WO2024247863A1 - Conductive adhesive film, method for manufacturing conductive adhesive film, connection body, and method for manufacturing connection body - Google Patents

Abstract

Provided is an conductive adhesive film that can efficiently use conductive particles, supports the miniaturization of the electrode size of an electronic component and fine pitch conversion thereof, and can ensure conduction reliability between connection electrodes and insulation performance between adjacent electrodes.　A conductive adhesive film 1 comprises a base material 2 and an adhesive material layer 4, which is provided on one surface of the base material 2 and contains conductive particles 3. The conductive particles 3 contained in the adhesive material layer 4 constitute a particle aggregate 5 in which a plurality of conductive particles are aggregated. In the adhesive material layer 4, array elements 6 each comprising the particle aggregate 5 are arranged in a prescribed arrangement pattern corresponding to an electrode arrangement of an electronic component 10 to which the conductive adhesive film 1 is affixed.

Description

Conductive adhesive film, method for producing conductive adhesive film, connection body, and method for producing connection body

This technology relates to a conductive adhesive film and a manufacturing method thereof, a connection body in which electronic components are connected to each other using a conductive adhesive film, and a manufacturing method for the connection body. This application claims priority based on Japanese Patent Application No. 2023-87249, filed in Japan on May 26, 2023, which application is incorporated herein by reference.

Conventionally, anisotropic conductive film (ACF) has been known as a connecting film for connecting various electronic components, etc.

JP 2020-198422 A Patent No. 6489516

In ACF, conductive particles are evenly dispersed in the adhesive layer, so only a portion of the conductive particles captured on the electrode contribute to the conductive connection, and conductive particles other than those captured on the electrode do not contribute to the conductive connection, resulting in waste. Currently, particle-aligned ACFs have been proposed in which relatively large conductive particles with an average particle size of 15 to 20 μm are regularly aligned, but in particle-aligned ACFs, as in dispersed ACFs, conductive particles other than those captured on the electrode do not contribute to the conductive connection, and the conductive particles are not used efficiently. It has also been proposed to process ACFs into the shape of the substrate or the electrode arrangement pattern to which the ACF is attached (see, for example, Patent Document 1), but the occurrence of conductive particles in positions other than on the electrodes is unavoidable.

Furthermore, as the electrode size of electronic components connected with anisotropic conductive film becomes smaller, the number of conductive particles that can be captured by the electrodes also becomes smaller, and there are cases where conventional anisotropic conductive films are unable to provide sufficient conductivity reliability. On the other hand, product trends for ACF for camera modules (CCMs), for example, demand higher pixel counts and higher transmission speeds, and anisotropic conductive films are also required to increase particle density to accommodate finer pitches, place more conductive particles on the electrodes, improve conductivity reliability, and prevent short circuits caused by conductive particles being present between adjacent electrodes.

The purpose of this technology is to provide a conductive adhesive film, a manufacturing method for a conductive adhesive film, a connection, and a manufacturing method for a connection that enable efficient use of conductive particles, can accommodate the miniaturization and fine pitch of the electrodes of electronic components, and can ensure reliable electrical continuity between connecting electrodes and insulation between adjacent electrodes.

In order to solve the above-mentioned problems, the conductive adhesive film according to the present technology has a substrate and an adhesive layer that is provided on one side of the substrate and contains conductive particles, the conductive particles contained in the adhesive layer constitute particle aggregates formed by agglomerating a plurality of the conductive particles, and the adhesive layer has array elements formed of the particle aggregates arranged in a predetermined array pattern that corresponds to the electrode array of an electronic component to which the conductive adhesive film is attached.

In addition, the method for producing a conductive adhesive film according to the present technology includes a substrate and an adhesive layer containing conductive particles that is provided on one side of the substrate, and includes an arrangement step of arranging, in the adhesive layer, array elements made of particle aggregates formed by agglomerating a plurality of the conductive particles in a predetermined array pattern that corresponds to the electrode array of an electronic component to which the conductive adhesive film is attached, and the arrangement step includes providing the conductive particles in the adhesive layer via a mask having predetermined openings.

The connection body according to the present technology is a connection body in which a first electronic component and a second electronic component are connected via a conductive adhesive film containing a plurality of conductive particles, the conductive adhesive film has a substrate and an adhesive layer containing conductive particles provided on one surface of the substrate, the conductive particles contained in the adhesive layer constitute particle aggregates formed by agglomerating a plurality of the conductive particles, and the adhesive layer has array elements made of the particle aggregates arranged in a predetermined array pattern corresponding to the electrode array of the first electronic component to which the conductive adhesive film is attached.

　In addition, the method for manufacturing a connection body according to the present technology includes an arrangement step of attaching a conductive adhesive film containing a plurality of conductive particles onto a first electronic component, and a connection step of connecting the first electronic component and a second electronic component via the conductive adhesive film, the conductive adhesive film includes a substrate and an adhesive layer containing conductive particles provided on one surface of the substrate, the conductive particles contained in the adhesive layer constitute a particle aggregate formed by agglomerating a plurality of the conductive particles, the adhesive layer has array elements made of the particle aggregates arranged in a predetermined array pattern corresponding to the electrode array of the first electronic component to which the conductive adhesive film is attached, and in the arrangement step, the electrodes of the first electronic component and the array elements are aligned, and the conductive adhesive film is attached onto the first electronic component.

With this technology, the array elements of the conductive adhesive film are composed of aggregates of conductive particles, making it easier to form an array pattern than if the conductive particles were handled individually. In addition, the array elements can be arranged in a desired pattern in a specific part of the adhesive layer, reducing unnecessary conductive particles that do not contribute to conductivity and conductive particles between adjacent electrodes, and efficiently improving the conductivity between connecting electrodes even with fine pitch while preventing short circuits between adjacent electrodes.

Figure 1(A) is a plan view showing a conductive adhesive film in which array elements are arranged in a predetermined array pattern, Figure 1(B) is a plan view showing conductive particle agglomerates that make up the array elements, and Figure 1(C) is a plan view showing conductive particles that make up the conductive particle agglomerates. FIG. 2 is a cross-sectional view that shows a schematic state in which the array elements are aligned on the electrode array of the first electronic component and a conductive adhesive film is attached. FIG. 3 is a plan view that shows a schematic state in which the array elements are aligned on the electrode array of the first electronic component and a conductive adhesive film is attached. 4A and 4B are plan views showing a conductive adhesive film provided with individual pieces each consisting of a plurality of array elements. FIG. 5(A) is a plan view showing a conductive adhesive film in which elements are arranged in accordance with the electrode arrangement of the first electronic component shown in FIG. 5(B), and FIG. 5(B) is a plan view showing an electronic component in which first to third terminal rows are formed, in which terminals (electrodes) are arranged on each of the three sides of a rectangular attachment area. Figure 6(A) is a plan view showing a conductive adhesive film in which an array element consisting of a single particle agglomerate is arranged in an adhesive layer in a predetermined array pattern corresponding to the electrode arrangement of a first electronic component, and Figure 6(B) is a plan view showing a conductive adhesive film in which the adhesive layer is divided into individual pieces corresponding to the attachment area of the first electronic component, and each individual piece has an array element consisting of a single particle agglomerate arranged therein. Figure 7(A) is a plan view showing a conductive adhesive film in which array elements consisting of two particle agglomerates are arranged in an adhesive layer in a predetermined array pattern corresponding to the electrode arrangement of a first electronic component, and Figure 7(B) is a plan view showing a conductive adhesive film in which the adhesive layer is divided into individual pieces corresponding to the attachment area of the first electronic component, and each individual piece has an array element consisting of two particle agglomerates arranged therein. Fig. 8(A) is a plan view showing a conductive adhesive film in which an array element is arranged in a hexagonal lattice shape of particle aggregates in a predetermined array pattern corresponding to the electrode array of a first electronic component on an adhesive layer. Fig. 8(B) is a plan view showing the array of conductive particle aggregates constituting each array element of the conductive adhesive film shown in Fig. 8(A). Fig. 8(C) is a plan view showing each conductive particle aggregate constituting the array element. Figure 9 shows a state in which the area of the array element is made smaller than the area of the electrode of the first electronic component, thereby preventing particle agglomerates from spilling out between adjacent electrodes even if misalignment occurs between the array element and the electrode, (A) being a cross-sectional view and (B) being a plan view. Figure 10 is a diagram showing the state in which the array elements (conductive particle aggregates) of the conductive adhesive film shown in Figures 6 (A) and (B) are arranged on an electrode, where (A) is a plan view showing the state in which the array elements (conductive particle aggregates) are arranged in the center of the width direction of the electrode without any misalignment, and (B) is a plan view showing the state in which the array elements (conductive particle aggregates) are shifted in the width direction of the electrode due to a shift in the attachment position of the conductive adhesive film. Figure 11 is a diagram showing the state in which the array elements (conductive particle aggregates) of the conductive adhesive film shown in Figures 7 (A) and (B) are arranged on an electrode, where (A) is a plan view showing the state in which the array elements (two conductive particle aggregates) are arranged in the center of the width direction of the electrode without any misalignment, and (B) is a plan view showing the state in which the array elements (two conductive particle aggregates) are misaligned in the width direction of the electrode due to a shift in the attachment position of the conductive adhesive film. FIG. 12 is a plan view showing a state in which misalignment occurs when the width W1 of an array element formed of an aggregate of conductive particles with an average particle size of 20 μm is set to 200 μm, which is the same as the width W2 of the electrode. FIG. 13 is a perspective view showing a typical example of a film roll. FIG. 14 is a cross-sectional view that typically illustrates an arrangement step in which conductive particles are printed on an adhesive layer supported on a substrate using a metal mask to arrange the arrangement elements. FIG. 15 is a cross-sectional view that typically illustrates an arrangement step in which conductive particles are printed on an adhesive layer supported on a substrate using a rotary screen to arrange arrangement elements. FIG. 16 is a cross-sectional view showing a placement step of placing a conductive adhesive film on the first electronic component. FIG. 17 is a cross-sectional view showing a state in which the base material has been peeled off from the adhesive layer in the disposing step. FIG. 18 is a cross-sectional view showing a connecting step of connecting a second electronic component to a first electronic component via an adhesive layer. FIG. 19 is a cross-sectional view showing a connection body in which a first electronic component and a second electronic component are connected via an adhesive layer. 20(A) is an oblique view showing a camera module evaluation board, FIG. 20(B) is an oblique view showing an anisotropic conductive film attached to an electrode of the camera module evaluation board, FIG. 20(C) is an oblique view showing an FPC placed on the camera module evaluation board with the anisotropic conductive film attached, FIG. 20(D) is an oblique view showing the process of pressing the FPC from above with a pressure bonding tool via silicone rubber, and FIG. 20(E) is an oblique view showing a connection sample in which an FPC is connected to a camera module evaluation board by an anisotropic conductive film.

Below, the conductive adhesive film to which the present technology is applied, the manufacturing method of the conductive adhesive film, the connection body, and the manufacturing method of the connection body will be described in detail with reference to the drawings. Note that the present technology is not limited to only the following embodiments, and various modifications are possible without departing from the gist of the present technology. In addition, the drawings are schematic, and the ratios of the dimensions may differ from the actual ones. Specific dimensions should be determined with reference to the following explanation. In addition, the drawings include parts in which the dimensional relationships and ratios differ from one another.

[Conductive adhesive film]
Figure 1(A) is a plan view showing a conductive adhesive film 1 in which array elements 6 are arranged in a predetermined array pattern, Figure 1(B) is a plan view showing a conductive particle agglomerate 5 that constitutes the array element 6, and Figure 1(C) is a plan view showing a conductive particle 3 that constitutes the conductive particle agglomerate 5.

The conductive adhesive film 1 to which this technology is applied is a conductive adhesive film having a substrate 2 and an adhesive layer 4 that is provided on one side of the substrate 2 and contains conductive particles 3, the conductive particles 3 contained in the adhesive layer 4 constitute particle aggregates 5 formed by agglomerating a plurality of conductive particles 3, and the adhesive layer 4 has array elements 6 made of the particle aggregates 5 arranged in a predetermined array pattern that corresponds to the electrode array of the first electronic component 10 to which the conductive adhesive film 1 is attached.

The conductive adhesive film 1 has an adhesive layer 4 continuously provided in the longitudinal direction of the substrate 2, and array elements 6 made of particle aggregates 5 arranged in the adhesive layer 4 in a predetermined array pattern corresponding to the electrode array of the first electronic component 10. The conductive adhesive film 1 is then aligned with the electrodes 11 of the first electronic component 10 (the adherend) and the array elements 6, and the adhesive layer 4 is attached onto the first electronic component 10. Thereafter, the electrodes 11 of the first electronic component 10 are aligned with the electrodes 13 of the second electronic component 12, and the first electronic component 10 and the second electronic component 12 are connected via the conductive adhesive film 1.

FIG. 2 is a cross-sectional view showing a state in which the array elements 6 are aligned on the electrode array of the first electronic component 10 and the conductive adhesive film 1 is attached. FIG. 3 is a plan view showing a state in which the array elements 6 are aligned on the electrode array of the first electronic component 10 and the conductive adhesive film 1 is attached. The array elements 6 of the conductive adhesive film 1 shown in FIGS. 2 and 3 are formed by densely gathering conductive particle aggregates 5 in a predetermined region corresponding to the electrode 11 of the first electronic component 10.

With the conductive adhesive film 1 to which this technology is applied, the arrangement pattern of the arrangement elements 6 made of particle aggregates 5 is designed to match the electrode design of the first electronic component 10 to which it is attached. In this case, since the arrangement elements 6 are made up of aggregates of conductive particles 3, the arrangement pattern can be formed more easily than when the conductive particles 3 are handled individually.

Furthermore, by arranging the array elements 6 in a desired pattern in a specific portion of the adhesive layer 4, the conductive particles 3 can be efficiently arranged on the electrodes 11 of the first electronic component 10, and the number of unnecessary conductive particles 3 that do not contribute to conductivity and the number of conductive particles 3 between adjacent electrodes can be reduced or eliminated. Therefore, the conductive particles 3 can be efficiently utilized, and even when the electrodes 11, 13 of the first and second electronic components 11, 12 are fine-pitched, the conductivity between the connecting electrodes of the electrodes 11 and 12 can be improved, and the risk of short circuits between adjacent electrodes can be reduced.

Furthermore, with the conductive adhesive film 1 to which this technology is applied, the minimum connection area between connecting electrodes in an anisotropic conductive connection can be made smaller. That is, in the past, a relatively large electrode area was required to capture the conductive particles necessary to establish stable conductivity as a means of ensuring conductivity between narrowed electrodes, but with this technology, conductivity can be ensured by concentrating the conductive particle aggregates 5 on the electrode 11, and stable conductivity can be established even with a narrowed electrode area. Therefore, the minimum connection area between connecting electrodes in an anisotropic conductive connection can be made smaller.

In addition, with the conductive adhesive film 1 to which this technology is applied, the conductive particle aggregates 5 are concentrated and arranged on the electrode 11, thereby improving the density of the conductive particles 3 captured between the connection electrodes. This makes it possible to reduce the conduction resistance between the connection electrodes compared to a dispersion-type conductive adhesive film in which conductive particles are dispersed over the entire surface of the adhesive layer, or an aligned-type conductive adhesive film in which conductive particles are evenly arranged over the entire surface of the adhesive layer.

In addition, in this technology, the array elements 6 of the conductive adhesive film 1 are treated not in units of individual conductive particles, but in units of aggregates 5 of conductive particles 3. Therefore, the conductive particle aggregates 5 constituting the array elements 6 do not need to be highly uniform with respect to the individual conductive particles 3. This increases the degree of freedom in the selection of the conductive particles 3. For example, metal particles with non-uniform particle diameters, such as solder particles, can also be used as the conductive particles 3. Furthermore, by treating the array elements 6 in units of conductive particle aggregates 5, it becomes easy to align and arrange the array elements 6 in accordance with the pattern of the electrodes 11 of the first electronic component 10, even if the particle diameters of the conductive particles 3 are non-uniform.

In addition, if an array pattern is formed by arranging conductive particles one by one in a predetermined position, as in the case of aligned anisotropic conductive films, it would be necessary to create a master on which an array pattern of individual conductive particles is formed for each electrode pattern, or difficult microfabrication would be required, resulting in increased manufacturing costs and making it difficult to flexibly accommodate connection electrode patterns. However, with the conductive adhesive film 1 to which this technology is applied, the array elements 6 are treated as aggregates 5 of conductive particles 3, so microfabrication to the extent of arranging individual conductive particles is not required, and array patterns can be formed flexibly to accommodate various connection electrode patterns, including from an economical perspective.

[Singulation]
The conductive adhesive film 1 may be provided with the adhesive layer 4 continuously in the longitudinal direction of the substrate 2, or may be provided with the adhesive layer 4 in which the arrangement elements 6 are arranged according to the electrode pattern of the first electronic component 10, as shown in Figs. 4 and 5, which is divided into pieces corresponding to the attachment areas of the first electronic component 10 to which the conductive adhesive film 1 is attached. In the conductive adhesive film 1 shown in Figs. 4 and 5, pieces 8 corresponding to the attachment areas of the first electronic component 10 are repeatedly provided in the longitudinal direction of the substrate 2. In each piece 8, the arrangement elements 6 are arranged in a pattern according to the electrode pattern of the first electronic component 10. For each piece 8 of the conductive adhesive film 1, the electrodes 11 of the first electronic component 10, which is the adherend, are aligned with the arrangement elements 6, and the adhesive layer 4 is attached to the first electronic component 10.

FIGS. 4(A) and (B) are plan views showing a conductive adhesive film 1 on which pieces 8 each made up of a plurality of array elements 6 are provided. In the conductive adhesive film 1 shown in FIG. 4(A) and (B), each piece 8 is attached to a first electronic component 10 having one or more electrodes 11 spaced apart in an attachment area, with the array elements 6 aligned and attached to the electrodes 11.

FIG. 5(A) is a plan view showing a conductive adhesive film 1 in which array elements 6 are arranged corresponding to the electrode array of the first electronic component 10 shown in FIG. 5(B). The first electronic component 10 shown in FIG. 5(B) has a first terminal row 21, a second terminal row 22, or a third terminal row 23 in which terminals (electrodes 11) are arranged on each of the three sides of a rectangular attachment area. The conductive adhesive film 1 shown in FIG. 5(A) has array elements 6 arranged in correspondence with each terminal of the first to third terminal rows 21 to 23 formed in the attachment area of each first electronic component 10 for each piece 8, and each array element 6 is aligned and attached onto the terminal of the first electronic component 10.

In addition, each piece 8 of the conductive adhesive film 1 shown in FIG. 5(A) has the adhesive layer 4 provided along three sides, rather than over the entire rectangular attachment area, so that it has a roughly U-shape that is open from the center of the attachment area to the one side where the terminal row is not formed. This prevents the center of the attachment area from being sealed with the adhesive layer 4, and also reduces the amount of adhesive layer 4 used. Furthermore, because the outer shape of the attachment area and the outer shape of the piece 8 match where necessary, excessive overflow of unnecessary resin after the pieces 8 are bonded together can be suppressed.

[Array elements]
The array elements 6 constituting the array pattern may be formed by a plurality of closely packed particle aggregates 5, or may be formed by one or two particle aggregates 5. The conductive adhesive film 1 shown in Fig. 6(A) has array elements 6 each consisting of one particle aggregate 5 arranged on the adhesive layer 4 in a predetermined array pattern corresponding to the electrode array of the first electronic component 10. The conductive adhesive film 1 shown in Fig. 6(B) has the adhesive layer 4 separated into individual pieces corresponding to the attachment areas of the first electronic component 10, and each individual piece 8 has an array element 6 each consisting of one particle aggregate 5 arranged thereon. The conductive adhesive film 1 shown in Figs. 6(A) and 6(B) is aligned so that the particle aggregate 5 is provided at the center of the width direction of the electrode 11.

The conductive adhesive film 1 shown in FIG. 7(A) has an arrangement element 6 consisting of two particle aggregates 5 arranged in an adhesive layer 4 in a predetermined arrangement pattern corresponding to the electrode arrangement of the first electronic component 10. The conductive adhesive film 1 shown in FIG. 7(B) has an adhesive layer 4 that has been individualized to correspond to the attachment area of the first electronic component 10, and each individual piece 8 has an arrangement element 6 consisting of two particle aggregates 5 arranged therein. The conductive adhesive film 1 shown in FIGS. 7(A) and (B) is aligned so that the two particle aggregates 5 are located at the center of the width of the electrode 11.

In addition, when the conductive adhesive film 1 has the array elements 6 formed of a plurality of particle aggregates 5, the particle aggregates 5 may be regularly aligned. FIG. 8(A) is a plan view showing a conductive adhesive film 1 in which the array elements 6 are formed by arranging the particle aggregates 5 in a hexagonal lattice shape in a predetermined array pattern corresponding to the electrode array of the first electronic component 10 in the adhesive layer 4. FIG. 8(B) is a plan view showing the array of the conductive particle aggregates 5 constituting each array element 6 of the conductive adhesive film 1 shown in FIG. 8(A). FIG. 8(C) is a plan view showing each conductive particle aggregate 5 constituting the array element 6. In the conductive adhesive film 1 shown in FIG. 8, the adhesive layer 4 may also be divided into individual pieces corresponding to the attachment area of the first electronic component 10. In addition to the configuration shown in FIG. 8(B), the conductive particle aggregates 5 constituting the array elements 6 may also be aligned in the configurations shown in FIGS. 4(A) and (B) described above.

The area of the array element 6 may be equal to or smaller than the area of the electrode of the first electronic component 10. The array element 6 is formed by filling or aligning the conductive particle aggregates 5 in the adhesive layer 4 through the openings 34 of the mask 33 described below. That is, the maximum area and shape of the array element 6 are determined by the area and shape of the openings 34 of the mask 33. For example, by opening the openings 34 in the same rectangular shape as the electrode 11 in correspondence with the rectangular electrode 11, an array element 6 having the same area and shape as the electrode 11 is formed, and by making the openings 34 smaller than the electrode 11, an array element 6 having an area smaller than the electrode area is formed. Therefore, the area of the array element 6 refers to the maximum area determined by the openings 34 of the mask 33.

The area of the array element 6 is set to be equal to or smaller than the area of the electrode 11 of the first electronic component 10, thereby allowing tolerance for misalignment between the array element 6 and the electrode. That is, when the conductive adhesive film 1 is attached to the attachment area of the first electronic component 10, the electrode 11 of the first electronic component 10 is aligned with the array element 6. If misalignment occurs, the conductive particle aggregates 5 that make up the array element 6 may protrude into the space between adjacent electrodes, and depending on the amount of protrusion, this may cause a short circuit between the adjacent electrodes.

Therefore, by making the area of the array element 6 equal to or smaller than the area of the electrode 11 of the first electronic component 10, even if there is a misalignment between the array element 6 and the electrode 11, the conductive particle agglomerates 5 can be prevented from protruding into the space between adjacent electrodes, or the amount of protrusion can be suppressed, thereby reducing the risk of a short circuit between adjacent electrodes. Furthermore, because the array element 6 is made up of the conductive particle agglomerates 5, even if some of the conductive particle agglomerates 5 protrude into the space between adjacent electrodes, the conductive particle agglomerates 5 located on the electrode 11 can ensure sufficient conductivity between the connecting electrodes.

Figure 9 shows a state in which the area of the array element 6 is made smaller than the area of the electrode 11 of the first electronic component 10, thereby preventing the particle aggregate 5 from spilling out between adjacent electrodes even if the alignment of the array element 6 and the electrode 11 is misaligned; (A) is a cross-sectional view, and (B) is a plan view.

Figure 10 shows the state in which the array elements 6 (conductive particle aggregates 5) of the conductive adhesive film 1 shown in Figures 6(A) and (B) are arranged on the electrode 11, where (A) is a plan view showing the state in which the array elements 6 (conductive particle aggregates 5) are arranged in the center of the width of the electrode 11 without any misalignment, and (B) is a plan view showing the state in which the array elements 6 (conductive particle aggregates 5) are misaligned in the width direction of the electrode 11 due to a shift in the attachment position of the conductive adhesive film 1.

Figure 11 shows the state in which the array elements 6 (conductive particle aggregates 5) of the conductive adhesive film 1 shown in Figures 7(A) and (B) are arranged on the electrode 11, where (A) is a plan view showing the state in which the array elements 6 (two conductive particle aggregates 5) are arranged in the center of the width of the electrode 11 without any misalignment, and (B) is a plan view showing the state in which the array elements 6 (two conductive particle aggregates 5) are misaligned in the width direction of the electrode 11 due to a misalignment in the attachment position of the conductive adhesive film 1.

In both Figures 10(B) and 11(B), the amount of particle aggregate 5 protruding between adjacent electrodes is suppressed, preventing short circuits between adjacent electrodes.

Furthermore, when the arrangement direction of the arrangement elements 6 in the arrangement pattern is the width direction of the arrangement elements 6, and the arrangement direction of the electrodes 11 in the electrode arrangement of the first electronic component 10 is the width direction of the electrodes 11, it is preferable that the width W1 of the arrangement elements 6 is 40% to 100% of the width W2 of the electrodes 11. The state in which the width W1 of the arrangement elements 6 is 100% of the width W2 of the electrodes 11 means that the width of the arrangement elements 6 is the same as the width of the electrodes 11. If it exceeds 100%, there is a risk that even a slight misalignment will cause a short circuit between adjacent electrodes. Figure 12 is a plan view showing a state in which misalignment occurs when the width W1 of the arrangement elements 6 formed by aggregates 5 of conductive particles 3 with an average particle size of 20 μm is 200 μm, which is the same as the width W2 of the electrodes 11. When the space S between adjacent electrodes is 200 μm, a slight misalignment (about 160 μm) is allowed to ensure conductivity between the connecting electrodes and prevent short circuits between adjacent electrodes.

The state where the width W1 of the array element 6 is 40% of the width W2 of the electrode 11 corresponds to, for example, the case where the particle diameter of the conductive particle aggregate 5 (the average particle diameter of the conductive particles 3 is 20 μm) is 80 μm and the width of the electrode 11 of the first electronic component 10 is 200 μm in the conductive adhesive film 1 shown in Figures 6 (A) (B) and 7 (A) (B). When the state where the conductive particle aggregate 5 is arranged at the center of the electrode 11 in the width direction is an ideal state without misalignment (see Figures 10 (A) and 11 (A)), even if a misalignment of about half the width of the electrode 11 (100 μm) occurs, a part of the conductive particle aggregate 5 is on the electrode 11, so that the conductivity between the connecting electrodes can be ensured and a short circuit between adjacent electrodes can be prevented.

[Conductive adhesive film]
Hereinafter, a specific description will be given of each component of the conductive adhesive film 1. As described above, the conductive adhesive film 1 has a substrate 2 and an adhesive layer 4 that is provided on one surface of the substrate 2 and contains conductive particles 3. The conductive particles 3 contained in the adhesive layer 4 constitute particle aggregates 5 formed by aggregating a plurality of conductive particles 3.

[Substrate]
The conductive adhesive film 1 is wound in a roll shape and provided as a film winding body 30. FIG. 13 is a perspective view showing a typical example of the film winding body. As shown in FIG. 13, the film winding body 30 is formed by winding the conductive adhesive film 1, which includes a tape-shaped substrate 2 and an adhesive layer 4 formed on the substrate 2, around a winding core 31. The winding core 31 has an axial hole into which a rotating shaft for rotating the reel is inserted, and connects one end of the conductive adhesive film 1 in the longitudinal direction to wind the conductive adhesive film 1. The length of the conductive adhesive film 1 wound around the film winding body 30 is not particularly limited, but the lower limit of the length is 5 m or more, 10 m or more, or 50 m or more, and the upper limit of the length is 5000 m or less, 3000 m or less, or 1000 m or less can be suitably used.

The substrate 2 is a support film formed into a tape shape and supporting the adhesive layer 4. Examples of the substrate 2 include PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), and PTFE (Polytetrafluoroethylene). In addition, the substrate 2 can be preferably one in which at least the surface on the adhesive layer 4 side has been subjected to a release treatment, for example, with a silicone resin.

The thickness of the substrate 2 is not particularly limited. The lower limit of the thickness of the substrate 2 is preferably 10 μm or more in order to separate it from the adhesive layer 4, more preferably 25 μm or more, and even more preferably 38 μm or more. The upper limit of the thickness of the substrate 2 is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 75 μm or less, because if the substrate 2 is too thick, there is a concern that excessive pressure will be applied to the adhesive layer 4. It may also be 50 μm or less.

The width of the substrate 2 is not particularly limited. The lower limit of the width of the substrate 2 is preferably 1 mm or more for winding purposes, more preferably 2 mm or more, and even more preferably 4 mm or more. The upper limit of the substrate width may be 250 mm or less, preferably 120 mm or less, more preferably 60 mm or less, and even more preferably 10 mm or less, because if the substrate width is too large, it may be difficult to carry or handle. The width of the substrate 2 may be appropriately adjusted based on the arrangement pattern of the arrangement elements 6. From the viewpoint of productivity, it is preferable that the width of the substrate 2 and the width of the adhesive layer 4 are the same, and that the ends in the width direction are aligned.

[Adhesive layer]
The adhesive layer 4 supported by the substrate 2 is a connection film used for conductive connection between the first electronic component 10 and the second electronic component. The curing type of the adhesive layer 4 is not particularly limited, and examples thereof include a heat curing type, a photocuring type, and a combined photo-and-thermal curing type. The adhesive layer 4 may also be a hot melt type using a thermoplastic resin.

The following description will be given by taking an anisotropic conductive film in which an aggregate 5 of conductive particles 3 is contained in an insulating binder as an example. The lower limit of the thickness of the anisotropic conductive film may be, for example, the same as the conductive particle diameter, and may be preferably 1.3 times or more the conductive particle diameter or 10 μm or more. The upper limit of the thickness of the anisotropic conductive film may be, for example, 40 μm or less or 2 times or less the conductive particle diameter. The anisotropic conductive film may be laminated with an insulating adhesive layer or pressure-sensitive adhesive layer that does not contain conductive particles 3, and the number of layers and the lamination surface can be appropriately selected according to the target or purpose. The insulating resin of the insulating adhesive layer or pressure-sensitive adhesive layer may be the same as that of the anisotropic conductive film. As described above, the conductive particle aggregate 5 may be dispersed in the resin or may be aligned. When the conductive particle aggregate 5 is dispersed in the resin, it may be in close contact with the conductive particle aggregate 5, or may be individually spaced apart without contacting with the conductive particle aggregate 5.

　A known insulating binder can be used as the insulating binder (insulating resin). Examples of the curing type include a heat-curing type, a photocuring type, and a combined photo- and heat-curing type. Examples include a photoradical polymerization type resin composition containing a (meth)acrylate compound and a photoradical polymerization initiator, a thermal radical polymerization type resin composition containing a (meth)acrylate compound and a thermal radical polymerization initiator, a thermal cationic polymerization type resin composition containing an epoxy compound and a thermal cationic polymerization initiator, and a thermal anionic polymerization type resin composition containing an epoxy compound and a thermal anionic polymerization initiator. Also, a known adhesive composition may be used. In the case of a hot melt type, the composition disclosed in JP 2014-060025 A can be used.

Below, as a specific example, a thermal radical polymerization type insulating binder containing a film-forming resin, an elastomer, a (meth)acrylic monomer, a polymerization initiator, and a silane coupling agent will be described. Note that the (meth)acrylic monomer includes both acrylic monomers and methacrylic monomers.

The film-forming resin is not particularly limited, and examples thereof include phenoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, etc. The film-forming resin may be used alone or in combination of two or more types. Among these, it is particularly preferable to use phenoxy resin from the viewpoints of film-forming property, processability, and connection reliability. Phenoxy resin is a resin synthesized from bisphenol A and epichlorohydrin, and an appropriately synthesized product or a commercially available product may be used. There is no particular limit to the content of the film-forming resin, and it is preferable that it is, for example, 10% by mass to 60% by mass.

The elastomer is not particularly limited, and examples include polyurethane resin (polyurethane-based elastomer), acrylic rubber, silicone rubber, butadiene rubber, etc.

The (meth)acrylic monomer is not particularly limited, and may be, for example, a monofunctional (meth)acrylic monomer or a polyfunctional (meth)acrylic monomer having two or more functionalities. From the viewpoint of stress relaxation of the polymer, it is preferable that 80 mass% or more of the (meth)acrylic monomers in the insulating binder are monofunctional (meth)acrylic monomers.

In addition, from the viewpoint of adhesion, it is preferable that the monofunctional (meth)acrylic monomer has a carboxylic acid. Furthermore, the molecular weight of the monofunctional (meth)acrylic monomer having a carboxylic acid is preferably 100 to 500, and more preferably 200 to 350. Furthermore, the content of the monofunctional (meth)acrylic monomer having a carboxylic acid in the insulating binder is preferably 3% by mass to 20% by mass, and more preferably 5% by mass to 10% by mass.

The polymerization initiator is not particularly limited as long as it can cure the (meth)acrylic monomer at the specified temperature during thermocompression bonding, and examples thereof include organic peroxides. Examples of organic peroxides include lauroyl peroxide, butyl peroxide, benzyl peroxide, dilauroyl peroxide, dibutyl peroxide, peroxydicarbonate, and benzoyl peroxide. These may be used alone or in combination of two or more. There is no particular limit to the content of the polymerization initiator in the insulating binder, and it is preferable that it is, for example, 0.5% by mass to 15% by mass.

There are no particular limitations on the silane coupling agent, and examples of the silane coupling agent include epoxy-based silane coupling agents, acrylic-based silane coupling agents, thiol-based silane coupling agents, and amine-based silane coupling agents. There are no particular limitations on the content of the silane coupling agent in the insulating binder, and it is preferable that the content be, for example, 0.1% by mass to 5.0% by mass.

[Conductive particles]
The conductive particles 3 can be appropriately selected from those used in known anisotropic conductive films. Examples of the conductive particles 3 include metal particles such as nickel, copper, silver, gold, and palladium, and metal-coated resin particles in which the surfaces of resin particles such as polyamide and polybenzoguanamine are coated with a metal such as nickel. The surface may be insulated to such an extent that the conductive performance is not hindered. The surface shape may also have protrusions. In addition, as the conductive particles 3, particles having good properties such as solder particles but large particle size variations may be used. This is because the conductive adhesive film 1 according to the present technology does not treat the conductive particles 3 as a single particle, but as a conductive particle aggregate 5. The particle size of the solder particles is not particularly limited, but type 5 (particle diameter 15 to 25 μm) is preferable. In addition, the type of solder particles is not particularly limited, and various solder particles such as tin, tin-bismuth, tin-bismuth-copper, indium, and tin-indium can be used.

The particle diameter of the conductive particles 3 is not particularly limited, but the lower limit of the particle diameter is preferably 2 μm or more, and the upper limit of the particle diameter is preferably 50 μm or less, for example, from the viewpoint of the thickness of the adhesive layer 4, and more preferably 20 μm or less. The particle diameter of the conductive particles 3 can be a value measured by an image type particle size distribution meter (for example, FPIA-3000: manufactured by Malvern Instruments). The number is preferably 1000 or more, and more preferably 2000 or more.

Particle aggregates/array elements
A plurality of conductive particles 3 aggregate to form conductive particle aggregates 5. The conductive particle aggregates 5 can be formed by providing openings 34 having an opening diameter twice or more larger than the average particle diameter of the conductive particles 3 in a mask 33 described below, and filling the adhesive layer 4 with the conductive particles 3 through the openings 34. For example, conductive particles 3 having a diameter of 20 μm are filled into openings 34 having an opening diameter of 80 μm to obtain conductive particle aggregates 5 having a diameter of 80 μm.

The aggregate diameter of the conductive particle aggregate 5 is not particularly limited, but the lower limit is preferably at least twice the particle diameter of the conductive particle 3. In addition, the upper limit of the aggregate diameter of the conductive particle aggregate 5 is preferably three times or less, and more preferably four times or less, from the viewpoint of the capture efficiency of the conductive particle aggregate 5 in the connector and the insulation resistance between adjacent electrodes. For example, when the particle diameter is 2 μm, the lower limit of the aggregate diameter is preferably 4 μm or more, and the upper limit of the aggregate diameter is preferably 6 μm or less, and more preferably 8 μm or less. In addition, when the particle diameter is 20 μm, the lower limit of the aggregate diameter is preferably 40 μm or more, and the upper limit of the aggregate diameter is preferably 60 μm or less, and more preferably 80 μm or less. The aggregate diameter of the conductive particle aggregate 5 can also be measured in the same manner as the particle diameter of the conductive particle 3. The number of particles measured is preferably 5 or more, and more preferably 10 or more.

As described above, one or more conductive particle aggregates 5 gather together to form an array element 6. The conductive particle aggregates 5 in each array element 6 may be densely packed or individually spaced apart, or may be aligned. There are no particular limitations on the alignment pattern, and it may be striped or lattice-like, with a hexagonal lattice pattern being preferred.

The array pattern of the array elements 6 corresponds to the array pattern of the electrodes 11 of the first electronic component 10, and are arranged in the same direction and at the same pitch as the array pattern of the electrodes 11. The array elements 6 are aligned with the electrodes 11 of the first electronic component 10, so that a large number of conductive particle aggregates 5 are superimposed over the entire surface of the electrode 11, or one or more conductive particle aggregates 5 are dispersed or aligned within the electrode 11.

[Conductive adhesive film manufacturing process]
Next, a description will be given of a manufacturing process of the conductive adhesive film 1. The manufacturing process of the conductive adhesive film 1 is a manufacturing method of a conductive adhesive film having a substrate 2 and an adhesive layer 4 that is provided on one surface of the substrate 2 and contains conductive particles 3, and includes an arrangement step of arranging arrangement elements 6 made of particle aggregates 5 formed by aggregating a plurality of conductive particles 3 on the adhesive layer 4 in a predetermined arrangement pattern corresponding to the electrode arrangement of the first electronic component 10 to which the conductive adhesive film 1 is attached. In the arrangement step, the arrangement elements 6 are provided by printing the conductive particles 3 on the adhesive layer 4 through a mask 33 having predetermined openings 34.

The adhesive layer 4 can be provided on the substrate 2 by applying an adhesive resin composition such as the insulating binder described above onto the substrate 2 such as a PET film, and drying it at a predetermined temperature.

In the adhesive layer 4 supported by the substrate 2, array elements 6 consisting of conductive particle aggregates 5 are arranged in a predetermined array pattern. A known metal mask 33a can be used as the mask 33 used in this arraying process (see FIG. 14). By making the opening diameter of the openings 34 of the mask 33 200% or more of the average particle diameter of the conductive particles 3, the conductive particles 3 can be filled into the adhesive layer 4 through the openings 34 to form the conductive particle aggregates 5. In addition, by using a rotary screen 33b as the mask 33, the array elements 6 can be formed continuously in the longitudinal direction of the adhesive layer 4 (see FIG. 15).

The processing of the openings 34 for arranging the conductive particle aggregates 5 can be performed easily and at low cost, and it is possible to prepare a mask 33 corresponding to a predetermined arrangement pattern corresponding to the electrode arrangement of various first electronic components 10. It is also easy to adjust the area of the arrangement elements 6 in anticipation of misalignment with the fine-pitch electrode pattern.

When dividing the adhesive layer 4 provided with the array elements 6, the conductive adhesive film 1 is subjected to half-cutting, punching, punch press, or the like to form the predetermined individual pieces 8. Also, only the adhesive layer 4 on the substrate 2 may be processed and removed. Furthermore, a step of providing a cover film on the adhesive layer 4 may be provided. Therefore, the substrate 2 and the adhesive layer 4 may be processed as described above, using the cover film as a support (substitute for the substrate 2). As described above, the substrate 2 is peeled off (separated) from the adhesive layer 4 during use, so the processing technique is highly difficult. The material of the cover film may be the same as that of the substrate 2 described above. It is preferable that the thickness is thinner than that of the substrate 2.

[Connector]
A connection body 40 to which the present technology is applied is formed by connecting a first electronic component 10 and a second electronic component 12 via a conductive adhesive film 1. In this specification, of the first and second electronic components 10 and 12 that are joined to each other, the electronic component to which the conductive adhesive film 1 is attached is referred to as the first electronic component 10.

[First Electronic Component/Second Electronic Component]
The first electronic component 10 and the second electronic component 12 are not particularly limited and can be appropriately selected depending on the purpose. Examples of the first electronic component 10 include a ceramic substrate, a rigid substrate, a flexible substrate (FPC: Flexible Printed Circuits), a glass substrate, a plastic substrate, a resin multilayer substrate, an IC (Integrated Circuit) module, an IC chip, etc. Examples of the second electronic component 12 include a ceramic substrate, a rigid substrate, a flexible substrate (FPC: Flexible Printed Circuits), a glass substrate, a plastic substrate, a resin multilayer substrate, etc.

The connector and manufacturing method thereof according to the present technology can be used in any electronic device that uses electrical connections and manufacturing methods thereof, such as semiconductor devices (including driver ICs, as well as all devices that use semiconductors, such as optical elements, thermoelectric conversion elements, and photoelectric conversion elements), display devices (monitors, televisions, head-mounted displays, etc.), mobile devices (tablet devices, smartphones, wearable devices, etc.), game consoles, audio equipment, imaging devices (using image sensors such as camera modules), electrical mounting for vehicles (mobile devices), medical equipment, sensor devices (touch sensors, fingerprint authentication, iris authentication, etc.), and home appliances.

[Manufacturing process of connector]
The manufacturing process of the connector 40 includes a placement process of attaching the conductive adhesive film 1 onto the first electronic component 10, and a connection process of placing the second electronic component 12 on the conductive adhesive film 1 and connecting the first electronic component 10 and the second electronic component 12 via the conductive adhesive film 1.

[Placement process]
FIG. 16 is a cross-sectional view showing the arrangement step of arranging the conductive adhesive film 1 on the first electronic component 10, and FIG. 17 is a cross-sectional view showing the state in which the substrate 2 is peeled off from the adhesive layer 4 in the arrangement step. In the arrangement step, the electrodes 11 of the first electronic component 10 and the arrangement elements 6 are aligned, and the adhesive layer 4 of the conductive adhesive film 1 is attached to the first electronic component 10. For example, a bonding device is used to press the conductive adhesive film 1 from the substrate 2 side, and the adhesive layer 4 is attached to the mounting surface of the first electronic component 10 on the stage. When the adhesive layer 4 is provided in a plurality of pieces on one substrate, such as when the adhesive layer 4 is divided into individual pieces, the plurality of pieces 8 may be attached to the electronic component 10 all at once, or each individual piece 8 may be attached. The conductive adhesive film 1 to which the adhesive layer 4 has been transferred is wound up with only the substrate 2.

[Connection process]
Next, the second electronic component 12 is placed on the adhesive layer 4, and the first electronic component 10 and the second electronic component 12 are connected via the conductive adhesive film 1 (see FIG. 2). The second electronic component 12 has electrodes 13 arranged in a pattern corresponding to the arrangement pattern of the electrodes 11 of the first electronic component 10. In the connection step, the electrodes 13 of the second electronic component 12 and the electrodes 11 of the first electronic component 10 are aligned, and the second electronic component 12 is mounted on the first electronic component 10 via the adhesive layer 4.

FIG. 18 is a cross-sectional view showing the connection process of connecting the second electronic component 12 to the first electronic component 10 via the adhesive layer 4. As shown in FIG. 18, in the connection process, for example, a crimping tool 42 is used to press the electrodes 11 of the first electronic component 10 and the electrodes 13 of the second electronic component 12 via a buffer material 41. Depending on the curing type of the adhesive layer 4, heating, light irradiation, etc. are performed to cure the adhesive layer 4, and the first electronic component 10 and the second electronic component 12 are connected.

FIG. 19 is a cross-sectional view showing a connector 40 that connects a first electronic component 10 and a second electronic component 12 via a cured film 4a formed by curing an adhesive layer 4. As shown in FIG. 19, in the connector 40, the electrode 11 of the first electronic component 10 and the electrode 13 of the second electronic component 12 are electrically connected via the conductive particle agglomerates 5 that constitute the array elements 6, and there are no conductive particle agglomerates 5 between adjacent electrodes in amounts sufficient to cause a short circuit.

First Example
Examples of the present technology are described below. In the first example, a connection was produced using an anisotropic conductive film as the adhesive layer of a conductive adhesive film, and the respective conductive characteristics (conductive resistance between connecting electrodes, insulation resistance between adjacent electrodes) were measured and evaluated when there was no misalignment between the anisotropic conductive film and the evaluation substrate and when there was misalignment.

[Preparation of connector]
20, a camera module evaluation substrate 10 (ceramic substrate, width 6.0 mm, width of mounting surface of terminal row 1.0 mm, electrode width 200 μm, electrode length 500 μm, line:space=1:1, terminal thickness 10 μm, Ni(base)/Au(surface) plating, cavity structure, terminal rows on two opposing sides) and an FPC 12 (polyimide film, 400 μm pitch, line:space=1:1, terminal thickness 12 μm, Ni(base)/Au(surface) plating) were thermocompression bonded via anisotropic conductive film 4 to produce a connector 40. Thermocompression bonding was performed by pressing a tool 42 down from the FPC side via a 200 μm thick silicone rubber 41 under the conditions of temperature: 130° C., pressure: 1 MPa, and time: 6 sec.

Figure 20(A) is a perspective view showing the evaluation substrate 10, Figure 20(B) is a perspective view showing the state where an anisotropic conductive film 4 is attached onto the electrode 11 of the evaluation substrate 10, Figure 20(C) is a perspective view showing the state where an FPC 12 is placed on the evaluation substrate 10 with the anisotropic conductive film 4 attached, Figure 20(D) is a perspective view showing the process of pressing the FPC 12 from above with a crimping tool 42 via silicone rubber 41, and Figure 20(E) is a perspective view showing a connection sample 40 in which the FPC 12 is connected to the evaluation substrate 10 by the anisotropic conductive film 4.

[Evaluation of Conduction Characteristics]
Using a digital multimeter (manufactured by Yokogawa Electric Corporation), the conductive resistance between the connection electrodes of the connector and the insulation resistance between adjacent electrodes were measured when a current of 1 mA was applied using a four-terminal method. Measurements were performed on the connector at the initial connection stage and on the connector after a reliability evaluation test under conditions of a temperature of 121°C, humidity of 100%, and atmospheric pressure of 2 atm for 24 hours. The conductive resistance of 10 connector samples was measured (N=10), and the sample with the highest resistance was used for evaluation.

Example 1
[Preparation of anisotropic conductive film]
Five parts by mass of resin core conductive particles (Ni (undercoat)/Au (surface) plating, resin core) having an average particle size of 20 μm and 95 parts by mass of an insulating binder consisting of the following components were prepared. The insulating binder was put into a planetary stirring device (product name: Awatori Rentaro, manufactured by THINKY Co., Ltd.) and stirred for 1 minute to prepare an adhesive composition. The adhesive composition was then applied onto a PET film having a thickness of 50 μm and dried in an oven at 80° C. for 5 minutes to form an adhesive layer consisting of the adhesive composition on the PET film, thereby preparing an insulating adhesive layer having a width of 6.0 mm and a thickness of 25 μm. Conductive particles were densely assembled and arranged on this insulating adhesive layer via a metal mask having an opening pattern corresponding to the electrode pattern formed on the evaluation substrate 10, and an array element consisting of conductive particle aggregates having an average particle size of 80 μm was formed. In Example 1, an anisotropic conductive film was used in which array elements 6 having the same shape as the electrodes 11 formed on the evaluation substrate 10 were arranged in accordance with the electrode pattern of the evaluation substrate 10 .

The insulating binder was a mixed solution of ethyl acetate and toluene containing 47 parts by mass of phenoxy resin (product name: YP-50, manufactured by Shin-Nikka Epoxy Manufacturing Co., Ltd.), 3 parts by mass of monofunctional monomer (product name: M-5300, manufactured by Toagosei Co., Ltd.), 25 parts by mass of urethane resin (product name: UR-1400, manufactured by Toyobo Co., Ltd.), 15 parts by mass of rubber component (product name: SG80H, manufactured by Nagase ChemteX Corporation), 2 parts by mass of silane coupling agent (product name: A-187, manufactured by Momentive Performance Materials Japan), and 3 parts by mass of organic peroxide (product name: Niper BW, manufactured by NOF Corporation) at a solid content of 50% by mass.

Example 2
In Example 2, an anisotropic conductive film was produced under the same conditions as Example 1, except that an arrangement element 6 was formed and arranged so that one conductive particle aggregate (average particle size 80 μm) was positioned at the center of the electrode width for an electrode 11 formed on an evaluation substrate 10, as shown in Figure 6 (A).

Example 3
In Example 3, as shown in Figure 7 (A), an anisotropic conductive film was produced under the same conditions as Example 1, except that an arrangement element 6 was formed and arranged so that two conductive particle aggregates (average particle size 80 μm) were arranged in parallel in the center of the electrode width and in the electrode length direction for an electrode 11 formed on an evaluation substrate 10.

<Comparative Example 1>
In Comparative Example 1, 5 parts by mass of resin core conductive particles (Ni (undercoat) / Au (surface) plating, resin core) with an average particle size of 20 μm and 95 parts by mass of an insulating binder consisting of the following components were added to a planetary mixing device (product name: Awatori Rentaro, manufactured by THINKY Co., Ltd.) and stirred for 1 minute to prepare an anisotropic conductive adhesive composition. The anisotropic conductive adhesive composition was then applied to a PET film with a thickness of 50 μm and dried in an oven at 80° C. for 5 minutes to form an adhesive layer consisting of the anisotropic conductive adhesive composition on the PET film, thereby preparing a dispersion-type anisotropic conductive film with a width of 6.0 mm and a thickness of 25 μm. The conductive particles were mixed so that the particle density was 300 pieces/mm ^2. The insulating binder was the same as in Example 1.

<Comparative Example 2>
In Comparative Example 2, a resin plate with recesses arranged in a hexagonal lattice pattern was prepared, the recesses were filled with conductive particles (average particle size 20 μm), and the conductive particles were transferred to an insulating adhesive layer prepared in the same manner as in Example 1, thereby producing an aligned anisotropic conductive film in which the conductive particles were arranged in a hexagonal lattice pattern over the entire surface. The conductive particles were aligned to a particle density of 600 particles/ ^mm2 .

<Comparative Example 3>
In Comparative Example 3, a method similar to that of Example 1 was used to produce an anisotropic conductive film in which agglomerates of conductive particles with an average particle size of 20 μm (average particle size 80 μm) were arranged in a hexagonal lattice pattern over the entire surface of the insulating adhesive layer.

[Initial connection]
First, the results of evaluation of the electrical continuity characteristics at the initial stage of connection immediately after the connection body was fabricated will be described.

[Insulation resistance between adjacent electrodes (no misalignment)]

Table 1 shows the results of measuring the occurrence of short circuits between adjacent electrodes when the space between adjacent electrodes was set to 20 μm, 40 μm, 90 μm, and 200 μm. No misalignment occurred between adjacent electrodes on the anisotropic conductive film and the evaluation substrate 10. An insulation resistance of 10 ⁸ Ω or more was rated as ○ (no short circuit), and an insulation resistance of less than 10 ⁸ Ω was rated as × (short circuit).

As shown in Table 1, in the connections according to Examples 1 to 3, the array elements could be arranged on the electrodes 11 of the evaluation substrate 10, and no short circuit occurred between adjacent electrodes regardless of the width of the space between adjacent electrodes. On the other hand, in Comparative Example 1, which was made of an anisotropic conductive adhesive composition with conductive particles dispersed over the entire surface as the anisotropic conductive film, a short circuit occurred when the space between adjacent electrodes was 40 μm or less. In Comparative Example 2, in which the anisotropic conductive film was made of conductive particles densely aligned over the entire surface of the adhesive layer, a short circuit occurred when the space between adjacent electrodes was 20 μm, which was less than the particle diameter. Furthermore, in Comparative Example 3, in which conductive particle aggregates were aligned over the entire surface of the adhesive layer, a short circuit occurred when the space between adjacent electrodes was 40 μm or less, which was smaller than the diameter of the conductive particle aggregate.

[Conductivity resistance between connection electrodes]

Table 2 shows the results of measuring the conductive resistance between the connection electrodes in a connection formed by causing misalignment between the electrodes of the anisotropic conductive film and the evaluation substrate. A conductive resistance of 50 mΩ or less was rated as ○○ (excellent), between 50 mΩ and 100 mΩ and less than ○ (good), between 100 mΩ and 120 mΩ and less than △ (passable), and over 120 mΩ (poor). Note that in Comparative Examples 1 to 3, since conductive particles or conductive particle aggregates are dispersed or aligned over the entire surface of the adhesive layer, there is no need to align the positions of the array elements and the electrodes of the evaluation substrate as in Examples 1 to 3, and therefore no misalignment occurs, so these are meant as reference examples.

As shown in Table 2, in Example 1, when the array elements formed with a width of 200 μm were misaligned by 200 μm, the conductive particle aggregates were not captured, resulting in poor conductivity. In Example 2, when the 200 μm-wide electrode was misaligned by 100 μm from the center in the width direction, only about half of the conductive particle aggregates were captured, resulting in high conductivity resistance, and when the array elements were misaligned by 120 μm, the conductive particle aggregates were not captured, resulting in poor conductivity. In Example 3, the array elements were configured so that two conductive particle aggregates were arranged for one electrode, so conductivity was ensured up to a misalignment of 120 μm, but when the array elements were misaligned by 140 μm, the conductive particle aggregates were not captured, resulting in poor conductivity.

[Insulation resistance between adjacent electrodes (with misalignment)]

Table 3 shows the results of measuring the insulation resistance between adjacent electrodes in a connection formed by causing misalignment between the electrodes of the anisotropic conductive film and the evaluation substrate. An insulation resistance of 10 ⁸ Ω or more was rated as ○ (no short circuit), and an insulation resistance of less than 10 ⁸ Ω was rated as × (short circuit). Note that in Comparative Examples 1 to 3, since conductive particles or conductive particle aggregates are dispersed or aligned over the entire surface of the adhesive layer, there is no need to align the positions of the array elements and the electrodes of the evaluation substrate as in Examples 1 to 3, and therefore no misalignment occurs, and therefore these are meant as reference examples.

As shown in Table 3, in Example 1, when the array elements formed with a width of 200 μm were misaligned to 200 μm, the same as the space width between adjacent electrodes, a short circuit occurred. In Examples 2 and 3, no short circuit occurred even when the elements were misaligned to 200 μm.

[Reliability test]
Next, the evaluation results of the electrical conductivity of the connector after the reliability test will be described. The reliability test was performed under the conditions of a temperature of 121° C., humidity of 100%, and atmospheric pressure of 2 atm for 24 hours. The electrical conductivity resistance between the connection electrodes and the insulation resistance between adjacent electrodes in the connector were measured in the same manner as in the initial connection. The evaluation criteria were the same as in the initial connection.

[Insulation resistance between adjacent electrodes (no misalignment)]

Table 4 shows the results of measuring whether or not short circuits occurred between adjacent electrodes when the spacing between adjacent electrodes was set to 20 μm, 40 μm, 90 μm, and 200 μm. No misalignment occurred between the adjacent electrodes on the anisotropic conductive film and the evaluation substrate.

As shown in Table 4, in the connections of Examples 1 to 3, the array elements could be arranged on the electrodes of the evaluation board, and even after the reliability test, no short circuits occurred, regardless of the width of the space between adjacent electrodes. On the other hand, in the connections of Comparative Examples 1 to 3, short circuits occurred, just as they did at the beginning of the connection. Furthermore, in Comparative Example 3, in which the conductive particle aggregates were aligned over the entire surface of the adhesive layer, short circuits occurred even when the space between adjacent electrodes was 90 μm, which was larger than the diameter of the conductive particle aggregates, and the insulation between adjacent electrodes deteriorated after the reliability test.

[Conductivity resistance between connection electrodes]

Table 5 shows the results of measuring the electrical resistance between connection electrodes in a connection formed by causing misalignment between the electrodes of the anisotropic conductive film and the evaluation substrate. Note that in Table 5, Comparative Examples 1 to 3 are also meant as reference examples.

As shown in Table 5, in Example 1, similar to the initial connection, when the array elements formed with a width of 200 μm were misaligned by less than 200 μm, the conductive particle aggregates were captured, but when the misalignment reached 200 μm, the conductive particle aggregates were not captured, resulting in poor electrical continuity. In Example 2, when the array elements were misaligned by less than 100 μm from the center of the width direction of the 200 μm-wide electrode, the conductive particle aggregates were captured, but when the misalignment reached 100 μm or more, the conductive particle aggregates were not captured, resulting in poor electrical continuity. In Example 3, when the array elements were misaligned by less than 120 μm, the conductive particle aggregates were captured, but when the misalignment reached 120 μm or more, the conductive particle aggregates were not captured, resulting in poor electrical continuity.

[Insulation resistance between adjacent electrodes (with misalignment)]

Table 6 shows the results of measuring the insulation resistance between adjacent electrodes in a connection formed by causing misalignment between the electrodes of the anisotropic conductive film and the evaluation substrate. Note that in Table 6, Comparative Examples 1 to 3 are also meant as reference examples.

As shown in Table 6, in Example 1, the array elements formed with a width of 200 μm did not cause short circuits until the misalignment reached 140 μm or less, but a short circuit occurred when the misalignment reached 180 μm. In Examples 2 and 3, no short circuits occurred even when the misalignment reached 200 μm.

Second Example
Next, a second example will be described. In the second example, conductive particles and anisotropic conductive films with different blending amounts of conductive particles were produced, and a connection sample 40 was produced in which an FPC 12 was connected to an evaluation substrate 10 using this anisotropic conductive film, and the conduction performance (conductive resistance between connection electrodes, insulation resistance between adjacent electrodes) was measured and evaluated. The evaluation substrate 10 and FPC 12 were the same as those in the first example.

The conduction resistance between the connecting electrodes was measured at the initial connection and after a reliability test. The reliability test conditions were the same as in the first embodiment. The measurement method and evaluation criteria for the conduction resistance between the connecting electrodes were also the same as in the first embodiment. The insulation resistance between adjacent electrodes was measured to see whether or not a short circuit occurred between adjacent electrodes when the space between the adjacent electrodes was set to 20 μm, 40 μm, and 80 μm. The measurement method and evaluation criteria for the insulation resistance between adjacent electrodes were also the same as in the first embodiment.

Example 4
In Example 4, a connection sample 40 was produced in which an FPC 12 was connected to an evaluation substrate 10 using the same anisotropic conductive film as in Example 1. There was no misalignment between the array elements 6 and the electrodes 11. The connection process was the same as in Example 1, except that the hot pressurization conditions of the tool were 130° C., 2 MPa, and 6 seconds.

Example 5
In Example 5, connection sample 40 was produced under the same conditions as in Example 4, except that solder particles with an average particle size of 20 μm were used as the conductive particles.

<Comparative Example 4>
In Comparative Example 4, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example 1 described above, except that the conductive particles were mixed so that the particle density was 150 particles/ ^mm2 . The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130°C, 2 MPa, and 6 seconds.

<Comparative Example 5>
In Comparative Example 5, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example 1. The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130° C., 2 MPa, and 6 seconds.

<Comparative Example 6>
In Comparative Example 6, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example 1, except that the conductive particles were mixed so that the particle density was 600 particles/ ^mm2 . The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130°C, 2 MPa, and 6 seconds.

<Comparative Example 7>
In Comparative Example 7, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example 2. The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130° C., 2 MPa, and 6 seconds.

<Comparative Example 8>
In Comparative Example 8, solder particles with an average particle size of 20 μm were used as the conductive particles, and were mixed so that the particle density was 150 particles/ ^mm2 . Except for this, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example 1 described above. The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130° C., 2 MPa, and 6 seconds.

<Comparative Example 9>
In Comparative Example 9, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example ⁸ described above, except that the particle density was adjusted to 300 particles/mm2. The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130°C, 2 MPa, and 6 seconds.

<Comparative Example 10>
In Comparative Example 9, a connection sample 40 was produced using the same anisotropic conductive film as in Comparative Example ⁸ described above, except that the particle density was adjusted to 600 particles/mm2. The connection process was the same as in the first example, except that the hot pressurization conditions of the tool were 130°C, 2 MPa, and 6 seconds.

As shown in Table 7, in Example 4, the array elements are formed with the same width as the electrode width, so the conductive resistance between the connection electrodes at the initial connection stage was evaluated as ○ (good). However, after the reliability test, the conductive resistance between the connection electrodes was evaluated as △ (fair). This is a phenomenon caused by the repulsion of the resin core of the conductive particles. In Example 5, in which the array elements are formed with the same width as the electrode width using solder particles, the conductive resistance between the connection electrodes at the initial connection stage and after the reliability test were both evaluated as ○○ (excellent). This shows that the anisotropic conductive film using solder particles as the conductive particles has excellent conductivity even at the initial connection stage and after the reliability test.

On the other hand, in Comparative Examples 4 to 10, the conductive resistance between the connection electrodes at the initial stage of connection was evaluated as ○○ (excellent), ○ (good), or △ (passable), but after the reliability test, it was evaluated as × (poor) except for Comparative Examples 8 to 10, which used solder particles.

Furthermore, in Examples 4 and 5, the array elements could be arranged on the electrodes of the evaluation board, and the insulation resistance between adjacent electrodes was evaluated as ○ (no short circuit) regardless of the width of the space between adjacent electrodes.

On the other hand, in Comparative Examples 4 to 10, the evaluation of the insulation resistance between adjacent electrodes deteriorated as the space between adjacent electrodes narrowed, and when the space between adjacent electrodes was 20 μm, all samples were rated × (short circuit occurred).

<Third Example>
Next, a third embodiment will be described. In the third embodiment, a connection sample 40 was produced by connecting an FPC 12 to an evaluation substrate 10 using the anisotropic conductive film used in the second embodiment, and the conductive performance (conductive resistance between connection electrodes, insulation resistance between adjacent electrodes) was measured and evaluated. The size of each electrode of the evaluation substrate 10 and the FPC 12 was 150 μm in width and 100 μm in length. That is, in the third embodiment, electrodes smaller in size were used compared to the second embodiment.

The conduction resistance between the connecting electrodes was measured at the initial connection and after a reliability test. The reliability test conditions were the same as in the first embodiment. The measurement method and evaluation criteria for the conduction resistance between the connecting electrodes were also the same as in the first embodiment. The insulation resistance between adjacent electrodes was measured to see whether or not a short circuit occurred between adjacent electrodes when the space between the adjacent electrodes was set to 20 μm, 40 μm, and 80 μm. The measurement method and evaluation criteria for the insulation resistance between adjacent electrodes were also the same as in the first embodiment.

As shown in Table 8, the evaluation of the electrical conduction resistance between the connection electrodes at the initial connection and after the reliability test for Examples 4 and 5 was the same as that for Example 2 (Table 7), and it can be seen that the electrical conduction performance is stable even when the electrode size is narrowed.

On the other hand, in Comparative Examples 4 to 10, except for Comparative Examples 9 and 10, the conductive resistance between the connection electrodes at the initial stage of connection was evaluated as △ (passable), and after the reliability test it was evaluated as × (poor).

Furthermore, in Examples 4 and 5, the array elements could be arranged on the electrodes of the evaluation board, and the insulation resistance between adjacent electrodes was evaluated as ○ (no short circuit) regardless of the width of the space between adjacent electrodes.

On the other hand, in Comparative Examples 4 to 10, the evaluation of the insulation resistance between adjacent electrodes deteriorated as the space between adjacent electrodes narrowed, and when the space between adjacent electrodes was 20 μm, all samples were rated × (short circuit occurred).

1 Conductive adhesive film, 2 Substrate, 3 Conductive particles, 4 Adhesive layer, 5 Conductive particle aggregate, 6 Array element, 8 Piece, 10 First electronic component, 11 Electrode, 12 Second electronic component, 21 First terminal row, 22 Second terminal row, 23 Third terminal row, 30 Film roll, 31 Roll core, 33 Mask, 34 Opening, 40 Connection body, 41 Cushioning material, 42 Crimping tool

Claims (10)

A substrate;
A conductive adhesive film having an adhesive layer containing conductive particles and provided on one surface of the substrate,
the conductive particles contained in the adhesive layer constitute a particle aggregate formed by aggregating a plurality of the conductive particles,
the adhesive layer has array elements made of the particle aggregates arranged in a predetermined array pattern corresponding to the electrode array of an electronic component to which the conductive adhesive film is attached;
Conductive adhesive film. The conductive adhesive film according to claim 1, wherein the array elements constituting the array pattern are made up of one or more of the particle aggregates. the array elements constituting the array pattern are each composed of a plurality of the particle aggregates,
The conductive adhesive film according to claim 1 , wherein the arrangement elements are formed by assembling, dispersing or aligning a plurality of the particle aggregates. The conductive adhesive film according to any one of claims 1 to 3, wherein the area of the array elements is equal to or less than the area of the electrodes that make up the electrode array. The conductive adhesive film according to any one of claims 1 to 3, wherein the width of the array elements is 40% to 100% of the width of the electrodes when the arrangement direction of the array elements in the array pattern is the width direction of the array elements and the arrangement direction of the electrodes in the electrode array is the width direction of the electrodes. A method for producing a conductive adhesive film having a substrate and an adhesive layer containing conductive particles and provided on one surface of the substrate, comprising:
an arrangement step of arranging, on the adhesive layer, arrangement elements each made of a particle aggregate formed by aggregating a plurality of the conductive particles in a predetermined arrangement pattern corresponding to an electrode arrangement of an electronic component to which the conductive adhesive film is attached;
The arranging step includes providing the conductive particles on the adhesive layer through a mask having a predetermined opening.
A method for producing a conductive adhesive film. The method for manufacturing a conductive adhesive film according to claim 6, wherein the arranging step uses a metal mask or a rotary screen as the mask to provide the conductive particles in the adhesive layer. The method for manufacturing a conductive adhesive film according to claim 6 or 7, wherein the opening diameter of the mask is 200% or more of the average particle diameter of the conductive particles. A connection body in which a first electronic component and a second electronic component are connected via a cured film of an adhesive layer containing a plurality of conductive particles of a conductive adhesive film,
The conductive adhesive film is
A substrate;
an adhesive layer provided on one surface of the base material and containing conductive particles;
the conductive particles contained in the adhesive layer constitute a particle aggregate formed by aggregating a plurality of the conductive particles,
the adhesive layer has array elements made of the particle aggregates arranged in a predetermined array pattern corresponding to the electrode array of the first electronic component to which the conductive adhesive film is attached;
Connection body. A placement step of attaching a conductive adhesive film containing a plurality of conductive particles onto a first electronic component;
a connecting step of connecting the first electronic component and the second electronic component via the conductive adhesive film,
The conductive adhesive film is
The adhesive layer includes a substrate and an adhesive layer that is provided on one surface of the substrate and contains conductive particles.
the conductive particles contained in the adhesive layer constitute a particle aggregate formed by aggregating a plurality of the conductive particles,
the adhesive layer has array elements made of the particle aggregates arranged in a predetermined array pattern corresponding to an electrode array of the first electronic component to which the conductive adhesive film is attached,
In the arranging step, the electrodes of the first electronic component and the array elements are aligned, and the conductive adhesive film is attached onto the first electronic component.
A method for manufacturing a connector.

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