TW202209356A - Anisotropic conductive film - Google Patents

Abstract

To provide an anisotropic conductive film capable of corresponding to a bump of a narrow pitch and reducing number density of conductive particles. Disclosed is an anisotropic conductive film 1A in which conductive particles 2 are arranged in an insulating resin binder 3. A repeating unit 5 of conductive particles composed of rows 2p, 2q, 2r of conductive particles 2 lined up in a row at intervals and formed by juxtaposing different numbers of conductive particles is repeatedly arranged over the entire surface of the anisotropic conductive film.

Description

Anisotropic Conductive Film

The present invention relates to an anisotropic conductive film.

Anisotropic conductive films in which conductive particles are dispersed in an insulating resin binder are widely used for mounting electronic components such as IC chips on wiring boards and the like. In anisotropic conductive films, it is strongly required to improve the trapping properties of conductive particles in the bumps and to avoid short circuits between adjacent bumps by narrowing the pitch of bumps accompanying high-density mounting of electronic components.

In response to such a requirement, it has been proposed to arrange the conductive particles in the anisotropic conductive film in a lattice-like arrangement, and to make the arrangement axis inclined with respect to the longitudinal direction of the anisotropic conductive film, and in this case , the distance between the conductive particles is separated by a specific ratio (Patent Document 1, Patent Document 2). In addition, it is proposed to form a region where the conductive particles are locally dense by connecting the conductive particles, thereby coping with the narrowing of the pitch (Patent Document 3).

Patent Document 1: Japanese Patent No. 4887700 Patent Document 2: Japanese Patent Laid-Open No. 9-320345 Patent Document 3: Japanese Patent Publication No. 2002-519473

[The problem to be solved by the invention]

As described in Patent Documents 1 and 2, when the conductive particles are arranged in a simple lattice shape, the bump layout is handled by the inclination angle of the arrangement axis or the distance between the conductive particles. Therefore, when the bumps have a narrow pitch, it is necessary to reduce the distance between the conductive particles, and it becomes difficult to avoid short circuits. In addition, the number density of the conductive particles increases, resulting in an increase in the manufacturing cost of the anisotropic conductive film.

On the other hand, when the distance between the conductive particles is not reduced, there is a possibility that a sufficient number of conductive particles cannot be captured by the terminals.

In addition, in the method of forming a region where conductive particles are locally dense by connecting conductive particles, the risk of short circuit increases when a plurality of connected conductive particles enter the space between bumps at the same time, which is not preferable.

Therefore, the subject of this invention is to provide the anisotropic conductive film which can cope with the bump of a narrow pitch, and can reduce the number density of electroconductive particle compared with the conventional anisotropic conductive film. [Technical means to solve the problem]

The inventors of the present invention found that if the conductive particles are spaced apart from each other and the units forming the conductive particles in a specific arrangement are repeatedly arranged on the entire surface of the anisotropic conductive film, the dense and dense regions of the conductive particles can be formed on the entire surface of the film. Bumps with narrow pitches can be connected in the dense area of the dense area, and the conductive particles are also separated from each other in the dense area, so the risk of short circuit is reduced, and further, the existence of the sparse area can reduce the conductive particles of the whole film the number density, and thus the present invention was conceived.

That is, the present invention provides an anisotropic conductive film in which conductive particles are arranged in an insulating resin binder, and The repeating units of the conductive particles are arranged repeatedly, and the repeating units of the conductive particles are conductive particle rows formed by the conductive particles being spaced apart and arranged in a row, and those with different numbers of conductive particles are juxtaposed. [Effect of invention]

According to the anisotropic conductive film of the present invention, the conductive particles are not arranged in a simple lattice-like arrangement, but a repeating unit of the conductive particles with a specific particle arrangement is repeatedly arranged, so that the conductive particles can be formed in the film. Since the dense area is formed, an increase in the number density of the conductive particles in the entire anisotropic conductive film can be suppressed. Therefore, it is possible to suppress an increase in the manufacturing cost due to an increase in the number density of the conductive particles. In addition, generally, when the number density of conductive particles increases, the thrust required to press the jig during anisotropic conductive connection also increases. However, according to the anisotropic conductive film of the present invention, the number density of conductive particles is suppressed from increasing. increase, and also suppress the increase of the thrust required to press the clamp during the anisotropic conductive connection, thereby preventing the electronic parts from being deformed due to the anisotropic conductive connection. In addition, since the pressing force does not need to be excessively large, the pressing force of the pressing force is stable, so that the quality such as the conduction characteristics of the electronic components connected by the anisotropic conduction is stable.

On the other hand, according to the anisotropic conductive film of the present invention, since repeating units forming regions with dense conductive particles are repeatedly formed in the vertical and horizontal directions, bumps with narrow pitches can be connected. Furthermore, in the repeating unit, the conductive particles are separated from each other, so even when the repeating unit spans the space between the terminals, the occurrence of short circuit can be avoided.

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

<Overall structure of anisotropic conductive film> 1A is a plan view showing an arrangement of conductive particles in an anisotropic conductive film 1A according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view thereof. The anisotropic conductive film 1A has a structure in which the conductive particles 2 are arranged in a single layer on the surface of the insulating resin adhesive 3 or its vicinity, and the insulating adhesive layer 4 is laminated thereon.

Furthermore, as the anisotropic conductive film of the present invention, the insulating adhesive layer 4 may be omitted, and the conductive particles 2 may be embedded in the insulating resin adhesive 3 .

（polybenzoguanamine）等樹脂粒子之表面而成之金屬被覆樹脂粒子等。配置之導電粒子的大小較佳為1～30 μm，更佳為1 μm以上且10 μm以下，進而較佳為2 μm以上且6 μm以下。<Electroconductive particle> As the conductive particle 2, a user of a well-known anisotropic conductive film can be appropriately selected and used. For example, metal particles such as nickel, copper, silver, gold, palladium, etc.;

Metal-coated resin particles formed on the surface of resin particles such as polybenzoguanamine. The size of the arranged conductive particles is preferably 1 to 30 μm, more preferably 1 μm or more and 10 μm or less, and still more preferably 2 μm or more and 6 μm or less.

The average particle size of the conductive particles 2 can be measured by an image-type or laser-type particle size distribution meter. The anisotropic conductive film can also be viewed from above, and the particle size can be measured and determined. In this case, it is preferable to measure 200 or more pieces, more preferably to measure 500 pieces or more, and still more preferably to measure 1000 pieces or more.

The surfaces of the conductive particles 2 are preferably covered by insulating coating or insulating particle treatment. Such a coating is easily peeled off from the surface of the conductive particle 2 and does not hinder the anisotropic connection. In addition, protrusions may be provided on the entire surface or a part of the conductive particles 2 . The height of the protrusions is within 20% of the conductive particle size, preferably within 10%.

<Arrangement of Conductive Particles> (repeating unit) The arrangement of the conductive particles 2 in the plan view of the anisotropic conductive film 1A is to arrange the repeating units 5 in which the conductive particle rows 2p, 2q, 2r and the individual conductive particles 2s are arranged in parallel on the entire surface of the anisotropic conductive film 1A. The directions (X direction, Y direction) are repeated, and the polygons formed by sequentially connecting the centers of the conductive particles forming the outer shape of the repeating unit 5 form a triangle. Furthermore, the anisotropic conductive film of this invention may have the area|region where electroconductive particle is not arrange|positioned as needed.

Each of the conductive particle rows 2p, 2q, and 2r is arranged in a row in a straight line with the conductive particles 2 being spaced apart from each other in a plan view. In addition, the number of conductive particles constituting the conductive particle arrays 2p, 2q, and 2r gradually changes, and the conductive particle arrays 2p, 2q, and 2r are arranged in parallel. As described above, by repeating the particle arrangement in which the conductive particle rows 2p, 2q, and 2r of gradually different particle numbers are arranged in parallel, the number density of the conductive particles is locally dense and dense. Therefore, when the anisotropic conductive film is attached to the In the case of electronic components, even if there is a slight dislocation, a stable number of conductive particles can be easily captured in any bump constituting the bump row. It is more effective in the case where anisotropic conductive connections are made continuously. That is, in the case of a simple lattice arrangement where the attachment of the anisotropic conductive film to the electronic component is slightly misaligned, the number of trapped particles, especially at the end of the bump, is likely to fluctuate due to the presence or degree of misalignment. In order to suppress this variation, it is considered to incline the angle of the lattice arrangement with respect to the longitudinal direction of the film (Patent Document 1, etc.). However, if the bump width or the inter-bump distance becomes narrower, the effect of tilting the lattice arrangement is limited. On the other hand, in the present invention, the number density of the conductive particles is generated in the range of the bump length so as to capture the conductive particles at any part of the range of the bump length. In other words, a location for capturing conductive particles and a location for not capturing conductive particles are simultaneously generated in one bump. Therefore, as long as the shape (area) of the bumps is the same in any bump arrangement, the number of conductive particles captured by the bumps becomes stable by appropriately setting the repeating interval of the repeating unit. Therefore, even when the anisotropic conductive film is adhered with a slight dislocation, the trapped state of the conductive particles in the bump array of each connecting body is easily stabilized when the connecting body is continuously produced on the production line. In addition, by simultaneously generating a position where conductive particles are captured and a position where they are not captured by one bump, reduction of inspection labor after anisotropic conductive connection and improvement of quality control can be expected. For example, by simultaneously generating a location for capturing conductive particles and a location for not capturing conductive particles by one bump, the comparison of continuously obtained connectors becomes easy during indentation inspection after anisotropic conductive connection. In addition, it is possible to compare the presence or absence of dislocation when the anisotropic conductive film is temporarily attached to the electronic component in the anisotropic conductive connection step between the continuously manufactured connectors, so that it is expected that the improvement of the connection device will be easily determined. .

The arrangement of the conductive particles 2 in the repeating unit 5 is an arrangement in which a part of the conductive particles 2 constituting the repeating unit 5 occupies a part of the vertices of the regular hexagons when the regular hexagons are arranged without gaps. Alternatively, when the equilateral triangles are arranged without gaps, the vertices of the equilateral triangles overlap with the conductive particles constituting the repeating unit 5 . In other words, the repeating unit 5 is the repeating unit 5 from the arrangement of the conductive particles present in each lattice point of the hexagonal lattice arrangement where the conductive particles are regularly removed from the specific lattice point. As described above, when the conductive particles 2 are arranged at the lattice points of the hexagonal lattice arrangement, the particle arrangement of the repeating unit 5 can be easily recognized and the design can be facilitated. Furthermore, as described below, the arrangement of the conductive particles in the repeating unit is not limited to those based on hexagonal lattices, but can also be based on square lattices, and can also be based on regular polygons with more than octagons arranged in the vertical and horizontal directions and adjacent to each other. An arrangement in which the sides of a regular polygon overlap each other.

(repeated form of repeating unit) In more detail, the repeating unit 5 in the anisotropic conductive film 1A shown in FIG. 1A is repeated in the X direction, and the repeating unit 5 repeats the particles in the repeating unit 5 at intervals. In addition, in the Y direction, the repeating unit 5B obtained by inverting the symmetry axis of the repeating unit 5 along the Y direction and the repeating unit 5 are alternately repeated at intervals. In this case, it is preferable to sequentially connect the centers of the conductive particles forming the outer shape of the repeating unit to form a polygon along the side of the long-side direction of the anisotropic conductive film when projected along the short-side direction of the anisotropic conductive film. The position in the repeat unit partially overlaps with the same position of the repeat unit adjacent to the repeat unit. The reason for this is that the width direction of the terminals of electronic components is usually the longitudinal direction of the anisotropic conductive film. Therefore, if the polygons forming the outer shape of the repeating unit are overlapped in the above-mentioned manner, the terminals of the electronic components capture the conductive particles. Chances are increased. Moreover, the long-side direction and the short-side direction of the anisotropic conductive film may be interchanged. The reason for this is that, depending on the terminal layout, there is also a situation where the exchange is appropriate.

Furthermore, when considering the situation of the repeating unit of the conductive particle 2, the unit formed by combining the repeating unit 5 and the repeating unit 5B obtained by inverting it can also be regarded as the repeating unit of the conductive particle, but in the present invention , the repeating unit is preferably a unit formed by juxtaposing a plurality of conductive particle rows and is the smallest unit repeating in the vertical and horizontal directions.

(size of repeating unit) The size of the anisotropic conductive film of the repeating unit 5 or the distance between the repeating units is preferably determined by the bump width or the space between the bumps of the electronic components connected by the anisotropic conductive film 1A.

For example, when the connection object is non-fine pitch, the size of the lengthwise direction of the anisotropic conductive film of the repeating unit 5 is preferably smaller than the bump width or the length of the space between bumps, whichever is narrower. Even with this size, by arranging the repeating units 5 repeatedly, the bumps can capture the minimum number of conductive particles required for connection, and the number of conductive particles that do not participate in the connection can be reduced, so that anisotropy can be achieved Cost reduction of conductive film. In addition, by making the sides of the polygon forming the outer shape of the repeating unit 5 obliquely cross the short-side direction of the anisotropic conductive film 1A, it is possible to obtain a stable operation regardless of the cutting position of the long-sized anisotropic conductive film. connection performance.

When the connection object is non-fine pitch, the distance between the adjacent repeating units 5 and 5B in the longitudinal direction of the anisotropic conductive film is preferably greater than the space between the bumps of the electronic parts connected by the anisotropic conductive film. short.

On the other hand, when the connection object is a fine pitch, it is preferable to set the size of the repeating units 5 and 5B in the longitudinal direction of the anisotropic conductive film to the size across the space between bumps.

In addition, regarding the boundary between a fine pitch and a non-fine pitch, as an example, a bump width of less than 30 μm can be made a fine pitch, and 30 μm or more can be made a non-fine pitch.

When the size of the repeating unit 5 is determined according to the connection object as described above, the number of conductive particles constituting the repeating unit 5 is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more. The reason for this is that it is generally preferable to trap 3 or more, especially 10 or more conductive particles between the opposite terminals connected by anisotropic conductive connection, so that the repeating unit is clamped to the opposite terminal. Over time, it can be confirmed that this amount of conductive particles is captured according to the indentation of one repeating unit.

(The specific variation of the repeating unit) In the present invention, the arrangement of the conductive particles 2 in the repeating unit 5 or the repeating pitch of the repeating unit 5 in the vertical and horizontal directions can be appropriately changed according to the shape of the terminal to be connected to the anisotropic conductive connection or the distance between the terminals. Therefore, compared with the case where the conductive particles 2 are arranged in a simple lattice shape, the entire anisotropic conductive film can achieve high capture performance with a small number of conductive particles.

For example, in addition to the repeating state shown in FIG. 1A , the repeating units 5 may be repeated in a staggered arrangement like the anisotropic conductive film 1B shown in FIG. 2 . In the staggered arrangement, the effect of the resin flow on the conductive particles during the anisotropic conductive connection of electronic parts is different between the bumps located in the center of the staggered arrangement and the bumps located on the outside, the bumps located in the center of the staggered arrangement and The risk of short circuit in the bumps located on the outside is also different, so the shape of the repeating unit 5 can be appropriately changed to adjust the flow direction of the resin.

The arrangement of the conductive particles 2 in the repeating unit 5 can also be appropriately changed according to the shape of the terminal to be connected to the anisotropic conductive connection or the distance between the terminals. For example, like the anisotropic conductive film 1C shown in FIG. 3 , the number of conductive particles constituting the conductive particle row 2p in one repeating unit 5 can be gradually increased and decreased, or the number of separate conductive particles can be repeatedly arranged as the repeating unit 5 repeats. Conductive particles 2s. Furthermore, in the three parallel rows of conductive particle rows in one repeating unit, the number of conductive particles constituting the conductive particle row in the center can be more or less than the number of conductive particles constituting the conductive particle rows on both sides. For example, like the anisotropic conductive film 1D shown in FIG. 4 , in each repeating unit 5 , a conductive particle row 2p in which four conductive particles 2 are arranged in the longitudinal direction of the anisotropic conductive film are arranged in parallel, and two conductive particles are arranged in parallel. The conductive particle row 2q of the particle 2, the conductive particle row 2r of three conductive particles 2, and one conductive particle 2s are arranged. If the number of conductive particles in a row of conductive particles arranged in a repeating unit is increased or decreased, the repeating unit becomes a complex polygonal shape, and it becomes easier to deal with a radial bump arrangement (so-called fan-out bumps). ) connection. The arrangement of the conductive particles in a repeating unit is represented by the number of conductive particles in the conductive particle row constituting the repeating unit. For example, when the repeating unit shown in FIG. 4 is represented as [4-2-3-1], the Variations of repeating units include [4-1-4-1], [4-3-1-2], [3-2-2-1], [4-1-2-3], [4] -2-1-3] etc. These combinations can also be repeatedly configured. For example, [4-2-3-1-2-1-4-3] is mentioned.

In addition, the distance between the conductive particles in one conductive particle row may be the same or different from each other in the parallel conductive particle rows in one repeating unit. For example, like the anisotropic conductive film 1E shown in FIG. 5 , the outer shape of the repeating unit 5 may be a rhombus, and the conductive particles 2 may be arranged in the center portion thereof. In this repeating unit, the conductive particle array 2m composed of 5 conductive particles, the conductive particle array 2n composed of 2 conductive particles, the conductive particle array 2o composed of 3 conductive particles, and the conductive particle array composed of 2 conductive particles. The particle array 2p and the conductive particle array 2q composed of 5 conductive particles are juxtaposed, the distance between the conductive particles in the conductive particle arrays 2m and 2q, the distance between the conductive particles in the conductive particle arrays 2n and 2p, and the conductive particles in the conductive particle array 2o. The distances between particles are different from each other. In the case of [4-3-2-1] of the above-mentioned notation, it may be an arrangement in which the conductive particles in the center of 3 are removed. The reason for this is that the risk of short-circuit generation can be further reduced.

In the above-mentioned anisotropic conductive films 1A, 1B, 1C, 1D, and 1E, the arrangement of the conductive particles 2 in the repeating units 5 and 5B exists at the lattice points of the hexagonal lattice, but as long as the conductive particle rows 2p are juxtaposed, the The anisotropic conductive film 1F shown in FIG. 6 may also be arranged based on a square lattice.

In the anisotropic conductive film 1G shown in FIG. 7, a repeating unit 5 composed of two rows of conductive particle rows 2p and 2q and a repeating unit 5B formed by rotating the arrangement axis of the conductive particles of the repeating unit 5 by 60° are arranged repeatedly, respectively. Formed on the entire surface of the membrane. As described above, a certain repeating unit and a repeating unit obtained by rotating it at a specific angle may be used in combination.

As the shape of the repeating unit, a polygon formed by sequentially connecting conductive particles to form the outer shape can be a regular polygon. Thereby, the identification of the arrangement|positioning of a conductive particle becomes easy, and it is preferable. In this case, each conductive particle forming the repeating unit may not exist in the lattice points of the hexagonal lattice or the square lattice. For example, the outer shape of the repeating unit 5 can be formed into a regular octagon like the anisotropic conductive film 1H shown in FIG. 8 . In this case, the conductive particles forming the outer shape of the repeating unit are arranged at the vertices of the regular octagon of the lattice in which the sides of the adjacent regular octagons are aligned vertically and horizontally, as shown by the dotted line in the figure. In the same way, the conductive particles can also be arranged at the vertices of a regular 12-sided polygon or a regular polygon above it. Furthermore, by arranging conductive particles at lattice points of a hexagonal lattice or a square lattice, a repeating unit having an outer shape of an octagonal or more substantially regular polygon may be formed. For example, the repeating unit 5 of the anisotropic conductive film 1I shown in FIG. 9 is formed by the conductive particles 2 arranged on the lattice points of the square lattice, and becomes the longitudinal direction and the short side direction of the anisotropic conductive film Symmetrical octagon. Thereby, the arrangement|positioning of an electroconductive particle can be recognized easily.

In addition, the rows of conductive particles arranged in the repeating unit may not necessarily be parallel to each other, but may also be arranged radially. For example, like the anisotropic conductive film 1J shown in FIG. 10 , repeating units 5 having conductive particle rows 2m, 2n, 2o, 2p, and 2q arranged radially can be repeatedly arranged in the vertical and horizontal directions. In this case, the conductive particles 2 may not exist in the lattice points of the hexagonal lattice or the square lattice.

(the direction of the edge of the repeating unit) In the above-mentioned anisotropic conductive film, for example, in the anisotropic conductive film 1A shown in FIG. 1A , each side of the triangle 5x formed by the center of the conductive particles forming the outer shape of the repeating unit 5 is sequentially connected to the anisotropic conductive film. The long-side direction or short-side direction of 1A is oblique. Thereby, the circumscribed line L1 of the longitudinal direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2b, and the conductive particle 2b is adjacent to the conductive particle 2a in the longitudinal direction of the anisotropic conductive film. Moreover, the outer tangent L2 of the short-side direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2c, and the conductive particle 2c is adjacent to the conductive particle 2a in the short-side direction of the anisotropic conductive film. Since the long-side direction of the anisotropic conductive film is usually the short-side direction of the bump during anisotropic conductive connection, if the side of the polygon 5x of the repeating unit 5 and the long-side direction of the anisotropic conductive film 1A or The diagonal direction of the short side can prevent a plurality of conductive particles from being arranged in a straight line along the edge of the bump, thereby avoiding the phenomenon that a plurality of conductive particles arranged in a straight line are separated from the terminal at the same time and become unhelpful for conduction. Therefore, the capture property of the conductive particle 2 can be improved.

Furthermore, when the long-side direction of the anisotropic conductive film becomes the short-side direction of the bump during the anisotropic conductive connection, the polygon 5x formed by the conductive particles forming the outer shape of the repeating unit 5 may not necessarily be all of the polygons 5x. The sides obliquely intersect with the long-side direction or short-side direction of the anisotropic conductive film, and in terms of the capture property of the conductive particles, preferably two or more sides, more preferably three or more sides and the length of the anisotropic conductive film It is preferable to cross the side direction or the short side direction obliquely.

On the other hand, when the arrangement pattern of the bumps is radial (so-called fan-out bumps), it is preferable that the polygon in which the repeating unit is formed has a side in the long-side direction or the short-side direction of the anisotropic conductive film. That is, in order to realize that the bumps to be connected will not be displaced even if the substrate on which the bumps are provided is thermally expanded, there is a case where the arrangement pattern of the bumps is made radial (for example, Japanese Patent Laid-Open No. 2007-19550, 2015-232660, etc.), in this case, the angle formed by the longitudinal direction of each bump and the longitudinal direction of the anisotropic conductive film gradually changes. Therefore, even if the sides of the polygon of the repeating unit 5 and the long-side direction or the short-side direction of the anisotropic conductive film are not obliquely crossed, the sides of the polygons of the repeating units 5 and 5B are also radially arranged with the bumps. The edges in the long-side direction are crossed obliquely. Therefore, during the anisotropic conductive connection, most of the conductive particles attached to the edges of the bumps are not captured by the bumps, and the phenomenon that the captureability of the conductive particles is reduced can be avoided. On the other hand, the radial arrangement pattern of the bumps is usually formed to be bilaterally symmetrical. Therefore, it is preferable that the polygonal shape forming the outer shape of the repeating unit 5 has the length of the anisotropic conductive film in terms of making it easy to confirm whether the connection state is good or not by the indentation after the anisotropic conductive connection. The edge in the side direction or the short side direction. Therefore, for example, when the repeating unit is formed into the same triangular shape as the anisotropic conductive film 1A shown in FIG. One side 5a of the triangular shape of the outer shape is arranged so as to be parallel to the longitudinal direction or the short side direction of the anisotropic conductive film. Moreover, like the repeating unit 5 of the anisotropic conductive film 1H shown in FIG. 8, it is also possible to have a side 5a parallel to the longitudinal direction of the anisotropic conductive film and a side 5b parallel to the short side direction.

Furthermore, the arrangement of the conductive particles in the present invention is not limited to the arrangement of the repeating units shown in the figure. For example, the arrangement of the illustration may be inclined. In this case, the aspect formed by inclining at 90°, that is, the long-side direction and the short-side direction of the exchange membrane is also included. Moreover, the space|interval of the repeating unit 5 or the space|interval of the electroconductive particle in a repeating unit may be changed.

<Distance between closest particles of conductive particles> The distance between the nearest particles of the conductive particles is preferably 0.5 times or more of the average conductive particle size between adjacent conductive particles in the repeating units 5 and between adjacent conductive particles between the repeating units 5 . The distance between the repeating units 5 is preferably longer than the distance between adjacent conductive particles in the repeating unit 5 . When the distance is too short, short-circuiting is likely to occur due to mutual contact of conductive particles. The upper limit of the distance between adjacent conductive particles is determined according to the shape of the bumps or the pitch of the bumps. For example, when the bump width is 200 μm and the inter-bump space is 200 μm, when there is at least one conductive particle in either the bump width or the inter-bump space, the distance between the conductive particles is set to is less than 400 μm. It is preferable to set it as less than 200 micrometers from the point which makes the capture|acquisition property of electroconductive particle reliable.

<Number Density of Conductive Particles> The number density of conductive particles is in terms of suppressing the manufacturing cost of the anisotropic conductive film and avoiding excessive thrust necessary for the pressing jig used in the anisotropic conductive connection. When the average particle diameter of the conductive particles is less than 10 μm, it is preferably 50,000 pieces/mm ² or less, more preferably 35,000 pieces/mm ² or less, and still more preferably 30,000 pieces/mm ² or less. On the other hand, if the number density of the conductive particles is too small, there is a possibility of poor conduction due to insufficient capture of the conductive particles in the terminals. Therefore, it is preferably 300 particles/mm ² or more, more preferably 500 particles/mm ² or more, and further It is preferably 800 pieces/mm ² or more.

When the average particle diameter of the conductive particles is 10 μm or more, it is preferably 15 particles/mm ² or more, more preferably 50 particles/mm ² or more, and still more preferably 160 particles/mm ² or more. The reason for this is that when the conductive particle size becomes larger, the area occupied by the conductive particles also increases. For the same reason, it is preferably 1800 pieces/mm ² or less, more preferably 1100 pieces/mm ² or less, and still more preferably 800 pieces/mm ² or less. Furthermore, the number density of the conductive particles may be partially (for example, 200 μm×200 μm) deviated from the above-mentioned number density.

＜Insulating resin adhesive＞ As the insulating resin adhesive 3, a thermally polymerizable composition, a photopolymerizable composition, a photothermal combined polymerizable composition, etc., which are used as insulating resin adhesives among known anisotropic conductive films, can be appropriately selected and used. Among them, the thermally polymerizable composition includes a thermally polymerizable resin composition containing an acrylate compound and a thermal radical polymerization initiator, and a thermally cationic polymerizable resin containing an epoxy compound and a thermal cationic polymerization initiator. Compositions, thermal anionic polymerizable resin compositions containing epoxy compounds and thermal anionic polymerization initiators, etc. Examples of photopolymerizable compositions include photo-radical polymerization containing acrylate compounds and photo-radical polymerization initiators resin composition, etc. As long as there is no particular problem, a plurality of polymerizable compositions may be used in combination. As an example of combined use, the combined use of a thermal cationically polymerizable composition and a thermally radically polymerizable composition, etc. are mentioned.

Here, as a photopolymerization initiator, a plurality of initiators that react with light having different wavelengths may be contained. Thereby, 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 parts to each other during the anisotropic connection can be distinguished.

When the insulating resin adhesive 3 is formed using a photopolymerizable composition, all or all of the photopolymerizable compounds contained in the insulating resin adhesive 3 can be cured by light curing during the production of the anisotropic conductive film. Partially photohardened. By this photocuring, the arrangement of the conductive particles 2 in the insulating resin adhesive 3 can be maintained or fixed, and the suppression of short circuits and the improvement of trapping are expected. Moreover, the viscosity of the insulating resin layer in the manufacturing process of anisotropic conductive film can be adjusted by adjusting the conditions of this photohardening.

The blending amount of the photopolymerizable compound in the insulating resin adhesive 3 is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. The reason for this is that when there are too many photopolymerizable compounds, the thrust applied by pressing at the time of anisotropic conductive connection increases.

On the other hand, the thermally polymerizable composition contains a thermally polymerizable compound and a thermally polymerizable initiator, and as the thermally polymerizable compound, one that also functions as a photopolymerizable compound can be used. Moreover, in addition to a thermally polymerizable compound, a photopolymerizable compound may be contained separately in a thermopolymerizable composition, and a photopolymerizable initiator may be contained. It is preferable to contain a photopolymerizable compound and a photopolymerization initiator separately in addition to a thermopolymerizable compound. For example, a thermal cationic polymerization initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermal polymerizable compound, a photoradical initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound . Cured products of these polymerizable compositions may also be contained in the insulating resin adhesive 3 .

As the acrylate compound used as the thermally or photopolymerizable compound, a conventionally known thermally polymerizable (meth)acrylate monomer can be used. For example, a monofunctional (meth)acrylate-based monomer, or a polyfunctional (meth)acrylate-based monomer having a difunctional or higher level can be used.

Moreover, the epoxy compound used as a polymerizable compound forms a three-dimensional network structure, and provides favorable heat resistance and adhesiveness, and it is preferable to use a solid epoxy resin and a liquid epoxy resin together. Here, the so-called solid epoxy resin means an epoxy resin which is solid at normal temperature. In addition, the liquid epoxy resin means the epoxy resin which is liquid at normal temperature. In addition, the normal temperature means the temperature range of 5-35 degreeC prescribed|regulated by JIS Z 8703. In the present invention, two or more epoxy compounds may be used in combination. Moreover, you may use together an oxetane compound other than an epoxy compound.

The solid epoxy resin is not particularly limited as long as it is compatible with the liquid epoxy resin and is solid at room temperature, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and polyfunctional epoxy resin. Resins, dicyclopentadiene-type epoxy resins, novolac-phenol-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, etc. may be used singly or in combination of two or more and use. Among these, bisphenol A type epoxy resins are preferably used.

The liquid epoxy resin is not particularly limited as long as it is liquid at room temperature, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak phenol type epoxy resin, and naphthalene type epoxy resin. Resin etc. may be used individually by 1 type from these, or may be used in combination of 2 or more types. In particular, it is preferable to use a bisphenol A type epoxy resin from the viewpoints of the viscosity and flexibility of the film.

Among the thermal polymerization initiators, the thermal radical polymerization initiators include, for example, organic peroxides, azo-based compounds, and the like. In particular, organic peroxides which do not generate nitrogen gas which causes bubbles can be preferably used.

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

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators for epoxy compounds can be used. In particular, aromatic perylene salts exhibiting good latency to temperature can be preferably used.

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

As the thermal anionic polymerization initiator, publicly known ones that are generally used can be used. For example, organic acid dihydrazine, dicyandiamide, amine compounds, polyamide amine compounds, cyanate ester compounds, phenol resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, Brünster Acid salts, polythiol-based hardeners, urea resins, melamine resins, isocyanate compounds, blocked isocyanate compounds, and the like may be used alone or in combination of two or more. Among these, a microcapsule-type latent hardener having an imidazole modified body as a core and coating the surface thereof with polyurethane is preferably used.

The film-forming resin is preferably contained in the thermally polymerizable composition. The film-forming resin corresponds to, for example, a high-molecular-weight resin having an average molecular weight of 10,000 or more, and preferably has an average molecular weight of about 10,000 to 80,000 from the viewpoint of film-forming properties. The film-forming resins include various resins such as phenoxy resins, polyester resins, polyurethane resins, polyesterurethane resins, acrylic resins, polyimide resins, butyral resins, and these may be used alone or may be used. Use in combination of two or more. Among these, from the viewpoints of film formation state, connection reliability, and the like, a phenoxy resin is preferably used.

In order to adjust the melt viscosity, an insulating filler may be contained in the thermopolymerizable composition. It can be exemplified by silica powder, alumina powder, and the like. The size of the insulating filler is preferably 20 to 1000 nm in particle diameter, and the blending amount is preferably 5 to 50 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable compound) such as an epoxy compound.

Furthermore, a filler, a softener, an accelerator, an antiaging agent, a colorant (pigment, dye), an organic solvent, an ion catcher agent, etc., which are different from the above-mentioned insulating fillers may be contained.

Moreover, a stress relaxation agent, a silane coupling agent, an inorganic filler, etc. may also be mix|blended as needed. As a stress relaxation agent, a hydrogenated styrene-butadiene block copolymer, a hydrogenated styrene-isoprene block copolymer, etc. are mentioned. Moreover, as a silane coupling agent, an epoxy type, a methacryloyloxy type, an amino type, a vinyl type, a mercapto/thioether type|system|group, a ureide type|system|group, etc. are mentioned. Moreover, as an inorganic filler, silica, talc, titanium oxide, calcium carbonate, magnesium oxide, etc. are mentioned.

The insulating resin adhesive 3 can be formed by forming a coating composition containing the above-mentioned resin into a film by a coating method, drying it, further curing it, or forming a film by a known method in advance. The insulating resin adhesive 3 can also be obtained by laminating resin layers as necessary. In addition, the insulating resin adhesive 3 is preferably formed on a release film such as a polyethylene terephthalate film subjected to release treatment.

(Viscosity of insulating resin adhesive) The minimum melt viscosity of the insulating resin adhesive 3 can be appropriately determined according to the manufacturing method of the anisotropic conductive film and the like. For example, when conducting a method of holding conductive particles on the surface of an insulating resin adhesive in a specific arrangement as a method for producing an anisotropic conductive film, and pressing the conductive particles into the insulating resin adhesive, the In the aspect of forming the insulating resin adhesive into a film, it is preferable to set the minimum melt viscosity of the resin to 1100 Pa·s or more. Further, as will be described later, as shown in FIG. 12 or FIG. 13 , concave portions 3 b are formed around the exposed portions of the conductive particles 2 pressed into the insulating resin adhesive 3 , or as shown in FIG. 14 , The minimum melt viscosity is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, and still more preferably 3000 Pa·s or more, in terms of forming the concave portion 3c directly above the conductive particles 2 incorporated into the insulating resin binder 3 ～15000 Pa·s, preferably 3000～10000 Pa·s. As an example of this minimum melt viscosity, a rotational rheometer (manufactured by TA Instruments) can be used, the temperature increase rate is 10°C/min, the measurement pressure is kept constant at 5 g, and a measurement plate with a diameter of 8 mm is used. and ask for. Furthermore, when the step of press-fitting the conductive particles 2 into the insulating resin adhesive 3 is performed at preferably 40 to 80° C., more preferably 50 to 60° C., the concave portion 3 b or 3 c is formed in the same manner as described above. On the other hand, the lower limit of the viscosity at 60°C is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, More preferably, it is 15000 Pa·s or less, and still more preferably 10000 Pa·s or less.

By setting the viscosity of the resin constituting the insulating resin adhesive 3 to a high viscosity as described above, when an anisotropic conductive film is used, the conductive particles 2 are sandwiched between the connection objects such as opposing electronic components. In the case of heating and pressing, the conductive particles 2 in the anisotropic conductive film can be prevented from flowing away due to the flow of the molten insulating resin binder 3 .

(Thickness of insulating resin adhesive) The thickness La of the insulating resin adhesive 3 is preferably 1 μm or more and 60 μm or less, more preferably 1 μm or more and 30 μm or less, and still more preferably 2 μm or more and 15 μm or less. Moreover, as for the relationship between the thickness La of the insulating resin binder 3 and the average particle diameter D of the electroconductive particle 2, it is preferable that the ratio (La/D) is 0.6-10. When the thickness La of the insulating resin adhesive 3 is too large, the conductive particles tend to be displaced during anisotropic conductive connection, and the ability to capture the conductive particles in the terminal decreases. This tendency is remarkable when La/D exceeds 10. Therefore, La/D is more preferably 8 or less, and still more preferably 6 or less. Conversely, if the thickness La of the insulating resin adhesive 3 is too small and La/D is less than 0.6, it is difficult to maintain the conductive particles in a specific particle dispersion state or a specific arrangement by the insulating resin adhesive 3 . In particular, when the terminals to be connected are high-density COG, the ratio (La/D) of the layer thickness La of the insulating resin adhesive 3 to the particle diameter D of the conductive particles 2 is preferably 0.8 to 2.

(Embedding of conductive particles in insulating resin adhesive) The embedded state of the conductive particles 2 in the insulating resin adhesive 3 is not particularly limited, and anisotropic conductive connection is performed by sandwiching an anisotropic conductive film between opposing parts and applying heat and pressure In this case, as shown in FIGS. 12 and 13 , it is preferable to expose a part of the conductive particles 2 from the insulating resin adhesive 3 to the surface 3 a of the insulating resin adhesive in the central portion between the adjacent conductive particles 2 . A recess 3b is formed around the exposed portion of the conductive particle 2, or as shown in FIG. 14, the insulating resin adhesive directly above the conductive particle 2 pressed into the insulating resin adhesive 3 In part, the concave portion 3c is formed with respect to the same tangent plane 3p as described above, and the surface of the insulating resin binder 3 directly above the conductive particle 2 has undulations. For the flattening of the conductive particles 2 that occurs when the conductive particles 2 are held between the electrodes of the opposing electronic components and heated and pressurized, the presence of the concave portion 3b as shown in FIGS. 12 and 13 and the absence of the concave portion 3b In contrast, the conductive particles 2 receive less resistance from the insulating resin binder 3 . Therefore, it becomes easy to hold the conductive particle 2 between the opposing electrodes, and the conduction performance is also improved. In addition, in the resin constituting the insulating resin binder 3, by forming the concave portions 3c on the surface of the resin directly above the conductive particles 2 (FIG. 14), the pressure during heating and pressurization changes compared with the case where the concave portions 3c do not exist. It is easy to concentrate on the conductive particles 2, and it becomes easy to hold the conductive particles 2 in the electrode, and the conduction performance is improved.

In terms of easily obtaining the effects of the concave portions 3b and 3c described above, the ratio of the maximum depth Le of the concave portion 3b (FIG. 12 and FIG. 13) around the exposed portion of the conductive particle 2 to the average particle diameter D of the conductive particle 2 (Le /D) is preferably less than 50%, more preferably less than 30%, and more preferably 20-25%. The maximum diameter Ld of the concave portion 3b (Fig. 12, Fig. 13) around the exposed portion of the conductive particle 2 is equal to The ratio (Ld/D) of the average particle diameter D of the conductive particles 2 is preferably 100% or more, more preferably 100 to 150%, and the maximum depth Lf of the concave portion 3c ( FIG. 14 ) of the resin directly above the conductive particles 2 is equal to The ratio (Lf/D) of the average particle diameter D of the conductive particles 2 is preferably greater than 0, and preferably less than 10%, more preferably less than 5%.

Furthermore, the diameter Lc of the exposed portion of the conductive particles 2 can be set to be equal to or less than the average particle diameter D of the conductive particles 2 , preferably 10 to 90% of the average particle diameter D. The conductive particle 2 may be exposed at one point of the top 2t of the conductive particle 2, or the conductive particle 2 may be completely embedded in the insulating resin binder 3, and the diameter Lc may be zero.

(Position of conductive particles in thickness direction of insulating resin adhesive) In terms of easily obtaining the effect of the concave portion 3b described above, the distance between the tangent plane 3p of the surface 3a of the insulating resin binder in the central portion between the adjacent conductive particles 2 and the deepest portion of the conductive particle 2 (hereinafter referred to as embedding) The ratio (Lb/D) (hereinafter referred to as the entrapment ratio) of Lb to the average particle diameter D of the conductive particles 2 (hereinafter referred to as the entrapment ratio) is preferably 60% or more and 105% or less.

<Insulating Adhesive Layer> In the anisotropic conductive film of the present invention, an insulating adhesive layer 4 having a viscosity or adhesiveness different from that of the resin constituting the insulating resin adhesive 3 may be laminated on the insulating resin adhesive 3 in which the conductive particles 2 are arranged.

In the case where the above-mentioned concave portion 3b is formed on the insulating resin adhesive 3, the insulating adhesive layer 4 can be laminated on the insulating resin adhesive 3 where the concave portion is formed like the anisotropic conductive film 1d shown in FIG. 15 . On the surface 3b, like the anisotropic conductive film 1e shown in FIG. 16, it may be laminated on the surface opposite to the surface on which the recessed portion 3b is formed. The same applies to the case where the insulating resin adhesive 3 is formed with the concave portion 3c. By laminating the insulating adhesive layer 4, when the electronic components are anisotropically conductively connected using the anisotropic conductive film, the spaces formed by the electrodes or bumps of the electronic components can be filled to improve the adhesiveness.

In addition, when the insulating adhesive layer 4 is laminated on the insulating resin adhesive 3, it is preferable that the insulating adhesive layer 4 is located on the IC chip regardless of whether the insulating adhesive layer 4 is located on the surface where the recesses 3b and 3c are formed. On the side of the first electronic component (in other words, the insulating resin adhesive 3 is on the side of the second electronic component such as the substrate). Thereby, the inadvertent movement of the conductive particles can be avoided, and the catchability can be improved. In addition, generally, the first electronic component such as an IC chip is placed on the pressing jig side, the second electronic component such as a substrate is placed on the stage side, and the anisotropic conductive film and the second electronic component are temporarily pressure-bonded, and then the first electronic component is placed on the stage. The electronic component and the second electronic component are formally crimped, but the anisotropic conductive film is temporarily attached to the first electronic component according to the size of the thermocompression bonding area of the second electronic component, and then the first electronic component and the second electronic component are temporarily bonded. Electronic parts are officially crimped.

As the insulating adhesive layer 4, one used as an insulating adhesive layer among known anisotropic conductive films can be appropriately selected and used. The insulating adhesive layer 4 may be the one that uses the same resin as the insulating resin adhesive 3 described above and further adjusts the viscosity to be lower. The greater the difference in the minimum melt viscosity between the insulating adhesive layer 4 and the insulating resin adhesive 3, the easier it is to fill the space formed by the electrodes or bumps of the electronic components with the insulating adhesive layer 4, and it can be expected to improve the mutual relationship between the electronic components. The effect of continuity. In addition, the more this difference exists, the smaller the amount of movement of the resin constituting the insulating resin adhesive 3 during the anisotropic conductive connection is relatively small, and the easier it is to improve the trapping properties of the conductive particles of the terminal. Practically speaking, the minimum melt viscosity of the insulating adhesive layer 4 and the insulating resin adhesive 3 is preferably 2 or more, more preferably 5 or more, and still more preferably 8 or more. On the other hand, if the ratio is too large, when the long anisotropic conductive film is made into a package, there is a risk of resin overflow or blocking, so 15 is practically preferable. the following. More specifically, the preferred minimum melt viscosity of the insulating adhesive layer 4 satisfies the above ratio, and is 3000 Pa·s or less, more preferably 2000 Pa·s or less, and still more preferably 100 to 2000 Pa·s.

As a method of forming the insulating adhesive layer 4, a coating composition containing the same resin as the resin forming the insulating resin adhesive 3 can be formed into a film by a coating method, dried, or further cured, or a It forms into a film by a well-known method.

The thickness of the insulating adhesive layer 4 is preferably 1 μm or more and 30 μm or less, and more preferably 2 μm or more and 15 μm or less.

In addition, the minimum melt viscosity of the entire anisotropic conductive film formed by combining the insulating resin adhesive 3 and the insulating adhesive layer 4 also depends on the ratio of the thicknesses of the insulating resin adhesive 3 and the insulating adhesive layer 4, and practically It can be set to 8000 Pa·s or less, and in order to easily fill between bumps, it can be 200 to 7000 Pa·s, preferably 200 to 4000 Pa·s.

Insulating fillers such as silica fine particles, alumina, and aluminum hydroxide may also be added to the insulating resin adhesive 3 or the insulating adhesive layer 4 as required. The blending amount of the insulating filler is preferably 3 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the resin constituting the layers. Thereby, even if the anisotropic conductive film is melted at the time of anisotropic conductive connection, it is possible to suppress unnecessary movement of the conductive particles due to the melted resin.

<Manufacturing method of anisotropic conductive film> As a method of producing an anisotropic conductive film, for example, a transfer mold for arranging conductive particles in a specific arrangement is produced, conductive particles are filled in the concave portion of the transfer mold, and an insulating resin adhesive formed on the release film is formed. The conductive particles 2 are pressed into the insulating resin adhesive 3 by covering the conductive particles 2 on the insulating resin adhesive 3 , so that the conductive particles 2 are transferred to the insulating resin adhesive 3 . Alternatively, the insulating adhesive layer 4 may be further laminated on the conductive particles 2 . In this way, the anisotropic conductive film 1A can be obtained.

In addition, after the concave part of the transfer mold is filled with conductive particles, the insulating resin adhesive is coated thereon, so that the conductive particles are transferred from the transfer mold to the surface of the insulating resin adhesive, and the conductive particles on the insulating resin adhesive are transferred. The particles are pressed into the insulating resin binder, whereby an anisotropic conductive film can also be produced. The embedded amount (Lb) of the conductive particles can be adjusted by the pressing force and temperature during the pressing. In addition, the shape and depth of the concave portions 3b and 3c can be adjusted by the viscosity of the insulating resin adhesive during the press-fitting, the press-fitting speed, and the temperature. For example, the lower limit of the viscosity of the insulating resin binder when the conductive particles are pressed is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and still more preferably 4500 Pa·s or more, and the upper limit is set to It is preferably 20,000 Pa·s or less, more preferably 15,000 Pa·s or less, and still more preferably 10,000 Pa·s or less. Moreover, such a viscosity can be obtained preferably at 40-80 degreeC, More preferably at 50-60 degreeC. More specifically, in the case of producing the anisotropic conductive film 1a having the concave portion 3b shown in FIG. 12 on the surface of the insulating resin adhesive, the viscosity of the insulating resin adhesive when the conductive particles are pressed can be set to 8000 Pa·s (50-60°C), in the case of manufacturing the anisotropic conductive film 1c having the concave portion 3c shown in Fig. 14, the viscosity of the insulating resin adhesive when the conductive particles are pressed into the resin can be set to 4500 Pa·s (50～60℃).

Furthermore, as the transfer mold, in addition to filling the concave portion with conductive particles, a micro-adhesive is applied to the top surface of the convex portion and the conductive particle is attached to the top surface.

These transfer molds can be produced by using or applying known techniques such as machining, photolithography, and printing.

In addition, as a method of arranging the conductive particles in a specific arrangement, a method using a biaxially stretched film or the like may be used instead of a method using a transfer mold.

＜Package body＞ In order to continuously supply the anisotropic conductive film to the connection of electronic parts, it is preferable to form a film roll body wound on a reel. The length of the film roll body may be 5 m or more, preferably 10 m or more. There is no upper limit in particular, but from the viewpoint of the operability of unloading the cargo, it is preferably 5,000 m or less, more preferably 1,000 m or less, and still more preferably 500 m or less.

The film package may be formed by connecting an anisotropic conductive film shorter than the entire length with a connection tape. The connection site may exist in a plurality of places, and may exist regularly or randomly. The thickness of the connection tape is not particularly limited as long as it does not hinder the performance, but if it is too thick, it will affect the overflow or adhesion of the resin, so it is preferably 10 to 40 μm. In addition, the width of the film is not particularly limited, but is 0.5 to 5 mm as an example.

According to the film roll, continuous anisotropic conductive connection can be realized, which helps to reduce the cost of the connection body.

<Connection structure> The anisotropic conductive film of the present invention is used to anisotropy the first electronic parts such as FPCs, IC chips, and IC modules, and the second electronic parts such as FPCs, rigid substrates, ceramic substrates, glass substrates, and plastic substrates by heat or light. It can be preferably used in the case of conductive connection. Moreover, IC chips or IC modules may be stacked to perform anisotropic conductive connection between the first electronic components. The thus obtained connecting structure and its manufacturing method are also part of the present invention.

As a method of connecting electronic components using anisotropic conductive film, it is preferable to temporarily stick the interface on the side where conductive particles are present in the thickness direction of the anisotropic conductive film, for example, on the side of improving connection reliability. A second electronic component such as a wiring board placed on a stage, a first electronic component such as an IC chip is mounted on the temporarily attached anisotropic conductive film, and thermocompression bonding is performed from the first electronic component side using a pressing jig. The same electronic components can also be connected by photohardening.

Furthermore, when it is difficult to temporarily attach the anisotropic conductive film to the second electronic parts such as the wiring board due to the size of the connection region of the second electronic component such as the wiring board, temporarily attach the anisotropic conductive film to the carrier. The first electronic component of the IC chip placed on the stage is then thermocompression bonded to the first electronic component and the second electronic component. Example

Experimental Example 1 to Experimental Example 8 (Fabrication of anisotropic conductive film) Regarding the anisotropic conductive film for COG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of the conductive particles on the film forming performance and conduction characteristics was investigated as follows.

First, the resin compositions for forming the insulating resin adhesive and the insulating adhesive layer were prepared with the compositions shown in Table 1, respectively. In this case, the minimum melt viscosity of the resin composition is adjusted by the preparation conditions of the insulating resin composition. The resin composition for forming the insulating resin adhesive was coated on a PET film with a film thickness of 50 μm by a bar coater, and dried in an oven at 80°C for 5 minutes to form the resin composition shown in Table 2 on the PET film. An insulating resin adhesive layer with a thickness of La. In the same manner, the insulating adhesive layer was formed on the PET film with the thickness shown in Table 2.

[Table 1] (parts by mass) Composition table for COG composition A B C D insulating resin adhesive Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 50 45 40 37 Silica filler (Aerosil R805, Japan Aerosil Co., Ltd.) 20 10 10 8 Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 25 40 45 50 Silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.) 2 2 2 2 Thermal cationic polymerization initiator (SI-60L, Sanxin Chemical Industry Co., Ltd.) 3 3 3 3 insulating adhesive layer Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 40 Silica filler (Aerosil R805, Japan Aerosil Co., Ltd.) 5 Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 50 Silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.) 2 Thermal cationic polymerization initiator (SI-60L, Sanxin Chemical Industry Co., Ltd.) 3

Next, a mold was prepared so that the arrangement of the conductive particles in plan view was the arrangement shown in Table 2, and the distance between the centers of the nearest conductive particles in the repeating units was 6 μm. The pellets of a known transparent resin were poured into the mold in a melted state, cooled and solidified, thereby forming a resin mold in which the concave portion was arranged as shown in Table 2. Here, in Experimental Example 8, the conductive particles were arranged in a hexagonal lattice arrangement (number density of 32,000 particles/mm ² ), and one of the lattice axes was inclined by 15% with respect to the longitudinal direction of the anisotropic conductive film. °.

Metal-coated resin particles (Sekisui Chemical Industry Co., Ltd., AUL703, average particle size 3 μm) were prepared as conductive particles, the conductive particles were filled in the concave portion of the resin mold, and the insulating resin adhesive was coated thereon. By pressing at 60° C. and 0.5 MPa, they were bonded together. Then, the insulating resin adhesive is peeled off from the mold, and the conductive particles on the insulating resin adhesive are pressed (pressing conditions: 60 to 70°C, 0.5 Mpa) to press them into the insulating resin adhesive. , and a film in which the conductive particles were embedded in the insulating resin adhesive in the state shown in Table 2 was produced. In this case, the embedded state of the conductive particles is controlled according to the pressing conditions. As a result, in Experimental Example 4, the film shape was not maintained after the conductive particles were pressed, and in the other experimental examples, a film in which conductive particles were embedded could be produced. In the observation with a metal microscope, as shown in Table 2, a concave portion was observed around the exposed portion of the embedded conductive particle or directly above the embedded conductive particle. Furthermore, in each of the experimental examples other than Experimental Example 4, both the concave portion around the exposed portion of the conductive particle and the concave portion directly above the conductive particle were observed, and Table 4 shows the most clearly observed by each experimental example. The measured value of the concave part.

An anisotropic conductive film whose resin layer is a two-layer type is produced by laminating an insulating adhesive on the side of the conductive particle-embedded film on the side where the conductive particles are pressed. However, in Experimental Example 4, since the shape of the film was not maintained after the conductive particles were pressed, the following evaluation was not performed.

(Evaluation) For the anisotropic conductive films of each experimental example, (a) initial on-resistance and (b) on-reliability were measured as follows. The results are shown in Table 2.

(a) Initial on-resistance The anisotropic conductive film of each experimental example was sandwiched between the glass substrate on the stage and the IC for conducting property evaluation on the pressing tool side, and each evaluation was obtained by heating and pressing (180° C., 5 seconds) with the pressing tool. Use a linker. In this case, the thrust obtained by the pressing tool was changed into three stages of low (40 MPa), medium (60 MPa), and high (80 MPa), and three types of connectors for evaluation were obtained.

Here, regarding the IC for conducting characteristic evaluation and the glass substrate, the terminal patterns of these correspond to each other, and the dimensions are as follows. Moreover, when connecting the IC for evaluation and a glass substrate, the long-side direction of an anisotropic conductive film and the short-side direction of a bump were aligned.

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

Glass substrate (ITO wiring) Glass material: 1737F made by Corning Shape: 30×50mm Thickness: 0.5 mm Electrode: ITO wiring

The initial on-resistance of the obtained connector for evaluation was measured and evaluated according to the following three-stage evaluation criteria. Evaluation criteria for initial on-resistance (practically, as long as it is less than 2 Ω, there is no problem) A: Less than 0.4 Ω B: 0.4 Ω or more and less than 0.8 Ω C: 0.8 Ω or more

(b) Turn-on reliability Carry out a reliability test in which the connector for evaluation prepared in (a) is placed in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 hours, and the on-resistance after measuring in the same manner as the initial on-resistance, according to the following three The evaluation criteria of the stage are evaluated.

Evaluation criteria for on-reliability (practically, as long as it is less than 5 Ω, there is no problem) A: Less than 1.2 Ω B: 1.2 Ω or more and less than 2 Ω C: 2 Ω or more

[Table 2] Experimental example 1 Experimental example 2 Experimental example 3 Experimental example 4 Experimental example 5 Experimental example 6 Experimental example 7 Experimental example 8 The composition of resin A B C D A A A A The shape of the film after the conductive particles are pressed OK OK OK NG OK OK OK OK Conductive particle size: D (μm) 3 3 3 3 3 3 3 3 Configuration of Conductive Particles Figure 1A Figure 1A Figure 1A Figure 1A Figure 5 Figure 7 Figure 4 Hexagonal lattice The distance between the centers of the nearest conductive particles (μm) 6 6 6 6 6 6 6 6 Thickness (μm) Insulating resin adhesive layer (La) 4 4 4 4 4 4 4 4 insulating adhesive layer 14 14 14 14 14 14 14 14 La/D 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Minimum melt viscosity (Pa s) Insulating resin adhesive layer 8000 2000 1500 800 8000 8000 8000 8000 insulating adhesive layer 800 800 800 800 800 800 800 800 Total melt viscosity 1200 900 900 800 1200 1200 1200 1200 Viscosity at 60℃（Pa·s） Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Buried state of conductive particles Buried rate (100×Lb/D)% >80 >95 >95 - >80 >80 >80 >80 Exposure diameter Lc (μm) <2.8 <2.5 <2.5 - <2.8 <2.8 <2.8 <2.8 The presence or absence of recesses Have Have Have - Have Have Have Have The maximum depth Le of the concave part (the ratio to the particle size D of the conductive particles) <50% <50% <50% - <50% <50% <50% <50% The maximum diameter Ld of the concave part (the ratio to the particle diameter D of the conductive particle) <1.3 <1.3 <1.3 - <1.3 <1.3 <1.3 <1.3 COG evaluation Thrust: low 40 MPa Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: Medium 60 MPa Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: High 80 MPa Initial on-resistance A A A - A A A A turn-on reliability A A A - A A A A

As can be seen from Table 2, in Experimental Example 4 in which the minimum melt viscosity of the insulating resin adhesive was 800 Pa·s, it was difficult to form a film having a concave portion in the insulating resin adhesive near the conductive particles. On the other hand, in the experimental example in which the minimum melt viscosity of the insulating resin adhesive was 1500 Pa·s or more, it was found that by adjusting the conditions at the time of embedding the conductive particles, it was possible to form near the conductive particles of the insulating resin adhesive. convex portion, and the thus obtained anisotropic conductive film has good conduction characteristics when used for COG. In addition, it was found that in Experimental Examples 1 to 7 in which the number density of conductive particles was low, anisotropic conductive connection could be performed at a lower pressure than in Experimental Example 8 in which the hexagonal lattice was arranged.

(c) Short circuit rate Using the anisotropic conductive films of Experimental Examples 1 to 3 and 5 to 8, using the following IC for evaluation of short-circuit rate, under the connection conditions of 180°C, 60 MPa, and 5 seconds, a connector for evaluation was obtained, and the obtained evaluation was measured. The short-circuit rate was calculated as the ratio of the number of short-circuits measured to the number of terminals of the evaluation IC using the number of short-circuits of the connector.

IC for short-circuit rate evaluation (comb-teeth TEG (test element group, test element group) in 7.5 μm space): Outline: 15×13 mm Thickness: 0.5 mm Bump specifications: size 25×140 μm, distance between bumps 7.5 μm, bump height 15 μm

As long as the short circuit is less than 50 ppm, it is practically preferable, and all the anisotropic conductive films of Experimental Examples 1 to 3 and 5 to 8 are less than 50 ppm.

Furthermore, in each of the experimental examples other than the experimental example 4, the conductive particles captured by each bump were measured, and as a result, 10 or more conductive particles were captured.

Experimental Examples 9 to 16 (Fabrication of anisotropic conductive film) Regarding the anisotropic conductive film used for FOG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of the conductive particles on the film forming performance and conduction characteristics was investigated as follows.

That is, resin compositions for forming an insulating resin adhesive and an insulating adhesive layer were prepared with the compositions shown in Table 3, and using these, an anisotropic conductive film was produced in the same manner as in Experimental Example 1. The arrangement of the conductive particles in this case and the distance between the centers of the closest particles are shown in Table 4. In Experimental Example 16, the conductive particles were arranged in a hexagonal lattice arrangement (number density of 15,000 particles/mm ² ), and one of the lattice axes was inclined by 15° with respect to the longitudinal direction of the anisotropic conductive film.

In the production step of the anisotropic conductive film, after the conductive particles were pressed into the insulating resin adhesive, the film shape was not maintained in Experimental Example 12, and the film shape was maintained in other experimental examples. Therefore, with respect to the anisotropic conductive films of the experimental examples other than the experimental example 12, the embedded state of the conductive particles was observed and measured with a metal microscope, and the following evaluations were further performed. Table 4 shows the embedded state of the conductive particles in each experimental example. The embedded state shown in Table 4 is the same as that in Table 2, and is the measured value in which the concave portion of the insulating resin adhesive was most clearly observed for each experimental example.

(Evaluation) For the anisotropic conductive films of each experimental example, (a) initial on-resistance and (b) on-reliability were measured as follows. The results are shown in Table 4.

(a) Initial on-resistance The anisotropic conductive film obtained in each experimental example was cut to 2 mm × 40 mm, sandwiched between the FPC for evaluation of conduction characteristics and the glass substrate, and heated and pressurized with a tool width of 2 mm (180°C, 5 seconds) , and obtained the linker for each evaluation. In this case, the thrust obtained by the pressing tool was changed into three stages of low (3 MPa), medium (4.5 MPa), and high (6 MPa), and three types of connectors for evaluation were obtained. The on-resistance of the obtained connector for evaluation was measured in the same manner as in Experimental Example 1, and the measured value was evaluated in three stages according to the following criteria.

FPC for evaluation: Terminal pitch: 20 μm Terminal width/space between terminals: 8.5 μm/11.5 μm Polyimide film thickness (PI) / copper foil thickness (Cu) = 38/8, tin plating (Sn plating)

Alkali-free glass substrate: Electrode: ITO wiring Thickness: 0.7 mm

Evaluation criteria for initial on-resistance A: Less than 1.6 Ω B: 1.6 Ω or more and less than 2.0 Ω C: 2.0 Ω or more

(b) Turn-on reliability The connector for evaluation prepared in (a) was placed in a constant temperature bath with a temperature of 85°C and a humidity of 85% RH for 500 hours, and the subsequent on-resistance was measured in the same manner as the initial on-resistance. The following criteria were used to evaluate the on-resistance in three stages. Measurements.

Evaluation Criteria for On-Reliability A: Less than 3.0 Ω B: 3.0 Ω or more and less than 4 Ω C: 4.0 Ω or more

From Table 4, in Experimental Example 12 in which the minimum melt viscosity of the insulating resin adhesive was 800 Pa·s, it was difficult to form a film having a concave portion. On the other hand, in the experimental example in which the minimum melt viscosity of the insulating resin layer was 1500 Pa·s or more, it was found that recesses could be formed in the vicinity of the conductive particles of the insulating resin binder by adjusting the conditions for burying the conductive particles. , and the thus obtained anisotropic conductive film has good conduction characteristics when used for FOG.

(c) Short circuit rate The number of short circuits in the evaluation connector for which the initial on-resistance was measured was measured, and the short-circuit occurrence rate was calculated from the number of short circuits obtained by the measurement and the number of gaps in the evaluation connector. As long as the short-circuit occurrence rate is less than 100 ppm, there is no practical problem. The short-circuit occurrence rates of Experimental Examples 9 to 11 and 13 to 16 were all less than 100 ppm.

Furthermore, in each of the experimental examples other than the experimental example 12, the conductive particles captured by each bump were measured, and as a result, 10 or more conductive particles were captured.

[table 3] (parts by mass) Composition table for FOG composition E F G H insulating resin adhesive Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 55 45 25 5 Phenoxy resin (FX-316ATM55, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.) 20 40 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Industry Co., Ltd.) 20 20 20 20 2-functional urethane acrylate oligomer (UN-9200A, Genshang Industrial Co., Ltd.) 25 35 35 35 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 1 1 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 1 1 1 Benzoyl peroxide (Nyper BW, Nippon Oil Co., Ltd.) 5 5 5 5 insulating adhesive layer Phenoxy resin (FX-316ATM55, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.) 50 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Industry Co., Ltd.) 20 2-functional urethane acrylate oligomer (UN-9200A, Genshang Industrial Co., Ltd.) 30 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 Benzoyl peroxide (Nyper BW, Nippon Oil Co., Ltd.) 5

[Table 4] FOG evaluation Experimental example 9 Experimental Example 10 Experimental Example 11 Experimental example 12 Experimental Example 13 Experimental Example 14 Experimental example 15 Experimental Example 16 The composition of resin E F G H E E E E The shape of the film after the conductive particles are pressed OK OK OK NG OK OK OK OK Conductive particle size: D (μm) 3 3 3 3 3 3 3 3 Configuration of Conductive Particles Figure 5 Figure 5 Figure 5 Figure 5 image 3 Figure 7 Figure 4 Hexagonal lattice The distance between the centers of the nearest conductive particles (μm) 9 9 9 9 9 9 9 9 Thickness (μm) Insulating resin adhesive layer (La) 4 4 4 4 4 4 4 4 insulating adhesive layer 14 14 14 14 14 14 14 14 La/D 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Minimum melt viscosity (Pa s) Insulating resin adhesive layer 8000 2000 1500 800 8000 8000 8000 8000 insulating adhesive layer 800 800 800 800 800 800 800 800 Total melt viscosity 1200 900 900 800 1200 1200 1200 1200 Viscosity at 60℃（Pa·s） Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Buried state of conductive particles Buried rate (100×Lb/D)% >80 >95 >95 - >80 >80 >80 >80 Exposure diameter Lc (μm) <2.8 <2.5 <2.5 - <2.8 <2.8 <2.8 <2.8 The presence or absence of recesses Have Have Have - Have Have Have Have The maximum depth Le of the concave part (the ratio to the particle size D of the conductive particles) <50% <50% <50% - <50% <50% <50% <50% The maximum diameter Ld of the concave part (the ratio to the particle diameter D of the conductive particle) <1.3 <1.3 <1.3 - <1.3 <1.3 <1.3 <1.3 FOG evaluation Thrust: 3 MPa lower Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: Medium 4.5 MPa Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: High 6 MPa Initial on-resistance A A A - A A A A turn-on reliability A A A - A A A A

1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1a, 1b, 1c, 1d, 1e: Anisotropic conductive film 2, 2a, 2b, 2c, 2s: Conductive particles 2m, 2n, 2o, 2p, 2q, 2r: Conductive particle array 2t: top of conductive particles 3: Insulating resin adhesive 3a: Surface of insulating resin adhesive 3b, 3c: Recess 3P: Tangent plane 4: Insulating adhesive layer 5, 5B: repeating unit 5a: Side parallel to the longitudinal direction of the anisotropic conductive film 5b: The side parallel to the short side direction of the anisotropic conductive film 5x: A polygon formed by sequentially connecting the centers of the conductive particles that form the outer shape of the repeating unit D: Average particle size L1, L2: Outer tangent La: Thickness of insulating resin adhesive Lb: embedded amount of conductive particles Lc: diameter of exposed portion of conductive particles Ld: Maximum diameter of the recess Le, Lf: maximum depth

1A is a plan view showing the arrangement of conductive particles in the anisotropic conductive film 1A of the example. 1B is a cross-sectional view of the anisotropic conductive film 1A of the example. 2] It is a top view of the anisotropic conductive film 1B of an Example. 3] It is a top view of the anisotropic conductive film 1C of an Example. 4] It is a top view of the anisotropic conductive film 1D of an Example. 5] It is a top view of the anisotropic conductive film 1E of an Example. 6] It is a top view of the anisotropic conductive film 1F of an Example. 7] It is a top view of the anisotropic conductive film 1G of an Example. 8] It is a top view of the anisotropic conductive film 1H of an Example. 9] It is a top view of the anisotropic conductive film 1I of an Example. 10 is a plan view of the anisotropic conductive film 1J of the example. 11 is a plan view of the anisotropic conductive film 1K of the example. 12 is a cross-sectional view of the anisotropic conductive film 1a of the example. 13 is a cross-sectional view of the anisotropic conductive film 1b of the embodiment. 14 is a cross-sectional view of the anisotropic conductive film 1c of the example. 15 is a cross-sectional view of the anisotropic conductive film 1d of the example. FIG. 16 is a cross-sectional view of the anisotropic conductive film 1e of the example.

Claims (14)

A method of manufacturing an anisotropic conductive film, comprising: Repeating units of conductive particles are repeatedly arranged on the insulating resin adhesive. The repeating units of the conductive particles are conductive particle rows in which conductive particles are spaced apart and arranged in a row, and those with different numbers of conductive particles are juxtaposed. The method for producing an anisotropic conductive film according to claim 1, wherein the repeating unit is arranged on the entire surface of the anisotropic conductive film. The method for producing an anisotropic conductive film according to claim 1, wherein the number of conductive particles constituting the row of conductive particles arranged in the repeating unit gradually varies. The method for producing an anisotropic conductive film as claimed in claim 1, wherein among the 3 rows of conductive particle rows juxtaposed in the repeating unit, the number of conductive particles constituting the central conductive particle row is more or less than the number of conductive particles constituting both sides The number of conductive particles in the column. The method for producing an anisotropic conductive film according to claim 1, wherein the sides of the polygon formed by sequentially connecting the centers of the conductive particles forming the outer shape of the repeating unit and the longitudinal direction or the short side of the anisotropic conductive film Oblique direction. The method for producing an anisotropic conductive film according to claim 1, wherein the polygons formed by sequentially connecting the centers of the conductive particles forming the outer shape of the repeating unit have a length parallel to the long-side direction or the short-side direction of the anisotropic conductive film edge. The method for producing an anisotropic conductive film according to claim 1, wherein the conductive particle rows in the repeating unit are parallel to each other. The method for producing an anisotropic conductive film according to claim 1, wherein separate conductive particles are repeatedly arranged together with the repeating unit. The method for producing an anisotropic conductive film according to claim 1, wherein in the repeating unit, the closest distance between adjacent conductive particles is 0.5 times or more the average particle diameter of the conductive particles. The method for producing an anisotropic conductive film according to claim 1, wherein the conductive particles constituting the repeating unit are formed by regularly removing specific lattice points from the arrangement of the conductive particles existing in each lattice point of the hexagonal lattice or the square lattice The configuration of the conductive particles. A design method of an anisotropic conductive film, which is a design method of an anisotropic conductive film in which conductive particles are arranged in an insulating resin adhesive, and includes: Repeating units of conductive particles are repeatedly arranged on the insulating resin adhesive. The repeating units of the conductive particles are conductive particle rows in which conductive particles are spaced apart and arranged in a row, and those with different numbers of conductive particles are juxtaposed. An anisotropic conductive film comprising conductive particles arranged in an insulating resin adhesive, and The repeating units of the conductive particles are arranged repeatedly, and the repeating units of the conductive particles are conductive particle rows formed by the conductive particles arranged in a row at intervals, and the centers of the conductive particles forming the outer shape of the repeating units are sequentially connected to form a polygon. There is a region where no conductive particles are arranged between the repeating units arranged repeatedly. A connection structure in which a first electronic component and a second electronic component are anisotropically conductively connected by the anisotropic conductive film of claim 12. A method of manufacturing a connection structure, which manufactures a connection structure of a first electronic component and a second electronic component by crimping a first electronic component and a second electronic component through an anisotropic conductive film, and its use is required The anisotropic conductive film of item 12 serves as an anisotropic conductive film.

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