Filled film

Abstract

The filler-containing film 10A such as an anisotropic conductive film includes a filler dispersion layer 3, and the filler dispersion layer 3 has: a resin layer 2, a first filler layer composed of fillers 1A dispersed in a single layer in the resin layer 2, and a second filler layer composed of fillers 1B dispersed in a single layer in the resin layer 2 at a depth different from that of the first filler layer. The fillers 1A of the first filler layer are exposed from one surface 2a of the resin layer 2 or are close to the surface 2a, and the fillers 1B of the second filler layer are exposed from the other surface 2b of the resin layer 2 or are close to the surface 2b.

Description

[0001] This application is a divisional application of a patent application with an original filing date of October 13, 2017, application number 201780063855.0 (international application number PCT / JP2017 / 037137), and invention title "Filler-containing film". Technical Field

[0002] The present invention relates to filler-containing films such as anisotropic conductive films. Background Art

[0003] Filler-containing films in which fillers are dispersed in a resin layer are used for various applications such as light-shielding films, films for capacitors, optical films, films for labels, antistatic films, and anisotropic conductive films (Patent Documents 1, 2, 3, 4).

[0004] As one aspect of filler-containing films, for example, anisotropic conductive films are widely used for mounting electronic components such as IC chips. From the viewpoint of making anisotropic conductive films compatible with high mounting density, in anisotropic conductive films, conductive particles are dispersed at a high density in their insulating resin layer. However, if the number density of the conductive particles is excessively increased, short circuits are likely to occur in the connection structure between electronic components using the anisotropic conductive film.

[0005] In response to this, it has been proposed to use a coating roll having regular grooves on its surface, such as a gravure coater, to coat a resin liquid containing conductive particles on an insulating resin layer or a release film when manufacturing an anisotropic conductive film, so that the conductive particles are regularly arranged in a single layer in the insulating resin layer (Patent Document 5). In addition, it has been proposed to use a transfer mold to transfer conductive particles dispersed in a predetermined configuration onto a first insulating resin layer and a second insulating resin layer respectively, and to bond the first insulating resin layer and the second insulating resin layer on which the conductive particles are transferred, so as to form a first conductive particle layer and a second conductive particle layer in which the conductive particles are regularly arranged at different depths in the anisotropic conductive film (Patent Document 6).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-15680;

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-138904;

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2013-103368;

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 2014-183266;

[0012] Patent Document 5: Japanese Patent Laid-Open No. 2016-31888

[0013] Patent Document 6: Japanese Patent Laid-Open No. 2015-201435. Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] According to the method for manufacturing an anisotropic conductive film described in Patent Document 5, since the conductive particles are regularly arranged, even if the number density of the conductive particles is increased, the susceptibility to short circuit is reduced compared to the case where the conductive particles are randomly arranged. However, since the conductive particles are arranged in a single layer on one side of the anisotropic conductive film, it is limited to accurately arrange the conductive particles so as not to cause a short circuit when increasing the number density.

[0016] According to the method for manufacturing an anisotropic conductive film described in Patent Document 6, since the conductive particles are respectively held on the first insulating resin layer and the second insulating resin layer, the number density of the conductive particles as a whole of the anisotropic conductive film can be increased, and the occurrence of short circuits can be suppressed. However, according to the method for manufacturing an anisotropic conductive film described herein, a curable resin is used for the first insulating resin layer and the second insulating resin layer, and the conductive particles are held on these resin layers by curing. If the first insulating resin layer and the second insulating resin layer are bonded, there is a concern that the adhesiveness of the surface of the anisotropic conductive film is reduced, and the operability during temporary pasting of the anisotropic conductive film to an electronic component or temporary crimping of the anisotropic conductive film to an electronic component at a low temperature and fixing it to an article is reduced.

[0017] In view of this, the problem of the present invention is: in a filler-containing film represented by an anisotropic conductive film, by having a first filler layer and a second filler layer at different depths, the number density of the fillers can be increased to improve functionality (for example, in response to high-density mounting). Specifically, the problem is: when the filler-containing film is formed as an anisotropic conductive film, in order to suppress the occurrence of short circuits in the connection structure between electronic components, improve the connection reliability, and improve the operability of temporary pasting or temporary crimping of the filler-containing film such as an anisotropic conductive film, adhesiveness is imparted to the film surface.

[0018] Means for Solving the Problems

[0019] The present inventors have found that: when manufacturing a filler-containing film that increases the number density of fillers and suppresses the occurrence of short circuits, particularly in the case of an anisotropic conductive film as a solution of the filler-containing film, by providing a first filler layer and a second filler layer at different depths in the resin layer, if fillers are pressed into both the front and back surfaces of the resin layer, the first filler layer is provided to be exposed from one surface of the resin layer or near its surface, and at the same time the second filler layer is provided to be exposed from the other surface of the resin layer or near its surface, the conductive particles are easily captured on the terminals of the anisotropically conductive connected electronic components, thereby improving the connection reliability, and it is also easy to ensure the adhesiveness of the film surface, and thus the present invention has been conceived. Thus, by providing fillers on both sides, it is possible to contribute to imparting or improving the performance of the filler-containing film, stabilizing the quality, and reducing the cost.

[0020] That is, the present invention provides a filler-containing film, which is a filler-containing film having a filler dispersion layer, and the filler dispersion layer has: a resin layer, a first filler layer composed of fillers dispersed in a single layer in the resin layer, and a second filler layer composed of fillers dispersed in a single layer in the resin layer at a depth different from that of the first filler layer.

[0021] The fillers of the first filler layer are exposed from one surface of the resin layer or close to the one surface.

[0022] The fillers of the second filler layer are exposed from the other surface of the resin layer or close to the other surface. In particular, the present invention provides: as a preferred embodiment of the filler-containing film, the fillers are conductive particles, the resin layer is an insulating resin layer, and the filler-containing film is used as an anisotropic conductive film.

[0023] In addition, the present invention provides a method for manufacturing the above-mentioned filler-containing film, and the manufacturing method is characterized in that fillers are held in a specified dispersed state on one surface of the resin layer, and the fillers are pressed into the resin layer, and other fillers are also held in a specified dispersed state on the other surface of the resin layer, and the fillers are pressed into the resin layer.

[0024] In addition, the present invention provides: a film laminate in which the above-described filler-containing film is adhered to an article; a connection structure in which a first article and a second article are connected via the above-described filler-containing film, and in particular, the following connection structure in which a first electronic component and a second electronic component are anisotropically conductively connected via a filler-containing film serving as an anisotropic conductive film. Further, the present invention provides a method for manufacturing a connection structure in which a first article and a second article are crimped via the above-described filler-containing film; and the following method for manufacturing a connection structure in which the first article and the second article are respectively a first electronic component and a second electronic component, and the first electronic component and the second electronic component are thermally crimped via a filler-containing film serving as an anisotropic conductive film, thereby manufacturing a connection structure in which the first electronic component and the second electronic component are anisotropically conductively connected.

[0025] Advantages of the Invention

[0026] According to the anisotropic conductive film which is one embodiment of the filler-containing film of the present invention, since the fillers are present so as to be exposed from or close to both front and back surfaces of the resin layer, when it is formed as an anisotropic conductive film, the conductive particles are easily captured on the terminals of the electronic components for anisotropic conductive connection. Therefore, the connection reliability is improved.

[0027] In addition, the number density of the first filler layer and the number density of the second filler layer are each lower than the number density of the fillers in the entire film. Therefore, even if the fillers are present at a high density in the entire film, it is possible to avoid the concern of reducing the adhesiveness of the film surface. Moreover, according to the filler-containing film such as the anisotropic conductive film of the present invention, since it is not necessarily required to fix the fillers to the resin layer to cure the resin layer, it is also possible to ensure adhesiveness on the film surface. In addition to the improvement of adhesiveness, by providing fillers not only on one surface but also on both surfaces of the filler-containing film, it is also possible to expect to impart different functionality from the case where fillers are provided only on one surface.

[0028] Moreover, by making the number density of the first filler layer and the number density of the second filler layer lower than the number density of the filler in the entire film, it becomes easy to precisely control the arrangement of the filler in each filler layer. And even if the film arrangement pitch of the filler-containing film as a whole, such as an anisotropic conductive film, is narrow, the filler can be precisely arranged in a specified configuration. Therefore, the above-mentioned improvement in capturability is also suitable for fine-pitch connections. For example, it can be used for connecting electronic components with a terminal width of 6 μm to 50 μm and a terminal-to-terminal interval of 6 μm to 50 μm. In addition, if the effective connection terminal width (the width of the overlapping part when looking down among the widths of a pair of terminals facing each other during connection) is 3 μm or more and the shortest terminal-to-terminal distance is 3 μm or more, the electronic components can be connected without causing a short circuit. Additionally, as another example, there is an optical film, but by adjusting the ratio of the number of non-contact portions in the thickness direction and when looking down in the resin layer of the filler, the optical properties of the filler can be adjusted. The same applies to films directly related to appearance, such as an extinction film. Since it can be adjusted on both sides, it is easy to contribute to improving performance or quality and reducing costs. Brief Description of the Drawings

[0029] Figure 1A Figure 1A It is a plan view showing the arrangement of the filler (conductive particles) of the filler-containing film (anisotropic conductive film as one of its embodiments) 10A of the embodiment.

[0030] Figure 1B Figure 1B It is a cross-sectional view of the filler-containing film 10A of the embodiment.

[0031] Figure 2 Figure 2 It is a cross-sectional view of a filler-containing film in which the embedding rate of the filler in the first filler layer and the filler in the second filler layer is approximately 100%, and the filler protrudes from the surface of the resin layer.

[0032] Figure 3 Figure 3 It is a cross-sectional view of a filler-containing film in which the embedding rate of the filler in the first filler layer and the filler in the second filler layer is approximately 100%, and the filler is embedded in the resin layer in such a way that the surface of the resin layer is flat.

[0033] Figure 4 Figure 4 It is a cross-sectional view of a filler-containing film in which the embedding rate of the filler slightly exceeds 100% and there is a depression on the surface of the resin layer directly above the filler.

[0034] Figure 5A Figure 5A It is a plan view showing the arrangement of the filler (conductive particles) of the filler-containing film (anisotropic conductive film as one of its embodiments) 10B of the embodiment.​​​​​​

[0035] Figure 5B Figure 5B is a cross-sectional view of the filler-containing film 10B of the embodiment.

[0036] Figure 6 Figure 6 is a cross-sectional view when the electronic component is anisotropically conductively connected with the filler-containing film 10A.

[0037] Figure 7A Figure 7A is a plan view showing the arrangement of the filler (conductive particles) of the filler-containing film (anisotropic conductive film as one of its embodiments) 10C of the embodiment.

[0038] Figure 7B Figure 7B is a cross-sectional view of the filler-containing film 10C of the embodiment.

[0039] Figure 8A Figure 8A is a plan view showing the arrangement of the filler (conductive particles) of the filler-containing film (anisotropic conductive film as one of its embodiments) 10D of the embodiment.

[0040] Figure 8B Figure 8B is a cross-sectional view of the filler-containing film 10D of the embodiment.

[0041] Figure 9 Figure 9 is a plan view showing the arrangement of the filler unit 1C before and after anisotropic conductive connection.

[0042] Figure 10 Figure 10 is a cross-sectional view of the connection structure obtained by anisotropically conductively connecting the electronic component using the filler-containing film 10D.

[0043] Figure 11A Figure 11A is a cross-sectional view of the filler-containing film (anisotropic conductive film as one of its embodiments) 10E having a second resin layer.

[0044] Figure 11B Figure 11B is a cross-sectional view of the filler-containing film (anisotropic conductive film as one of its embodiments) 10F having a second resin layer.

[0045] Figure 11C Figure 11C is a cross-sectional view of the filler-containing film (anisotropic conductive film as one of its embodiments) 10G having a second resin layer.

[0046] Figure 12 ​​​​​​​​​​​​] Figure 12 1 and 2 are process diagrams for explaining a method for producing a filler-containing film (anisotropic conductive film as one embodiment thereof) 10 having a second resin layer. DETAILED DESCRIPTION

[0047] Hereinafter, the filler-containing film of the present invention will be described in detail mainly with reference to the drawings as one embodiment thereof, mainly an anisotropic conductive film. In the drawings, the same reference numerals represent the same or equivalent components.

[0048] <Overall composition of filled film>

[0049] Figure 1A 1 is a plan view illustrating a filler arrangement of a filler-containing film 10A according to an embodiment of the present invention, Figure 1B This is its XX cross-section diagram.

[0050] The filler-containing film 10A is composed of a filler dispersion layer 3, which is formed by the following layers: a resin layer 2, a first filler layer composed of a filler 1A dispersed in a single layer at a predetermined depth along the film thickness direction from a surface 2a on one side of the resin layer 2, and a second filler layer composed of a filler 1B dispersed in a single layer at a depth different from that of the first filler layer. The filler 1A of the first filler layer is present on the surface 2a side of one side of the resin layer 2 and is exposed from the surface 2a, and the filler 1B of the second filler layer is present on the surface 2b side of the other side of the resin layer 2 and is exposed from the surface 2b. It should be noted that in the figure, the filler 1A of the first filler layer is represented by a dark color, and the filler 1B of the second filler layer is represented by a white color.

[0051] In addition, unless otherwise specified, the dispersion state of the filler in the present invention includes a state in which the fillers 1A and 1B are randomly dispersed and a state in which the fillers 1A and 1B are dispersed in a regular arrangement.

[0052] In addition, in the filler-containing film 10A of the present embodiment, in the long side direction of the film, the number density of the filler 1A in the first filler layer and the number density of the filler 1B in the second filler layer gradually increase on one side, while the other side gradually decreases, and the number density of the fillers 1A and 1B in the first filler layer and the second filler layer combined has excellent uniformity in the entire film.

[0053] <Packing>

[0054] The fillers 1A and 1B are appropriately selected from known inorganic fillers (such as metals, metal oxides, metal nitrides, etc.), organic fillers (such as resin particles, rubber particles, etc.), and fillers in which organic materials and inorganic materials coexist (for example, particles whose core is formed of a resin material and whose surface is plated with a metal (metal-coated resin particles), fillers in which insulating fine particles are attached to the surface of conductive particles, fillers whose surface of conductive particles is subjected to insulation treatment, etc.) according to the use of the filler-containing film, in accordance with properties required for the use such as hardness and optical properties. For example, silica fillers, titanium oxide fillers, styrene fillers, acrylic fillers, melamine fillers, or various titanates can be used in optical films or matte films. Titanium oxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate, and their mixtures, etc. can be used in films for capacitors. Polymer-based rubber particles, silicone rubber particles, etc. can be contained in adhesive films. Conductive particles can be contained in anisotropic conductive films. Examples of the conductive particles include metal particles such as nickel, cobalt, silver, copper, gold, and palladium, alloy particles such as solder, metal-coated resin particles, and metal-coated resin particles with insulating fine particles attached to the surface. Two or more types can also be used in combination. Among them, metal-coated resin particles are preferred from the viewpoint of the resin particles rebounding after connection and easily maintaining contact with the terminals and stable conduction performance. In addition, the surface of the conductive particles can be subjected to an insulation treatment that does not hinder the conduction characteristics by a known technique. The above fillers listed by use are not limited to that use, and other filler-containing films for other uses can be contained as needed. In addition, in the filler-containing films for each use, two or more types of fillers can be used in combination as needed.

[0055] The shape of the fillers is appropriately selected and determined from spheres, ellipsoids, columns, needles, combinations thereof, etc. according to the use of the filler-containing film. Spheres are preferred from the viewpoint of easy confirmation of the filler arrangement and easy maintenance of an even state. In particular, when the filler-containing film is formed as an anisotropic conductive film, the conductive particles as the fillers are preferably approximate spheres. By using approximate spherical particles as the conductive particles, for example, as described in Japanese Patent Laid-Open No. 2014-60150, when manufacturing an anisotropic conductive film in which conductive particles are arranged using a transfer mold, the conductive particles are smoothly transferred onto the transfer mold, and thus the conductive particles can be filled into the specified positions on the transfer mold with high precision. Therefore, the conductive particles can be accurately arranged.

[0056] The particle diameters DA and DB of the fillers 1A and 1B are preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and 9 μm or less, in order to cope with the deviation of the wiring height, suppress the increase in the conduction resistance, and suppress the occurrence of short circuits.

[0057] The particle diameters of the fillers 1A in the first filler layer and the fillers 1B in the second filler layer may be the same or different. When the filler-containing film is used as an anisotropic conductive film, in terms of the compression state such as the flatness ratio after anisotropic conductive connection of both fillers 1A and 1B as conductive particles, especially when the conductive particles are metal-coated resin particles, it is preferable that their compression states are the same to stabilize the conduction performance. From this perspective, they are preferably the same. In addition, the materials or hardnesses (e.g., compression elastic modulus, etc.) of the fillers 1A and 1B may be the same or different.

[0058] It should be noted that the particle diameters of the fillers 1A and 1B can be measured by a common particle size distribution measuring device, and the average particle diameter can also be obtained using a particle size distribution measuring device. As an example of the measuring device, FPIA-3000 (manufactured by Malvern) can be cited. The filler diameter in the film can be obtained by observation with a metallurgical microscope or electron microscope observation such as SEM. In this case, it is desirable to set the number of samples for measuring the filler diameter to 200 or more. In addition, when the shape of the filler is not spherical, the maximum length or the diameter of a shape imitating a sphere can be regarded as the particle diameter of the filler based on the planar image or cross-sectional image of the filler-containing film.

[0059] <Position of the fillers in the film thickness direction>

[0060] Regarding the positions of the fillers 1A and 1B in the film thickness direction, Figure 1BA solution in which the filler 1A of the first filler layer is exposed from the surface 2a on one side of the resin layer 2 and the filler 1B of the second filler layer is exposed from the surface 2b on the other side. The present invention includes: a solution in which the filler 1A of the first filler layer is exposed from the surface 2a on one side of the resin layer 2, or the filler 1A is completely buried in the resin layer 2 but located close to the surface 2a of the resin layer 2, and the filler 1B of the second filler layer is exposed from the surface 2b on the other side of the resin layer 2, or the filler 1B of the second filler layer is completely buried in the resin layer 2 but located close to the surface 2b of the resin layer 2. Here, the filler 1A and 1B being completely buried in the resin layer 2 but close to its surfaces 2a and 2b means, as an example, that the filler 1A and 1B are not exposed from the resin layer 2 and the embedding rate described later is 110% or less, preferably 105% or less. If the filler 1A and 1B are exposed from the surfaces 2a and 2b of the resin layer 2, the particle diameters of the filler 1A and 1B can be the same or different. When the filler-containing film is formed as an anisotropic conductive film, the capture property of the filler 1A and 1B as conductive particles during anisotropic conductive connection is significantly improved, so it is preferred. In addition, if the filler 1A and 1B are buried in the resin layer 2 and close to its surfaces 2a and 2b, the viscosity of the filler-containing film is increased without impairing the capture property of the filler 1A and 1B, so it is preferred. In particular, if the filler 1A and 1B approach the surfaces 2a and 2b of the resin layer 2 by less than 0.1 μm, the capture property of the filler 1A and 1B is improved without impairing the viscosity, so it is preferred. In addition, the number density of the filler is 5000 pieces / mm 2 For the filler layer with 2% or more of the above or area occupancy rate, it is preferred that the filler 1A and 1B are buried in the resin layer 2 and are substantially flush with the surfaces 2a and 2b of the resin layer 2. Thus, compared with the case where the filler is exposed from the resin layer, the viscosity of the filler-containing film is not reduced, and compared with the case where the embedding rate exceeds 100% and the filler is completely buried, when the filler-containing film is formed as an anisotropic conductive film, the filler as a conductive particle during anisotropic conductive connection is less likely to be affected by resin flow, so the capture property is improved. In contrast, if either the first filler layer or the second filler layer is not exposed from the resin layer 2 and is not located near the surfaces 2a and 2b of the resin layer 2, when the filler-containing film is formed as an anisotropic conductive film, the filler as a conductive particle during anisotropic conductive connection is likely to be affected by resin flow, and there is a concern that the capture property will be reduced. Or, there is also a concern that it will be difficult to make the resin exclusion near the filler uniform, which will have an adverse effect on the pressing-in of the filler. This also applies to filler-containing films other than anisotropic conductive films.

[0061] The ratio (L1 / DA) of the distance (hereinafter referred to as the embedding amount) L1 from the section of the surface 2a of the resin layer 2 at the central part between adjacent fillers 1A in the first filler layer to the deepest part of the filler 1A to the particle diameter DA of the filler 1A, that is, the embedding rate, is preferably 30% or more and 110% or less, more preferably 30% or more and 105% or less, further preferably more than 30% and 100% or less, and particularly preferably 60% or more and 100% or less. Similarly, for the filler 1B in the second filler layer, the ratio (L2 / DB) of the distance (embedding amount) L2 from the section of the surface 2b of the resin layer 2 at the central part between adjacent fillers 1B to the deepest part of the filler 1B to the particle diameter DB of the filler 1B, that is, the embedding rate, is preferably 30% or more and 110% or less, more preferably 30% or more and 105% or less, further preferably more than 30% and 100% or less, and particularly preferably 60% or more and 100% or less. By setting the embedding rates (L1 / DA) and (L2 / DB) to 30% or more, the fillers 1A and 1B are easily maintained in a specified regular arrangement or specified alignment by the resin layer 2. In addition, by setting it to 110% or less, preferably 105% or less, when the filler-containing film is formed as an anisotropic conductive film, unnecessary flow of the conductive particles between the terminals, that is, the fillers, is difficult to occur due to the flow of the resin during anisotropic conductive connection. In addition, in the filler-containing film, by making the embedding rates of the fillers in the resin layer 2 uniform, an effect of improving its characteristics can be expected. As one example, when the performance of the optical film depends on the fillers, if the dispersibility (independence) and the embedding state in a plan view have a certain degree of regularity or more, it can be presumed that the performance is improved or the quality is stabilized compared with that obtained by coating a simply kneaded adhesive or the like.

[0062] The embedding rate of the filler 1A in the first filler layer and the embedding rate of the filler 1B in the second filler layer may be the same or different.

[0063] Here, the filler diameters DA and DB are the average values of the filler diameters of the filler 1A in the first filler layer and the filler 1B in the second filler layer, respectively.

[0064] In addition, in the present invention, the numerical values of the embedding rates (L1 / DA) and (L2 / DB) mean that 80% or more, preferably 90% or more, and more preferably 96% or more of all the fillers (for example, conductive particles) contained in the filler-containing film such as an anisotropic conductive film become the numerical values of the embedding rates (L1 / DA) and (L2 / DB). The embedding rates (L1 / DA) and (L2 / DB) can be obtained by arbitrarily extracting 10 or more regions with an area of 30 mm 2 or more from the filler-containing film such as an anisotropic conductive film, observing a part of the cross section of the film in an SEM image, and measuring 50 or more fillers in total. In order to further improve the accuracy, it is also possible to measure 200 or more fillers to obtain.

[0065] As an example of a particularly preferred embedding scheme of the fillers 1A and 1B in the resin layer 2, the following can be cited: as Figure 1B shown, the embedding rate of both the fillers 1A and 1B is 60% or more and 100% or less, and the fillers 1A and 1B are exposed from the surfaces 2a and 2b of the resin layer 2 respectively, and a recess 2x is formed in the resin layer 2 around the exposed fillers 1A and 1B, or as Figure 2 shown, the embedding rate of both the fillers 1A and 1B is approximately 100%, and on the front and back surfaces of the resin layer 2, the fillers 1A and 1B are flush with the surfaces 2a and 2b of the resin layer 2 respectively, the fillers 1A and 1B are exposed from the surfaces 2a and 2b of the resin layer 2, and a recess 2x is formed in the resin layer 2 around the exposed fillers 1A and 1B. By forming the recess 2x, when the filler-containing film is used as an anisotropic conductive film, for the flattening of the fillers 1A and 1B generated when the fillers 1A and 1B as conductive particles are clamped between terminals during anisotropic conductive connection, the resistance received from the resin is reduced compared to the case without the recess 2x, and the capture property of the fillers in the terminals is improved. Even as a filler-containing film, compared with those obtained by coating a simply kneaded adhesive, etc., as described above, due to the specific state of the fillers and the resin, characteristics in terms of performance or quality can also be expected.

[0066] On the other hand, when the filler-containing film is used as an anisotropic conductive film, when connecting electronic components to each other using the anisotropic conductive film, from the perspective of avoiding air entrainment, as Figure 3 shown, it is preferable to adopt a scheme in which the embedding rate of the fillers 1A and 1B as conductive particles is approximately 100% and the fillers 1A and 1B are embedded in the resin layer 2 with the surface of the filler dispersion layer 3 being flat.

[0067] In addition, when the embedding rate exceeds 100%, as Figure 4 shown, it is preferable to adopt a scheme in which a recess 2y is formed in the region directly above the fillers 1A and 1B on the surfaces 2a and 2b of the resin layer 2 close to the fillers 1A and 1B. By forming the recess 2y, compared with the case without the recess 2y, when the filler-containing film is used as an anisotropic conductive film, the pressure during anisotropic conductive connection is likely to concentrate on the fillers 1A and 1B as conductive particles, and the capture property of the fillers 1A and 1B in the terminals is improved. Even as a filler-containing film, compared with those obtained by coating a simply kneaded adhesive, etc., as described above, due to the specific state of the fillers and the resin, characteristics in terms of performance or quality can also be expected.

[0068] <Arrangement of fillers>

[0069] In Figure 1AIn the filler-containing film 10A shown, the fillers 1A in the first filler layer and the fillers 1B in the second filler layer are respectively arranged in a square lattice. Thus, in the filler-containing film of the present invention, it is preferable that the fillers 1A and 1B are regularly arranged. As the regular arrangement, in addition to Figure 1A the square lattice shown, lattice arrangements such as a rectangular lattice, a rhombic lattice, and a hexagonal lattice can be cited. As a regular arrangement other than the lattice arrangement, a particle row in which the fillers are arranged in a straight line at a prescribed interval and the particle rows are juxtaposed at a prescribed interval can be cited. By arranging the fillers 1A and 1B in a regular arrangement such as a lattice shape, when the filler-containing film is formed as an anisotropic conductive film, pressure can be evenly applied to each of the fillers 1A and 1B as conductive particles during anisotropic conductive connection, and the deviation of the conduction resistance can be reduced.

[0070] The arrangement of the fillers 1A in the first filler layer and the arrangement of the fillers 1B in the second filler layer may be the same or different. In the case of being the same, for example, as in Figure 5A , Figure 5B in the filler-containing film 10B shown, in a plan view of the filler-containing film, the fillers 1A in the first filler layer and the fillers 1B in the second filler layer may not overlap, or a filler unit formed by the fillers 1A in the first filler layer coming into contact with or approaching the fillers 1B in the second filler layer may be formed. In this case, it is preferable that the filler units are regularly arranged without contacting each other. Thereby, the occurrence of a short circuit can be suppressed.

[0071] For example, in the first filler layer and the second filler layer, the arrangements of the fillers 1A and 1B themselves are the same, but the arrangement of one of the fillers 1A is offset by a prescribed distance in the film surface direction with respect to the arrangement of the other fillers 1B, and a filler unit in which a part of the fillers 1A in the first filler layer and the fillers 1B in the second filler layer overlap can be formed in a plan view of the filler-containing film. In this case, as in the anisotropic conductive film which is a variant of the filler-containing film 10A shown in Figure 1A , if a filler unit 1C in which the fillers 1A and 1B partially overlap is formed, since the filler-containing film is an anisotropic conductive film, an effect that either of the fillers 1A and 1B as conductive particles is easily captured in the terminal during anisotropic conductive connection can be expected. That is, when the terminals 20 of the first electronic component 30 and the terminals 21 of the second electronic component 31 are anisotropically conductively connected using the anisotropic conductive film which is a variant of the filler-containing film 10A shown in Figure 1A , as in Figure 6As shown, if the filler 1A is located at the edge of the terminals 20 and 21, since there is a filler 1B at the position where the filler-containing film (anisotropic conductive film) overlaps with the filler 1A in plan view, even if the positions of the fillers 1A or 1B shift during heating and pressing, in either of the adjacent fillers 1A and 1B, the terminals 20 and 21 can be connected, and the capture property of the filler in the terminals can be improved. In addition, in this case, if resin flow occurs during heating and pressing, the distance between the fillers 1A and 1B becomes farther, so the risk of short circuit also decreases. Moreover, partially overlapping the fillers 1A and 1B in this way is premised on the fact that in the overall anisotropic conductive film, which is considered as a solution of the filler-containing film, factors such as the diameter or number density of the fillers, the distance between the fillers, the size of the connected terminals or the distance between the terminals are taken into account, and it is assumed that no short circuit occurs in the design when the fillers 1A and 1B are partially overlapped. If the fillers 1A and 1B are partially overlapped, it is easy to satisfy the effect of improving the capture property while satisfying the effect of suppressing short circuits, so it is preferred. In addition, when the adjacent fillers 1A and 1B are substantially flush with the front and back surfaces 2a and 2b of the resin layer 2, or when they are exposed from these front and back surfaces 2a and 2b, these effects are further enhanced, so it is preferred. It should be noted that when the filler-containing film is formed as an anisotropic conductive film, in the above-mentioned filler-containing film, assuming that the filler 1A in the first filler layer and the filler 1B in the second filler layer completely overlap in the film thickness direction, if it is used for anisotropic conductive connection, since there may be a case where the resin melts or flows during the heating and pressing for anisotropic conductive connection, and due to the position shift of the already overlapped fillers 1A and 1B, there is no practical problem. The same can be said for solutions other than the anisotropic conductive film.

[0072] On the other hand, when the arrangement of the filler 1A in the first filler layer is different from the arrangement of the filler 1B in the second filler layer, for example, if the shapes of both arrangements are similar, etc., it is preferred that there are common points in the arrangement. This is not limited to the anisotropic conductive film.

[0073] In addition, the arrangement of filler 1A and the arrangement of filler 1B can be made into a regular arrangement such as a lattice by taking the arrangements of filler 1A and filler 1B as parts of a regular arrangement respectively and combining them. For example, when the arrangements of filler 1A and filler 1B are combined to form a hexagonal lattice, the arrangement of filler 1A has the arrangement of hexagons contained in the hexagonal lattice, and the arrangement of filler 1B becomes the arrangement at the centers of the hexagons. It should be noted that the regular arrangement in this case is not limited to the hexagonal lattice. In addition, the arrangements of filler 1A and filler 1B are not limited to being any part of the regular arrangement formed by the combination of both. The regular arrangement formed by combining the arrangements of filler 1A and filler 1B can be distorted with respect to an accurate lattice arrangement. For example, a lattice axis that should originally be a straight line can become zigzag. In this way, by simply reproducing difficult arrangement conditions, batch management can be carried out, and traceability (the property of being traceable) can also be imparted to the filler-containing film and the connection structure using the same. This is also effective for preventing forgery, authenticity determination, and preventing unauthorized use of the filler-containing film or the connection structure using the same. In addition, generally speaking, in anisotropic conductive connection, it may happen that a considerable number of linearly arranged conductive particles are not captured at the edge portions of the terminals. However, by making the arrangement zigzag, such a situation can be avoided. Thereby, it is possible to easily keep the number of conductive particles captured in the terminals within a certain range, which is therefore preferable. In addition, by repeating such distortion, it is possible to easily judge whether the arrangement shape is appropriate by sampling inspection or the like.

[0074] It should be noted that the above-mentioned distorted arrangement of the filler can be formed using one transfer mold, but it can also be formed by combining two transfer molds, namely, the transfer mold for filler 1A and the transfer mold for filler 1B. By using two transfer molds, namely, the transfer mold for filler 1A and the transfer mold for filler 1B, to form the arrangement of the filler (such as conductive particles) of the entire filler-containing film such as an anisotropic conductive film, it becomes possible to form various arrangements, and it is easy to respond to design changes in a short period, which can contribute to reducing the manufacturing cost. Moreover, it becomes possible to reduce the total cost of manufacturing the filler-containing film such as an anisotropic conductive film, including the costs required for holding, component management, maintenance, etc. of the manufacturing apparatus for manufacturing various filler-containing films such as anisotropic conductive films with different arrangements of the filler. The present invention can adopt: a design method of the arrangement state of the filler (such as conductive particles) in the top view of the entire filler-containing film such as an anisotropic conductive film using two transfer molds, namely, the transfer mold for filler 1A and the transfer mold for filler 1B, as described above, or a manufacturing method of the filler-containing film such as an anisotropic conductive film using two transfer molds according to the design method.

[0075] It should be noted that the fillers 1A and 1B may have vacancies in their arrangement states within the range where the expected inventive effects of the filler-containing film can be obtained. This can be confirmed by regularly existing in a specified direction of the film. In addition, by repeatedly having vacancies of the fillers in the long side direction of the film, or by gradually increasing or decreasing the vacancies of the fillers in the long side direction of the film, the same effects as the above-mentioned distortion can be obtained. That is, batch management can be carried out, and traceability (the property of being traceable) can be imparted to the filler-containing film and the connection structure using the same. This is also effective for preventing forgery, authenticity determination, and preventing unauthorized use of the filler-containing film or the connection structure using the same.

[0076] In each of the first filler layer and the second filler layer, the lattice axis or the arrangement axis of the arrangement of the fillers 1A and 1B may be parallel to the long side direction of the filler-containing film 10A such as an anisotropic conductive film, or may intersect the long side direction of the filler-containing film 10A such as an anisotropic conductive film. For example, in the case of an anisotropic conductive film, since it can be determined according to the width of the connected terminals, the terminal pitch, etc., there is no particular limitation. For example, in the case of an anisotropic conductive film for fine pitch, as Figure 1A shown, the lattice axis A of the filler 1A in the first filler layer is inclined with respect to the long side direction of the filler-containing film 10A such as an anisotropic conductive film, and the angle θ formed by the long side direction (the short side direction of the film) of the terminal 20 connected through the filler-containing film 10A such as an anisotropic conductive film and the lattice axis A is preferably set to 6° to 84°, more preferably set to 11° to 74°. Even for uses other than anisotropic conductive films, by making such an inclination, an effect of stabilizing the capture state can be expected.

[0077] The inter-particle distance of the fillers 1A and 1B is appropriately determined according to the presence or absence of the formation of the filler (for example, conductive particle) unit 1C, the size of the terminals connected by the filler-containing film such as an anisotropic conductive film, the terminal pitch, etc. For example, the closest inter-particle distance L3 between adjacent fillers 1A in the first filler layer and the closest inter-particle distance L4 between adjacent fillers 1B in the second filler layer ( Figure 1A) In the case of an anisotropic conductive film, when the fillers 1A and 1B, which are adjacent conductive particles, do not belong to one filler unit (conductive particle unit), from the viewpoint of suppressing short circuits, it is preferably 1.5 times or more the particle diameters DA and DB of the fillers 1A and 1B. In addition, in terms of ensuring the minimum number of fillers captured in the terminals and obtaining stable conduction, it is preferably 66 times or less. In particular, when the filler-containing film is used as an anisotropic conductive film, when the anisotropic conductive film corresponds to a fine-pitch COG (Chip On Glass), the closest inter-particle distances L3 and L4 are preferably 1.5 to 5 times the particle diameter. When corresponding to a larger-pitch FOG (Film On Glass), it is preferably 10 to 66 times the particle diameter. Except for anisotropic conductive films, it can be appropriately adjusted according to their characteristics.

[0078] It should be noted that, as described later, when forming the filler unit 1C with multiple fillers 1A in the first filler layer or when forming the filler unit 1C with multiple fillers 1B in the second filler layer, in the case of an anisotropic conductive film as one aspect of the filler-containing film, it is preferably that the distance between the fillers 1A in the first filler layer within one filler unit 1C is 1 / 4 times or less the particle diameter DA of the filler 1A, and the fillers 1A can also be in contact with each other. Similarly, it is preferably that the distance between the fillers 1B in the second filler layer within one filler unit 1C is 1 / 4 times or less the particle diameter DB of the filler 1B, and the fillers 1B can also be in contact with each other. Except for anisotropic conductive films, it can be appropriately adjusted according to their characteristics.

[0079] <Number density of fillers>

[0080] Since the number density of the fillers in the entire filler-containing film of the present invention is appropriately adjusted according to its use, required characteristics, particle diameters of the fillers 1A and 1B, arrangement, etc., there is no particular limitation, and the following case of anisotropic conductive films can be applied. Since the manufacturing conditions of the filler-containing film are substantially the same as those of anisotropic conductive films, it is considered that the conditions of the number density of the fillers are also substantially the same. When the filler-containing film is used as an anisotropic conductive film, it is appropriately adjusted according to the pitch of the terminals in the electronic components connected by the anisotropic conductive film, the particle diameters of the fillers (conductive particles) 1A and 1B in the anisotropic conductive film, the arrangement, etc. For example, regarding the upper limit of the number density, in order to suppress short circuits, it is preferably 70,000 pieces / mm 2 Hereinafter, it is more preferably 50,000 pieces / mm 2 Hereinafter, it is further preferably 35,000 pieces / mm 2 Hereinafter. On the other hand, regarding the lower limit of the number density, in order to reduce the fillers (conductive particles) to suppress costs and satisfy the conduction performance, it is also preferably 100 pieces / mm2 More preferably, it is 150 pieces / mm or more 2 Further preferably, it is 400 pieces / mm or more 2 or more. In particular, in the case of a fine pitch application where the connection area of the smallest terminal of the electronic component connected by the anisotropic conductive film is 2000 μm or less, 10000 pieces / mm or more is preferred 2 The designed number density of the filler 1A in the first filler layer and the designed number density of the filler 1B in the second filler layer may be the same or different. 2 When manufacturing the filler-containing film, in the case where the filler is attached in the long side direction of the filler-containing film, when there is a tendency that voids or non-uniformity of the distribution of the filler inevitably increases, it is preferred that one of the number density of the filler 1A in the first filler layer and the number density of the filler 1B in the second filler layer gradually increases and the other gradually decreases in the long side direction of the filler-containing film, that is, it is preferred that the direction of increase or decrease of the number density is opposite between the first filler layer and the second filler layer. When the average value of the number density of the filler 1A in the first filler layer in the entire filler-containing film such as the anisotropic conductive film is the same, as described above, by gradually increasing or decreasing the number density of the filler, in one end 10Ap and the other end 10Aq of the filler-containing film, the magnitude relationship between the number density of the filler 1A in the first filler layer and the number density of the filler 1B in the second filler layer is opposite, and the uniformity of the number density of the filler in the entire filler-containing film is improved. This is the case for an anisotropic conductive film, and in the case where the uniformity of the number density of the filler over the entire surface is strongly required, the manufacturing difficulty is reduced, and thus the effect can be expected. Moreover, the effect of cost reduction can be expected in the same way for both the use of the anisotropic conductive film and other uses.

[0081] Regarding the number density of the filler in the first filler layer or the second filler layer in the long side direction of the filler-containing film such as the anisotropic conductive film, in the region where it is 20% or more of the entire film length or 3 m or more in the long side direction of the filler-containing film, as the measurement region of the number density of the filler, a plurality of rectangular regions (preferably 5 or more, more preferably 10 or more) with each side being 100 μm or more are set at different positions in the long side direction of the filler-containing film, and the total area of the measurement regions is preferably 2 mm

[0082] 2 ​As described above, the number density of the fillers in each measurement region is measured using a metallurgical microscope and averaged, or an image of an area of 20% or more of the entire length of the above-mentioned film or an area of 3 m or more is taken, and the number density of the fillers is measured using image analysis software (for example, WinROOF, Mitani Corporation, etc.). Thus, it can be obtained. In addition, if the number density of the fillers gradually increases or decreases, it can be confirmed by monotonically increasing or decreasing the number density of the fillers measured in each measurement region with respect to the long side direction of the filler-containing film such as the anisotropic conductive film. It should be noted that in the connection object with a bump pitch of 50 μm or less, there is at least one bump region in the area of 100 μm × 100 μm. Moreover, the measurement region can appropriately adjust the upper limit of each side of the measurement region according to the number density of the fillers. In the case of significant density or sparseness, for example, the number of fillers can be adjusted so that the total area is 200 or more, preferably 1000 or more.

[0083] When the filler-containing film is formed as an anisotropic conductive film, when the anisotropic conductive film is used for connecting the minimum terminals of electronic components, and the connection area is 2000 μm 2 In the case of a fine pitch application with a connection area of 2000 μm or less, the difference (NpAB - NqAB) between the number density NpAB of the fillers 1A and 1B, which are a combination of the first filler layer and the second filler layer, at one end 10Ap of the filler-containing film (anisotropic conductive film) and the number density NqAB of the fillers 1A and 1B, which are a combination of the first filler layer and the second filler layer, at the other end 10Aq, with respect to their average value ((NpAB + NqAB) / 2), is preferably within ±2%, more preferably within ±1.5%, and further preferably within ±1%. In the case of a normal pitch with a connection area of the minimum terminal exceeding 2000 μm 2 (NpAB - NqAB) is preferably within ±20%, more preferably within ±10%, with respect to ((NpAB + NqAB) / 2).

[0084] When the arrangement and number density of the fillers in the design of the first filler layer and the second filler layer are the same, as the process of forming the first filler layer and the second filler layer on the resin layer 2, as described later, it is preferably manufactured as follows: when attaching the filler 1A that will become the first filler layer to the resin layer 2 and when attaching the filler 1B that will become the second filler layer to the resin layer 2, the running direction of the resin layer 2 is reversed, and the same process is repeated. Reversing the running direction in this way means that if there are defects in the transfer mold used for attaching the fillers, the defect positions on the front and back sides of the filler-containing film such as the anisotropic conductive film do not overlap, and the risk of forming defects can be avoided as a whole film. Considering from this perspective, it is also preferred.

[0085] On the other hand, when the number densities of the fillers 1A and 1B in the first filler layer and the second filler layer are different, from the perspective of improving the capture property of the fillers in the terminals, it is preferable to set the filler layer with the higher number density at a position closer to the outer interface of the filler-containing film such as the anisotropic conductive film. In addition, when the filler layer is exposed on the outer surface of the filler-containing film such as the anisotropic conductive film, from the perspective of suppressing the reduction in the viscosity of the filler-containing film such as the anisotropic conductive film, it is preferable that the number density of the exposed filler layer is low (the side with the lower number density). Thus, in the filler-containing film, the number densities of the fillers 1A and 1B in the first filler layer and the second filler layer can be appropriately different according to the required characteristics.

[0086] <Resin layer>

[0087] (Viscosity of the resin layer)

[0088] There is no particular limitation on the minimum melt viscosity of the resin layer 2, and it can be appropriately determined according to the use of the filler-containing film or the manufacturing method of the filler-containing film, etc. For example, as long as the above-mentioned recesses 2x and 2y can be formed, it can also be set to about 1000 Pa·s by the manufacturing method of the filler-containing film. On the other hand, as a manufacturing method of the filler-containing film, when a method of holding the fillers on the surface of the resin layer in a prescribed configuration and pressing the fillers into the resin layer is performed, from the perspective of the resin layer being capable of film forming, it is preferable to set the minimum melt viscosity of the resin to 1100 Pa·s or more. The recesses 2x and 2y can exist on both sides or only on one side (that is, either side of the fillers 1A and 1B).

[0089] In addition, as described in the manufacturing method of the filler-containing film described later, from the perspective of forming a recess 2x around the exposed portion of the fillers 1A and 1B pressed into the resin layer 2 as shown in Figure 1B or forming a recess 2y directly above the fillers 1A and 1B pressed into the resin layer 2 as shown in Figure 4 , it is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, further preferably 3000 to 15000 Pa·s, and still further preferably 3000 to 10000 Pa·s. As an example, this minimum melt viscosity can be obtained using a rotational rheometer (manufactured by TA instruments), maintaining a constant measurement pressure of 5 g, and using a measurement plate with a diameter of 8 mm. More specifically, it can be obtained by setting the heating rate to 10 °C / minute, the measurement frequency to 10 Hz, and the load variation on the above-mentioned measurement plate to 5 g in the temperature range of 30 to 200 °C.

[0090] By setting the minimum melt viscosity of the resin layer 2 to a high viscosity of 1500 Pa·s or more, unnecessary movement of the filler can be suppressed during the thermocompression bonding of the filler-containing film to the article. In particular, when the filler-containing film is used as an anisotropic conductive film, it is possible to prevent the conductive particles that should be held between the terminals from flowing due to resin flow during anisotropic conductive connection.

[0091] In addition, in the case where the filler dispersion layer 3 of the filler-containing film 10A is formed by pressing the fillers 1A and 1B into the resin layer 2, with respect to the resin layer 2 when the fillers 1A and 1B are pressed in, when the fillers 1A and 1B are pressed into the resin layer 2 and the fillers 1A and 1B are exposed from the resin layer 2, the resin layer 2 undergoes plastic deformation and becomes a highly viscous body that forms a depression 2x ( Figure 1B ) around the fillers 1A and 1B, or, when the fillers 1A and 1B are pressed in and the fillers 1A and 1B are not exposed from the resin layer 2 but are buried in the resin layer 2, it becomes a highly viscous body that forms a depression 2y ( Figure 4 ) on the surface of the resin layer 2 directly above the fillers 1A and 1B. Therefore, regarding the viscosity of the resin layer 2 at 60°C, the lower limit is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and further preferably 10000 Pa·s or less. This measurement can be carried out by the same measurement method as the minimum melt viscosity, and the value at a drawing temperature of 60°C is obtained.

[0092] Regarding the specific viscosity of the resin layer 2 when the fillers 1A and 1B are pressed into the resin layer 2, depending on the shape or depth of the depressions 2x and 2y to be formed, etc., the lower limit is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and further preferably 10000 Pa·s or less. In addition, such a viscosity is obtained preferably at 40 to 80°C, more preferably at 50 to 60°C.

[0093] As described above, by forming a depression 2x around the fillers 1A and 1B exposed from the resin layer 2 ( Figure 1B) For the flattening of fillers 1A and 1B generated when the filler-containing film is pressed against an article, the resistance exerted on the resin is reduced compared to the case where there is no depression 2x. Therefore, when the filler-containing film is used as an anisotropic conductive film, it becomes easier to hold the conductive particles in the terminals during anisotropic conductive connection, thereby improving the conduction performance and the capture performance. Particularly in the anisotropic conductive film, since fillers 1A and 1B as conductive particles are present on both sides of the resin layer 2, in order to reduce the resistance exerted on the resin, such a depression 2x preferably exists on either side, and more preferably on both sides.

[0094] In addition, by forming a depression 2y on the surface of the resin layer 2 directly above the fillers 1A and 1B that are buried without being exposed from the resin layer 2 ( Figure 4 ), the pressure during the pressing of the filler-containing film against the article is more likely to concentrate on the fillers 1A and 1B compared to the case where there is no depression 2y. Therefore, when the filler-containing film is used as an anisotropic conductive film, it becomes easier to hold the conductive particles in the terminals during anisotropic conductive connection, thereby improving the capture performance and the conduction performance. Particularly in the anisotropic conductive film, for the same reason as described above, such a depression 2y preferably exists on either side, and more preferably on both sides. 2x and 2y can exist on a single side respectively, or can be mixed.

[0095] <"Inclination" or "undulation" instead of depression>

[0096] As Figure 1B 、 Figure 4 shown, the "depressions" 2x and 2y of the filler-containing film can also be explained from the perspective of "inclination" or "undulation". Hereinafter, an explanation will be given with reference to the drawings.

[0097] The filler-containing film 10A such as an anisotropic conductive film is composed of a filler dispersion layer 3 ( Figure 1B ). In the filler dispersion layer 3, the fillers 1A and 1B are regularly dispersed in a state of being exposed on a single surface of the resin layer 2. In the top view of the film, the fillers 1A and 1B do not contact each other, and in the film thickness direction, the fillers 1A and 1B do not overlap each other either and are regularly dispersed, constituting a single-layer filler layer in which the positions of the fillers 1A and 1B in the film thickness direction are aligned.

[0098] The surfaces 2a and 2b of the resin layer 2 around the respective fillers 1A and 1B form an inclination 2x with respect to the section plane 2p of the resin layer 2 at the center between adjacent fillers. It should be noted that, as will be described later, in the filler-containing film of the present invention, undulations 2y can be formed on the surface of the resin layer directly above the fillers 1A and 1B buried in the resin layer 2 ( Figure 4 ).

[0099] In the present invention, "tilt" means a state in which the surface flatness of the resin layer near the fillers 1A and 1B is impaired, a part of the resin layer is missing with respect to the above-mentioned cut surface 2p, resulting in a reduction in the amount of resin. In other words, in "tilt", the surface of the resin layer around the filler is missing with respect to the cut surface. On the other hand, "undulation" means that there are waves on the surface of the resin layer directly above the filler, and there are parts with height differences like waves, resulting in a reduction in resin. In other words, the amount of resin in the resin layer directly above the filler is less than when the surface of the resin layer directly above the filler is at the cut surface. These can be identified by comparing the part directly above the filler equivalent to the filler and the flat surface part between the fillers ( Figure 1B , Figure 4 ). It should be noted that sometimes the starting point of the undulation also exists in the form of tilt.

[0100] As described above, by forming a tilt 2x ( Figure 1B ) around the fillers 1A and 1B exposed from the resin layer 2, when the filler-containing film is used as an anisotropic conductive film, for the flattening of the fillers 1A and 1B generated when the fillers 1A and 1B are clamped between terminals during anisotropic conductive connection, the resistance received from the resin is reduced compared to the case without the tilt 2x. Therefore, the clamping of the fillers in the terminals becomes easier, thereby improving the conduction performance and the capturing property. This tilt preferably follows the outer shape of the filler. This is because, in addition to the effect during connection being more easily manifested, it is also easy to identify the filler, and thus inspections during the manufacture of filler-containing films such as anisotropic conductive films are easy to perform. In addition, sometimes a part of the tilt and undulation disappears due to hot pressing or the like on the resin layer, and the present invention includes such cases. In this case, the filler sometimes exposes at a point on the surface of the resin layer. It should be noted that when the filler-containing film is constituted as an anisotropic conductive film, there are various electronic components to be connected. In addition to adjusting according to these, a high degree of design freedom is expected to meet various requirements. Therefore, the tilt or undulation can also be reduced or partially disappeared for use.

[0101] In addition, by forming an undulation 2y ( Figure 4 ) on the surface of the resin layer 2 directly above the fillers 1A and 1B buried without being exposed from the resin layer 2, in the same way as in the case of tilt, when the filler-containing film is constituted as an anisotropic conductive film, the pressing force from the terminal is easily applied to the filler during anisotropic conductive connection. In addition, due to the existence of the undulation, compared with the case where the resin is piled up flatly, the amount of resin directly above the filler is reduced. Therefore, the exclusion of the resin directly above the filler during connection is likely to occur, and the terminal and the filler are easily contacted. Therefore, the capturing property of the filler in the terminal is improved, and the conduction reliability is improved.

[0102] From the perspective of easily obtaining the tilt 2x of the resin layer 2 around the exposed part of the above-mentioned fillerFigure 1B ) or the undulation 2y of the resin layer directly above the filler Figure 4 ) From the perspective of the effect of, the ratios (Le / DA) and (Le / DB) of the maximum depth Le of the inclination 2x around the exposed portions of the fillers 1A and 1B to the particle diameters DA and DB of the fillers 1A and 1B are preferably less than 50%, more preferably less than 30%, and further preferably 20 - 25%. The ratios (Ld / DA) and (Ld / DB) of the maximum diameter Ld of the inclination 2x around the exposed portions of the fillers 1A and 1B to the particle diameters DA and DB of the fillers 1A and 1B are preferably 100% or more, more preferably 100 - 150%. The ratios (Lf / DA) and (Lf / DB) of the maximum depth Lf of the undulation 2y in the resin directly above the fillers 1A and 1B to the particle diameters DA and DB of the fillers 1A and 1B are greater than 0, preferably less than 10%, and more preferably 5% or less.

[0103] It should be noted that the diameter Lc of the exposed portion of the fillers 1A and 1B can be set to be equal to or less than the particle diameters DA and DB of the fillers 1A and 1B, preferably 10 - 90% of the particle diameters DA and DB. In addition, it can be set to expose at a point on the top of the fillers 1A and 1B, or it can be set that the fillers 1A and 1B are completely buried in the resin layer 2, and the diameter Lc is 0.

[0104] In such an invention of the present invention, the presence of the inclination 2x and the undulation 2y on the surface of the resin layer 2 can be confirmed by observing the cross-section of the filler-containing film such as the anisotropic conductive film with a scanning electron microscope, and can also be confirmed in a planar field of view observation. The inclination 2x and the undulation 2y can also be observed with an optical microscope or a metallurgical microscope. In addition, the sizes of the inclination 2x and the undulation 2y can also be confirmed by adjusting the focus during image observation. The same is true even after reducing the inclination or undulation by thermocompression as described above. This is because there are residual traces.

[0105] (Thickness of the resin layer)

[0106] In a filler-containing film such as the anisotropic conductive film of the present invention, the ratios (La / DA) and (La / DB) of the layer thickness La of the resin layer 2 to the average particle diameters DA and DB of all the fillers 1A and 1B are preferably 0.3 or more, more preferably 0.6 to 10, further preferably 0.6 to 8, and particularly preferably 0.6 to 6. As the average particle diameters DA and DB, when the average particle diameters of the filler 1A in the first filler layer and the filler 1B in the second filler layer are different, they can be the average values thereof. If the layer thickness La of the resin layer 2 is too large and the ratio exceeds 10, when the filler-containing film is formed as an anisotropic conductive film, the positions of the fillers 1A and 1B as conductive particles are likely to shift during anisotropic conductive connection, and the capture property of the fillers 1A and 1B in the terminals is reduced. On the contrary, if the layer thickness La of the resin layer 2 is too small and the ratio is less than 0.3, it is difficult for the fillers 1A and 1B in the resin layer 2 to maintain a prescribed arrangement.

[0107] (Composition of resin layer)

[0108] The resin layer 2 can be conductive or insulating according to the use of the filler-containing film, and can also be plastic or curable, but it is preferably formed from an insulating curable resin composition. For example, it can be formed from an insulating thermopolymerizable composition containing a thermopolymerizable compound and a thermopolymerization initiator. A photoinitiator can be contained in the thermopolymerizable composition as needed. These known resins or compounds can be used. Hereinafter, taking an anisotropic conductive film as an example of one embodiment of the filler-containing film, the case of an insulating resin will be described.

[0109] When a thermopolymerization initiator and a photoinitiator are used in combination, a compound that functions both as a thermopolymerizable compound and as a photoinitiable compound can be used, or a photoinitiable compound can be further contained in addition to the thermopolymerizable compound. It is preferable to further contain a photoinitiable compound in addition to the thermopolymerizable compound. For example, a cationic curing initiator is used as the thermopolymerization initiator, an epoxy resin is used as the thermopolymerizable compound, a photo radical polymerization initiator is used as the photoinitiator, and an acrylate compound is used as the photoinitiable compound.

[0110] As the photoinitiator, a plurality of types that react with light of different wavelengths can also be contained. Thus, when the filler-containing film is formed as an anisotropic conductive film, the wavelengths used in the photocuring of the resin constituting the insulating resin layer and the photocuring of the resin for bonding electronic components to each other during anisotropic conductive connection can be used separately during the manufacture of the anisotropic conductive film.

[0111] In the photocuring during the production of an anisotropic conductive film in a filler-containing film, all or part of the photopolymerizable compound contained in the resin layer can be photocured. By this photocuring, the arrangement of the fillers 1A and 1B in the resin layer 2 is maintained or immobilized, and suppression of short circuits and improvement of capture performance can be expected. In addition, by this photocuring, the viscosity of the resin layer in the manufacturing process of the anisotropic conductive film can also be appropriately adjusted.

[0112] The blending amount of the photopolymerizable compound in the resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and further preferably less than 2% by mass. This is because if there is too much photopolymerizable compound, the thrust required for pressing during connection increases. This is particularly preferred in the case of anisotropic conductive connection. This is because both resin flow and pressing of the conductive particles held in the resin can be achieved.

[0113] Examples of the thermopolymerizable composition include: a thermoradical-polymerizable acrylate-based composition containing a (meth)acrylate compound and a thermoradical polymerization initiator, a thermocationic-polymerizable epoxy-based composition containing an epoxy compound and a thermocationic polymerization initiator, etc. A thermoanionic-polymerizable epoxy-based composition containing a thermoanionic polymerization initiator can also be used in place of the thermocationic-polymerizable epoxy-based composition containing a thermocationic polymerization initiator. In addition, as long as there are no particular obstacles, a plurality of polymerizable compounds can be used in combination. An example of the combination use is the combination of a thermocationic-polymerizable compound and a thermoradical-polymerizable compound.

[0114] Here, as the (meth)acrylate compound, conventionally known thermopolymerizable (meth)acrylate monomers can be used. For example, monofunctional (meth)acrylate-based monomers and polyfunctional (meth)acrylate-based monomers having two or more functional groups can be used.

[0115] Examples of the thermoradical polymerization initiator include organic peroxides, azo compounds, etc. In particular, organic peroxides that do not generate nitrogen causing bubbles can be preferably used.

[0116] Regarding the usage amount of the thermoradical polymerization initiator, if it is too small, curing is poor, and if it is too large, the product life is reduced. Therefore, relative to 100 parts by mass of the (meth)acrylate compound, it is preferably 2 to 60 parts by mass, and more preferably 5 to 40 parts by mass.

[0117] Examples of the epoxy compound include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, their modified epoxy resins, alicyclic epoxy resins, etc., and two or more of them can be used in combination. In addition, an oxetane compound can also be used in combination with the epoxy compound.

[0118] As a thermal cationic polymerization initiator, a compound known as a thermal cationic polymerization initiator for epoxy compounds can be used. For example, iodonium salts, sulfonium salts, phosphonium salts, ferrocene compounds, etc. that generate acid by heat can be used. In particular, aromatic sulfonium salts that exhibit good latency with respect to temperature can be preferably used.

[0119] Regarding the usage amount of the thermal cationic polymerization initiator, if it is too small, there is a tendency for poor curing, and if it is too large, there is a tendency for the product life to decrease. Therefore, relative to 100 parts by mass of the epoxy compound, it is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass.

[0120] The thermopolymerizable composition preferably contains a film-forming resin or a silane coupling agent. Examples of the film-forming resin include phenoxy resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyurethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, etc., and two or more of them can be used in combination. Among these, phenoxy resin can be preferably used from the viewpoints of film-forming property, processability, and connection reliability. The weight average molecular weight is preferably 10,000 or more. In addition, examples of the silane coupling agent include epoxy-based silane coupling agents and acrylic-based silane coupling agents. These silane coupling agents are mainly alkoxysilane derivatives.

[0121] In the thermopolymerizable composition, in order to adjust the melt viscosity, in addition to the above-mentioned fillers 1A and 1B, an insulating filler can also be contained. Examples thereof include silica powder and alumina powder. The insulating filler is preferably a fine filler having a particle size of 20 to 1000 nm. In addition, the blending amount is preferably set to 5 to 50 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable compound) such as an epoxy compound. The insulating filler contained in addition to fillers 1A and 1B is preferably used when the use of the filler-containing film is an anisotropic conductive film, but depending on the use, it may not be insulating. For example, a conductive fine filler may also be contained. When the filler-containing film is an anisotropic conductive film, a finer insulating filler (so-called nano filler) different from fillers 1A and 1B can be appropriately contained as needed in the resin layer forming the filler dispersion layer.

[0122] In the filler-containing film of the present invention, in addition to the above-mentioned insulating or conductive fillers, a filler, a softening agent, a promoter, an anti-aging agent, a coloring agent (pigment, dye), an organic solvent, an ion trap, etc. can also be contained.

[0123] <Deformation schemes of the filler-containing film>

[0124] (Filler unit)

[0125] Regarding the arrangement of the fillers in the filler-containing film of the present invention, various schemes can be adopted.

[0126] For example, asFigure 7A , Figure 7B In the case of a filler-containing film 10C such as an anisotropic conductive film shown, examples include: a filler unit 1C1 formed by a plurality of fillers 1A in the first filler layer, a filler unit 1C2 formed by a plurality of fillers 1B in the second filler layer, the filler units 1C1 and 1C2 not contacting each other and not overlapping even in a plan view of the filler-containing film, and the filler units 1C1 and 1C2 being arranged in a lattice pattern. In this case, the number of fillers 1A in each filler unit 1C1 of the first filler layer can be set to, for example, 2 to 9, particularly 2 to 4. In the filler unit, the fillers 1A can be arranged in a line or aggregated into a block. Similarly, the number of fillers 1B in each filler unit 1C2 of the second filler layer can be set to, for example, 2 to 9, particularly 2 to 4. In the filler unit, the fillers 1B can be arranged in a line or aggregated into a block. In the case of an anisotropic conductive film, this can also be applied by arranging the filler units so as to reduce the risk of short circuit according to the terminal layout. When used for applications other than anisotropic conductive films, it can be appropriately adjusted according to the purpose.

[0127] In the case of an anisotropic conductive film, from the viewpoint of improving the capture of fillers (conductive particles) while suppressing short circuits, it is preferably composed of fillers in which the filler units 1C1 of the first filler layer and the filler units 1C2 of the second filler layer are respectively arranged in a line, and it is preferably such that their long side directions are not parallel, as Figure 7A , Figure 7B shown, and particularly preferably perpendicular.

[0128] In addition, as Figure 8A , Figure 8B shown, in the case of a filler-containing film 10D such as an anisotropic conductive film, a plurality of fillers 1A in the first filler layer that are in contact with or close to each other and a plurality of fillers 1B in the second filler layer that are in contact with or close to each other are brought into contact with or close to each other to form a filler unit 1C. It is preferably such that the filler units 1C do not contact each other, and the filler units 1C are regularly arranged. In addition, it is preferred that: the number of fillers 1A in the first filler layer of each filler unit 1C is preferably 2 to 9, particularly 2 to 4, and the fillers 1B in the second filler layer are 2 to 9, particularly 2 to 4. This is the same as above. In the case of an anisotropic conductive film, this can also be applied by arranging the filler units so as to reduce the risk of short circuit according to the terminal layout. When used for applications other than anisotropic conductive films, it can be appropriately adjusted according to the purpose.

[0129] In the case of an anisotropic conductive film, when the filler-containing film 10D having such a filler unit 1C formed by a plurality of fillers (conductive particles) 1A and 1B is used for anisotropic conductive connection and pressed in the film thickness direction, then as Figure 9As shown, the fillers (conductive particles) 1A and 1B that have come into contact with each other can be radially (radially) diffused and the fillers (conductive particles) 1A and 1B can be separated from each other. In this case, as Figure 10 shown, in the inter-terminal region where the terminals 20 and 21 facing each other of the fillers (conductive particles) 1A and 1B are not pressed, the fillers 1A and 1B forming the filler unit 1C are separated before anisotropic conductive connection. Therefore, according to this filler-containing film 10D, short circuits between adjacent terminals can be suppressed. On the other hand, when the fillers (conductive particles) 1A and 1B are located at the edge portions of the terminals 20 and 21 facing each other before anisotropic conductive connection, at least one of the fillers 1A and 1B is captured at the terminals 20 and 21 through anisotropic conductive connection. Therefore, according to this filler-containing film 10D, the capture efficiency of the conductive particles is improved. For uses other than anisotropic conductive films, such a filler unit 1C can also be formed according to the purpose. It is considered preferably applicable to the case of being pressed by a crimping roller. This is because: it is easy to apply a pressing load in a direction other than the thickness direction of the film.

[0130] (Scheme of compensating for the vacancy in the arrangement of one filler layer with another filler layer)

[0131] One filler layer of the first filler layer and the second filler layer is formed in a specified arrangement and a specified number density in design, and then the arrangement and number density of the fillers are confirmed for the entire region. In order to match the particle configuration of this one conductive particle layer, another filler layer is further formed as needed to compensate for the vacancy in the particle configuration of one filler layer. As the filler-containing film as a whole such as an anisotropic conductive film, the vacancy can be eliminated by setting the fillers in a specified configuration. Therefore, the number density of the subsequently formed filler layer can be changed in the long side direction of the filler-containing film. By operating in this way, the yield of the filler-containing film is improved, and the effect of cost reduction can be expected.

[0132] (Lamination of the second resin layer)

[0133] As Figure 11A shown in the filler-containing film 10E such as an anisotropic conductive film, a second resin layer 4 can be laminated on one surface side of the filler dispersion layer 3. The second resin layer 4 preferably has a minimum melt viscosity lower than that of the resin layer 2 forming the filler dispersion layer 3. In addition, when the embedding rate in the resin layer 2 of the first filler layer and the second filler layer is different and the first filler layer protrudes from the resin layer more than the second filler layer, as Figure 11B shown in the filler-containing film 10F such as an anisotropic conductive film, the second resin layer 4 can be laminated on the side of the first filler layer with a larger protruding amount from the resin layer 2, as Figure 11CLike the filler-containing film 10G such as the anisotropic conductive film shown, the second resin layer 4 can be laminated on the surface of the resin layer 2 where the filler layer does not protrude. By laminating the second resin layer 4, when anisotropically conducting and connecting electronic components using a filler-containing film such as an anisotropic conductive film, the space formed by the electrodes or bumps of the electronic components can be filled, thereby improving the adhesiveness. It should be noted that in the case of laminating the second resin layer 4, it is preferable to paste the second resin layer 4 on the electronic components pressed by a tool (paste the resin layer 2 on the electronic components supported on the stage). By operating in this way, unintended movement of the filler can be avoided, and the capture performance can be improved.

[0134] The greater the difference in the minimum melt viscosity between the resin layer 2 and the second resin layer 4, the easier it is for the second resin layer 4 to fill the space formed by the electrodes or bumps of the electronic components, and the effect of improving the adhesiveness between the electronic components can be expected. In addition, the greater this difference, the relatively smaller the amount of movement of the resin layer 2 present in the filler dispersion layer 3, so it is easy to improve the capture performance of the filler in the terminals. The minimum melt viscosity ratio of the resin layer 2 to the second resin layer 4 is preferably 2 or more, more preferably 5 or more, and further preferably 8 or more in practical use. On the other hand, if this ratio is too large, there is a concern of resin overflow or adhesion when making a roll of a long filler-containing film such as an anisotropic conductive film, so it is preferably 15 or less in practical use. More specifically, the preferred minimum melt viscosity of the second resin layer 4 satisfies the above ratio and is 3000 Pa·s or less, more preferably 2000 Pa·s or less, and particularly preferably 100 - 2000 Pa·s.

[0135] It should be noted that the second resin layer 4 can be formed by adjusting the viscosity in the same resin composition as the resin layer.

[0136] The layer thickness of the second resin layer 4 is preferably 4 - 20 μm. Or, it is 1 - 8 times the filler diameter.

[0137] In addition, the minimum melt viscosity of the entire filler-containing film 10E, 10F, 10G such as the anisotropic conductive film incorporating the resin layer 2 and the second resin layer 4 is 8000 Pa·s or less, preferably 200 - 7000 Pa·s or less, and particularly preferably 200 - 4000 Pa·s in practical use.

[0138] (Lamination of the third resin layer)

[0139] It is also possible to sandwich the resin layer 2 with the second resin layer 4 and provide a third resin layer on the opposite side. The third resin layer can function as an adhesive layer.

[0140] The resin composition, viscosity, and thickness of the third resin layer may be the same as or different from those of the second resin layer. The minimum melting viscosity of the anisotropic conductive film incorporating the resin layer 2, the second resin layer 4, and the third resin is not particularly limited, and may be 8000 Pa·s or less, preferably 200 to 7000 Pa·s or less, and particularly preferably 200 to 4000 Pa·s for practical use.

[0141] (Other lamination schemes)

[0142] Depending on the use of the filler-containing film, multiple filler dispersion layers 3 may be laminated, or a filler-free layer may be interposed between the laminated filler dispersion layers as in the second resin layer, and a second resin layer or a third resin layer may be provided on the outermost layer.

[0143] <Manufacturing method of filler-containing film>

[0144] As the resin layer, the filler-containing film of the present invention having a single-layer filler dispersion layer 3 can be obtained, for example, by holding the filler 1A in a predetermined dispersion state (preferably in a predetermined arrangement) on one surface side of the resin layer 2, pressing the filler 1A into the resin layer 2 using a flat plate or a roller, etc., and similarly holding the filler 1B in a predetermined dispersion state (preferably in a predetermined arrangement) on the other surface side of the resin layer 2 and pressing it in. In addition, when holding the filler in a predetermined dispersion state on both surfaces of the resin layer, it can be attached using a coating roller, attached using a transfer mold, or attached by various methods, but it is preferable that the direction of holding the filler on one surface of the resin layer is opposite (180 degrees) to the direction of holding the filler on the other surface. Thus, when observing the front and back sides integrally, the non-uniformity of the dispersion state of the filler on the film surface and the non-uniformity of the dispersion state of the filler on the back side can be alleviated.

[0145] In addition, a filler-containing film such as an anisotropic conductive film having a second resin layer 4 laminated on the filler dispersion layer 3 can be obtained, for example Figure 12 as shown. That is, the filler 1A is attached (Figure a in the same drawing), pressed in (Figure b in the same drawing) on one surface side of the resin layer 2, and then the second resin layer 4 is laminated on the surface where the filler 1A is pressed in (Figure c in the same drawing). The filler 1B is attached (Figure d in the same drawing) on the surface of the resin layer 2 on the side opposite to the second resin layer 4, and the filler 1B is pressed into the resin layer 2 (Figure e in the same drawing). Thus, a filler-containing film 10 such as an anisotropic conductive film having a second resin layer 4 laminated on the filler dispersion layer 3 can be obtained. In this case, by appropriately setting the arrangement of the filler 1A pressed in from one surface side of the resin layer 2 and the arrangement of the filler 1B pressed in from the other surface side, a filler unit 1C in which these fillers 1A and 1B are in contact or close to each other is formed when viewed from above.

[0146] Regarding a filler-containing film such as an anisotropic conductive film in which the resin layer is formed of a single layer of the filler dispersion layer 3, a filler-containing film such as an anisotropic conductive film in which the second resin layer 4 is laminated on the filler dispersion layer 3, and further regarding a scheme in which the third resin layer is laminated, as a method of attaching the fillers 1A and 1B to the resin layer 2 or a method of forming the resin layer 2 in which the fillers 1A and 1B are dispersed, examples include: a method of transferring the fillers to the resin layer using a transfer mold, a method of dispersing the fillers on the resin layer, and a method of coating a resin liquid containing the fillers on the resin layer or the release film using a coating roll having regular grooves on the surface, such as a gravure coater, in the same manner as the method described in Patent Document 1. It should be noted that in the method of coating a resin liquid containing the fillers on the release film using a coating roll, the resin layer thus formed can be set as the resin layer 2. In the method described in Patent Document 1, as described above, it is presumed that the fillers cannot be precisely and regularly arranged as compared with the method using a transfer mold. However, in the present invention, if the attachment directions of the filler 1A forming the first filler layer and the filler 1B forming the second filler layer are opposite in the long side direction of the anisotropic conductive film, then when forming the conductive particle layer, even in the case where voids or non-uniformities in the number density of the fillers are formed, in both the first filler layer and the second filler layer, there is almost no overlap of the portions with voids or non-uniformities in the number density of the fillers. Therefore, the influence of the voids or non-uniformities in the number density of the fillers in the respective filler layers on the conduction characteristics can be reduced.

[0147] Among the above methods, from the viewpoint of improving the accuracy of filler arrangement, it is preferable to use a transfer mold. As the transfer mold, for example, a transfer mold having openings formed in an inorganic material such as silicon, various ceramics, glass, metals such as stainless steel, or an organic material such as various resins by a known opening formation method such as photolithography can be used. In addition, the transfer mold can be formed in a plate shape, a roll shape, or the like.

[0148] Generally, in the process of attaching fillers such as conductive particles to a resin layer using a transfer mold, in order to manufacture a long strip anisotropic conductive film or other filler-containing film, the conductive particles are sequentially attached in the direction from one end to the other end of the resin layer. However, as the filler attachment process continues, due to clogging of the mold, the filler cannot be attached to the resin layer, and there is a tendency for the number of voids in the filler-containing film such as the anisotropic conductive film to increase. Therefore, when attaching the filler that forms the first filler layer from one end to the other end of the resin layer, it is preferable that the filler that forms the second filler layer is attached from the other end to one end of the resin layer. By making the attachment directions opposite in this way, in the region where the probability of voids in the conductive particles is high in the first filler layer, in the second filler layer, it becomes a region where the probability of voids in the filler is low, and as a whole filler-containing film such as an anisotropic conductive film, the number density of the filler can be made uniform, and excessive voids (connection failure in the case of an anisotropic conductive film) that affect the performance of the filler can be eliminated in anisotropic conductive connection. In addition, since a long strip anisotropic conductive film or other filler-containing film is usually manufactured as a roll, when manufacturing with the attachment directions of the first filler layer and the second filler layer being opposite, it is preferable: First, attach the filler that forms the first filler layer from one end to the other end of the long strip resin layer while forming the resin layer into a roll, and then while rolling back this roll, attach the filler that forms the second filler layer to the resin layer in a direction opposite to the attachment direction of the first filler layer and form the resin layer into a roll. Thereby, compared to rolling back the roll of the resin layer having the first filler layer formed thereon and then attaching the filler that forms the second filler layer to the resin layer again in the same attachment direction as the first filler layer, the process can be simplified, and thus an effect of cost reduction can be expected. It should be noted that when making the attachment directions opposite, if necessary, the clogged transfer mold can be replaced with a new one or cleaned. When the product can allow voids in the filler to a certain extent, since the frequency of replacement or cleaning of the transfer mold can be reduced, an effect of cost reduction can also be expected.

[0149] In the method of coating a resin layer or a release film with a resin liquid containing conductive particles using a coating roll, since the grooves on the surface of the coating roll are clogged as the coating continues, the filler is preferably coated from the other end to one end of the film.

[0150] In addition, in the method of dispersing the filler on the resin layer, there are also cases where voids in the filler occur periodically. In such a case, when attaching the filler that forms the first filler layer to the resin layer and when attaching the filler that forms the second filler layer to the resin layer, from the perspective that the occurrence positions of the voids in the filler do not overlap on the front and back sides of the resin layer, it is preferable to make the running direction of the resin layer opposite.

[0151] Even when manufacturing in any of the above-described manufacturing methods, in the case of manufacturing a filler-containing film such as a long-strip anisotropic conductive film, it is predictable that voids of the filler will inevitably be formed. However, by making the attachment directions of the fillers in the long-side direction of the filler-containing films such as the first filler layer and the second filler layer of the anisotropic conductive film opposite to each other, the voids in the filler-containing films such as the anisotropic conductive film will not concentrate in one place, and the voids can be dispersed. Therefore, it can contribute to improving the yield of the filler-containing films such as the anisotropic conductive film or reducing the manufacturing cost.

[0152] It should be noted that making the attachment direction of the first filler layer and the attachment direction of the second filler layer in the filler-containing film such as the anisotropic conductive film opposite to each other is effective in reducing the deviation of the number density of the fillers in the filler-containing films such as the anisotropic conductive film, whether the arrangement pattern or the number density of the fillers in the first filler layer and the arrangement pattern or the number density of the fillers in the second filler layer are the same or different. For example, in the design of the filler-containing film such as the anisotropic conductive film, when the arrangement of the fillers is the same in the first filler layer and the second filler layer and the respective number densities are set to, for example, 400 pieces / mm 2 in the case, according to the above-described manufacturing method, the absolute value of the difference in the number density between one end and the other end in the long-side direction of the actually manufactured filler-containing film such as the anisotropic conductive film is preferably 160 pieces / mm 2 or less, more preferably 80 pieces / mm 2 or less. Similarly, when the number densities of the conductive particles in the first filler layer and the second filler layer are respectively set to 65,000 pieces / mm 2 in the case, the absolute value of the difference in the number density between one end and the other end in the long-side direction of the anisotropic conductive film is preferably 26,000 pieces / mm 2 or less, more preferably 13,000 pieces / mm 2 or less. That is, the absolute value of the difference in the number density between one end and the other end in the long-side direction of the filler-containing film such as the anisotropic conductive film is within the range of preferably ±20%, more preferably ±10% of the average of the number densities of the conductive particles combined with the first filler layer and the second filler layer, which is 800 to 130,000 pieces / mm 2 . Moreover, the case where the number density is less than 400 pieces / mm 2 is not excluded in the present invention. In addition, the anisotropic conductive film is taken as an example for description, but it is not limited thereto. For example, in the optical film, it can be easily speculated that the performance can be stabilized by making the number density uniform. The same can be said for films directly related to the appearance such as the extinction film.

[0153] The embedding amounts of the fillers 1A and 1B attached to the resin layer 2 can be adjusted by the pressing force, temperature, etc. when the fillers 1A and 1B are pressed in. In addition, the presence, shape, and depth of the depressions 2x and 2y can be adjusted by the viscosity of the resin layer 2, the pressing speed, temperature, etc. during pressing. As a pressing method with an embedding rate exceeding 100%, a method of pressing using a pressing plate having convex portions corresponding to the arrangement of the fillers can be cited.

[0154] The filler-containing film such as an anisotropic conductive film formed in a long strip is appropriately sheared and becomes a product of the filler-containing film such as an anisotropic conductive film as a wound body. Therefore, the filler-containing film such as the anisotropic conductive film of the present invention has a length of, for example, 5 to 5000 m and can be a wound body.

[0155] In order to economically connect electronic components by using the anisotropic conductive film contained in the filler-containing film, it is preferable that the anisotropic conductive film is a certain length. Therefore, the length of the filler-containing film is preferably 5 m or more, more preferably 10 m or more, and further preferably 25 m or more. On the other hand, if the anisotropic conductive film is too long, it is difficult to use the existing connecting devices used when manufacturing electronic components using the anisotropic conductive film, and the operability is also poor. Therefore, the length of the anisotropic conductive film is preferably 5000 m or less, more preferably 1000 m or less, and further preferably 500 m or less. From the viewpoint of excellent operability, this long strip of the anisotropic conductive film is preferably formed into a wound body wound around a core.

[0156] <Method of using the filler-containing film>

[0157] The filler-containing film of the present invention can be used in the same manner as the conventional filler-containing film as long as the filler-containing film can be adhered, and there is no particular limitation on the article. It can be adhered to various articles by crimping, preferably by thermocompression bonding, according to the use of the filler-containing film. When adhering, light irradiation can be used, or heat and light can be used in combination. For example, when the resin layer of the filler-containing film has sufficient adhesiveness to the article to which the filler-containing film is to be adhered, by gently pressing the resin layer of the filler-containing film onto the article, a film adhered body in which the filler-containing film is adhered to the surface of one article can be obtained. In this case, the surface of the article is not limited to a flat surface, and it can have irregularities or can be curved as a whole. When the article is in the form of a film or a flat plate, a crimping roller can also be used to adhere the filler-containing film to these articles. Thereby, the filler of the filler-containing film can also be directly joined to the article.

[0158] In addition, the filler-containing film can be interposed between two opposing articles, and the two opposing articles can be connected using a thermocompression bonding roller or a crimping tool, and the filler can be clamped between the articles. In addition, the filler can be sandwiched between the articles without directly contacting the filler with the article.

[0159] In particular, when the filler-containing film is used as an anisotropic conductive film, a thermocompression bonding tool can be used. Via this anisotropic conductive film, it is preferably used for anisotropic conductive connection between a first electronic component such as an IC chip, an IC module, and an FPC and a second electronic component such as an FPC, a glass substrate, a plastic substrate, a rigid substrate, and a ceramic substrate. The anisotropic conductive film can also be used to stack IC chips or wafers for multi-layerization. It should be noted that the electronic components connected by the anisotropic conductive film of the present invention are not limited to the above-mentioned electronic components. In recent years, it can be used for a variety of diverse electronic components.

[0160] Therefore, the present invention includes: a connection structure obtained by pasting the filler-containing film of the present invention to various articles by pressing, and a manufacturing method thereof. In particular, when the filler-containing film is used as an anisotropic conductive film, it also includes a manufacturing method of a connection structure for anisotropically conducting connection between electronic components using the anisotropic conductive film, and the connection structure thus obtained, that is, a connection structure obtained by anisotropically conducting connection between electronic components through the anisotropic conductive film of the present invention.

[0161] As a method for connecting electronic components using an anisotropic conductive film, when the anisotropic conductive film is composed of a single layer of a conductive particle dispersion layer, for a second electronic component such as various substrates, it is temporarily pasted and temporarily pressed from the side where the conductive particles of the anisotropic conductive film are buried into the surface, and a first electronic component such as an IC chip is combined and thermocompression bonded on the side where the conductive particles of the temporarily pressed anisotropic conductive film are not buried into the surface, whereby it can be manufactured. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermopolymerizable compound but also a photoinitiator and a photopolymerizable compound (which may be the same as the thermopolymerizable compound), it can also be a pressing method using both light and heat. As long as such an operation is performed, the unintended movement of the conductive particles can be suppressed to a minimum. In addition, the side where the conductive particles are not buried can be temporarily pasted to the second electronic component for use. It should be noted that the anisotropic conductive film can also be temporarily pasted to the first electronic component instead of the second electronic component.

[0162] In addition, when the anisotropic conductive film is formed of a laminate of a conductive particle dispersion layer and a second insulating resin layer, the conductive particle dispersion layer is temporarily pasted to a second electronic component such as various substrates and temporarily pressed, and the second insulating resin layer side of the temporarily pressed anisotropic conductive film is aligned with a first electronic component such as an IC chip and placed, and then thermocompression bonded. The second insulating resin layer side of the anisotropic conductive film can also be temporarily pasted to the first electronic component. In addition, the conductive particle dispersion layer side can also be temporarily pasted to the first electronic component for use. Examples

[0163] Hereinafter, an anisotropic conductive film, which is an embodiment of the filler-containing film of the present invention, will be specifically described by way of examples.

[0164] (1) Fabrication of the anisotropic conductive film

[0165] (1-1) Examples 1A, 1B to Example 8

[0166] According to the blending shown in Table 1, resin compositions for forming the following layers were prepared: (i) a first insulating resin layer with high viscosity for forming a conductive particle dispersion layer (hereinafter, also referred to as layer A), (ii) a second insulating resin layer with a lower viscosity than the first insulating resin layer (hereinafter, also referred to as layer N), and (iii) a third insulating resin layer for forming an adhesive layer.

[0167] Using a bar coater, the resin composition for forming the first insulating resin layer (layer A) was coated on a PET film with a thickness of 50 μ μm, dried in an oven at 80 °C for 5 minutes, and an insulating resin layer with the thickness shown in Table 2 was formed on the PET film. Similarly, the second insulating resin layer (layer N) and the third insulating resin layer (adhesive layer) were formed on the PET film with the thicknesses shown in Table 3.

[0168] [Table 1]

[0169]

[0170] On the other hand, a mold was fabricated such that the conductive particles (average particle size 3 μ μm) of the first conductive particle layer were arranged in a square lattice pattern as shown in a top view, and the surface density of the conductive particles was 800 particles / mm Figure 1A for FOG applications as shown in Table 2 (Examples 1A, 1B), or 10,000, 20,000, or 30,000 particles / mm 2 for COG applications as shown in Table 3 (Examples 2 to 8). That is, a mold was fabricated with the convex pattern of the mold arranged in a square lattice, and the angle formed by the lattice axis and the short side direction of the anisotropic conductive film 2 was 15°. A known transparent resin in a molten state was injected into this mold and cooled and solidified to form a resin mold with the recessed pattern arranged as shown in θ and in a roll shape. Figure 1A The conductive particles (JSR Corporation, AUL703, average particle size 3

[0171] μm) μm) Fill the concave portion of the resin mold, and coat the above-mentioned first insulating resin layer (A layer) thereon. Press at 60 °C and 0.5 MPa using a pressure roller, and paste conductive particles from one end to the other end of the first insulating resin layer with a length of 300 m. Then, peel the first insulating resin layer (A layer) from the mold, and press the conductive particles on the first insulating resin layer (A layer) into the first insulating resin layer (A layer) through a pressure roller (pressing conditions: 70 °C, 0.5 MPa) to form a first conductive particle layer. Set the pressing rate to 100% so that the conductive particles and the surface of the first insulating resin layer (A layer) are flush. Around the pressed conductive particles, depressions are formed with respect to the cross-section of the first insulating resin layer at the center between adjacent conductive particles.

[0172] Next, bond the second insulating resin layer (N layer) to the surface of the first insulating resin layer (A layer) into which the conductive particles are pressed by heating and pressing (45 °C, 0.5 MPa). On the opposite side surface, make conductive particles adhere in the same manner as above. After a length of 300 m, form a second conductive particle layer by pressing in conductive particles to obtain a conductive particle dispersion layer. In this case, stagger the previously pressed conductive particles (first conductive particle layer) and the subsequently pressed conductive particles (second conductive particle layer) by 3 μm in the short side direction of the film. Make the traveling direction of the first insulating resin layer with the adhered conductive particles opposite to that in the case of forming the first conductive particle layer. In addition, in the case of forming the second conductive particle layer, also set the pressing rate to 100% so that the conductive particles and the surface of the first insulating resin layer (A layer) are flush. Around the pressed conductive particles, depressions are formed with respect to the cross-section of the first insulating resin layer at the center between adjacent conductive particles.

[0173] In Examples 1A, 2, 3, 4, 6, 7, and 8, use the conductive particle dispersion layer obtained by the above operations as the anisotropic conductive film. In Example 1B, make the traveling direction of the film when the conductive particles forming the first conductive particle layer adhere to the first insulating resin layer the same as the traveling direction of the film when the conductive particles forming the second conductive particle layer adhere to the first insulating resin layer.

[0174] In Example 5, bond the third insulating resin layer (adhesive layer) to the surface opposite to the second insulating resin layer (N layer) of the conductive particle dispersion layer by heating and pressing (45 °C, 0.5 MPa).

[0175] In the region with a length of 300 m from one end to the other end of the anisotropic conductive film in each embodiment, 10 rectangular regions with each side being 200 μm were set at different positions in the long side direction as the measurement regions for the number density of conductive particles. The first conductive particle layer and the second conductive particle layer were observed in these measurement regions with a metal microscope, and the number density of conductive particles in each conductive particle layer was obtained. The variation tendency (increasing or decreasing tendency) of the number density of conductive particles from the above-mentioned one end to the other end was studied. The results are shown in Tables 2 and 3.

[0176] (1-2) Comparative Examples 1 to 3

[0177] In the same manner as in Example 1, the first insulating resin layer (A layer), the second insulating resin layer (N layer), and the third insulating resin layer (adhesive layer) having the resin compositions shown in Table 1 were formed.

[0178] However, in Comparative Example 1, conductive particles were uniformly dispersed in the resin composition for forming the first insulating resin layer (A layer), coated on a PET film, and dried, thereby forming a monodispersed conductive particle dispersion layer with a surface density of 40,000 particles / mm 2

[0179] In Comparative Example 2, as the conductive particle layer, only the first conductive particle layer on the side of the second insulating resin layer (N layer) was formed with a surface density of 40,000 particles / mm 2

[0180] In Comparative Example 3, as the conductive particle layer, only the second conductive particle layer on the side opposite to the second insulating resin layer (N layer) was formed with a surface density of 40,000 particles / mm 2

[0181] Regarding the anisotropic conductive films of Comparative Examples 1 to 3, the variation tendency (increasing or decreasing tendency) of the number density of conductive particles from one end to the other end was studied. The results are shown in Tables 2 and 3.

[0182] (2) Evaluation

[0183] For the anisotropic conductive films of the examples and comparative examples prepared in (1), they were cut with an area sufficient for connection, and the following operations were performed to measure or evaluate (a) the initial conduction resistance, (b) the conduction resistance after the reliability test, (c) the particle capture ability, (d) the short-circuit rate, and (e) the temporary crimping property. The results are shown in Tables 2 and 3.

[0184] ​​​In this case, as the specimens for evaluation, in Example 1A and Example 1B (anisotropic conductive films for FOG), one end and the other end in the long side direction of the anisotropic conductive film with a length of 300 m were used, and in Examples 2 to 8 and Comparative Examples 1 to 3 (anisotropic conductive films for COG), the middle part in the long side direction of the anisotropic conductive film (the part 150 m away from one end) was used.

[0185] (a) Initial conduction resistance

[0186] (a1) Evaluation of the conduction characteristics of the anisotropic conductive film for FOG (Examples 1A, 1B)

[0187] The specimen of the anisotropic conductive film was sandwiched between the FPC for evaluating the conduction characteristics and the glass substrate, and heat-pressed (200 °C, 5 MPa, 5 s) with a tool width of 1.5 mm to obtain each evaluation connector, and the conduction resistance of the obtained evaluation connector was measured. The initial conduction resistance was desirably 1 Ω or less for practical use. Here, an initial conduction of 1 Ω or less was set as OK, and a case where it exceeded 1 Ω was set as NG.

[0188] Here, regarding the FPC for evaluation and the glass substrate, their terminal patterns corresponded, and the dimensions were as follows. In addition, when connecting the FPC for evaluation and the glass substrate, the long side direction of the anisotropic conductive film was made to coincide with the short side direction of the terminal.

[0189] FPC for evaluating conduction characteristics

[0190] Terminal pitch: 50 μm;

[0191] Terminal width: Terminal interval = 1:1;

[0192] Polyimide film thickness / copper foil thickness (PI / Cu) = 38 / 8, Sn plating.

[0193] Glass substrate

[0194] Electrode: ITO coating;

[0195] Thickness: 0.7 mm.

[0196] (a2) Evaluation of the conduction characteristics of the anisotropic conductive film for COG (Examples 2 to 8, Comparative Examples 1 to 3)

[0197] The specimen of the anisotropic conductive film was sandwiched between the IC for evaluating the conduction characteristics and the glass substrate, and heat-pressed (180 °C, 80 MPa, 5 s) to obtain each evaluation connector, and the conduction resistance of the obtained evaluation connector was measured. The initial conduction resistance was desirably 1 Ω or less for practical use. Here, an initial conduction of 1 Ω or less was evaluated as OK, and a case where it exceeded 1 Ω was evaluated as NG.

[0198] Here, for the evaluation IC and the glass substrate, their terminal patterns correspond, and the dimensions are as follows. In addition, when connecting the evaluation IC and the glass substrate, the long side direction of the anisotropic conductive film is aligned with the short side direction of the bump.

[0199] Evaluation IC for conduction characteristics

[0200] Outer shape: 1.8 × 20.0 mm;

[0201] Thickness: 0.5 mm;

[0202] Bump specifications: size 30 × 85 μm, bump pitch 50 μm, bump height 15 μm.

[0203] Glass substrate

[0204] Glass material: 1737F manufactured by Corning;

[0205] Outer shape: 30 × 50 mm;

[0206] Thickness: 0.5 mm;

[0207] Electrode: ITO wiring.

[0208] (b) Conduction resistance after reliability test

[0209] The conduction resistance after placing the evaluation connector produced in (a) in a constant temperature bath at 85°C and 85% RH for 500 hours was measured in the same manner as the initial conduction resistance. The conduction resistance after the reliability test is preferably 6 Ω or less for practical use. Here, 6 Ω or less is set as OK, and the case where it exceeds 6 Ω is set as NG.

[0210] (c) Particle capture property

[0211] (c1) Evaluation of particle capture property of anisotropic conductive film for FOG (Examples 1A and 1B)

[0212] In the connector for evaluating conduction characteristics, for 100 regions of 25 × 400 μm in the FPC terminals of the connection part, the number of captured conductive particles was measured, the minimum number of captures was obtained, and evaluation was performed according to the following criteria.

[0213] A (good): 3 or more;

[0214] B (no problem in practice): less than 3.

[0215] (c2) Evaluation of particle capture property of anisotropic conductive film for COG (Examples 2 to 8, Comparative Examples 1 to 3)

[0216] Using an IC for evaluating particle capture property, aligning the evaluation IC with a glass substrate corresponding to a terminal pattern with an offset of 6 μ m, heating and pressing (180 °C, 60 MPa, 5 s), for 100 6 μ m×66.6 μ m regions where the bumps of the evaluation IC overlap with the terminals of the substrate, measuring the number of captured conductive particles, obtaining the minimum capture number, and evaluating according to the following criteria. Practically, a B evaluation or above is preferably used.

[0217] IC for evaluating particle capture property

[0218] Outer shape: 1.6×29.8 mm;

[0219] Thickness: 0.3 mm;

[0220] Bump specifications: size 12×66.6 μm, bump pitch 22 μm, bump height 12 μm.

[0221] Evaluation criteria for particle capture property

[0222] A (good): 5 or more;

[0223] B (practically no problem): 3 or more and less than 5;

[0224] C (bad): less than 3.

[0225] (d) Short - circuit rate

[0226] (d1) Evaluation of the short - circuit rate of the anisotropic conductive film for FOG (Examples 1A, 1B)

[0227] Pressing a FPC identical to the FPC for evaluating conduction characteristics on a non - alkaline glass (thickness 0.7 mm) by heating (200 °C, 5 MPa, 5 s), measuring the number of short - circuits of the obtained evaluation connector, calculating the short - circuit incidence rate based on the measured number of short - circuits and the number of gaps of the evaluation connector, and evaluating according to the following criteria.

[0228] A (good): less than 50 ppm;

[0229] B (practically no problem): 50 ppm or more and less than 200 ppm;

[0230] C (bad): 200 ppm or more.

[0231] (d2) Evaluation of the short - circuit rate of the anisotropic conductive film for COG (Examples 2 - 8, Comparative Examples 1 - 3)

[0232] The evaluation IC using the short - circuit rate obtains an evaluation connector in the same way as in (a) the evaluation of the initial on - resistance, measures the number of short - circuits of the obtained evaluation connector, calculates the short - circuit incidence rate based on the measured number of short - circuits and the number of gaps in the evaluation connector, and conducts evaluation according to the following criteria.

[0233] IC for evaluating the short - circuit rate (comb - shaped TEG (test element group) with a 7.5 - μm pitch)

[0234] Outline: 15×13 mm;

[0235] Thickness: 0.5 mm;

[0236] Bump specifications: size 25×140 μm, bump - to - bump distance 7.5 μm, bump height 15 μm.

[0237] Short - circuit rate evaluation criteria

[0238] A: Less than 50 ppm;

[0239] B: 50 ppm or more and less than 200 ppm;

[0240] C: 200 ppm or more.

[0241] (e) Temporary crimpability

[0242] Using a crimping tool, an anisotropic conductive film (width 1.5 mm, length 50 mm) with a PET film attached is pressed onto ITO glass at a temperature of 60 °C or 70 °C, a crimping pressure of 1 MPa, and a crimping time of 1 second for temporary crimping. In this case, a 350 - μm - thick silicone rubber as a buffer material is placed between the crimping tool and the PET film. For 100 temporary crimping samples where the anisotropic conductive film is pressed onto ITO glass in this way, the PET film is peeled off. At this time, the case where none of the anisotropic conductive films are peeled off from the ITO glass together with the PET film is set as OK, and the case where even one is peeled off is set as NG to facilitate the determination of the success or failure of temporary crimping.

[0243] A: OK at 60 °C or higher;

[0244] B: OK at 70 °C or higher;

[0245] C: NG at 70 °C or higher.

[0246] [Table 2]

[0247]

[0248] [Table 3]

[0249]

[0250] As shown in Table 2, in Example 1A where the conductive particles are embedded in the front and back surfaces of the insulating resin layer at an embedding rate of 100% respectively, and the increasing and decreasing tendency of the number density of the conductive particles from one end to the other end in the long side direction of the anisotropic conductive film is in the opposite direction in the first conductive particle layer and the second conductive particle layer, at one end or the other end of the anisotropic conductive film, any one of the conduction resistance, the reliability of the conduction resistance, the particle capture rate, the short-circuit rate, and the temporary crimpability was well evaluated. In contrast, in Example 1B where the increasing and decreasing tendency of the number density is the same in the first conductive particle layer and the second conductive particle layer, at one end of the film where the number density of the conductive particles combined with the first conductive particle layer and the second conductive particle layer is low, there is a portion with poor particle capture property, and at the other end of the film where the number density is high, a good evaluation including the particle capture property was obtained. It should be noted that in this evaluation, due to a sufficient connection area, even if it is a B evaluation of less than 3, it is judged that there is no problem in practical use.

[0251] As shown in Table 3, for the anisotropic conductive films of Examples 2 to 8, the conductive particles are also embedded in the front and back surfaces of the insulating resin layer at an embedding rate of 100% respectively, and the increasing and decreasing tendency of the number density of the conductive particles in the long side direction of the anisotropic conductive film is in the opposite direction in the first conductive particle layer and the second conductive particle layer, and all are good in any evaluation item. In particular, it can be seen from Example 2 and Example 5 that the anisotropic conductive film of the present invention has good temporary adhesion, excellent operability, and excellent particle capture property even without providing a sticky layer.

[0252] In addition, it can be seen from Comparative Example 1 that if the conductive particles are monodispersed in the conductive particle dispersion layer, both the particle capture rate and the short-circuit rate are poor. It can be seen from Comparative Example 2 that if the conductive particle layer is formed only on the side of the second insulating resin layer (N layer), the particle capture property is poor, and it can be seen from Comparative Example 3 that if the conductive particle layer is formed only on the side opposite to the second insulating resin layer (N layer), the temporary crimpability is poor. It should be noted that in Comparative Example 3, if the temporary crimping temperature is set to 75°C, even if 500 temporary crimping samples are used, the anisotropic conductive film will not peel off from the ITO glass, so it can be considered that Comparative Example 3 can be used in actual use according to the setting of the temporary crimping temperature.

[0253] (3) Transfer rate

[0254] Regarding the anisotropic conductive film of Example 1, the transfer rate of the conductive particles when forming the first conductive particle layer (the first time) and the transfer rate of the conductive particles when forming the second conductive particle layer (the second time) were measured respectively.

[0255] Here, the transfer rate is the ratio of the number of conductive particles transferred to the first insulating resin layer to the number of conductive particles filled in the resin mold.

[0256] The measurement of the transfer rate is to measure the number of conductive particles in the first conductive particle layer or the second conductive particle layer present in an area of 1 mm in length at 0 m, 50 m, 100 m, 200 m, and 300 m of the anisotropic conductive film using a metal microscope and calculate the average value. It should be noted that the first conductive particle layer (the first time) is formed by transferring conductive particles in the direction from the 0 m side to the 300 m side of the anisotropic conductive film, and the second conductive particle layer (the second time) is formed by transferring in the direction from the 300 m side to the 0 m side of the anisotropic conductive film. 2 As a result, in both the first conductive particle layer and the second conductive particle layer, the transfer rate exceeded 99.9% from the transfer starting point to 100 m, but the transfer rate decreased as the transfer proceeded. However, the transfer rate of the combined first conductive particle layer and the second conductive particle layer exceeded 99.9% from the transfer starting point to 300 m.

[0257] Legend

[0258] 1A, 1B: Filler

[0259] 1C, 1C

[0260] 1C2: Filler unit 1、 1C2: Filler unit

[0261] 2: Resin layer

[0262] 2a, 2b: Surfaces of the resin layer

[0263] 2x: Depression

[0264] 2y: Depression

[0265] 3: Filler dispersion layer

[0266] 4: Second resin layer

[0267] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G: Filler-containing films of the examples

[0268] 10Ap: One end of the filler-containing film

[0269] 10Aq: The other end of the filler-containing film

[0270] 20, 21: Terminals

[0271] 30: First electronic component

[0272] 31: Second electronic component

[0273] A: Lattice axis of the arrangement of the filler

[0274] DA, DB: Particle diameters

[0275] La: Layer thickness of the resin layer

[0276] L1, L2: Embedded amount

[0277] L3: Nearest inter-particle distance between fillers in the first filler layer

[0278] L4: Nearest inter-particle distance between fillers in the second filler layer

[0279] Lc: Diameter of the exposed portion of the filler

[0280] Ld: Maximum diameter of the depression (inclination)

[0281] Le: Maximum depth of the depression (inclination)

[0282] Lf: Maximum depth of the depression (undulation)

[0283] θ : Angle formed by the long side direction of the terminal and the lattice axis of the arrangement of the conductive particles.

Claims

1. A filler-containing film, which is a filler-containing film having a filler dispersion layer, and the filler dispersion layer has: a resin layer, a first filler layer composed of fillers dispersed in a single layer in the resin layer, and a second filler layer composed of fillers dispersed in a single layer in the resin layer at a depth different from that of the first filler layer. The fillers of the first filler layer are exposed from one surface of the resin layer or buried in the resin layer, such that the ratio L1 / DA of the distance L1 from one surface of the resin layer to the deepest part of the fillers of the first filler layer to the particle diameter DA of the fillers of the first filler layer is 30% or more and 110% or less. The fillers of the second filler layer are exposed from the other surface of the resin layer or buried in the resin layer, such that the ratio L2 / DB of the distance L2 from the other surface of the resin layer to the deepest part of the fillers of the second filler layer to the particle diameter DB of the fillers of the second filler layer is 30% or more and 110% or less.

2. The filled film according to claim 1, wherein, The ratio La / D of the layer thickness La of the resin layer to the average particle diameter D of the fillers is 0.6 to 10.

3. The filled film according to claim 1, wherein, In the long side direction of the filler-containing film, the number density of the fillers of one of the first filler layer and the second filler layer gradually increases, while the other gradually decreases.

4. The filled film according to claim 1, wherein, There are formed filler units in which the fillers of the first filler layer are in contact with or close to each other, or the fillers of the second filler layer are in contact with or close to each other. The filler units do not contact each other, and the filler units are regularly arranged.

5. The filled film according to claim 1, wherein, There are formed filler units in which the fillers of the first filler layer and the fillers of the second filler layer are in contact with or close to each other. The filler units do not contact each other, and the filler units are regularly arranged.

6. The filled film according to claim 4, wherein, In plan view, the long side direction of the filler units of the first filler layer is not parallel to the long side direction of the filler units of the second filler layer.

7. The filled film according to claim 1, wherein, The filler dispersion layer is laminated with a second resin layer, and the lowest melt viscosity after lamination is 8000 Pa·s.

8. The filled film according to claim 1, wherein, There is a third resin layer on the opposite side with the second filler layer sandwiched between the second resin layer. The lowest melt viscosity after lamination is 8000 Pa·s.

9. The filled film according to claim 1, wherein, The surface of the resin layer near the fillers has an inclination or undulation with respect to the tangent plane of the resin layer at the center between adjacent fillers. In this inclination, the surface of the resin layer around the fillers is defective with respect to the tangent plane. In this undulation, the resin amount of the resin layer directly above the fillers is reduced compared to when the surface of the resin layer directly above the fillers is located on the tangent plane.

10. The filled film according to claim 1, wherein, The fillers are composed of any one of inorganic fillers, organic fillers, and fillers in which organic materials and inorganic materials coexist.

11. The filled film according to claim 1, wherein, The fillers are conductive particles.

12. The filled film according to claim 1, wherein, The fillers are composed of two or more types of fillers.

13. The filler-containing film according to any one of claims 1 to 12, wherein the filler-containing film is used as an anisotropic conductive film, The fillers are conductive particles, and the resin layer is an insulating resin layer.

14. A method for manufacturing the filler-containing film according to any one of claims 1 to 12, characterized in that fillers are held in a predetermined dispersed state on one surface of the resin layer, and the fillers are pressed into the resin layer. Also, other fillers are held in a predetermined dispersed state on the other surface of the resin layer, and the fillers are pressed into the resin layer.

15. A method for manufacturing a filler-containing film according to any one of claims 1 to 12, wherein the filler-containing film is used as an anisotropic conductive film, wherein, The fillers are conductive particles, and the resin layer is an insulating resin layer. The manufacturing method is characterized in that fillers are held on one surface side of the resin layer in a prescribed dispersed state, and the fillers are pressed into the resin layer, and other fillers are also held on the other surface side of the resin layer in a prescribed dispersed state, and the fillers are pressed into the resin layer.

16. The manufacturing method according to claim 14 or 15, wherein, When fillers are held on both surfaces of the resin layer in a prescribed dispersed state, the direction of holding the fillers on one surface side of the resin layer is opposite to the direction of holding the fillers on the other surface side.

17. Membrane adhesive body, wherein, The filler-containing film according to any one of claims 1 to 13 is pasted on an article.

18. Connecting structure, wherein, A first article and a second article are connected via the filler-containing film according to any one of claims 1 to 13.

19. The connection structure according to claim 18, wherein, A first electronic component and a second electronic component are anisotropically conductively connected via the filler-containing film according to claim 13.

20. Method for manufacturing a connecting structure, wherein, The first article and the second article are crimped via the filler-containing film according to any one of claims 1 to 13.

21. The manufacturing method of the connection structure according to claim 19, wherein, The first article and the second article are a first electronic component and a second electronic component respectively, and the first electronic component and the second electronic component are thermally crimped via the filler-containing film according to claim 13, whereby a connection structure in which the first electronic component and the second electronic component are anisotropically conductively connected is manufactured.

22. A filler-containing film, which is a filler-containing film having a filler dispersion layer, the filler dispersion layer having: a resin layer, a first filler layer composed of fillers dispersed in a single layer in the resin layer, and a second filler layer composed of fillers dispersed in a single layer in the resin layer at a depth different from that of the first filler layer The fillers of the first filler layer are exposed from one surface side of the resin layer or are close to the one surface side. The fillers of the second filler layer are exposed from the other surface side of the resin layer or are close to the other surface side. A filler unit is formed by aggregating any one of the fillers of the first filler layer or the fillers of the second filler layer into a lump, and the surface of the resin layer near the fillers has an inclination or undulation with respect to the cut surface of the resin layer at the center between adjacent fillers. In this inclination, the surface of the resin layer around the fillers is defective with respect to the cut surface, and in this undulation, the resin amount of the resin layer directly above the fillers is reduced compared with when the surface of the resin layer directly above the fillers is located at the cut surface.

23. The filled film according to claim 22, wherein, The ratio La / D of the layer thickness La of the resin layer to the average particle diameter D of the fillers is 0.6 to 10.

24. The filled film according to claim 22, wherein, In the filler unit, a plurality of fillers are arranged in a line or aggregated into a lump.

25. The filled film according to claim 22, wherein, In the longitudinal direction of the filler-containing film, the number density of the fillers of the first filler layer and the number density of the fillers of the second filler layer gradually increase on one side and gradually decrease on the other side.

26. The filled film according to claim 22, wherein, A filler unit is formed by the fillers of the first filler layer contacting or approaching each other or the fillers of the second filler layer contacting or approaching each other. The filler units do not contact each other, and the filler units are regularly arranged.

27. The filler-containing film according to claim 22, wherein, A filler unit is formed by the fillers of the first filler layer and the fillers of the second filler layer contacting or approaching each other. The filler units do not contact each other, and the filler units are regularly arranged.

28. The filled film according to claim 26, wherein, In a plan view, the longitudinal direction of the filler unit of the first filler layer is not parallel to the longitudinal direction of the filler unit of the second filler layer.

29. The filled film according to claim 22, wherein, The filler dispersion layer is laminated with a second resin layer, and the lowest melt viscosity after lamination is 8000 Pa·s.

30. The filled film according to claim 22, wherein, The second filler layer is clamped between the second resin layer, and the third resin layer is present on the opposite side. The lowest melt viscosity after lamination is 8000 Pa·s.

31. The filled film according to claim 22, wherein, The filler is composed of any one of an inorganic filler, an organic filler, and a filler in which an organic material and an inorganic material coexist.

32. The filler-containing film according to claim 22, wherein, The filler is conductive particles.

33. The filled film according to claim 22, wherein, The filler is composed of two or more kinds of fillers.

34. The filled film according to claim 22, wherein, The massive one is conductive particles.

35. The filled film according to claim 34, wherein, The conductive particles are any one of metal particles, alloy particles, and metal-coated resin particles.

36. The filled film according to claim 22, wherein, The filler other than the filler aggregated into a massive shape is conductive particles.

37. The filler-containing film according to claim 36, wherein, The conductive particles are any one of metal particles, alloy particles, and metal-coated resin particles. The filled film according to claim 22, wherein, The fillers other than the massive and aggregated massive fillers are all conductive particles.

39. The filled film according to claim 38, wherein, The conductive particles are any one of metal particles, alloy particles, and metal-coated resin particles.

40. The filled film according to any one of claims 22 to 39, wherein the filled film is used as an anisotropic conductive film, The filler is conductive particles, and the resin layer is an insulating resin layer.

41. The method for manufacturing a filler-containing film according to any one of claims 22 to 39, wherein the method is characterized in that a filler is held in a predetermined dispersed state on one surface of the resin layer, and the filler is pressed into the resin layer, and another filler is also held in a predetermined dispersed state on the other surface of the resin layer, and the filler is pressed into the resin layer.

42. The method for manufacturing a filler-containing film according to any one of claims 22 to 39, wherein the filler-containing film is used as an anisotropic conductive film, The filler is conductive particles, and the resin layer is an insulating resin layer. The method is characterized in that a filler is held in a predetermined dispersed state on one surface of the resin layer, and the filler is pressed into the resin layer, and another filler is also held in a predetermined dispersed state on the other surface of the resin layer, and the filler is pressed into the resin layer.

43. The manufacturing method according to claim 41 or 42, wherein, When the filler is held in a predetermined dispersed state on both surfaces of the resin layer, the direction of holding the filler on one surface of the resin layer is opposite to the direction of holding the filler on the other surface.

44. Membrane laminate, wherein, The filler-containing film according to any one of claims 22 to 40 is pasted on an article.

45. Connecting structure, wherein, The first article and the second article are connected via the filler-containing film according to any one of claims 22 to 40.

46. The connection structure according to claim 45, wherein, The first electronic component and the second electronic component are anisotropically conductively connected via the filler-containing film according to claim 40.

47. Method for manufacturing a connection structure, wherein, The first article and the second article are crimped via the filler-containing film according to any one of claims 22 to 40.

48. The manufacturing method of the connection structure according to claim 46, wherein, The first article and the second article are the first electronic component and the second electronic component respectively, and the first electronic component and the second electronic component are thermally crimped via the filler-containing film according to claim 40, thereby manufacturing a connection structure in which the first electronic component and the second electronic component are anisotropically conductively connected.

Images