lattice areas, is preferably more than twice the average particle size of the conductive particles 13 or more than the same multiple of the lattice area 15. The upper limit of the shortest distance between adjacent lattice areas is appropriately set according to the bump layout. In the length direction of the film, it can be set to an interval of less than 200 times, more preferably less than 100 times, and even more preferably less than 34 times the average particle size of the conductive particles. This is because, when L/S=1 and the bump width is 200μm, lattice lines will inevitably exist along the bump width direction. In addition, this is also because, in order to fully capture the conductive particles, there can be more than 2 or more than 3 lattice lines along the bump width direction (in addition, the lattice lines may not be parallel to the bump width direction). When there are multiple lattice lines, for example, even if there is a missing conductive particle on the lattice point that becomes one, it can be used practically without any problems. This makes it easy to improve the yield rate, and thus has an advantage in manufacturing cost. If the conductive particles become one lattice point with more than three consecutive points in a lattice axis direction, it can be dealt with by designing with a margin when arranging the design, and there is no problem in practice. In addition, if the bump is long, such as in FOG (Film on Glass), it will partially contact, so the shortest distance between adjacent lattice regions is more preferably more than 2 times and less than 20 times the conductive particle diameter. If it is within this range, when the anisotropic conductive film of the present invention is applied to anisotropic conductive connection, better initial conductivity (initial on-resistance) and conduction reliability after aging can be achieved, and the occurrence of short circuits can be further suppressed.

(Grid area diameter)

When the lattice area is circular, its radius is preferably more than 2 times and less than 7 times the average particle size of the conductive particles 13, and more preferably more than 2 times and less than 5 times. This value can be appropriately set according to the bump layout. If it is within this range, it only spans the gap between one bump and one bump, and does not span multiple bumps, which can easily avoid the occurrence of short circuits. In addition, when the gap between the bumps is sufficiently large relative to the conductive particle size, it can be a rectangular shape with one side less than 100 times, preferably within 50 times, and more preferably within 33 times the particle size.

Furthermore, the length of the lattice region in the longitudinal direction of the film is preferably less than half the width of the bump, thereby achieving the effects of anisotropic connection stability and capture reliability.

(Conductive particle group)

In the present invention, the reason for forming a "conductive particle group" 14 from two or more conductive particles 13 is to prevent short circuits by forming a collection of conductive particles that do not span multiple bumps (in other words, forming a collection of conductive particles that span only the gaps between bumps). The number of conductive particles constituting the conductive particle group varies depending on the average particle size of the conductive particles, the grid spacing of the planar lattice pattern, and other factors, but is preferably at least 2 and no more than 200. Furthermore, the conductive particles are present only on a single plane and preferably do not overlap.

Furthermore, if the distance between lattice points is set to be substantially equal to or larger than the size of the conductive particle group, the conductive particle group can be easily identified.

(Shortest distance between adjacent conductive particles)

Furthermore, the plurality of conductive particles 13 constituting the conductive particle group 14 within the lattice region 15 may be randomly or regularly arranged, but preferably, they are not in excessive contact with each other. This is to prevent short circuits. The shortest distance between adjacent conductive particles when the conductive particles are not in contact is at least 25% of the average particle size of the conductive particles.

In addition, when the conductive particles 13 are arranged regularly in the conductive particle group 14, the number of conductive particles is preferably 3 or more, more preferably 4 or more. In this case, the lattice area containing the conductive particle group 14 can be set as a circle in which the conductive particles are inscribed, or a polygonal shape consisting of 3 or more conductive particles can be set as the lattice area. In addition, although not shown, the conductive particles constituting the conductive particle group can be arranged in a row while maintaining a predetermined distance (preferably 0.5 times or more of the conductive particle diameter), or can be arranged in two rows crosswise in an X-shaped manner (or can be arranged in a manner that multiple rows cross one row). When the directions of the arrangement of one row in all the conductive particle groups are aligned, it can be seen that there are lines consisting of conductive particles located at the lattice points and no conductive particles in the area without the lattice points, and the lines consisting of conductive particles exist as dotted lines when observed macroscopically in a plan view. The arrangement direction can be the length direction of the anisotropic conductive film or the width direction. It can also be a direction intersecting with them. Furthermore, the arrangement direction of this "arrangement of one row" can be regularly changed.

When the lattice region of the conductive particle group composed of three conductive particles is triangular, it is preferred that at least two of the three sides are neither parallel to the longitudinal direction of the anisotropic conductive film nor parallel to the width direction perpendicular to the longitudinal direction, and more preferably all three sides meet the above conditions. If they are not parallel to the longitudinal direction, the occurrence of short circuits can be expected to be suppressed. If they are not parallel to the width direction, the conductive particles at the ends of the bumps will not be arranged in a straight line, thus suppressing the variation in the number of conductive particles captured on each bump.

In addition, the triangular shape of the lattice area formed by the conductive particle group consisting of 3 conductive particles may be an equilateral triangle or may not be an equilateral triangle. Due to the following reasons, it is preferably a triangle (from the perspective of easily grasping the arrangement shape, it may be an isosceles triangle) in the form of the length direction side or width direction protruding of the anisotropic conductive film. If it is a triangle that protrudes to the length direction side, the distance between the gaps between the bumps becomes larger relatively, so it is possible to avoid the risk of short circuit. In addition, if it is a triangle that protrudes to the width direction, the side of the triangle intersects with the bump end to form an acute angle, so it is especially possible to expect the effect of easy capture in the case of micro-pitch. In this case, the tangent line of the film length direction side of the conductive particles constituting the side is preferably present in a manner passing through each conductive particle.

In the case that the lattice region of the conductive particle group that is made up of 4 conductive particles is quadrilateral, owing to forming the combination of two triangles, thus can be considered in the same manner as the situation of triangle.In addition, quadrilateral can be square, rectangle, parallelogram that are made up of two triangles of identical shape, but quadrilateral can also be quadrilaterals such as trapezoid that are made up of the combination of triangles of different shapes, and all sides, length and angle also can be all different.In addition, in the case that the lattice region of the conductive particle group that is made up of 4 conductive particles is parallelogram, can be the shape that makes two equilateral triangles be combined, also can not be equilateral triangle.In this case, owing to the reason same as the situation of triangle, therefore preferably at least 2 sides are neither parallel to the length direction of anisotropic conductive film, also not parallel to the width direction orthogonal to the length direction.

When the lattice region of the conductive particle group consisting of 5 conductive particles is a pentagon, it can be a combination of three triangles or a combination of a triangle and a quadrilateral, and thus can be considered in the same manner as the triangular situation. When the lattice region of the conductive particle group consisting of 6 or more conductive particles is a corresponding polygonal shape, it can be a combination of triangles, a combination of triangles and a quadrilateral or a pentagon, and thus can be considered in the same manner as these polygons. In addition, the lattice region can also be considered as a circle (including an ellipse). Conductive particles can be present in the center of a circle. This is because the polygonal shape formed by the combination of triangles is considered as a circle.

In addition, the regular arrangement of the conductive particles constituting the conductive particle group can be the same in all conductive particle groups as shown in FIG2B (a square lattice-shaped quadrilateral), or can change regularly as shown in FIG2C (a method in which the number of conductive particles repeatedly decreases or increases one by one within a certain range). In addition, the shape can be changed regularly with the same number as shown in FIG2D (a method in which the length of the base of an isosceles triangle is lengthened by a certain length). The angle relative to the length direction of the film can also be changed regularly with the same number and the same shape as shown in FIG2E (a method in which a square lattice-shaped quadrilateral is rotated). In addition, the regular arrangement of the conductive particles constituting the conductive particle group is not limited to the methods shown in these drawings. From the perspectives of the number of conductive particles, the shape of the conductive particle group, etc., various regular change methods can also be combined. This is because it corresponds not only to the bump layout, but also to various changes such as the combination of the insulating adhesive of the anisotropic conductive film and the crimping conditions of the anisotropic connection.

In the case where the regular arrangement is a regular change, there may be the following side, that is, the side formed by the regular arrangement of the conductive particles constituting the conductive particle group located at a portion of the lattice points of the change can exist as a side parallel to the length direction of the anisotropic conductive film and the width direction orthogonal to the length direction. Since the conductive particle group is arranged in a lattice, if, for example, the length direction of the bump is sufficiently larger than the conductive particle group, a plurality of lattice points may be present on the long side of the bump. In such a case, the conductive particles present at the end of the bump can be captured by any conductive particle at the lattice point, so it is not easy to generate the worry that the number of conductive particles captured is reduced and the on-resistance becomes unstable. Therefore, it is easy to obtain the configuration state of the conductive particles such as the state after the connection when the anisotropic conductive film is manufactured, which easily improves the accuracy of the analysis elements and contributes to the reduction of the total cost. For example, when Figure 2D and Figure 2E are continuously moved in a certain direction (as the length direction of the winding direction and the unwinding direction of the film, the direction of the production line when the anisotropic connection is continuously performed), since the way of change is regular, it is easy to find that it is bad. For example, by scrolling Figure 2E on a display to simulate the movement of an anisotropic conductive film in an actual production line, it can be easily understood that when the regular arrangement of the conductive particles undergoes continuous changes, it is easier to determine whether the change is a discontinuous abnormal state or a state of no change. As described above, in the present invention, the regular arrangement of the conductive particles constituting the conductive particle group can take a variety of forms. This facilitates the design of the arrangement of the conductive particles in the anisotropic conductive film and is part of the present invention.

(Approximate number of conductive particles)

In addition, as an index for evaluating the conductive particle group, the number of conductive particles that are close to the configuration around any conductive particle can be used. Here, the surrounding of the conductive particles refers to the concentric circles of radius 2.5r drawn on the plane of the film when the conductive particles are assumed to be spheres and their average particle size is set to r. In addition, close means a state of contact with or at least partial overlap with the concentric circles. The number of conductive particles close to each other can be measured by the observation results of the plan view. The number is preferably more than 1 and less than 14, more preferably more than 1 and less than 10. The reason for such a number is that the shortest distance between the bumps when set to micro-pitch is, for example, less than 4 times the conductive particle diameter. In other words, this is to achieve a balance between the following two: suppressing the occurrence of short circuits caused by excessive density of conductive particles and avoiding the occurrence of poor anisotropic connections caused by excessive sparse conductive particles.

(Conductive particles)

As the conductive particles 13, conductive particles used in known anisotropic conductive films can be appropriately selected and used. For example, metal particles such as nickel, copper, silver, gold, and palladium, and metal-coated resin particles formed by coating the surface of resin particles such as polyamide and polybenzoguanamine with metals such as nickel can be mentioned. In addition, the average particle size can be 1 μm to 30 μm. From the perspective of operability during production, it is preferably 1 μm to 10 μm, and more preferably 2 μm to 6 μm. As described above, the average particle size can be measured using an image-type or laser-type particle size distribution analyzer.

The amount of conductive particles present in the anisotropic conductive film depends on the lattice spacing of the planar lattice pattern and the average particle size of the conductive particles, and is usually 300 to 40,000 particles/ ^{mm 2 .}

(Insulating adhesive base)

As the insulating adhesive base layer 11, a material used as an insulating adhesive base layer in a known anisotropic conductive film can be appropriately selected and used. For example, a photo-radical polymerizable resin layer containing an acrylate compound and a photo-radical polymerization initiator, a thermal-radical polymerizable resin layer containing an acrylate compound and a thermal-radical polymerization initiator, a thermal-cationic polymerizable resin layer containing an epoxy compound and a thermal-cationic polymerization initiator, a thermal-anionic polymerizable resin layer containing an epoxy compound and a thermal-anionic polymerization initiator, or a cured resin layer thereof can be used. In addition, these resin layers can be appropriately selected to contain a silane coupling agent, a pigment, an antioxidant, an ultraviolet absorber, etc., as needed.

The insulating adhesive base layer 11 can be formed by forming a film of a coating composition containing the above-mentioned resin by a coating method, drying, and further curing, or by forming a film in advance by a known method.

The thickness of the insulating adhesive base layer 11 can be 1 μm to 60 μm, preferably 1 μm to 30 μm, and more preferably 2 μm to 15 μm.

(Insulating adhesive cover)

As the insulating adhesive cover layer 12, a material used as an insulating adhesive cover layer in a known anisotropic conductive film can be appropriately selected and used. Alternatively, a material formed of the same material as the insulating adhesive base layer 11 described above can be used.

The insulating adhesive cover layer 12 can be formed by forming a film of a coating composition containing the above-mentioned resin by a coating method, drying, and further curing, or by forming a film in advance by a known method.

The thickness of the insulating adhesive cover layer 12 is preferably from 1 μm to 30 μm, and more preferably from 2 μm to 15 μm.

Furthermore, insulating fillers such as silica particles, alumina, and aluminum hydroxide may be added to the insulating adhesive base layer 11 and the insulating adhesive cover layer 12 as needed. The amount of insulating filler added is preferably 3 parts by mass to 40 parts by mass per 100 parts by mass of the resin constituting these layers. This prevents unwanted movement of the conductive particles 13 due to the molten resin even if the anisotropic conductive film 10 melts during anisotropic conductive connection.

(Lamination of Insulating Adhesive Base Layer and Insulating Adhesive Cover Layer)

When the insulating adhesive base layer 11 and the insulating cover layer 12 are laminated with the conductive particles 13 interposed therebetween, this can be done using a known method. In this case, the conductive particles 13 are present near the interface between these layers. Here, "present near the interface" means that a portion of the conductive particles is embedded in one layer, and the remaining portion is embedded in the other layer.

<Manufacturing of anisotropic conductive films>

Next, the method for manufacturing the anisotropic conductive film of the present invention is described. The anisotropic conductive film of the present invention is an anisotropic conductive film having a structure in which conductive particles are arranged on the surface or near the surface of an insulating adhesive base layer (Figure 1A), or an anisotropic conductive film having a structure in which an insulating adhesive base layer and an insulating adhesive cover layer are stacked and conductive particles are arranged near their interface. It is an anisotropic conductive film in which two or more conductive particles are aggregated to form a conductive particle group, and the conductive particle group is arranged in the lattice area of a planar lattice pattern (Figure 1B). The method for manufacturing an anisotropic conductive film having a structure in which conductive particles are arranged on the surface or near the surface of an insulating adhesive base layer has the following steps (I) to (IV), and the method for manufacturing an anisotropic conductive film having a structure in which an insulating adhesive base layer and an insulating adhesive cover layer are stacked and conductive particles are arranged near their interface has the following steps (I) to (V). Each step is described in detail with reference to the accompanying drawings. It should be noted that the present invention is not particularly limited to this manufacturing method.

(Step (I))

First, as shown in FIG3A , a transfer body 100 is prepared, the surface of which is formed with convex portions 101 corresponding to the lattice area of a plane lattice pattern. The shape of the convex portion 101 can take various shapes such as roughly cylindrical, roughly hemispherical, and rod-shaped. It is called "roughly" because it can be a case where the convex portion always has the same width in the height direction, or it can be a case where the width narrows upwards, etc. Here, roughly cylindrical means roughly cylindrical or roughly prismatic (triangular prism, square prism, hexagonal prism, etc.). It is preferably roughly cylindrical.

The height of the convex portion 101 can be determined based on the terminal spacing, terminal width, gap width, average particle size of the conductive particles to be anisotropically conductively connected, but is preferably 1.2 times or more and less than 4 times the average particle size of the conductive particles used. In addition, the half-value width (width at half height) of the convex portion 101 is preferably 2 times or more and less than 7 times the average particle size of the conductive particles, and more preferably 2 times or more and less than 5 times. If the height and width are within these ranges, the effect of avoiding continuous falling off and missing can be obtained.

Furthermore, the projections 101 preferably have top surfaces that are flat enough to allow the conductive particles to adhere stably.

＊Specific examples of transfer media

The transfer body to be prepared in step (I) can be produced using known methods. For example, a metal plate can be processed into a master disc, which is then coated with a curable resin composition and cured. Specifically, a flat metal plate is cut to produce a master disc having recesses corresponding to the protrusions. The resin composition constituting the transfer body is then applied to the surface of the master disc where the recesses are formed. After curing, the resin composition is separated from the master disc to obtain the transfer body. The area surrounded by the recognizable outline of the protrusion when viewed from above corresponds to the grid point area of a planar lattice pattern.

(Step (II))

Next, as shown in FIG3B , at least two slightly adhesive portions 102 are formed on the top surface of the convex portions 101 of the transfer member 100 having a plurality of convex portions 101 formed in a planar lattice pattern on the surface. The shortest distance between the slightly adhesive portions 102 is preferably set to at least 0.25 times the average particle size of the conductive particles used, and more preferably at least 0.5 times.

＊Slightly adhesive portion of the transfer body

The slightly adhesive portion 102 exhibits a temporary adhesive force that maintains the conductive particles until they are transferred to the insulating adhesive base layer that constitutes the anisotropic conductive film. It is formed on at least the top surface of the protrusion 101. Therefore, the entire protrusion 101 may exhibit slightly adhesive properties. However, to prevent unintentional aggregation of the conductive particles, the present invention provides two or more slightly adhesive portions 102 that are separated from each other. Furthermore, the thickness of the slightly adhesive portion 102 can be appropriately determined based on the material of the slightly adhesive portion 102, the particle size of the conductive particles, and other factors. Furthermore, "slightly adhesive" means that the conductive particles, when transferred to the insulating adhesive base layer, have a weaker adhesive force than the insulating adhesive base layer.

The slightly adhesive portion 102 may be a slightly adhesive portion used in a known anisotropic conductive film, and may be formed by, for example, applying a silicone adhesive composition to the top surface of the protrusion 101 .

In addition, when manufacturing an anisotropic conductive film with regularly arranged conductive particles as shown in Figures 2B to 2E, a height difference can be formed in the concave portion of the transfer body original plate so that a micro-adhesion layer corresponding to the regularly arranged pattern of the conductive particles is formed on the convex portion of the transfer body, or a micro-adhesion layer can be formed on the top surface of the convex portion of the transfer body using a well-known method such as screen printing and photolithography.

(Step (III))

Next, as shown in FIG3C , conductive particles 103 are attached to the slightly adhered portions 102 of the protrusions 101 of the transfer body 100. Specifically, conductive particles 103 are spread from above the protrusions 101 of the transfer body 100, and conductive particles 103 not attached to the slightly adhered portions 102 are blown away with a blower. Here, multiple conductive particles 103 are attached to a single protrusion 101, and these multiple conductive particles 103 constitute a conductive particle group 114.

In addition, the direction of the surface in Figure 3C can be reversed so that the top surface of the protrusion is attached to the surface covered with conductive particles. This is to prevent unnecessary stress from being applied to the conductive particles. By attaching only the conductive particles required for configuration to the top surface of the protrusion, it is easy to recycle the conductive particles, which is more economical than the method of filling the opening and taking out the conductive particles. In addition, in the case of the method of filling the opening and taking out the conductive particles, there is concern that the conductive particles that are not filled are susceptible to unnecessary stress.

(Step (IV))

Next, as shown in FIG3D , the surface of the transfer body 100 on the side to which the conductive particle group 114 is attached is overlapped and pressed with the insulating adhesive base layer 104 that is to constitute the anisotropic conductive film, so that the conductive particle group 114 is transferred to a single side of the insulating adhesive base layer 104 ( FIG3E ). In this case, it is preferable to overlap and press the transfer body 100 with the insulating adhesive base layer 104 with its protrusion 101 facing downward. This is because by setting it downward and blowing air, it is easy to remove the conductive particles that are not attached to the top surface of the protrusion. In addition, in this process, the transferred conductive particles can be further squeezed into the insulating adhesive base layer 104. For example, further pressing can be performed using the transfer body, or the conductive particle transfer surface of the insulating adhesive base layer can be pressed using a conventional heated pressing plate. In this way, the anisotropic conductive film of FIG1A with a structure in which conductive particles are arranged on or near the surface of the insulating adhesive base layer can be obtained.

(Process (V))

3F, an insulating adhesive cover layer 105 is laminated from the conductive particle transfer surface side onto the insulating adhesive base layer 104 to which the conductive particles 103 are transferred. Thus, the anisotropic conductive film 200 (FIG. 1B) of the present invention is obtained.

＜Connection structure＞

Regarding the anisotropic conductive film of the present invention, by being arranged between the terminals (e.g., bumps) of a first electronic component (e.g., an IC chip) and the terminals (e.g., bumps, gaskets) of a second electronic component (e.g., a wiring substrate), and being thermally pressed from the first or second electronic component side, it is completely cured to perform an anisotropic conductive connection, thereby obtaining a connection structure such as a so-called COG (chip on glass) or FOG (film on glass) in which short circuits and poor conduction are suppressed.

Example

Hereinafter, the present invention will be described in detail.

Example 1

A 2mm thick nickel plate was prepared. Cylindrical recesses (8μm inner diameter, 8μm maximum depth) were formed in a square lattice pattern. Furthermore, linear grooves with a depth of 1μm and a width of 1μm were randomly formed on the bottom (the total area of the grooves being within 70% of the total area of the bottom). This was used to create a transfer master. The distance between adjacent recesses was 12μm. Therefore, the density of the recesses was 2500/ ^mm² . The inner diameter and distance between adjacent recesses corresponded to the diameter and the shortest distance between adjacent convex portions of the transfer material.

For the obtained transfer body original plate, a photopolymerizable resin composition containing 60 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 29 parts by mass of an acrylate resin (M208, Toagosei Co., Ltd.), and 2 parts by mass of a photopolymerization initiator (IRGACUR184, BASF Japan Co., Ltd.) was applied on a PET (polyethylene terephthalate) film in a dry thickness of 30 μm. After drying at 80°C for 5 minutes, the film was irradiated with light at 1000 mJ using a high-pressure mercury lamp to prepare a transfer body.

The transfer body was peeled off from the original disc and wound onto a stainless steel roller with a diameter of 20 cm with the convex portion on the outside. While the roller was rotated, it came into contact with an adhesive sheet made by impregnating a non-woven fabric with a micro-adhesive composition containing 70 parts by mass of an epoxy resin (jER828, Mitsubishi Chemical Co., Ltd.) and 30 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.). The micro-adhesive composition was adhered to the top surface of the convex portion to form a micro-adhesive layer with a thickness of 1 μm to obtain a transfer body.

The slightly adhesive layer is formed in a dot shape by the grooves provided on the bottom of the transfer master.

Conductive particles (nickel-plated resin particles (AUL704, Sekisui Chemical Co., Ltd.)) having an average particle diameter of 4 μm were scattered on the surface of the transfer body, and then the conductive particles not adhering to the slightly adhesive layer were removed by air blowing.

For the transfer body with conductive particles attached, a sheet-like thermosetting insulating adhesive film with a thickness of 5 μm serving as an insulating adhesive base layer (a film formed by an insulating resin composition containing 40 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), 40 parts by mass of an epoxy resin (jER828, Mitsubishi Chemical Co., Ltd.), 2 parts by mass of a cationic curing agent (SI-60L, Sanshin Chemical Co., Ltd.), and 20 parts by mass of a silica particle filler (Aerosil RY200, Japan Aerosil Co., Ltd.)) is pressed at a temperature of 50°C and a pressure of 0.5 MPa from the surface on which the conductive particles are attached to the sheet-like thermosetting insulating adhesive film serving as an insulating adhesive base layer.

A transparent, 15-μm-thick insulating adhesive film (formed from a thermosetting resin composition containing 60 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 40 parts by mass of an epoxy resin (jER828, Mitsubishi Chemical Co., Ltd.), and 2 parts by mass of a cationic curing agent (SI-60L, Sanshin Chemical Co., Ltd.)) was placed over the conductive particle-attached surface of the insulating adhesive base layer. The layers were laminated at a temperature of 60°C and a pressure of 2 MPa. This produced an anisotropic conductive film.

Example 2

When preparing a transfer master, the anisotropic conductive film was obtained by repeating Example 1 except that the distance between adjacent concave portions was changed to 8 μm. The density of the concave portions of the transfer master was 3900/mm ² .

Example 3

When preparing a transfer master, the anisotropic conductive film was obtained by repeating Example 1 except that the inner diameter of the recesses was set to 12 μm and the distance between adjacent recesses was changed to 8 μm. The density of the recesses in the transfer master was 2500/mm ² .

Example 4

When preparing the transfer master, the anisotropic conductive film was obtained by repeating Example 1 except that the inner diameter of the concave portion was set to 20 μm and the distance between adjacent concave portions was changed to 20 μm. The density of the concave portions of the transfer master was 625/mm ² .

Comparative Example 1

When preparing a transfer master, the anisotropic conductive film was obtained by repeating Example 1 except that the inner diameter of the recesses was set to 12 μm and the distance between adjacent recesses was changed to 4 μm. The density of the recesses in the transfer master was 3900/mm ² .

Comparative Example 2

In Example 2, except that the scattering of the conductive particles and the air blowing treatment were performed twice, the same procedure as in Example 2 was repeated to obtain an anisotropic conductive film.

Comparative Example 3

When preparing a transfer master, the anisotropic conductive film was obtained by repeating Example 1 except that the inner diameter of the recesses was set to 8 μm and the distance between adjacent recesses was changed to 80 μm. The density of the recesses was 130/mm ² .

＜Evaluation＞

(Evaluation of Grid Area)

The shortest distance between adjacent conductive particles, the shortest distance between adjacent lattice regions, and the lattice region diameter of the anisotropic conductive films of Examples and Comparative Examples were measured using an optical microscope (MX50, Olympus Corporation).

(Approximate number of conductive particles)

100 randomly selected conductive particles from the anisotropic conductive films of the Examples and Comparative Examples were measured using an optical microscope (MX50, Olympus Corporation) to determine the number of conductive particles that at least partially overlapped with a concentric circle with a radius of 2.5r in the horizontal direction, assuming each conductive particle was spherical and had an average particle diameter of r. The results (minimum number (MIN) and maximum number (MAX)) are shown in Table 1. Practically, a number of 10 or fewer is preferred.

Furthermore, observations during this measurement revealed that the conductive particles were densely packed because the scattering and air blowing treatments were repeated twice in Comparative Example 2. This can also be understood from the large number of conductive particles that were close together.

(Initial conductivity (initial on-resistance))

Using the anisotropic conductive films of the examples and comparative examples, an IC chip with gold bumps having a gap of 12 μm between bumps, a height of 15 μm, and a diameter of 30 × 50 μm and a glass substrate with wiring having a gap of 12 μm was anisotropically conductively connected at 180°C, 60 MPa, and 5 seconds to obtain a connection structure. The initial on-resistance value of the obtained connection structure was measured using a resistance meter (digital multimeter, Yokogawa Electric Corporation). The results are shown in Table 1. It is expected to be 1Ω or less.

(Conduction reliability)

The connection structure used in the initial on-resistance measurement was placed in an aging tester set at 85°C and 85% humidity. The on-resistance after 500 hours was measured in the same manner as for the initial on-resistance. The results are shown in Table 1. It is desirable to have an on-resistance of 5Ω or less.

(Short circuit occurrence rate)

The same connection structure as that used for the initial on-resistance was prepared, and the occurrence of short circuits between adjacent wirings was investigated. The results are shown in Table 1. The short circuit occurrence rate is expected to be 50 ppm or less.

[Table 1]

As can be seen from the results in Table 1, the connection structures using the anisotropic conductive films of Examples 1 to 4 showed good results in the evaluation items of initial conductivity (initial on-resistance), conduction reliability, and short circuit occurrence rate.

On the other hand, the anisotropic conductive films of Comparative Examples 1 and 2 had an excessively large number of conductive particles close together when viewed from above, resulting in a significantly higher incidence of short circuits compared to the examples, making them undesirable anisotropic conductive films. The anisotropic conductive film of Comparative Example 3 had an excessively sparse number of conductive particles, resulting in insufficient conduction reliability and poorer initial conductivity than the examples.

Example 5

An insulating adhesive base layer was prepared in the same manner as in Example 1, except that the insulating adhesive cover layer was omitted. The phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.) was changed from 40 parts by mass to 50 parts by mass, the silica fine particle filler (Aerosil RY200, Japan Aerosil Co., Ltd.) was changed from 20 parts by mass to 10 parts by mass, and the thickness was changed from 5 μm to 20 μm. The conductive particles were transferred and pressed to produce an anisotropic conductive film having conductive particles arranged in the insulating adhesive base layer, as shown in FIG1A . The connection structure using this anisotropic conductive film exhibited good results in the evaluation criteria of initial conductivity (initial on-resistance), conduction reliability, and short-circuit occurrence rate, as in Example 1.

Example 6

To produce an anisotropic conductive film in which the conductive particles were regularly arranged as shown in FIG2B , a transfer substrate was used having recesses of 14 μm × 14 μm (a step was provided at each corner of the recess so that the micro-adhesive layer was provided only at the corresponding corners of the transfer substrate), a recess density of 125/mm ² , and a distance of 75 μm between adjacent recesses. A micro-adhesive layer was formed on the corners of the top surface of the convex portions of the transfer substrate, so that the number of conductive particles in the conductive particle group was 4 and the distance between the conductive particles in the conductive particle group was 4 μm. The anisotropic conductive film was obtained in the same manner as in Example 1, except that the phenoxy resin (YP-50, Nippon Steel & Sumitomo Metal Chemicals Co., Ltd.) in the insulating adhesive base layer of Example 1 was changed from 40 to 50 parts by mass, and the silica fine particle filler (Aerosil RY200, Japan Aerosil Co., Ltd.) was changed from 20 to 10 parts by mass. The number density of the conductive particles was 500/mm ² .

Furthermore, the obtained anisotropic conductive film was sandwiched between a glass substrate (ITO solid electrode) and a flexible wiring substrate (bump width: 200μm, L (line spacing) / S (gap) = 1, wiring height 10μm). Anisotropic conductive connection was performed at 180°C, 5MPa, and 5 seconds with a bump length of 1mm to obtain an evaluation connection structure. The "initial on-resistance value" of the obtained connection structure and the "conductivity reliability" after 500 hours in a constant temperature bath at 85°C and 85% RH were measured using a digital multimeter (34401A, manufactured by Agilent) with a current of 1A and a four-terminal method. In the case of "initial conductivity", the measured value was evaluated as good when it was 2Ω or less, and as poor when it exceeded 2Ω. In the case of "conductivity reliability", the measured value was evaluated as good when it was 5Ω or less, and as poor when it was 5Ω or more. As a result, all the connection structures of this example were evaluated as "good". Furthermore, the “short circuit occurrence rate” was measured in the same manner as in Example 1, and good results were obtained in the same manner as in Example 1.

Example 7

An anisotropic conductive film was obtained in the same manner as in Example 6 except that a transfer master having a recess density of 500/mm ² and a distance between adjacent recesses of 31 μm was used so that the number density of the conductive particles was 2000/mm ² .

The resulting anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The resulting connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 6, with good results obtained in all cases.

Example 8

In order to produce an anisotropic conductive film in which conductive particles are arranged regularly as shown in FIG2C , a transfer body original plate with a recess size of 20 μm×20 μm (the recess is provided with a height difference so that a micro-adhesive layer is provided only at a predetermined position of the transfer body), a recess density of 125/mm ² , and a distance between adjacent recesses of 69 μm is used. The number of conductive particles in the conductive particle group is continuously changed to 6, 5, 4, and 3, and the shortest distance between the conductive particles in the conductive particle group is 3 μm or more in any shape. In addition, any shape is set to have substantially the same outer shape. In addition, with respect to the shape, it is appropriate to adjust the length of any side of a regular hexagon, a regular pentagon, a square, and an equilateral triangle to form a shape similar to them. Except for providing a micro-adhesive layer on the top surface of the convex portion of the transfer body, an anisotropic conductive film is obtained in the same manner as in Example 6. The number density of the conductive particles is 500/mm ² .

The obtained anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The obtained connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 6, with good results obtained in all cases.

Example 9

An anisotropic conductive film was obtained in the same manner as in Example 8 except that a transfer master having a recess density of 500/mm ² and a distance between adjacent recesses of 25 μm was used so that the number density of the conductive particles was 2000/mm ² .

The resulting anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The resulting connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 5, with good results obtained in all cases.

Example 10

To produce an anisotropic conductive film having conductive particles arranged regularly as shown in FIG2D , a transfer substrate was used having recesses of 20 μm × 20 μm (the recesses were provided with height differences so that the slightly adhesive layer was provided only at predetermined locations on the transfer substrate), a recess density of 167/mm ² , and a distance of 57 μm between adjacent recesses. The slightly adhesive layer was provided on the top surface of the convex portions of the transfer substrate in a manner such that the number of conductive particles in the conductive particle group was 3, the shape of the conductive particle group was an isosceles triangle, and the distances between the conductive particles were (4 μm, 12 μm, and 12 μm) or (8 μm, 13 μm, and 13 μm). An anisotropic conductive film was obtained in the same manner as in Example 6, except that the number density of the conductive particles was 500/mm ² .

The obtained anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The obtained connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 6, with good results obtained in all cases.

Example 11

An anisotropic conductive film was obtained in the same manner as in Example 10 except that a transfer master having a recess density of 667 particles/mm ² and a distance between adjacent recesses of 19 μm was used so that the number density of the conductive particles was 2000 particles/mm ² .

The obtained anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The obtained connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 6, with good results obtained in all cases.

Example 12

To produce an anisotropic conductive film in which the conductive particles were regularly arranged as shown in FIG2E , a transfer master was used in which the inclination of each rectangular conductive particle group increased by 15 degrees in the longitudinal and width directions of the film. The anisotropic conductive film was obtained in the same manner as in Example 6, except that the number density of the conductive particles was 500 particles/mm ² .

The obtained anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The obtained connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 6, with good results obtained in all cases.

Example 13

An anisotropic conductive film was obtained in the same manner as in Example 12 except that a transfer master having a recess density of 500/mm ² and a distance between adjacent recesses of 31 μm was used so that the number density of the conductive particles was 2000/mm ² .

The resulting anisotropic conductive film was sandwiched between a glass substrate and a flexible wiring substrate in the same manner as in Example 6 to achieve anisotropic conductive connection, thereby obtaining a connection structure for evaluation. The resulting connection structure was evaluated for "initial conductivity," "conduction reliability," and "short circuit occurrence rate" in the same manner as in Example 5, with good results obtained in all cases.

In addition, in Examples 6 to 13, except for the method of directly filling the transfer mold with recesses with conductive particles and transferring the conductive particles to the insulating adhesive base layer, the corresponding examples were repeated to produce anisotropic conductive films and evaluate them. The results were substantially the same as those in Examples 6 to 13.

Industrial applicability

The anisotropic conductive film of the present invention uses a transfer body with protrusions formed on its surface corresponding to the lattice points of a planar lattice pattern. At least two or more slightly adhesive portions are formed on the top surfaces of these protrusions. Conductive particles are attached to these slightly adhesive portions before being transferred to an insulating adhesive base layer. Consequently, a conductive particle group consisting of two or more conductive particles is arranged in the lattice points of the planar lattice pattern. Thus, the anisotropic conductive film obtained by the manufacturing method of the present invention can achieve anisotropic conductive connection between narrow-pitch IC chips and wiring substrates while significantly reducing the occurrence of short circuits and poor conduction.

Explanation of symbols

10,200 anisotropic conductive film

11, 104 Insulating adhesive base

12, 105 Insulating adhesive covering layer

13.103 Conductive particles

14, 114 Conductive particle group

15 Grid area of a planar lattice pattern

100 transfer body

101 convex part

102 micro-adhesive part

P grid

Claims (17)

1. An anisotropic conductive film, which is an anisotropic conductive film with conductive particles disposed on or near the surface of an insulating adhesive substrate. Three or more conductive particles aggregate to form a conductive particle group. The conductive particle array is arranged in a grid region of a planar lattice pattern, and the conductive particles are regularly arranged within the conductive particle array. The number of conductive particles arranged close to a conductive particle is more than one and less than ten. "Close to" refers to a concentric circle with a radius of 2.5r drawn on the plane of the membrane when the conductive particle is assumed to be a sphere and its average particle size is set to r. "Close to" means in contact with or at least partially overlapping with this concentric circle. The polygonal shape formed by the conductive particles within the conductive particle group has at least two sides that are not parallel to the length direction of the anisotropic conductive film and the direction orthogonal to the length direction. 2. An anisotropic conductive film, comprising an insulating adhesive base layer and an insulating adhesive cover layer stacked together, with conductive particles disposed near their interface. Three or more conductive particles aggregate to form a conductive particle group. The conductive particle array is arranged in a grid region of a planar lattice pattern, and the conductive particles are regularly arranged within the conductive particle array. The number of conductive particles arranged close to a conductive particle is more than one and less than ten. "Close to" refers to a concentric circle with a radius of 2.5r drawn on the plane of the membrane when the conductive particle is assumed to be a sphere and its average particle size is set to r. "Close to" means in contact with or at least partially overlapping with this concentric circle. The polygonal shape formed by the conductive particles in the conductive particle group has at least two sides that are not parallel to the length direction of the anisotropic conductive film and the direction orthogonal to the length direction. 3. In the anisotropic conductive film according to claim 1 or 2, within the conductive particle group, the shortest distance between adjacent conductive particles when the conductive particles are not in contact is more than 25% of the average particle size. 4. In the anisotropic conductive film according to claim 1 or 2, the grid region of the planar grid pattern is a circle centered on the grid point, and its radius is more than 2 times and less than 7 times the average particle size of the conductive particles. 5. The anisotropic conductive film according to claim 1 or 2, wherein the shortest distance between adjacent grid regions is more than twice the average particle size of the conductive particles or more than an equal multiple of the grid regions. 6. In the anisotropic conductive film according to claim 1 or 2, the multiple conductive particles in the grid region do not contact each other. 7. The anisotropic conductive film according to claim 1 or 2, wherein the number of conductive particles in each conductive particle group varies regularly. 8. The anisotropic conductive film according to claim 1 or 2, wherein the distance between conductive particles in the conductive particle group varies regularly in each conductive particle group. 9. The anisotropic conductive film according to claim 1 or 2, wherein the polygonal shape formed by the conductive particles in the conductive particle group changes regularly at an angle relative to the length direction of the film. 10. The anisotropic conductive film according to claim 2, wherein at least one of the insulating adhesive base layer or the insulating adhesive cover layer contains an insulating filler. 11. The anisotropic conductive film according to claim 1, wherein the insulating adhesive base layer contains insulating filler. 12. A manufacturing method, which is the manufacturing method of the anisotropic conductive film according to claim 1, comprising the following steps (I) to (IV): <Process (I)> The process of preparing a transfer body with raised areas on the surface that correspond to a planar grid pattern; <Process (II)> The process of forming at least two micro-adhesive portions on the top surface of the protrusion of the transfer body; <Process (III)> The process of attaching conductive particles to the micro-adhesive portion of the raised part of the transfer body; and <Process (IV)> The process of transferring conductive particles to the insulating adhesive base layer by overlapping and pressing an insulating adhesive base layer with the surface of the transfer body on the side where conductive particles are attached. 13. A manufacturing method, which is the manufacturing method of the anisotropic conductive film according to claim 2, comprising the following steps (I) to (V): <Process (I)> The process of preparing a transfer body with raised areas on the surface that correspond to a planar grid pattern; <Process (II)> The process of forming at least two micro-adhesive portions on the top surface of the protrusion of the transfer body; <Process (III)> The process of attaching conductive particles to the micro-adhesive portion of the raised part of the transfer body; <Process (IV)> The process of transferring conductive particles to the insulating adhesive base layer by overlapping and pressing the insulating adhesive base layer with the surface of the transfer body on which the conductive particles are attached; and <Process (V)> For an insulating adhesive substrate to which conductive particles have been transferred, the process involves stacking insulating adhesive coating layers from the conductive particle transfer surface side. 14. The manufacturing method according to claim 12 or 13, wherein the transfer body used in step (I) is made by processing a metal plate to form a master disc, coating it with a curable resin composition, and curing it. 15. In the manufacturing method according to claim 12 or 13, the height of the protrusion of the transfer body in step (I) is more than 1.2 times and less than 4 times the average particle size of the conductive particles, and the half-width of the protrusion is more than 2 times and less than 7 times the average particle size of the conductive particles. 16. The manufacturing method according to claim 14, wherein the height of the protrusion of the transfer body in step (I) is more than 1.2 times and less than 4 times the average particle size of the conductive particles, and the half-width of the protrusion is more than 2 times and less than 7 times the average particle size of the conductive particles. 17. A connection structure, wherein the terminals of a first electronic component and the terminals of a second electronic component are anisotropically conductively connected by an anisotropic conductive film according to any one of claims 1 to 11.