Filler-containing film and method for manufacturing the same, and connecting structure and method for manufacturing the same

Abstract

The aim is to enable the individualization of filler-containing films, such as conductive films and anisotropic conductive films, without the need for die-cutting, half-cutting, or laser processing. Furthermore, when producing filler-containing films as narrow-width reel products, the aim is to provide narrow-width filler-containing films that do not severely restrict the design flexibility of the filler-containing films in terms of film width, film thickness, and film composition. [Solution] A filler-containing film having a filler-holding insulating resin layer and a filler has a recess and a protrusion on one side of the filler-holding insulating resin layer. At least one filler group consisting of multiple fillers is arranged on the protrusion, and the width of the protrusion in the short direction of the film is less than the width of the filler-holding insulating resin layer, preferably 95% or less of that width.

Description

[Technical Field]

[0001] The present invention relates to a filler-containing film and a method for manufacturing the same, as well as a connecting structure and a method for manufacturing the same. [Background technology]

[0002] Generally, in small displays for mobile devices such as smartphones and tablets, medium-sized displays for laptops, and large displays for large LCD televisions, driver IC chips are mounted on the glass panel using COG (chip on glass) via an anisotropic conductive film, which is a type of filler-containing film in which conductive particles are held in an insulating resin layer. Alternatively, flexible printed circuits (FPCs) are mounted on the glass panel using FOG (film on glass) via an anisotropic conductive film.

[0003] In recent years, with the increasing functionality, precision, and complexity of small electronic components such as IC chips and IC modules, anisotropic conductive films used in COG mounting and FOG mounting have been designed to regularly align conductive particles on an insulating resin layer (Patent Document 1). However, in addition to the conventionally required improvements in performance such as improved capture efficiency and avoidance of short circuits, the demands have diversified. As a result, it has been proposed to create individual pieces of anisotropic conductive film according to the size and shape of the electronic components to be connected (Patent Document 2), and, in the case of reel products of anisotropic conductive film, to slit them to an even narrower width than before for various reasons, such as reducing the connection area (Patent Document 3). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2007-80522 [Patent Document 2] Japanese Patent Publication No. 2020-198422 [Patent Document 3] Japanese Patent Publication No. 2012-232392 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Incidentally, when a conductive film or anisotropic conductive film 300, which has a structure in which a conductive particle-holding layer 31 holding conductive particles (not shown) is laminated on a base film 30, as shown in Figure 25, is to be divided into relatively large pieces of several millimeters in size, die cutting, half-cutting, or printing are used. When dividing into relatively small pieces of sub-millimeter size, laser processing may also be used in addition to these methods. In these cases, as shown in Figures 26A, 26B, 27A, and 27B, in the divided conductive film or anisotropic conductive film 300a having divided conductive particle-holding layers 31a and 31b, the conductive particle-holding layers that were laminated on the base film 30 other than the divided conductive particle-holding layers 31a and 31b must be peeled off from the base film 30 and discarded, which presents a problem of unavoidable increases in the manufacturing cost and environmental burden of the conductive film or anisotropic conductive film.

[0006] Furthermore, in the case of reel products of anisotropic conductive film, as shown in Figure 28, the conductive film or anisotropic conductive film 300 is slit by a pair of slitting blades 310 set to a predetermined width and then wound onto a reel. However, because wide conductive films or anisotropic conductive films are transported and slit at high speed, the film may vibrate during transport, leading to a decrease in film width accuracy, adhesion of resin to the slitting blades, or snagging of the slitting blades on the film, which can cause blocking in the reel product. For this reason, there has been a problem in that the design freedom of conductive films or anisotropic conductive films is greatly restricted in terms of film width, film thickness, and film composition.

[0007] The present invention aims to solve these conventional problems by enabling the individualization of filler-containing films, such as conductive films and anisotropic conductive films, without the need for die-cutting, half-cutting, printing, or laser processing. Furthermore, it aims to provide narrow-width filler-containing films so that the design freedom of the filler-containing film is not severely restricted in terms of film width, film thickness, and film composition when the filler-containing film is made into a narrow-width reel product. If such a narrow-width filler-containing film can be realized, it will be possible to provide only the amount of conductive particles or other fillers needed in the insulating resin layer, thereby reducing both the manufacturing cost and environmental impact of the filler-containing film. [Means for solving the problem]

[0008] The present inventors have found that the objective of the present invention can be achieved by providing recesses and protrusions on one side of the insulating resin layer for retaining fillers in a filler-containing film having an insulating resin layer for retaining fillers, arranging a group of fillers consisting of multiple fillers on the protrusions, and further setting the width of the protrusions in the short direction of the film to be less than the width of the insulating resin layer for retaining fillers, thereby completing the present invention.

[0009] In other words, the present invention relates to a filler-containing film having an insulating resin layer for retaining fillers and a filler, A recess and a protrusion are formed on one side of the insulating resin layer for retaining the filler. At least one filler group consisting of multiple fillers is arranged on the aforementioned protrusion. The present invention provides a filler-containing film in which the width of the protrusions in the short direction of the film is less than the width of the insulating resin layer for retaining the filler, preferably 95% or less.

[0010] In the filler-containing film of the present invention, it is preferable that each filler constituting the filler group is arranged such that at least a portion of it is embedded on the surface of the protrusions or in the insulating resin layer for holding the fillers that constitutes the protrusions. In this case, the protrusions may be arranged randomly, but it is preferable that they are arranged in a regular pattern, and within the filler group, multiple fillers may be arranged randomly, but it is preferable that they are arranged in a regular pattern. In either case, it is preferable that the fillers are spaced apart from each other. Even if there is aggregation or aggregation of fillers in the protrusions, if the protrusions are spaced apart from each other, it may not cause any performance problems in the filler-containing film. Such cases may be preferable from the viewpoint of productivity and cost. Such cases are suitable for the demand for cost reduction.

[0011] On the other hand, it is preferable that no filler is placed in the recess. At least a portion of the recess may be through.

[0012] Furthermore, in the filler-containing film of the present invention, it is preferable that a base film is laminated on the back surface of the insulating resin layer for retaining the filler. In this case, the recesses may penetrate, and the protrusions may be separated from other protrusions by the penetrated recesses. Alternatively, the protrusions may be separated from other protrusions by cutting. The separated protrusions may be laminated independently on another resin layer. That is, the protrusions may be scattered on another resin layer. There may be one or more protrusions.

[0013] Furthermore, in the filler-containing film of the present invention, a plurality of protrusions may be arranged spaced apart from each other in the longitudinal direction of the film.

[0014] When the filler-containing film of the present invention is viewed in plan, grooves may be formed on the protrusions, and the protrusions may be formed from a plurality of sub-protrusions that are spaced apart from each other but close together.

[0015] In the filler-containing film of the present invention, it is preferable that the width W1 of the base film in the film, the width W2 of the insulating resin layer for holding the filler, and the width W3 of the convex portion have a relationship of the inequality: W1 ≥ W2 > W3.

[0016] In the filler-containing film of the present invention, a convex portion covering insulating resin layer may be laminated on the insulating resin layer for holding the filler so as to cover the convex portion. Further, in the method for manufacturing the film, when a plurality of convex portions are arranged at intervals in the width direction (the short side direction of the film) of the film and the space between the convex portions is slit, it may be preferable that the convex portion covering insulating resin layer does not exist on the side surface (the side cross section of the film) of the convex portion. For example, when a plurality of convex portions are arranged at intervals in the short side direction of the film, it is preferable that the convex portion covering insulating resin layer is not laminated between adjacent convex portions in terms of facilitating avoidance of resin adhesion during slitting.

[0017] Further, the present invention provides the following steps A to C as the method for manufacturing the filler-containing film of the present invention described above: (Step A) A step of forming an insulating resin layer for holding a filler on a release film subjected to a release treatment; (Step B) A step of forming a concave portion and a convex portion on one side of the insulating resin layer for holding the filler by performing hot pressing with a pressing die having a concave portion corresponding to the convex portion of the filler-containing film abutted against the insulating resin layer for holding the filler; and (Step C) A step of transferring the filler onto the top surface of the convex portion by opposing the filler arrangement surface of the filler transfer sheet in which a plurality of fillers are arranged on one side of the filler transfer base material to the top surface of the convex portion and pressing from the filler transfer base material side and provides a manufacturing method having the above steps.

[0018] This manufacturing method further includes the following step D and / or step E: (Step D) A step of embedding each filler transferred to the top surface of a protrusion into a filler-retaining insulating resin layer such that at least a portion of it is embedded; (Process E) A process of laminating another insulating resin layer onto the insulating resin layer for retaining the filler, starting from the side of the convex portion where the filler has been transferred. The film obtained in this process may be slit or made into a single sheet. The single sheet of film can be placed in a tray and shipped.

[0019] This manufacturing method replaces or adds the following step F to step E: (Process F) The process involves removing the release film and laminating another insulating resin layer onto the filler-holding insulating resin layer, starting from the opposite side of the convex portion where the filler was transferred. It can have.

[0020] Furthermore, the present invention provides, as an alternative embodiment of the method for manufacturing the filler-containing film of the present invention described above, the following steps a to c: (Step a) A process of forming an insulating resin layer for retaining fillers on a release film that has been subjected to a release treatment, and then laminating another insulating resin layer onto the formed insulating resin layer for retaining fillers; (Step b) A step of forming recesses and protrusions on one side of the insulating resin layer for retaining fillers by applying a press mold having recesses corresponding to the protrusions of the filler-containing film to the insulating resin layer for retaining fillers from which the release film has been peeled off, and performing a heat press; and (Step c) The process involves placing the filler-placed side of a filler transfer sheet, which has multiple fillers arranged on one side of a filler transfer substrate, against the top surface of the protrusion, and pressing from the filler transfer substrate side to transfer the filler to the top surface of the protrusion. The present invention provides a manufacturing method for which the present invention is located.

[0021] This alternative method of manufacturing further involves the following steps d and / or e: (Step d) A step of embedding each filler transferred to the top surface of a protrusion into a filler-retaining insulating resin layer such that at least a portion of it is embedded; (Step e) A process of laminating another insulating resin layer onto the insulating resin layer for retaining the filler, starting from the side of the convex portion where the filler has been transferred. The film obtained in this process may be slit or made into a single sheet. The single sheet of film can be placed in a tray and shipped.

[0022] In the method for manufacturing a filler-containing film of the present invention, it is preferable that the mold is a concave single sheet. Furthermore, the "other insulating resin layer" may have the same composition as the "insulating resin layer for retaining the filler" or it may be different. It may also be a resin layer containing a curable resin or a curing agent, or it may be an adhesive layer that does not contain them. The "other insulating resin layers" used in different processes may be the same or different. When carrying out the method for manufacturing a filler-containing film of the present invention, release films and cover films may be applied to intermediates and the final product as appropriate for handling intermediates and the final product during manufacturing.

[0023] Furthermore, the present invention provides a connection structure in which a first article is connected to a second article via the filler-containing film of the present invention described above. In this case, if the filler is conductive particles and a conductive film or an anisotropic conductive film is used as the filler-containing film, a connection structure in which the first article and the second article are electrically connected or anisotropically conductive can be preferably obtained.

[0024] Furthermore, the present invention provides a method for manufacturing a connecting structure, characterized by sandwiching the aforementioned filler-containing film of the present invention between a first article and a second article and pressing them together. In this case as well, if a conductive film or an anisotropic conductive film is used as the filler-containing film, the connecting structure can be preferably manufactured by electrically connecting or anisotropically conductive connecting the first article and the second article. [Effects of the Invention]

[0025] The filler-containing film of the present invention comprises a filler-holding insulating resin layer and fillers, and preferably has a plurality of recesses and protrusions on one side of the filler-holding insulating resin layer. At least one filler group consisting of multiple fillers is arranged in each protrusion. These protrusions can be manufactured so as to correspond basically one-to-one with electronic components such as IC chips and FPCs to be placed on a substrate such as glass wiring using the filler-containing film. Moreover, it is possible to transfer the filler only to the top surface of the protrusions from a filler transfer sheet in which the filler is regularly arranged over the entire surface, while leaving the bottom of the recesses without filler. Therefore, when various electronic components are anisotropically conductively connected to a wiring board or the like, the protrusion portions of the filler-containing film can function as substantially individual pieces of filler-containing film without concern for short circuits. Furthermore, since a thin insulating resin layer can be left in the recesses, there is also the advantage that a decrease in tack and adhesive performance can be suppressed. Furthermore, since the width of the protrusions in the short direction of the film is less than the width of the insulating resin layer for filler retention relative to the width of the base film, preferably 95% or less, resin flow can be suppressed when, for example, a filler-containing film is applied to a conductive connection or anisotropic conductive connection.

[0026] Furthermore, in the method for manufacturing a filler-containing film of the present invention, a press mold having recesses corresponding to the protrusions of the filler-containing film is brought into contact with the filler-holding insulating resin layer, and a heat press is performed to form a plurality of protrusions and recesses on one side of the filler-holding insulating resin layer. Such a press mold can be formed by photolithography, which is a high-precision and high-resolution processing technique. Therefore, by using such a press mold processing method, the planar shape and surface area of ​​the top surface of the protrusions of the filler-containing film, and the cross-sectional shape and height of the protrusions are compared. It is possible to form with high precision and resolution relatively easily. Moreover, since it is not necessary to create fine holes in this mold to arrange minute fillers, preferably in a regular arrangement, it is possible to manufacture the mold at a low cost. Furthermore, in the method for manufacturing filler-containing film of the present invention, the filler can be transferred only to the protrusions formed by the mold using a conventional filler transfer sheet in which the filler is arranged all over. In other words, even if the arrangement of the filler group in the filler-containing film is changed, for example from random arrangement to a regular arrangement or to a dispersed state, it is possible to create a new mold that can be manufactured relatively easily and at low cost. Since the dispersed state has fewer constraints on the mold, it is thought that it can be made even cheaper. Furthermore, since a release treatment can be applied to the mold, it is possible to avoid the adhesion of insulating resin to the mold during mold processing, making it suitable for the production of long films. [Brief explanation of the drawing]

[0027] [Figure 1Aa] Figure 1Aa is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1Ab] Figure 1Ab is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1Ac] Figure 1Ac is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1Ad] Figure 1Ad is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1B] Figure 1B is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1C] Figure 1C is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 1D] Figure 1D is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 4]Figure 4 is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view of the filler-containing film of the present invention. [Figure 6] Figure 6 is an explanatory diagram of the filler group on the top surface of the convex portion of the filler-containing film of the present invention. [Figure 7] Figure 7 is an explanatory diagram of the filler group on the top surface of the convex portion of the filler-containing film of the present invention. [Figure 8] Figure 8 is a schematic cross-sectional view of another embodiment of the filler-containing film of the present invention. [Figure 9A] Figure 9A is a schematic cross-sectional view of another embodiment of the filler-containing film of the present invention. [Figure 9B] Figure 9B is a schematic cross-sectional view of another embodiment of the filler-containing film of the present invention. [Figure 9C] Figure 9C is a schematic cross-sectional view of another embodiment of the filler-containing film of the present invention. [Figure 10] Figure 10 is a schematic cross-sectional view of another embodiment of the filler-containing film of the present invention. [Figure 11] Figure 11 is a diagram illustrating the process of the method for producing the filler-containing film of the present invention. [Figure 12] Figure 12 is a diagram illustrating the process of the method for producing the filler-containing film of the present invention. [Figure 13] Figure 13 is a plan view of deformation embodiment 2 of the filler-containing film of the present invention. [Figure 14] Figure 14 is a plan view of deformation embodiment 3 of the filler-containing film of the present invention. [Figure 15] Figure 15 is a plan view of deformation embodiment 3 of the filler-containing film of the present invention. [Figure 16] Figure 16 is a plan view of deformation embodiment 4 of the filler-containing film of the present invention. [Figure 17] Figure 17 is a schematic cross-sectional view of deformation embodiment 5 of the filler-containing film of the present invention. [Figure 18] Figure 18 is a schematic cross-sectional view of deformation embodiment 5 of the filler-containing film of the present invention. [Figure 19] Figure 19 is a process diagram illustrating the method for producing the filler-containing film of the present invention. [Figure 20] Figure 20 is a process diagram illustrating the method for producing the filler-containing film of the present invention. [Figure 21] Figure 21 is a process diagram illustrating the method for producing the filler-containing film of the present invention. [Figure 22] Figure 22 is a process diagram illustrating the method for producing the filler-containing film of the present invention. [Figure 23A] Figure 23A is a schematic cross-sectional view of a filler-containing film obtained by steps A to C of the method for producing a filler-containing film according to the present invention. [Figure 23B] Figure 23B is a schematic cross-sectional view of a filler-containing film obtained by steps A to D of the method for manufacturing a filler-containing film according to the present invention. [Figure 23C] Figure 23C is a cross-sectional perspective view of the filler-containing film of the present invention, corresponding to Figure 26B. [Figure 23D] Figure 23D is a cross-sectional perspective view of the filler-containing film of the present invention, corresponding to Figure 27B. [Figure 24] Figure 24 is a plan view of the convex side surface of the filler-containing film of the present invention. [Figure 25] Figure 25 is a schematic cross-sectional view of a conventional conductive film or an anisotropic conductive film. [Figure 26A] Figure 26A is an explanatory diagram of the individualization of conventional conductive films or anisotropic conductive films. [Figure 26B] Figure 26B is a cross-sectional perspective view of Figure 26A along the x1-x2 line. [Figure 27A] Figure 27A is an explanatory diagram of the individualization of conventional conductive films or anisotropic conductive films. [Figure 27B] Figure 27B is a cross-sectional perspective view of Figure 27A along the line y1-y2. [Figure 28] Figure 28 is a diagram illustrating a conventional slit for a conductive film or anisotropic conductive film. [Modes for carrying out the invention]

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0029] <Filler-containing film> Figure 1Aa is a cross-sectional view of the filler-containing film 10 in the short direction of the film. As shown in Figure 1Aa, the filler-containing film 10 of the present invention has a filler-holding insulating resin layer 1 and a filler 2. On one side of the filler-holding insulating resin layer 1, preferably a plurality of recesses 3 and protrusions 4 are formed. The protrusions 4 are portions that hold the filler 2, and at least one filler group 20 consisting of a plurality of fillers 2 is arranged on each protrusion 4. The width W3 of these protrusions 4 in the short direction of the film will coincide with the width of the connection area 40 for, for example, COG connection or FOG connection. Specifically, in the case of COG connection, as shown in Figure 1Ab (cross-sectional view in the short direction of the film), the width of the connection area of ​​the protrusion 4 will consist of the width of the output area 40a and the width of the input area 40b. Also, in the case of FOG connection, as shown in Figure 1Ac (cross-sectional view in the short direction of the film), the width of the connection area 40 of the protrusion 4 will correspond to the width of the heat-sealing tool T.

[0030] In the filler-containing film of the present invention, as shown in Figure 1Ab, protrusions of different widths (for example, a relatively wide protrusion corresponding to the output region 40a and a relatively narrow protrusion corresponding to the input region 40b) may be arranged in parallel and spaced apart from each other in the short direction of the film (film width direction). In such a case, the widths of the wide protrusions and the narrow protrusions are mainly determined according to the widths of the regions to be connected (for example, the output region and the input region). The width of the wide protrusions is preferably 10% or more, more preferably 15% or more, preferably 80% or less, more preferably 60% or less, and even more preferably 30% or less of the width of the insulating resin layer 1 for filler retention. The width of the narrow protrusions is preferably 1% or more, more preferably 5% or more, preferably 40% or less, and even more preferably 20% or less of the width of the insulating resin layer 1 for filler retention. Furthermore, the distance between the wide and narrow protrusions is determined according to the distance between the areas to be connected, preferably 5% or more of the width of the insulating resin layer 1 for filler retention, more preferably 25% or more, even more preferably 50% or more, preferably 90% or less, and more preferably 80% or less. The width of the top surfaces of the wide and narrow protrusions, and the distance between the spaced-out protrusions can be adjusted appropriately from these numerical ranges and are not limited to these ranges, as they should be adjusted according to the specifications of the parts to be connected. One can think of it as having two protrusions with different lengths (widths) in the short direction of the film, and each protrusion being spaced apart in the short direction of the film. These are located on the outside in the longitudinal direction of the film. Alternatively, instead of dummy bumps, there may be additional protrusions between the spaced-out protrusions, in which case there will be three protrusions in parallel.

[0031] Furthermore, in the filler-containing film of the present invention, the protrusions may be spaced apart in the longitudinal direction, as shown in Figure 13. However, even when protrusions of different widths are spaced apart and arranged in parallel in the short direction of the film (see Figure 1Ab), the protrusions may be spaced apart in the longitudinal direction of the film while maintaining that parallel arrangement. This makes it easier to handle the filler-containing film in sheet form.

[0032] In Figures 1Aa, 1Ab, and 1Ac, the fillers 2 constituting the filler group 20 are arranged on the surface of the protrusion 4. However, as shown in Figures 1B to 1D, each filler 2 constituting the filler group 20 may be arranged such that at least a portion of it is embedded in the filler-holding insulating resin layer 1 that constitutes the protrusion 4. For example, in Figure 1B, approximately half of the filler 2 is embedded in the filler-holding insulating resin layer 1; in Figure 1C, the end of the filler 2 is embedded so as to be flush with the filler-holding insulating resin layer 1; and in Figure 1D, the filler 2 is completely embedded without being exposed to the filler-holding insulating resin layer 1. When the filler is arranged on the protrusion of the filler-containing film 10 of the present invention in this way, the filler is not transferred to the inner bottom surface of the recess (non-protrusion) portion. This is because the filler contained in the opening of the transfer mold (Japanese Patent No. 6187665) used to place the filler in the protrusions, and the filler 2 placed on the filler placement surface of the filler transfer sheet 51 shown in Figure 22 (described later), do not reach (or have difficulty reaching) the bottom of the recesses in the filler-containing film during filler transfer. Another factor is that the resin thickness at the bottom of the recesses in the filler-containing film is much thinner than the resin thickness in the protrusions, which greatly reduces the adhesive strength of the recesses and makes it difficult to transfer the filler. As a result, each protrusion functions as a substantially individual piece of filler-containing film. Therefore, when the filler is conductive particles, the filler-containing film can function as a substantially individual piece of conductive film or an anisotropic conductive film.

[0033] The term "containing" in "filler-containing film" has two meanings. One meaning is that, as shown in Figure 1Aa, the protrusions 4 rising from the recesses 3 are randomly or regularly arranged (for example, a square grid arrangement, a hexagonal grid arrangement, etc., but not limited to a grid arrangement). The other meaning is that the fillers 2 within the filler group 20 arranged on the protrusions 4 are randomly or regularly arranged (for example, a square grid arrangement, a hexagonal grid arrangement, etc.). From the viewpoint of filler captureability and manufacturing cost, it is preferable that the arrangement of the protrusions 4 and the arrangement of the fillers 2 are regularly arranged (especially a hexagonal grid arrangement). The fillers 2 may be dispersed rather than arranged. When arranged, regardless of whether they are randomly or regularly arranged, it refers to a state in which preferably 95% or more, more preferably 98% or more of the total number of fillers are individually separated and not in contact with each other. However, units that are intentionally assembled may be counted as one filler.

[0034] (Insulating resin layer 1 for retaining filler) The insulating resin layer 1 for retaining the filler, which constitutes the filler-containing film 10 of the present invention, can have the same configuration as the insulating resin layer for retaining fillers in conventional conductive films and anisotropic conductive films, and can be formed from, for example, a thermosetting resin composition. Such a thermosetting resin composition preferably contains a rubber component, a film-forming resin, a thermosetting resin, a thermosetting agent, and an inorganic filler. This inorganic filler is different from the filler arranged in the protrusions 4 and is uniformly dispersed in the insulating resin layer 1 for retaining the filler. The insulating resin layer 1 for retaining the filler may contain other known additives as needed, as long as they do not impair the effects of the invention. The thickness of the insulating resin layer 1 for retaining the filler can be appropriately determined according to the shape and surface area of ​​the recesses 3 and protrusions 4, but is preferably 1 / 2 times or more, more preferably 2 / 3 times or more, even more preferably the same or more than, the average particle diameter of the filler, preferably 20 times or less, more preferably 10 times or less, and even more preferably 5 times or less. If the insulating resin layer 1 for retaining the filler is too thick, the resin will flow excessively during mounting, and if the filler is arranged in a regular pattern, there is a concern that the regular arrangement of the particles will be greatly disrupted. Conversely, if it is too thin, there will be insufficient resin in the protrusions 4, making it difficult to position the filler, and there is a concern that the filler will protrude from the surface of the protrusions, making temporary bonding difficult. As an example of the insulating resin layer 1 for retaining the filler, one can refer to a general conductive film or an anisotropic conductive film that functions as an adhesive or connecting film with adhesive properties.

[0035] *Rubber component The rubber component contained in the thermosetting resin composition is a component that imparts toughness and cushioning (shock absorption) to the filler-holding insulating resin layer 1, and is not particularly limited as long as it is an elastomer with good cushioning properties. Specific examples include acrylic rubber, silicone rubber, butadiene rubber, and polyurethane resin (polyurethane elastomer). Among these, it is preferable that one or more selected from acrylic rubber and silicone rubber be used. The content of the rubber component is preferably 1 part by mass or more, more preferably 2 parts by mass or more, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler.

[0036] *Film forming resin As film-forming resins, from the viewpoint of film-forming properties, various resins such as phenoxy resins, polyester resins, polyurethane resins, polyester urethane resins, acrylic resins, polyimide resins, and butyral resins, with a weight-average molecular weight of about 10,000 to 80,000, are preferably used individually or in combination of two or more types. Among these, phenoxy resin is preferred from the viewpoint of film formation state and connection reliability. The content of the film-forming resin is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 35 parts by mass or more, preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler.

[0037] *Thermosetting resin Examples of thermosetting resins include epoxy compounds and (meth)acrylate compounds, with epoxy compounds being particularly preferred. These compounds may be monomers, oligomers, or polymers. The content of the thermosetting resin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler.

[0038] The epoxy compound that can be used as a thermosetting resin is not particularly limited as long as it has one or more epoxy groups in its molecule. For example, it may be a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a urethane-modified epoxy resin. Among these, a high-purity bisphenol A type epoxy resin is preferably used. A specific example of a high-purity bisphenol A type epoxy resin is the product name "YL980" manufactured by Mitsubishi Chemical Corporation. When using an epoxy compound as a thermosetting resin, the content of the epoxy compound is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 45 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler.

[0039] *Thermosetting agent The thermosetting agent is selected according to the thermosetting resin. For example, if the thermosetting resin is an epoxy compound, a thermal anionic polymerization initiator or a thermal cationic polymerization initiator can be preferably selected, and a thermal cationic polymerization initiator that suppresses the curing reaction by laser light and allows for rapid curing by heat can be more preferably selected. The content of the thermosetting agent can be determined according to the type of thermosetting agent and the type of thermosetting resin. The content of the thermosetting agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent and inorganic filler.

[0040] Furthermore, suitable thermal cationic polymerization initiators for epoxy compounds are those that generate an acid capable of cationic polymerization of cationic polymer-type compounds upon heating, and known iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc., can be used. Among these, aromatic sulfonium salts, which exhibit good latent properties with respect to temperature, can be preferably used. A specific example of an aromatic sulfonium salt-based polymerization initiator is, for example, the product name "San-Aid SI-60L" manufactured by Sanshin Chemical Industry Co., Ltd. The content of such thermal cationic polymerization initiator is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, per 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler.

[0041] *Inorganic filler The inorganic filler in the thermosetting resin composition is used to adjust the durometer A hardness, the storage modulus at a frequency of 200 Hz, and the storage modulus after curing of the insulating resin layer 1 for filler retention. Examples of inorganic fillers that can be used include silica, talc, titanium dioxide, calcium carbonate, magnesium oxide, silane coupling agents, fillers, softeners, colorants, flame retardants, and thixotropic agents. The inorganic filler may be used alone or in combination of two or more types.

[0042] The inorganic filler content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 8 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler. In particular, when the rubber component content is 2 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total of the rubber component, film-forming resin, thermosetting resin, thermosetting agent, and inorganic filler, setting the inorganic filler content to 8 parts by mass or more and 12 parts by mass or less makes it possible to easily achieve the desired durometer A hardness, the desired storage modulus at a desired frequency of 200 Hz, and the desired storage modulus after curing. For example, the storage modulus obtained by the Vibron dynamic viscoelasticity tester (A&D Co., Ltd.) after curing can be set to 0.1 GPa or more and 3 GPa or less (30°C).

[0043] (Convex part 4) The protrusion 4 holds the filler 2, preferably on its top surface or in the filler-holding insulating resin layer 1 that constitutes the protrusion 4. When a second article, such as an IC chip or an FPC, is joined to a first article, such as a plastic substrate, a glass substrate, or a wiring board, it is preferable that such a protrusion 4 is formed at a position corresponding to the second article. In this case, it is preferable that the second article and the protrusion 4 correspond in a 1:1 ratio, but one protrusion 4 may correspond to two or more second articles.

[0044] In the present invention, the width W3 of the protrusions 4 in the short direction of the film is less than the width of the insulating resin layer 1 for filler retention relative to the base film, preferably 95% or less, more preferably 90% or less, and even more preferably 80% or less, in order to avoid adhesion between adjacent protrusions after the protrusions are formed by the press mold and to ensure the positional accuracy of the press mold. Furthermore, in order to reduce the yield of protrusions (individual pieces) and the width of the thin film portion that does not contribute to conductivity as much as possible, the width is preferably 25% or more, more preferably 50% or more, of the width of the insulating resin layer 1 for filler retention.

[0045] Furthermore, it is preferable that the planar shape and size (area) of the protrusion 4 substantially match the planar shape and size of the second article to be joined or its electrode. Depending on the purpose of use and application of the filler-containing film, the planar shape, size, and number of protrusions may be adjusted. For example, if the second article is an IC chip or FPC, it is preferable that the planar shape and size of the protrusion 4 be substantially the same as the outer shape of the IC chip or FPC or one electrode inside the IC chip or FPC. For example, the width W3 of the protrusion 4 in the short direction of the filler-containing film is preferably 20 μm or more, more preferably 80 μm or more, even more preferably 120 μm or more, preferably 5 mm or less, more preferably 2.5 mm or less, and even more preferably 2 mm or less. Also, in Figures 1Aa, 1Ab, 1Ac, 1B, 1C, and 1D, the side surface of the protrusion 4 rises vertically from the recess 3, but it may have an inclination as shown in Figure 2, or it may be stepped as shown in Figure 3. The planar shape and size (area) of the protrusion 4 were explained using IC chips and FPCs as examples of the second item to be connected, but the size of the protrusion 4 can be adjusted to match the size of the connected item, which may differ in size. For example, the width W3 of the protrusion 4 can be set to ±130% of the above-mentioned numerical range.

[0046] The height t0 of the protrusion 4 (see Figure 1Aa) corresponds to the thickness of the insulating resin layer 1 for filler retention. Considering the difficulty of incorporating the filler and the strength required when joining the second article, the lower limit is preferably 1 μm or more, more preferably 2 μm or more, the upper limit is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less, and it is preferable that it is 1 to 2 times the average particle diameter of the filler 2. By making the height of the protrusion 4 greater than the bump height of the connecting part, and smaller than the sum of the thickness and bump height of the connecting part, a fillet can be formed around the part without the connecting part being completely embedded in the insulating resin layer 1 for filler retention. It is preferable that the planar shape, size (area), height, and relationship between the convex and bottom surfaces of the protrusion 4 are all the same, but it is not limited to this.

[0047] Number density of protrusions 4 [pieces / 100cm] 2 The optimal number density can be appropriately selected depending on the intended use of the filler-containing film and the objects to be bonded. Generally, 10 [pieces / 100cm] 2 ]More than 10000[pcs / 100cm 2 However, when the filler-containing film is used as a conductive film or anisotropic conductive film and applied to the mounting of IC chips, preferably 50 [pieces / 100cm²] 2 ] More preferably 300 [pieces / 100cm 2 ] More than 1000 [pieces / 100cm] 2 ] More preferably 500 [pieces / 100cm 2 ] or less. Furthermore, the minimum distance between the protrusions 4 is preferably 0.1 mm or more to avoid adhesion between separated protrusions (individual pieces) during the filler transfer process and component mounting. Also, when the filler-containing film is a reel product (a form in which the protrusions are arranged in a single row), there is no limit to the width of the film (in the case of a normal anisotropic conductive film, it is about 0.5 mm to 2 mm wide), but the number density of the protrusions 4 [pieces / m] is preferably 5 [pieces / m] or more, more preferably 10 [pieces / m] or more, preferably 100 [pieces / m] or less, and more preferably 50 [pieces / m] or less. The relationship between the number density of the protrusions and the number of protrusions is adjusted as appropriate depending on the object to be connected, including the dimensions and number of protrusions. There are also cases where values ​​outside the numerical ranges listed here are applicable to the concept of the present invention.

[0048] There is no particular limit to the number of fillers provided on one protrusion 4, but in order to minimize the number of fillers and improve cost-effectiveness, it is preferable that the lower limit be 2 or more, and in order to satisfy the capture of the fine-pitch connection area with one protrusion, it is preferable that the upper limit be 1500 or less.

[0049] (Recess 3) The recess 3 is formed reflexively during the formation of the protrusion 4, and has the function of separating the protrusion 4 from adjacent protrusions 4. The depth t1 of the recess 3 and the width W of the recess 3 in the short direction of the film. 10There are no particular restrictions, and the shape and size of the second article to be joined with the filler-containing film can be appropriately determined. In Figures 1Aa, 1Ab, 1Ac, 1B, 1C, and 1D, the inner wall of the recess 3 is vertical and the bottom is flat, but it is not limited to this. As shown in Figure 4, it may have an incline, or as shown in Figure 5, it may be stepped. Also, the side surface of the convex portion 4 may be inclined as shown in Figure 2, or stepped as shown in Figure 3. Furthermore, as shown in Figure 1Ad, there may be no rise of the recess 3 at the short-side end of the film.

[0050] Furthermore, reducing the thickness of the bottom of the recess 3 improves the light transmittance of that portion, making it easier to optically distinguish it from the protrusion 4, and making it easier to handle the protrusion 4 as substantially individual pieces of filler-containing film 10. Note that at least a portion of the bottom surface of the recess 3 may be penetrated, as long as the protrusion 4 is not completely separated from the filler-containing film 10. Note that if a base film or another insulating resin layer is present on the back surface of the filler-holding insulating resin layer 1, the recess 3 can be penetrated to completely separate the protrusion 4 into individual pieces.

[0051] (Filler 2) As the filler 2 placed on the protrusion 4, various fillers used in known filler-containing films can be appropriately selected and used according to the application of the filler-containing film (conductive film, anisotropic conductive film, adhesive film, optical film, ferromagnetic film, etc.). For example, known inorganic fillers (metals, metal oxides, metal nitrides, etc.), organic fillers (resin particles, rubber particles, etc.), and fillers containing a mixture of organic and inorganic materials (for example, particles with a metal layer such as a core made of resin material and a metal-plated surface (metal-coated resin particles), particles with insulating fine particles attached to the surface of conductive particles, particles with the surface of conductive particles insulated, etc.) can be appropriately selected according to the performance required for the application, such as hardness and optical performance. For example, in optical films and matte films, silica fillers, titanium oxide fillers, styrene fillers, acrylic fillers, melamine fillers, and various titanates can be used. Capacitor films can use fillers such as titanium dioxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate, and mixtures thereof. Adhesive films can contain polymer-based rubber particles, silicone rubber particles, etc. Conductive films and anisotropic conductive films contain conductive particles. Examples of 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 be used in combination. Among these, metal-coated resin particles are preferred because the resin particles repel each other after connection, making it easier to maintain contact with the terminals and stabilizing conductivity. Furthermore, the surface of the conductive particles may be treated with an insulating treatment that does not impair conductivity using known techniques. The fillers listed above for each application are not limited to those applications and may be applied to filler-containing films for other applications as needed. Furthermore, for each type of filler-containing film, two or more types of fillers can be used in combination as needed.

[0052] The shape of filler 2 is determined by appropriately selecting from spherical, ellipsoidal, columnar, needle-shaped, or combinations thereof, depending on the application of the filler-containing film. A spherical shape is preferred because it makes it easy to confirm the filler arrangement and maintain a uniform state. In particular, for anisotropic conductive films, it is preferable that the conductive particles are approximately spherical. By using approximately spherical conductive particles, for example, when manufacturing a filler-containing film in which the conductive particles or other fillers are arranged or aligned using a transfer mold as described in Japanese Patent Application Publication No. 2014-60150, the conductive particles or other fillers roll smoothly on the transfer mold, so that the conductive particles or other fillers can be filled into predetermined positions on the transfer mold with high precision. Therefore, the conductive particles or other fillers can be accurately arranged in the filler-containing film. When the conductive particles or other fillers are arranged randomly or in a dispersed state, they can also be created using a transfer mold. In the case of a dispersed state, there is the advantage that constraints such as the precision of the transfer mold can be eliminated.

[0053] Here, "nearly spherical" means that the degree of sphericity calculated by the following formula is between 70 and 100.

[0054]

number

[0055] In the above formula, So is the area of ​​the circumcircle of the filler in the planar image of the filler, and Si is the area of ​​the incircle of the filler in the planar image of the filler.

[0056] In this calculation method, planar images of the filler are taken of the filler-containing film in both a surface view and a cross-sectional view. For each planar image, the area of ​​the circumscribed circle and the area of ​​the inscribed circle of 100 or more (preferably 200 or more) arbitrary fillers are measured, and the average values ​​of the circumscribed circle areas and the average values ​​of the inscribed circle areas are calculated and used as the aforementioned So and Si. Furthermore, it is preferable that the sphericity is within the above range in both the surface view and the cross-sectional view. The difference in sphericity between the surface view and the cross-sectional view is preferably within 20, and more preferably within 10. During production inspection of the filler-containing film, the surface view is used, and detailed quality judgment after heat-pressing onto an article is performed using both the surface view and the cross-sectional view, so a small difference in sphericity is preferable. Note that if the filler is alone, this sphericity can also be determined using a wet flow particle size and shape analyzer FPIA-3000 (Malvern Panalytical).

[0057] The particle size D of the filler is determined appropriately depending on the application of the filler-containing film. For example, in the case of anisotropic conductive films, in order to accommodate variations in wiring height, suppress an increase in conductivity resistance, and suppress the occurrence of short circuits, the particle size D of the filler used is preferably 1 μm or more, more preferably 2.5 μm or more, more preferably 30 μm or less, and more preferably 9 μm or less. Depending on the object to be connected, it may be preferable to use a particle size D of the filler that is larger than 9 μm. For example, if the object to be connected has a surface that is not flat, such as the ceramic substrate described in Japanese Patent Application Publication No. 2016-131152, but has "undulations" or "steps", the particle size D of the filler used may be 10 μm or more, or 10 μm or more and 30 μm or less.

[0058] The particle size D of the filler before it is placed on the protrusions 4 of the filler-containing film 10 can be measured using a general particle size distribution analyzer, and the average particle size can also be determined using a particle size distribution analyzer. An example of a particle size distribution analyzer is the FPIA-3000 (Malvern Panalytical). On the other hand, the particle size D of the filler in the filler-containing film can be determined by electron microscope observation such as SEM. In this case, it is desirable to measure 200 or more samples for particle size D and to use the obtained average particle size as the particle size D. Also, if the shape of the filler is not spherical, the maximum length or the diameter of a shape that mimics a sphere can be used as the particle size D of the filler.

[0059] In this invention, the variation in the particle size D of the fillers in the filler-containing film is set to a CV value (standard deviation / mean) of 20% or less. By setting the CV value to 20% or less, the filler-containing film is more easily pressed evenly when it is pressed onto an article, and in particular when the fillers are regularly arranged, localized concentration of pressing force can be prevented, contributing to connection stability. Furthermore, the connection state can be accurately evaluated by indentation after connection. Specifically, when the filler-containing film is configured as a conductive film or anisotropic conductive film, the connection state can be accurately confirmed by indentation during the inspection of conductive connections or anisotropic conductive connections between the conductive film or anisotropic conductive film and electronic components, regardless of whether the terminal size is large (such as FOG) or small (such as COG). Therefore, inspection after conductive connections or anisotropic conductive connections becomes easier, and it is expected that the productivity of the connection process will be improved.

[0060] Here, the variation in particle size can be calculated using an image-type particle size analyzer or the like. The particle size of fillers that are not contained in the filler-containing film but are used as raw material particles for the filler-containing film can also be determined using the wet flow-type particle size and shape analyzer FPIA-3000 (Malvern Panalytical Corporation) described above. In this case, if 1000 or more fillers, preferably 3000 or more, and more preferably 5000 or more fillers are measured, the variation in particle size of the fillers alone can be accurately determined. When fillers are arranged in a filler-containing film, the sphericity can be determined using a planar or cross-sectional image, similar to the sphericity described above.

[0061] (Filler group 20) The filler group 20 consists of a plurality of fillers arranged on the protrusion 4 to enhance the capture of the fillers when joining the second article to the first article via the filler-containing film 10. In the present invention, as described above, at least one filler group 20 consisting of a plurality of fillers 2 is arranged on the protrusion 4. Therefore, a plurality of filler groups 20 may be arranged on one protrusion. In that case, as shown in Figure 6 (a plan view of one protrusion), it is preferable that adjacent filler groups (20a and 20b) on one protrusion 4 are completely separated, but as shown in Figure 7, they may be separated so that some fillers 2a are common. In particular, when the filler groups are completely separated as in Figure 6, for example, when connecting an IC chip with a filler-containing film, by corresponding the separated filler groups 20a and 20b to the separated electrodes of the IC chip, it is possible to prevent short circuits from occurring between them. Furthermore, as already mentioned, the fillers 2 within the filler group 20 may be randomly arranged, but it is preferable from the viewpoint of filler capture and manufacturing cost that they be arranged in a regular pattern (for example, a square lattice pattern, a hexagonal lattice pattern, etc., but not limited to a lattice pattern). Note that the filler group provided on one protrusion 4 may also include a configuration in which multiple filler groups are spaced apart. This is because when arranging the filler group 20 on the protrusion 4, it may be designed in advance to consist of multiple filler groups to suit the target object (for example, arranged only on the electrode). One of the preferred features of the present invention is that the outer circumference or outer edge of the filler group and at least the outer shape of the top surface of the protrusion 4 are the same.

[0062] Furthermore, in this invention, the protrusions are isolated and spaced apart, and multiple fillers are arranged on each protrusion. While placing one filler on each protrusion is effective in fixing each individual filler, from a practical standpoint, multiple such protrusions must be densely packed together, requiring increased thrust to press the fillers into the resin. This tendency is further amplified when the resin holding the fillers is high viscosity. Therefore, a low viscosity resin design is necessary, but with low viscosity, it becomes difficult to release the fillers from the transfer mold in a balanced manner, making resin design difficult. On the other hand, in this invention, where multiple fillers are arranged on each protrusion, the amount of resin is relatively less relative to the amount of filler compared to the case where one filler is arranged on each protrusion, so excessive thrust is not particularly necessary during pressing. In other words, there is an advantage in being able to adjust conditions such as resin flow and resin filling depending on the design conditions of the protrusions, and the increased freedom in resin design can be said to be a major feature of this invention. For example, by designing a single protrusion to span a single terminal array region (electrode region), the size of the protrusion and the average particle size of the filler provided on the protrusion can be adjusted to match design conditions such as the electrode area and the distance between electrodes. This allows for the selection of the region where the filler is located, which can significantly contribute to productivity. Multiple protrusions may also be designed to form a single terminal array region (electrode region). This is to control resin flow and the resulting density of filler. When considering connecting a single terminal array region with a single protrusion, the specifications of the protrusion are not particularly limited as long as the filler is held in place by the electrode. For example, if the dimensions of the IC chip are 1.5 mm x 20 mm and it is considered that one protrusion will connect a single terminal array region, the specifications of the protrusion are not particularly limited as long as the filler is held in place by the electrode, however, it is preferable that the dimensions of the protrusion be 1.5 mm or more x 20 mm or more, and that there be 600,000 or more fillers (conductive particles) on a single protrusion. The same considerations apply when multiple protrusions are used to connect a single terminal array region. However, when two protrusions are used to connect a single terminal array region, the dimensions of the protrusions are preferably 0.75 mm x 20 mm or larger, and it is preferable that there are 300,000 or more fillers (conductive particles) on each protrusion.The lower limit is not particularly limited and may be adjusted according to the size of the terminal and the number of terminals. Theoretically, it is preferable to have three or more fillers on one convex portion. Connecting the electronic components with a plurality of convex portions reduces the constraints on the pressing device side such as the thrust during connection, which can be said to be a remarkable effect of the present invention.

[0063] In the case of COG connection, assuming that a plurality of output terminal regions in a plurality of rows are connected by one convex portion, by connecting the output terminal region and the input terminal region with different convex portions, there is an economic merit that the fillers (conductive particles) in the region therebetween can be reduced. This is the reason why there may be two or more convex portions in the film width direction (that is, the film short side direction). Therefore, a mode in which a plurality of convex portions are arranged in parallel in the film short side direction is also an aspect of the present invention. Also, in the case of FOG connection, the tool width may be the effective connection area. When connecting with a tool width narrower than the width of the film, by shifting the film attachment position and the position pressed by the tool, the necessary amount of fillers (conductive particles) can be used. Thus, it is an advantage of the present invention that both the resin and the fillers (conductive particles) can be reduced. Also, there may be a plurality of convex portions in the longitudinal direction of the film, and the convex portions themselves are separated to prevent short circuits. To satisfy capture, the convex portions may be provided in a staggered manner. Therefore, as the lower limit of the number density of fillers on one convex portion, it is preferably 5 pieces / mm 2 or more, more preferably 500 pieces / mm 2 or more, still more preferably 2000 pieces / mm 2 or more. The fillers may be provided so as to have a number density of preferably 60000 pieces / mm 2 or less, more preferably 30000 pieces / mm 2 or less, still more preferably 8000 pieces / mm 2 or less. Needless to say, these can be appropriately changed depending on the object. As described above, in the connection, the constraints on the pressing device side such as the thrust are reduced, which can be said to be a remarkable effect of the present invention.

[0064] There are no particular restrictions on the number density of fillers in the filler group 20, and it is determined appropriately according to the intended use of the filler-containing film, the size of the external dimensions of the object to be connected, the electrode layout, and the degree of fine pitching, but the unit area [mm²] of the isolated protrusions 4 2 As for the area per ] (which can be thought of as the area formed by connecting only the protrusions), there is no particular limit on the lower limit, but it should be 5 or more, preferably 100 or more, more preferably 1000 or more, and even more preferably 10000 or more. As for the upper limit, it depends on the length of the protrusions, so there is no particular limit, but it may be 1,000,000 or less, preferably 300,000 or less, more preferably 200,000 or less, and even more preferably 100,000 or less.

[0065] Furthermore, as described above, a key feature of the filler-containing film of the present invention is that the filler is concentrated in the convex portions. When the filler is metal-coated resin particles used in conductive films or anisotropic conductive films, controlling the degree of filler concentration can be expected to make it easier to control how force is transmitted to the core resin particles. Therefore, it is expected that the degree of freedom in designing the hardness of the core resin particles (compression hardness such as the 20%K value) and the size and number of protrusions provided on the surface or inside the metal-coated resin particles will increase.

[0066] <Deformation of filler-containing film 1> The filler-containing film of the present invention can have another insulating resin layer laminated on at least one side of the insulating resin layer 1 for retaining the filler. For example, as shown in Figure 8, a second insulating resin layer 5 may be provided on the side of the protrusion 4 of the insulating resin layer 1 for retaining the filler, or a third insulating resin layer 6 may be provided on the opposite side of the protrusion 4, as shown in Figure 9A. In this case, as shown in Figure 9B, the recess 3 may be extended all the way through to the third insulating resin layer 6, or as shown in Figure 9C, the extended recess 3 may separate the protrusion 4 from the other protrusions and make it independent. Note that in the case of Figure 9B, even if the third insulating resin layer 6 is not provided, there is a recess 3 that is not extended, so the extended recess 3 can be maintained as extended. Also, as shown in Figure 10, the second insulating resin layer 5 and the third insulating resin layer 6 may be provided simultaneously.

[0067] The second insulating resin layer 5 and the third insulating resin layer 6 can be formed from the same composition as the filler-holding insulating resin layer 1, and their compositions may be changed or adjusted according to the purpose. For example, they may be adhesive layers that do not contain curable resin or curing agents. Furthermore, when the third insulating resin layer 6 functions as a base film, films widely used as base films, such as polyester film or nylon film, can be used as the third insulating resin layer 6, and when it functions as a release film, a film with a release agent such as silicone applied to its surface can be used. The total resin layer thickness of the filler-containing film including these layers is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 50 μm or more, preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0068] Furthermore, the second insulating resin layer 5 and the third insulating resin layer 6 can function as insulating resin layers for black matrix formation if they contain a black coloring agent. For example, as shown in Figure 11, when the filler-containing film 10 shown in Figure 8 is sandwiched between the first item, the wiring board 100, and the second item, the IC chip 200, and heat-pressed with a heat-press tool T, a fillet F is formed on the side surface of the IC chip 200 from the insulating resin layer for black matrix formation, as shown in Figure 12, and this fillet F can function as a black matrix.

[0069] As the black coloring agent, known black inorganic pigments such as carbon black and titanium black, which exhibit high light absorption over a wide range from the visible light region to the near-infrared region, can be used. Among these, titanium black, which has an extremely low content of impurity ions and is itself an insulator, can be preferably used. When titanium black is used as the black inorganic pigment, the titanium black content in the insulating resin composition for black matrix formation is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 40% by mass or less, and more preferably 30% by mass or less. The average particle diameter (primary particle diameter) of these black inorganic pigments is not particularly limited as long as the effects of the invention can be expressed, but it is desirable that it be smaller than the average particle diameter of the filler (e.g., conductive particles). The lower limit is preferably 1 nm or more, more preferably 10 nm or more, even more preferably 30 nm or more, and the upper limit is preferably 700 nm or less, more preferably 500 nm or less, even more preferably 400 nm or less, and particularly preferably 100 nm or less.

[0070] Furthermore, as a black coloring agent, a black organic pigment that blocks (absorbs) visible light in the 400-700 nm range and transmits near-infrared light in the 800-1200 nm range can also be used. Examples of such black organic pigments include, preferably, at least one of the following: lactam-based black pigments (e.g., lactam black), perylene-based black pigments (e.g., perylene black), azo-based black pigments (e.g., monoazochrome complex compounds), aniline-based black pigments (e.g., aniline black), bisbenzofuranone-based black pigments (e.g., black pigments consisting of bisbenzofuranone compounds or black pigments having bisbenzofuranone as the main skeleton), and cyanine-based black pigments (e.g., cyanine black). Among these, lactam-based black pigments, perylene-based black pigments, or bisbenzofuranone-based black pigments are preferred. Additionally, lactam-based, perylene-based, azo-based, aniline-based, bisbenzofuranone-based, and cyanine-based black organic pigments can be used. These can be considered organic fillers. From the viewpoint of spectroscopic properties and availability, perylene black (e.g., Black S0084, DIC Corporation) can be preferably used. Furthermore, from the viewpoint of high black color development, a black pigment having bisbenzofuranone as the main backbone (e.g., Irgaphor Black S0100CF, DIC Corporation) can be more preferably used. This Irgaphor Black S0100CF (DIC Corporation) may also be considered as lactam black.

[0071] Furthermore, as long as the effects of the present invention are not impaired, black dyes such as leuco dyes can also be used as black colorants that exhibit high light absorption (in other words, light shielding) over a wide range from the visible light region to the near-infrared region. This is because it is necessary to adjust the color tone depending on the appearance specifications of the display. Dyes disclosed in Japanese Patent Publication No. 2014-149918 and Japanese Patent Publication No. 2014-210856 may be used. Known colorants can also be combined as described in Japanese Patent Publication No. 2019-081831, Japanese Patent Publication No. 2019-081857 and Japanese Patent Publication No. 2020-132776. In addition, two or more black colorants may be used in combination, and colorants of other colors may be used in combination for color tone adjustment.

[0072] The average particle size (primary particle size) of the black organic pigment applicable to the present invention is not particularly limited as long as the effects of the invention are achieved. However, in order to achieve both visible light shielding and near-infrared transmittance, the lower limit is preferably 1 nm or more, more preferably 10 nm or more, and even more preferably 30 nm or more, and the upper limit is preferably 700 nm or less, more preferably 500 nm or less, and even more preferably 400 nm or less. The average particle size of the pigment or colorant can be determined by observation using a known laser diffraction scattering particle size distribution analyzer, a flow particle image analyzer (e.g., FPIA-3000, Malvern Panalytical, N=1000 or more is preferred), or a TEM (transmission electron microscope, N=200 or more is preferred).

[0073] The content of the black organic pigment in the insulating adhesive layer is preferably 6% by mass or more, more preferably 8% by mass or more, preferably 30% by mass or less, and more preferably 20% by mass or less. If it is less than 6% by mass, the visible light shielding properties of the filler-containing film, such as a conductive film or anisotropic conductive film, will not be sufficient, and the light shielding properties of the black matrix will decrease. If it exceeds 30% by mass, not only will the near-infrared transmittance decrease, but the conductivity and the fixation of light-emitting elements such as μLEDs will also decrease when the filler-containing film is used as a conductive film or anisotropic conductive film, which is undesirable.

[0074] <Deformation of filler-containing film, part 2> As shown in Figure 13, the filler-containing film 10 of the present invention may have a plurality of protrusions 4 arranged spaced apart from each other in the longitudinal direction of the film when viewed from above (the protrusions 4 are the filler-holding insulating resin layer portions that hold the filler, but the description of the filler is omitted in Figure 13 and Figures 14, 15, and 16 described later). Arranging the plurality of protrusions 4 as shown in Figure 13 allows the filler to be present in advance in the amount to be used, eliminating the effect of radiant heat during connection and providing the advantage of reducing the amount of filler and resin used. The area around the protrusions 4 corresponds to the recesses 3. The length of the protrusions 4 in the longitudinal direction of the film depends on the size of the objects to be joined, but is preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 20 mm or more, in order to reduce the influence of radiant heat during joining, such as anisotropic conductive connections between adjacent protrusions. Furthermore, if the length becomes too long, the overall length of the film also needs to be increased, which imposes constraints when making it into a reel and makes it difficult to carry. Therefore, it is acceptable to have a length of 100mm or less, preferably 50mm or less, more preferably 40mm or less, and even more preferably 30mm or less.

[0075] <Deformation of filler-containing film 3> As shown in Figure 14, the filler-containing film 10 of the present invention may have grooves 11 that do not penetrate the protrusions 4 when viewed from above, or as shown in Figure 15, the protrusions 4 may be composed of a plurality of sub-protrusions 4a that are spaced apart from each other and located close together. In the case of Figure 15, the recesses 3 around the sub-protrusions 4a penetrate to the base film (not shown). The shape, size, number, etc., of the grooves 11 and sub-protrusions 4a can be appropriately selected according to the intended use of the filler-containing film. By providing such grooves 11 and sub-protrusions 4a, it is possible to separate the fillers at the intended positions, avoid contact between fillers, and reduce the amount of filler used.

[0076] <Deformation of filler-containing film 4> In the filler-containing film 10 of the present invention, as shown in Figure 16, it is preferable that the width W1 of the base film 30 (or release film) in the short direction of the film, the width W2 of the insulating resin layer 1 for retaining the filler in the short direction of the film, and the width W3 of the protrusion 4 in the short direction of the film satisfy the inequality: W1≧W2>W3. By satisfying this relationship, the resin moves away from the slit cross-section of the film, making it easier to avoid overflow, and even if the resin flows in the short direction of the film during connection, the effect of resin flow can be suppressed. Specifically, it is more preferable that the relationship W1:W2=1:0.8~0.95 and W2:W3=1:0.5~0.99 is satisfied. When W1 is greater than W2, there is an advantage that the resin moves away from the slit cross-section of the film, making it easier to avoid overflow. Also, when W2 is greater than W3, there is room for the resin to flow, which can suppress the effect of overflow in the resin flow.

[0077] <Deformation of filler-containing film 5> In the filler-containing film 10 of the present invention, as shown in Figure 17, it is preferable that a convex-coating insulating resin layer 15 is laminated on the filler-holding insulating resin layer 1 so as to cover the convex portions 4. This provides the effect of making it easier to fill the gaps between bumps and other irregularities with resin. For this reason, the viscosity of the convex-coating insulating resin layer 15 may be lower than the viscosity of the filler-holding insulating resin layer 1. The convex-coating insulating resin layer 15 can be made from an insulating resin similar to the insulating resin used in the filler-containing film. Its layer thickness is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0078] In the embodiment shown in Figure 17, a convex-coating insulating resin layer 15 was laminated over the entire surface of one side of the filler-holding insulating resin layer 1. However, as shown in Figure 18, it is preferable not to provide a convex-coating insulating resin layer 15 between adjacent convex portions 4. This can suppress the problem of the insulating resin overflowing.

[0079] <Method for manufacturing filler-containing film> The filler-containing film of the present invention can be manufactured by a manufacturing method comprising the following steps A to C. Preferably, this manufacturing method includes step D and / or step E following step C.

[0080] (Process A) Step A is a step of forming a filler-retaining insulating resin layer 1 on a release film (PET) 30 that has been subjected to a release treatment, as shown in Figure 19. The filler-retaining insulating resin layer can be formed by a conventional method, for example, by applying a filler-retaining insulating resin composition to the release film and forming a film.

[0081] (Process B) Step B is a process in which, as shown in Figure 20, a mold 8 having recesses 7 corresponding to the convex portions of the filler-containing film is brought into contact with the insulating resin layer 1 for filler retention obtained in Step A, and heat pressing is performed to form recesses 3 and convex portions 4 on one side of the insulating resin layer for filler retention (see Figure 21). Heat pressing allows for easy deformation of the resin shape and also lowers the viscosity of the resin, making it easier to pour into the mold. While molding techniques using molds and photopolymerizable resins require the resin to be liquid or have a low viscosity close to liquid, this restriction does not exist with heat pressing, making it easier to handle and increasing productivity. Furthermore, the number of steps can be reduced, similarly increasing productivity. A release film may be interposed during contact. As the mold 8, a single sheet of metal or resin having recesses 7 is preferred, but a roll with recesses may also be used. A film with recesses may also be used. As for the heat pressing method, general heat tools, laminators, vacuum laminators, etc., can be used. Furthermore, the shape, depth, and pitch of the recess 7 can be appropriately determined according to the shape, height, and pitch of the protrusions of the filler-containing film (in other words, the shape, thickness, pitch, surface area, etc., of the second article to be connected).

[0082] (Process C) Step C is a process in which, as shown in Figure 22, the filler-placed surface of a filler transfer sheet 51, on which multiple fillers 2 are arranged on one side of a filler transfer substrate 50, is placed opposite the top surface of the protrusion 4 of the filler-holding insulating resin layer 1, and pressure is applied from the filler transfer substrate 50 side to transfer the multiple fillers 2 to the top surface of the protrusion 4. After the transfer, the filler transfer sheet 51 is peeled off and removed to obtain a filler-containing film 10 laminated on a release film 30, as shown in Figure 23A. The release film 30 may be replaced with a base film. Figure 24 shows an example of a schematic diagram of the filler-containing film 10 as seen from the top surface on the protrusion side. On the surface of the protrusion 4, the fillers 2 are randomly arranged, and there are no fillers in the recesses 3 (in the case of dispersion, it can be assumed that those in contact can be identified). In Figure 22, the filler 2 is held on the surface of the adhesive filler transfer substrate 50 of the filler transfer sheet 51. However, a transfer mold having a recess for accommodating the filler may be used as the filler transfer substrate 50.

[0083] (Process D) In the method for manufacturing the filler-containing film of the present invention, following step C, it is preferable to embed the filler 2 transferred to the top surface of the protrusion 4 into the filler-holding insulating resin layer 1 by a known heating and pressing method such as a hot press via a release film (PET). This yields a filler-containing film 10 as shown in Figure 23B. A detailed explanation of the lamination of another insulating resin layer is omitted, but it is possible to prepare a pre-laminated layer or to laminate it after step D. Note that the filler-containing film 10 of the present invention, corresponding to the conventional conductive film or anisotropic conductive film 300a shown in Figures 26B and 27B, is shown as Figures 23C and 23D, respectively. In these embodiments, the surface of the recess 3 is also covered with a thin film of the same material as the filler-holding insulating resin layer.

[0084] (Process E) In the method for manufacturing a filler-containing film of the present invention, it is preferable to laminate another insulating resin layer (for example, a protrusion-coating insulating resin layer) onto the filler-holding insulating resin layer from the side of the protrusions to which the filler has been transferred, following step C or following step D. When step E is performed following step D, a filler-containing film as shown in Figure 17 or Figure 18 is obtained. The film obtained in this step may be slit or made into a single sheet. The single sheet of film can be placed in a tray and shipped. The embodiment in Figure 18 can be preferably applied when slitting the filler-containing film because no protrusion-coating insulating resin layer is formed between adjacent protrusions 4.

[0085] Furthermore, this manufacturing method may substitute or add the following step F to step E: (Process F) The process involves removing the release film and laminating another insulating resin layer onto the filler-holding insulating resin layer, starting from the opposite side of the convex portion where the filler was transferred. The method may include the step F in addition to step E (i.e., a step that combines steps E and F), in which case the manufacturing method includes the step of laminating another insulating resin layer on both sides of the filler-holding insulating resin layer to which the filler has been transferred.

[0086] Furthermore, the present invention can be manufactured by a manufacturing method comprising the following steps a to c, as an alternative embodiment of the method for manufacturing the filler-containing film of the present invention described above. This manufacturing method may have steps d and / or e following step c.

[0087] (Step a) Step a is a process in which an insulating resin layer for retaining a filler is formed on a release film that has undergone a release treatment, and then another insulating resin layer is laminated onto the formed insulating resin layer for retaining a filler. In this step, a laminate of release film / insulating resin layer for retaining a filler / another insulating resin layer is formed.

[0088] (Step b) Step b is a process in which a mold having recesses corresponding to the convex portions of the filler-retaining insulating resin layer is brought into contact with the filler-retaining insulating resin layer from which the release film has been peeled off, and heat pressing is performed to form recesses and convex portions on one side of the filler-retaining insulating resin layer. The release film is peeled off from the laminate obtained in step a, and recesses and convex portions are formed on the exposed filler-retaining insulating resin layer.

[0089] (Step c) Step c is a process in which the filler-placed surface of a filler transfer sheet, on which multiple fillers are arranged on one side of a filler transfer substrate, is placed opposite the top surface of the protrusion, and the filler is transferred to the top surface of the protrusion by pressing from the filler transfer substrate side. This process yields a filler-containing film in which a filler-holding insulating resin layer, on which fillers are held on one side, is laminated with another insulating resin layer.

[0090] This alternative embodiment of the manufacturing method may further include the following steps d and / or e.

[0091] (Step d) Step d is a step of embedding each filler transferred to the top surface of the protrusions into a filler-retaining insulating resin layer such that at least a portion of it is embedded. This step yields a filler-containing film in which a filler-retaining insulating resin layer with fillers pressed into one side is laminated onto another insulating resin layer.

[0092] (Step e) In another embodiment of the method for manufacturing a filler-containing film of the present invention, it is preferable to laminate another insulating resin layer (for example, a protrusion-coating insulating resin layer) onto the filler-holding insulating resin layer from the side of the protrusions onto which the filler has been transferred, following step c or following step d. In either case, a filler-containing film is obtained in which another insulating resin layer is laminated on both sides of a filler-holding insulating resin layer on which the filler is held or pressed on one side. The film obtained in this step may be slit or made into sheets. Film made into sheets can be placed in a tray and shipped. It may be used as is or cut into pieces when used.

[0093] In the method for manufacturing a filler-containing film of the present invention, it is preferable that the mold is a concave single sheet. Furthermore, the "other insulating resin layer" may have the same composition as the "insulating resin layer for retaining the filler" or it may be different. It may also be a resin layer containing a curable resin or a curing agent, or it may be an adhesive layer that does not contain them. The "other insulating resin layers" used in different processes may be the same or different. When carrying out the method for manufacturing a filler-containing film of the present invention, release films and cover films may be applied to intermediates and the final product as appropriate for handling intermediates and the final product during manufacturing.

[0094] As described above, one feature of the method for manufacturing a filler-containing film of the present invention is the use of a press mold in step B. By using such a press mold, it is possible to obtain a filler-containing film that can function as individual pieces, in which the filler is contained only in the convex portions formed at the intended positions on the filler-containing film. Moreover, at least one or more fillers can be placed in the convex portions of the filler-containing film, and the convex and concave portions can be placed at the desired positions on the entire film. Furthermore, since the film thickness is thinner in the concave portions, it has excellent light transmittance and visibility. In addition, the presence of concave portions where no filler is present greatly reduces the risk of short circuits when the filler-containing film is used as an anisotropic conductive film. Furthermore, since the filler-containing film can be constructed from a single resin film, and other resin layers can also be laminated, there is also the advantage of increased design flexibility.

[0095] Furthermore, although the filler transfer sheet 51 has filler 2 placed on one side of the filler transfer substrate 50, the filler is not transferred to the recesses 3 of the filler-holding insulating resin layer 1. Therefore, the filler can be randomly or regularly placed or arranged across the entire surface of the filler transfer sheet 51, making it easy to create the filler transfer sheet 51. In addition, the number density of fillers in the filler transfer sheet 51 is the same as the number density of fillers in the filler group of the filler-containing film.

[0096] <Connecting structure and method for manufacturing the same> The filler-containing film of the present invention is preferably applicable to the filler-containing film in a connection structure in which a plurality of second articles are connected to a relatively large first article, such as a wiring board, via the filler-containing film. It is also preferably applicable to the filler-containing film in a method for manufacturing a connection structure, characterized by sandwiching the filler-containing film between the first article and the second article, preferably so that the protrusions of the second article and the protrusions of the filler-containing film correspond to each other, and then pressing them together (e.g., by heat pressing). In these cases, the correspondence between the second article and the protrusions of the filler-containing film may be multiple to one or one to many, but from the viewpoint of ease of design and positional accuracy, a one-to-one correspondence is preferred. Furthermore, it is preferable that the first article and the second article are equipped with electrodes so that they are electrically conductive when facing each other. It can also be used for conductive connections or anisotropic conductive connections by sandwiching it between a first article and a second article equipped with opposing electrodes. In particular, the connection structure of the present invention is preferably applicable to the manufacture of a connection structure in which the first article is a transparent display substrate with transparent electrodes arranged on one side, the second article is an IC chip or FPC with electrodes formed on one side, the filler arranged on the protrusions of the filler-containing film is conductive particles, and the filler-containing film itself functions as a conductive film. Therefore, not only the connection structure itself but also the manufacturing method itself is a variation of the present invention. In addition, an anisotropic conductive film can be used instead of a conductive film.

[0097] (Connection structure) An electronic device such as a liquid crystal display, in which an IC chip is placed on a substrate such as a glass substrate or a plastic substrate using the filler-containing film of the present invention, is manufactured by aligning and attaching the filler-containing film to the electrodes of the substrate, aligning and attaching the filler-containing film to the IC chip, and then heating and pressing to connect the electrodes of the IC chip to the electrodes of the substrate. In this case, the connection may be made by heating and pressing in a two-stage method (Japanese Patent Application Publication No. 2019-216097). Alternatively, if the conductive particles are solder particles or the like, the connection may be made by reflow. An FPC may be used instead of an IC chip. A ceramic substrate or a rigid substrate may be used instead of a glass substrate or a plastic substrate.

[0098] Although the filler-containing film of the present invention is substantially in the shape of individual pieces, it can also be used as a filler-containing film in which the convex portions are completely separated from the entire film. In that case, the temporary attachment of the separated filler-containing film can be done using known methods such as stamping materials or laser methods (laser lift-off method) or methods that apply thereto (for example, the methods described in Japanese Patent Publication No. 9-124020, Japanese Patent Publication No. 2011-76808, Japanese Patent No. 6636017, Japanese Patent No. 6187665, etc.), and is not particularly limited as long as the method can achieve the effects of the invention. Similarly, when creating a filler transfer sheet or mounting it on a substrate such as an IC chip or FPC, known methods such as stamping materials or laser methods (laser lift-off method) or methods that apply thereto can be used. [Industrial applicability]

[0099] The filler-containing film of the present invention allows for conductive and anisotropic conductive connections of small electronic components such as IC chips and FPCs to wiring boards, etc., without the risk of short circuits. The protruding portions of the filler-containing film function substantially as individual pieces of filler-containing film, enabling conductive and anisotropic conductive connections. Furthermore, the filler-containing film of the present invention has a structure that can be formed using a simple transfer mold. Therefore, the filler-containing film of the present invention has a structure comparable to that of individual pieces formed by the laser lift-off method, making it useful for the manufacture of small, medium, and large displays. Alternatively, it contributes to cost reduction throughout the entire process.

[0100] In the present invention, the filler-containing film was described using conductive films, anisotropic conductive films, and conductive connections and anisotropic conductive connection methods utilizing them as examples. The content of that description can also be applied to other connection films and connection methods utilizing them as examples, as long as the effects of the present invention are not impaired. [Explanation of Symbols]

[0101] 1. Insulating resin layer for filler retention 2, 2a Filler, conductive particles 3 recesses 4. Convex part 4a Sub-protrusion 5. Second insulating resin layer 6. Third insulating resin layer 7. Recess of the mold 8 press molds 10 Filler-containing film 11 Groove 15. Insulating resin layer covering the protruding portion. 20, 20a, 20b filler group 30 Release film, base film 31a, 31b Fragmented conductive particle holding layer 40 connection areas 40a Output area 40b Input area 50 Filler Transfer Substrates 51 Filler Transfer Sheet 100 Wiring boards 200 IC chips 300 Conductive film or anisotropic conductive film 300a Individually segmented conductive film or anisotropic conductive film 310 Slit blade D filler particle size F Fillet T Heat-sealing tool t0 Height of the convex part Depth of the recess t1 W1 base film width in the short direction of the film Width of the insulating resin layer 1 for retaining W2 filler in the short direction of the film Width of the film in the short direction of the W3 protrusion W 10 Width of the recess in the short direction of the film

Claims

1. A filler-containing film having an insulating resin layer for retaining the filler and a filler, A recess and a protrusion are formed on one side of the insulating resin layer for retaining the filler. At least one filler group consisting of multiple fillers is arranged on the aforementioned protrusion. A filler-containing film in which the width of the protrusions in the short direction of the film is less than the width of the insulating resin layer for retaining the filler.

2. The filler-containing film according to claim 1, wherein each filler constituting the filler group is arranged such that at least a portion of it is embedded on the surface of the protrusion or in the insulating resin layer for holding the filler constituting the protrusion.

3. A filler-containing film according to claim 1, wherein the protrusions are arranged in a regular pattern.

4. A filler-containing film according to claim 1, wherein multiple fillers are arranged in a regular pattern within a group of fillers.

5. The filler-containing film according to claim 1, wherein no filler is placed in the recessed area.

6. The filler-containing film according to claim 1, wherein at least a portion of the recess is perforated.

7. The filler-containing film according to claim 1, wherein a base film is laminated on the back surface of an insulating resin layer for retaining fillers.

8. The filler-containing film according to claim 7, wherein the recesses penetrate and the protrusions are separated from other protrusions by the penetrating recesses.

9. The filler-containing film according to claim 1, wherein a plurality of protrusions are arranged spaced apart from each other in the longitudinal direction of the film.

10. The filler-containing film according to claim 1, wherein protrusions of different widths are arranged in parallel and spaced apart from each other in the short direction of the film, and spaced apart in the long direction of the film.

11. The filler-containing film according to claim 1, wherein grooves are formed in the convex portion when the filler-containing film is viewed in plan view.

12. The filler-containing film according to claim 1, wherein the protrusion is formed from a plurality of sub-protrusions that are spaced apart from and close to each other.

13. The width W of the base film in the short direction of the film １ The width W of the insulating resin layer for retaining the filler. ２ And the width W of the protrusion ３ The inequality is: W １ ≧W ２ >W ３ A filler-containing film according to claim 1 having the relationship described above.

14. The filler-containing film according to claim 1, wherein a layer of insulating resin covering the protrusions is laminated on an insulating resin layer for retaining the filler so as to cover the protrusions.

15. The filler-containing film according to claim 1, wherein another insulating resin layer is laminated on the side opposite to the convex portion of the insulating resin layer for retaining the filler.

16. The filler-containing film according to claim 14, wherein another insulating resin layer is laminated on the side opposite to the convex portion of the insulating resin layer for retaining the filler.

17. The filler-containing film according to claim 14, wherein a plurality of protrusions are arranged spaced apart from each other in the short direction of the film, and no protrusion-coating insulating resin layer is laminated between adjacent protrusions.

18. A method for producing a filler-containing film according to claim 1, comprising the following steps A to C: (Process A) A step of forming an insulating resin layer for retaining fillers on a release film that has been subjected to a release treatment; (Process B) A step of forming recesses and protrusions on one side of an insulating resin layer for retaining a filler by applying a mold having recesses corresponding to the protrusions of a filler-containing film to the insulating resin layer for retaining the filler and performing a heat press; and (Process C) The process involves placing the filler-placed side of a filler transfer sheet, which has multiple fillers arranged on one side of a filler transfer substrate, against the top surface of the protrusion, and pressing from the filler transfer substrate side to transfer the filler to the top surface of the protrusion. A method for producing a filler-containing film having the following characteristics.

19. Following process C, the following processes D and / or E: (Process D) A step of embedding each filler transferred to the top surface of a protrusion into a filler-retaining insulating resin layer such that at least a portion of it is embedded; (Process E) A process of laminating another insulating resin layer (a protruding portion covering insulating resin layer) onto the filler-holding insulating resin layer, starting from the side of the protruding portion to which the filler has been transferred. A method for producing a filler-containing film according to claim 18, further comprising the above.

20. In place of or in addition to process E, the following process F: (Process F) The process involves removing the release film and laminating another insulating resin layer onto the filler-holding insulating resin layer, starting from the opposite side of the convex portion where the filler was transferred. The manufacturing method according to claim 19, further comprising the above.

21. A method for manufacturing a filler-containing film according to claim 15, comprising the following steps a to c: (Step a) A process of forming an insulating resin layer for retaining fillers on a release film that has been subjected to a release treatment, and further laminating another insulating resin layer onto the formed insulating resin layer for retaining fillers; (Step b) A step of forming recesses and protrusions on one side of the insulating resin layer for retaining fillers by applying a press mold having recesses corresponding to the protrusions of the filler-containing film to the insulating resin layer for retaining fillers from which the release film has been peeled off, and performing a heat press; and (Step c) The process involves placing the filler-placed side of a filler transfer sheet, which has multiple fillers arranged on one side of a filler transfer substrate, against the top surface of the protrusion, and pressing from the filler transfer substrate side to transfer the filler to the top surface of the protrusion. A manufacturing method having

22. Furthermore, the following steps d and / or e: (Step d) A step of embedding each filler transferred to the top surface of a protrusion into a filler-retaining insulating resin layer such that at least a portion of it is embedded; (Step e) A process of laminating another insulating resin layer onto the insulating resin layer for retaining the filler, starting from the side of the convex portion where the filler has been transferred. A manufacturing method according to claim 21, having the following characteristics.

23. The manufacturing method according to claim 18 or 21, wherein the pressing die is a concave single sheet.

24. A connecting structure comprising a first article connected to a second article via a filler-containing film as described in claim 1.

25. The connection structure according to claim 24, wherein the filler-containing film is a conductive film or an anisotropic conductive film, and the first article and the second article are connected by a conductive connection or an anisotropic conductive connection.

26. A method for manufacturing a connecting structure, characterized by sandwiching and pressing a filler-containing film according to claim 1 between a first article and a second article.

27. A method for manufacturing a connection structure according to claim 26, wherein the filler-containing film is a conductive film or an anisotropic conductive film, and the first article and the second article are connected by a conductive or anisotropic conductive connection.

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