Filled film

Abstract

A filler-containing film having a filler dispersed in a resin layer suppresses unnecessary flow of the filler caused by unnecessary flow of the resin layer at the time of press bonding of the filler-containing film to an article. The filler-containing film 10A has a filler-dispersed layer 3 having a filler 1 dispersed in a resin layer 2. In the filler-dispersed layer 3, the surface of the resin layer near the filler 1 has a tilt 2b or a undulation 2c with respect to the section 2p of the resin layer at the center between adjacent fillers. The CV value of the particle diameter of the filler 1 is 20% or less.

Description

[0001] This application is a divisional application of the original patent application filed on October 12, 2017, with original application number 201780061886.2 (international application number PCT / JP2017 / 036993) and entitled "Membrane Containing Filler". Technical Field

[0002] This invention relates to membranes containing fillers. Background Technology

[0003] Filler-containing films, in which fillers are dispersed in a resin layer, are used in a wide variety of applications, including matte films, capacitor films, optical films, label films, antistatic films, and anisotropic conductive films (Patent Documents 1, 2, 3, and 4). From the perspective of optical, mechanical, and electrical properties, it is desirable to suppress unnecessary resin flow that would otherwise form the filler-containing film when the filler-containing film is heat-pressed onto an article that serves as the adherend, thereby suppressing filler agglomeration. In particular, when anisotropic conductive films containing conductive particles as fillers are manufactured for mounting electronic components such as IC chips, if the conductive particles are dispersed at a high density in the insulating resin layer to accommodate high-density mounting of electronic components, these highly dispersed conductive particles will move unnecessarily due to resin flow during the mounting of the electronic components, resulting in agglomeration between terminals and becoming a major cause of short circuits.

[0004] In response to this, in order to reduce short circuits and improve the operability of temporarily pressing anisotropic conductive films onto a substrate, an anisotropic conductive film (Patent Document 5) was proposed, which is formed by laminating a single layer of photocurable resin containing conductive particles and an insulating adhesive layer. As a method of using this anisotropic conductive film, temporary pressing is performed while the photocurable resin layer is still tacky and uncured. Then, the photocurable resin layer is photocured to fix the conductive particles, and finally, the substrate and electronic components are formally pressed together.

[0005] Furthermore, to achieve the same objective as Patent Document 5, an anisotropic conductive film with a three-layer structure, in which a first connecting layer is sandwiched between a second connecting layer and a third connecting layer, which are mainly composed of insulating resin, has been proposed (Patent Documents 6 and 7). Specifically, in the anisotropic conductive film of Patent Document 6, the first connecting layer has a structure in which conductive particles are arranged in a single layer along the planar direction of the second connecting layer side of the insulating resin layer, and the thickness of the insulating resin layer in the central region between adjacent conductive particles is thinner than the thickness of the insulating resin layer near the conductive particles. On the other hand, the anisotropic conductive film of Patent Document 7 has a structure with undulating boundaries between the first and third connecting layers, and the first connecting layer has a structure in which conductive particles are arranged in a single layer along the planar direction of the third connecting layer side of the insulating resin layer, and the thickness of the insulating resin layer in the central region between adjacent conductive particles is thinner than the thickness of the insulating resin layer near the conductive particles.

[0006] Existing technical documents

[0007] Patent documents

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

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

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

[0011] Patent document 4: Japanese Patent Application Publication No. 2014-183266;

[0012] Patent document 5: Japanese Patent Application Publication No. 2003-64324;

[0013] Patent document 6: Japanese Patent Application Publication No. 2014-060150;

[0014] Patent document 7: Japanese Patent Application Publication No. 2014-060151. Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] However, the anisotropic conductive film described in Patent Document 5 has the following problems: During temporary pressing of the anisotropic conductive connection, the conductive particles are prone to movement; after the anisotropic conductive connection is established, the precise arrangement of the conductive particles before the connection cannot be maintained, or the distance between the conductive particles cannot be sufficiently separated. Furthermore, if such anisotropic conductive film is temporarily pressed onto a substrate, and then a photocurable resin layer is photocured, and the photocured resin layer containing the embedded conductive particles is bonded to the electronic component, there is a problem that the conductive particles are difficult to capture at the ends of the protrusions of the electronic component, or that pressing in the conductive particles requires excessive force, potentially resulting in insufficient indentation. Additionally, research in Patent Document 5 from the perspective of exposing the conductive particles from the photocurable resin layer to improve particle indentation is insufficient.

[0017] Therefore, instead of a photocurable resin layer, a high-viscosity insulating resin layer that reaches a high viscosity during anisotropic conductive bonding is considered to disperse conductive particles, thereby suppressing the flowability of conductive particles during anisotropic conductive bonding and improving the operability of bonding anisotropic conductive films to electronic components. However, even if conductive particles are temporarily precisely arranged in such an insulating resin layer, if the resin layer flows during anisotropic conductive bonding, the conductive particles will also flow simultaneously. Therefore, it is difficult to fully improve the capture of conductive particles in the terminal or reduce short circuits, and it is also difficult to maintain the initial precise arrangement of conductive particles after anisotropic conductive bonding, and it is also difficult to keep the conductive particles separated from each other.

[0018] Furthermore, in the case of the three-layer anisotropic conductive film described in Patent Documents 6 and 7, although no problems were found regarding the anisotropic conductive connection characteristics at the basic points, the three-layer structure necessitates reducing manufacturing time from a manufacturing cost perspective. Additionally, near the conductive particles on one side of the first connecting layer, the first connecting layer as a whole or a portion thereof bulges significantly along the shape of the conductive particles. The insulating resin layer forming the first connecting layer itself is not flat, and conductive particles are retained in this bulging portion. Therefore, there is a possibility of increased constraints on the retention of conductive particles and the design for improving terminal-based catchability.

[0019] In contrast, the objective of this invention is to suppress unnecessary flow of filler caused by the flow of the resin layer during hot pressing of the filler-containing film, even if a three-layer structure is not necessary and even if the resin layer containing the filler, such as conductive particles, does not bulge significantly above the shape of the filler near the filler, in particular, when the filler-containing film is constructed as an anisotropic conductive film, to improve the trapping ability of conductive particles and reduce short circuits.

[0020] Methods for solving problems

[0021] Regarding filler-containing films having a filler dispersion layer in which conductive particles or other fillers are dispersed in a resin layer, the inventors have obtained the following insights into the relationship between the surface shape near the filler in the resin layer and the viscosity of the resin layer. Specifically, in the anisotropic conductive film described in Patent Document 5, the surface of the insulating resin layer (i.e., the photocurable resin layer) on the side where the conductive particles are embedded becomes flat. In contrast, (i) when the conductive particles or other fillers are exposed from the resin layer, if the surface of the resin layer around the filler is inclined in a concave manner relative to the cross-section of the resin layer at the center between adjacent fillers, a partial defect is formed on the surface of the resin layer. As a result, when the filler-containing film is pressed onto an article to bond the filler to the article, unnecessary resin that might hinder the bonding between the filler and the article can be reduced; furthermore, (ii) when the filler is not exposed from the resin layer but embedded within it... In the case where a small, wave-like undulation (hereinafter referred to as undulation) is formed on the resin layer directly above the filler, with the cross-section of the resin layer relative to the central part between adjacent fillers considered as the embedment mark of the filler, then because the amount of resin in the recessed portion of the undulation is reduced, the filler is easily pressed into the article when the filler-containing membrane is pressed into the article; (iii) Therefore, if two opposing articles are pressed together by the filler-containing membrane, it is found that the filler held by the opposing articles is well connected to the articles. In other words, the capture of the filler in the article, or the consistency of the configuration state of the filler held by the articles before and after pressing, is improved, and thus the inspection of the product containing the filler membrane or the confirmation of the use surface becomes easier. Furthermore, it has been found that when a filler dispersion layer is formed by pressing the filler into the resin layer, such a depression in the resin layer can be formed by adjusting the viscosity of the resin layer into which the filler is to be pressed.

[0022] The present invention is based on the above-mentioned understanding and provides a filler-containing membrane, which is a filler-containing membrane having a filler dispersion layer in which filler is dispersed in a resin layer, wherein the surface of the resin layer near the filler is inclined or undulating relative to the cross section of the resin layer at the center between adjacent fillers.

[0023] In this tilt, the surface of the resin layer surrounding the filler is defective relative to the aforementioned cross-section.

[0024] In this undulation, compared to when the surface of the resin layer directly above the filler is located at the aforementioned cross-section, the amount of resin in the resin layer directly above the filler is reduced.

[0025] The CV value of the filler particle size is less than 20%.

[0026] Furthermore, the present invention provides a method for manufacturing a filler-containing membrane, which is a method for manufacturing a filler-containing membrane having a step of forming a filler dispersion layer in which filler is dispersed in a resin layer, wherein,

[0027] The process of forming the filler dispersion layer includes: a process of maintaining fillers with a particle size CV value of 20% or less on the surface of the resin layer; and

[0028] The process of pressing the filler held on the surface of the resin layer into the resin layer.

[0029] In the process of holding the filler on the surface of the resin layer, the filler is dispersed on the surface of the resin layer. In the process of pressing the filler into the resin layer, the surface of the resin layer near the filler is inclined or undulating relative to the cross section of the resin layer at the center between adjacent fillers. The viscosity of the resin layer, the pressing speed or the temperature of the filling are adjusted so that the surface of the resin layer around the filler is defective relative to the cross section in the inclination, and the amount of resin in the resin layer directly above the filler is reduced in the undulation compared to when the surface of the resin layer directly above the filler is at the cross section.

[0030] Invention Effects

[0031] The filler-containing membrane of the present invention has a filler dispersion layer in which filler is dispersed in a resin layer. In this filler-containing membrane, the surface of the resin layer forming the filler dispersion layer near the filler is inclined in a concave manner relative to the cross-section of the resin layer at the center between adjacent fillers, or has undulations relative to the cross-section. More specifically, when the filler is exposed from the resin layer, the resin layer around the exposed filler is inclined; when the filler is not exposed from the resin layer but embedded in the resin layer, the resin layer directly above the filler is undulating. It should be noted that undulations may also exist when the filler embedded in the resin layer is in contact with the surface of the resin layer at a single point.

[0032] The tilt and undulation are formed in the filler-containing membrane manufactured by the method of manufacturing the filler-containing membrane of the present invention. That is, according to the method of manufacturing the filler-containing membrane of the present invention, the filler is embedded in the resin layer by pressing the filler into the resin layer. Therefore, near the filler, depending on the degree of embedment, there are cases where the filler is entirely embedded in the resin layer while the resin of the resin layer exists directly above the filler (see, for example, [reference]). Figure 4 , Figure 6 Or, in cases where the top of the filler protrudes from the resin layer, and the resin layer near the filler is dragged into the interior by the embedment of the filler (see, for example, reference...). Figure 1B , Figure 2 Furthermore, there are also cases where both exist in combination. From the perspective of formation mechanism, the inclination is formed when the resin layer near the filler is dragged into the interior by the embedment of the filler, thus forming an incline around the filler. Additionally, when the filler is entirely embedded in the resin layer due to its embedment, the undulation is a wave formed on the surface of the resin layer directly above the filler, as a trace of its embedment.

[0033] Thus, since the tilting and undulation are formed when the filler is pressed into a high-viscosity resin layer, the presence of tilting or undulation in the resin layer indicates that the resin layer is of high viscosity, capable of forming tilting or undulation. If the resin layer is of high viscosity, unnecessary resin flow can be suppressed during hot pressing of the filler-containing film and the article, and the filler flow due to resin flow can be suppressed. Moreover, since there is no or less resin that would hinder the bonding between the filler and the article during hot pressing, even if the resin layer is of high viscosity, the resin layer will not impede the bonding between the article and the filler.

[0034] Furthermore, if the resin layer is formed of a high-viscosity resin capable of forming tilts or undulations, by thinning the resin layer itself and layering it with a second resin layer of lower viscosity, the adhesive properties of the filler-containing film when hot-pressed onto an article can be maintained, and unnecessary filler flow during hot pressing can be suppressed. Thinning the resin layer also provides margin for obtaining the heating and pressurizing conditions of the bonding tool. This effect is more pronounced if the filler particle size deviation is small. In this invention, since the CV value of the filler particle size is as low as 20% or less, the above-mentioned effects can be fully realized.

[0035] Moreover, since the tilt or undulation of the resin layer exists near the filler, the dispersion of the filler can be easily determined by observing the appearance of the filler-containing membrane during the manufacturing process.

[0036] If the resin layer has the aforementioned tilt or undulation, the following effect can also be obtained: when the filler-containing membrane is pressed onto an article as an adherend from the filler side of the filler-containing membrane, unnecessary flow of the resin layer can be reduced. Therefore, for example, when the filler-containing membrane is constructed as an anisotropic conductive membrane, during anisotropic conductive bonding of the first electronic component and the second electronic component via the anisotropic conductive membrane through heat pressing, the influence of unnecessary resin flow can be minimized, and the capture of conductive particles during anisotropic conductive bonding is improved.

[0037] Furthermore, due to the tilt, the amount of resin near the filler is reduced to only a degree of tilt compared to Patent Documents 6 or 7. Therefore, when the filler-containing membrane is pressed onto an article, resin flow is reduced, and the filler easily holds the article in place. Additionally, when two articles are pressed together via the filler-containing membrane, the resin is less likely to obstruct the clamping of the filler or cause it to collapse into a flat shape. Moreover, the degree to which the amount of resin around the filler is reduced due to the tilt reduces resin flow associated with unnecessary filler flow. Therefore, the filler trapping ability of the article is improved; in particular, when the filler-containing membrane is configured as an anisotropic conductive membrane, the trapping ability of conductive particles in the terminals is improved, thereby increasing conductivity reliability.

[0038] In cases where the insulating resin layer directly above the conductive particles embedded within the insulating resin layer has undulations, similar to cases where it is tilted, pressure from the terminals is easily applied to the conductive particles during anisotropic conductive connections. This is because the amount of resin directly above the conductive particles is reduced due to the depressions accompanying the undulations. Therefore, compared to the case where the resin is flatly deposited directly above the conductive particles (see...),... Figure 8 Compared to other methods, the ability to capture conductive particles in the terminals is improved, resulting in increased conductivity reliability.

[0039] As described above, when the filler-containing membrane according to the present invention is pressed onto an article which is an adherend containing the filler-containing membrane, unnecessary resin flow can be suppressed, thereby also suppressing unnecessary flow of filler and improving the adhesion between the filler and the article.

[0040] Therefore, if the filler-containing film of the present invention is used as an anisotropic conductive film, and the first electronic component and the second electronic component are connected using this anisotropic conductive film, the conductive particles on the terminals are less likely to flow. Thus, the trapping ability of the conductive particles is improved, and the arrangement of the conductive particles during anisotropic conductive connection can be precisely controlled. Therefore, it can be used, for example, to connect electronic components with fine pitches of 6μm to 50μm in terminal width and 6μm to 50μm in spacing between terminals. Furthermore, when the size of the conductive particles is less than 3μm (e.g., 2.5 to 2.8μm), if the effective connection terminal width (the width of the overlapping portion of a pair of opposing terminals when connected, viewed from above) is 3μm or more, and the shortest distance between terminals is 3μm or more, electronic components can be connected without short circuits.

[0041] Furthermore, since the arrangement of conductive particles can be precisely controlled, when connecting electronic components with standard spacing, the layout of the conductive particle arrangement area, or the area where the number and density of conductive particles are changed, can correspond to the layout of the terminals of various electronic components.

[0042] Furthermore, in the filler-containing membrane of the present invention, if the resin layer directly above the filler embedded in the resin layer has a depression formed by the aforementioned undulations, the position of the filler can be clearly determined by visual inspection of the filler-containing membrane. Therefore, product inspection is easy by appearance, and the front and back of the membrane surface are also easy to identify. Thus, when pressing the filler-containing membrane onto an article, it is easy to confirm which side of the filler-containing membrane should be adhered to the article. The same advantages can be obtained when manufacturing the filler-containing membrane.

[0043] Furthermore, according to the filler-containing membrane of the present invention, it is not necessary to light-cure the resin layer to fix the filler configuration. Therefore, when the filler-containing membrane is pressed onto an article, the resin layer can be adhesive. Thus, the operability is improved when temporarily pressing the filler-containing membrane onto an article, and the operability is also improved when pressing a second article after the temporary pressing.

[0044] On the other hand, according to the method for manufacturing a filler-containing membrane according to the present invention, by adjusting the viscosity of the resin layer when the filler is embedded in the resin layer, the aforementioned tilt or undulation is formed on the resin layer. Therefore, the filler-containing membrane of the present invention that exhibits the above-mentioned effects can be easily manufactured.

[0045] Brief description of the attached diagram [ Figure 1A ] Figure 1A This is a plan view showing the arrangement of conductive particles in an anisotropic conductive film 10A, which is an embodiment of a filler-containing film according to the present invention.

[0046] [ Figure 1B ] Figure 1B This is a cross-sectional view of an anisotropic conductive film 10A, which is an embodiment of the filler-containing film of the present invention.

[0047] [ Figure 2 ] Figure 2 This is a cross-sectional view of an anisotropic conductive film 10B, which is an embodiment of the filler-containing film of the present invention.

[0048] [ Figure 3A ] Figure 3A This is a cross-sectional view of an anisotropic conductive film 10C, which is an embodiment of the filler-containing film of the present invention.

[0049] [ Figure 3B ] Figure 3B This is a cross-sectional view of an anisotropic conductive film 10C', which is an embodiment of the filler-containing film of the present invention.

[0050] [ Figure 4 ] Figure 4 This is a cross-sectional view of an anisotropic conductive film 10D, which is an embodiment of the filler-containing film of the present invention.

[0051] [ Figure 5 ] Figure 5 This is a cross-sectional view of an anisotropic conductive film 10E, which is an embodiment of the filler-containing film of the present invention.

[0052] [ Figure 6 ] Figure 6 This is a cross-sectional view of an anisotropic conductive film 10F, which is an embodiment of the filler-containing film of the present invention.

[0053] [ Figure 7 ] Figure 7 This is a cross-sectional view of an anisotropic conductive film 10G, which is an embodiment of the filler-containing film of the present invention.

[0054] [ Figure 8 ] Figure 8This is a cross-sectional view of an anisotropic conductive film 10X, which is a comparative example of the filler-containing film of the present invention.

[0055] [ Figure 9 ] Figure 9 This is a cross-sectional view of an anisotropic conductive film 10H, which is an embodiment of the filler-containing film of the present invention.

[0056] [ Figure 10 ] Figure 10 This is a cross-sectional view of an anisotropic conductive film 10I, which is an embodiment of the filler-containing film of the present invention.

[0057] [ Figure 11A ] Figure 11A This is a photograph of the upper surface of an anisotropic conductive film, which is an embodiment of the filler-containing film of the present invention.

[0058] [ Figure 11B ] Figure 11B This is a photograph of the upper surface of an anisotropic conductive film, which is an embodiment of the filler-containing film of the present invention.

[0059] [ Figure 12 ] Figure 12 The results are the measurements or evaluations of the anisotropic conductive films of the examples and comparative examples prepared in (1) described later. Detailed Implementation

[0060] Hereinafter, an example of the filler-containing membrane of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the figures, the same symbols represent the same or equivalent constituent elements.

[0061] <Overall Composition of the Filler Membrane>

[0062] Figure 1A This is a plan view illustrating the particle configuration of a filler membrane 10A according to an embodiment of the present invention. Figure 1B This is its XX cross-sectional view. The filler-containing membrane 10A is used as an anisotropic conductive membrane, and the conductive particles, as filler 1, are dispersed in the insulating resin layer 2.

[0063] The filler-containing membrane 10A can be configured as a strip of membrane with a length of 5m or more, or as a roll wound on a winding core.

[0064] The filler-containing membrane 10A is composed of a filler dispersion layer 3, in which filler 1 is regularly dispersed in a state where one side is exposed above the resin layer 2. When viewed from above, the filler 1 does not contact each other, and in the film thickness direction, the filler 1 is also regularly dispersed without overlapping each other, forming a single-layer filler layer in which the filler 1 is aligned in the film thickness direction.

[0065] Near each filler 1, on the surface 2a of the resin layer 2 surrounding that filler 1, an inclination 2b is formed relative to the cross-section 2p of the resin layer 2 at the center between adjacent fillers. It should be noted that, as described later, in the filler-containing membrane of the present invention, undulations 2c may also be formed on the surface of the resin layer directly above the filler 1 embedded in the resin layer 2. Figure 4 , Figure 6 ).

[0066] In this invention, "tilting" refers to a state where the surface flatness of the resin layer 2 near or around the filler 1 is impaired, resulting in a partial defect in the resin layer relative to the aforementioned cross-section 2p, thereby leading to a reduction in resin content. On the other hand, "undulation" refers to a state where the surface of the resin layer directly above the conductive particles has waves, with accompanying depressions, resulting in a reduction in resin content. This can be determined by comparing the surface of the resin layer with the flat surface portion corresponding to the area directly above the filler and between the fillers. Figure 1B , 4 6 of 2f. Figure 11A The outer side of 2b Figure 11B The outer side of 2c. ) to identify. It should be noted that sometimes the starting point of the undulation also exists in the form of a slope.

[0067] <Dispersion state of the packing>

[0068] The dispersion state of the filler in this invention includes both a random dispersion state and a regularly arranged dispersion state of the filler 1. In either case, in order to suppress unnecessary flow of the filler when hot-pressing the filler-containing film onto an article that is an adherend containing the filler film, it is preferable to align the position in the film thickness direction, especially when the filler-containing film is an anisotropic conductive film, which is preferable from the perspective of the capture stability of conductive particles in the terminals of electronic components. Here, the alignment of the filler 1 in the film thickness direction is not limited to a single depth alignment in the film thickness direction, but also includes a scheme in which conductive particles are present at or near the front and back interfaces of the resin layer 2.

[0069] To ensure uniform optical, mechanical, or electrical properties of the filler-containing film, especially when the filler is used as the conductive particle and the filler-containing film is configured as an anisotropic conductive film, it is preferable that the filler 1 is regularly arranged in a top view of the film to balance the trapping stability of the conductive particles in the terminals and the suppression of short circuits. The arrangement scheme is not particularly limited; for example, it can be arranged as follows in a top view of the film: Figure 1AThe diagram shows a square grid arrangement. Other possible arrangements of the filler material include rectangular, rhomboid, hexagonal, and triangular grids. It can also be a combination of multiple grids of different shapes. As for the arrangement of the filler material, it can also be arranged in a linear column of particles at predetermined intervals. Additionally, it can be a arrangement where filler gaps are regularly present in a predetermined direction on the membrane.

[0070] By arranging the filler 1 in a regular pattern, such as non-contacting or forming a grid, pressure can be applied evenly to each filler 1 when the filler-containing membrane is pressed onto an article, reducing deviations in the connection state. Furthermore, by repeatedly creating filler voids along the long side of the membrane, or by gradually increasing or decreasing the number of voids along the long side, batch management is possible, and the filler-containing membrane and the connecting structures using it can be traced (a traceable property). This is also effective for preventing counterfeiting, verifying authenticity, and preventing improper use of filler-containing membranes or connecting structures using them.

[0071] Therefore, when the filler-containing film is configured as an anisotropic conductive film, by forming the conductive particles into a regular arrangement that prevents them from contacting each other, the deviation in conduction resistance when anisotropically conductively connecting the first electronic component and the second electronic component using the anisotropic conductive film can be reduced. It should be noted that whether the filler forms a regular arrangement can be determined, for example, by observing whether the specified configuration of the filler repeats along the long side of the film. Furthermore, when the filler-containing film is configured as an anisotropic conductive film, in order to balance the trapping stability and short-circuit suppression of conductive particles in the terminals when anisotropically conductively connecting the first electronic component and the second electronic component using the anisotropic conductive film, it is more preferable that the conductive particles are regularly arranged in a top view of the film and aligned in the film thickness direction.

[0072] On the other hand, when the terminals of the connected electronic components are widely spaced and short circuits are not easily caused, the conductive particles may not be arranged regularly, but rather randomly dispersed while having conductive particles to a degree that does not hinder conduction.

[0073] When the filler is arranged in a regular pattern, the grid axis or arrangement axis can be parallel to or perpendicular to the long side of the filler-containing film, or it can intersect the long side of the filler-containing film, depending on the item to be pressed with the filler-containing film. For example, when the filler-containing film is used as an anisotropic conductive film, the grid axis or arrangement axis of the regularly arranged conductive particles can be determined based on the width, spacing, and layout of the terminals connected through the anisotropic conductive film. More specifically, when the filler-containing film is used as an anisotropic conductive film for fine-pitch applications, such as... Figure 1AAs shown, the lattice axis A of the conductive particle 1 is oriented obliquely relative to the long side direction of the anisotropic conductive film 10A. The angle θ between the long side direction (short side direction of the film) of the terminal 20 connected through the anisotropic conductive film 10A and the lattice axis A is preferably set to 6° to 84°, and more preferably to 11° to 74°.

[0074] The distance between fillers in a filler-containing film can also be determined according to the items to be connected. When the filler-containing film is used as an anisotropic conductive film, the distance between conductive particles, which are fillers 1, can be appropriately determined based on the size of the terminals or the terminal spacing connected through the anisotropic conductive film. For example, when the anisotropic conductive film corresponds to a fine-pitch COG (Chip On Glass), from the perspective of preventing short circuits, it is preferable that the closest filler distance (i.e., the closest particle distance) is 0.5 times or more, more preferably greater than 0.7 times the diameter D of the conductive particles. On the other hand, the upper limit of the closest filler distance can be determined according to the purpose of the filler-containing film. For example, from the perspective of the ease of manufacturing the filler-containing film, the closest particle distance can be set to preferably 100 times or less, more preferably 50 times or less, the diameter D of the conductive particles. In addition, from the perspective of the capture of conductive particles 1 in the terminals during anisotropic conductive connection, it is preferable that the closest particle distance is 4 times or less, more preferably 3 times or less, the diameter D of the conductive particles.

[0075] In addition, in the filler-containing membrane of the present invention, the area occupancy rate of the filler calculated by the following formula is preferably set to 0.3% or more, so as to reflect the effect of the filler.

[0076] Area occupancy (%) = [number density of fillers in top view] × [average area of ​​1 filler in top view] × 100. This area occupancy becomes an indicator of the thrust necessary for pressing the filler-containing membrane onto the article using a pressing clamp (jig). As will be described later, from the perspective of suppressing the thrust necessary for pressing the filler-containing membrane onto the article using a pressing clamp, the area occupancy is preferably 35% or less, more preferably 30% or less.

[0077] Here, the area for measuring the number density of fillers is preferably set at multiple locations (preferably 5 or more, more preferably 10 or more) with one side being a rectangular area of ​​100 μm or more, and the total area of ​​the measurement area is set to 2 mm. 2 The size or number of each region can be adjusted appropriately according to the density. One example of a case with a high density of anisotropic conductive films used for fine-pitch applications is 200 locations (2 mm) of arbitrarily selected 100 μm × 100 μm regions from a filler-containing film. 2The number density is determined by measuring observation images based on metal microscopes, etc., and then averaged to obtain the "number density of filler under top view" in the above formula. When the filler-containing film is used as an anisotropic conductive film, a region with an area of ​​100μm×100μm becomes a region with more than one bump in a connected object with a bump spacing of 50μm or less.

[0078] It should be noted that as long as the area occupancy rate is within the above range, there is no particular limitation on the number density. When using the filler-containing film as an anisotropic conductive film, the practical number density is 30 particles / mm. 2 The above is sufficient, with an optimal selection of 150–70,000 pieces / mm. 2 Especially in fine-pitch applications, a density of 6000–42000 particles / mm is preferred. 2 More preferably, it is 10,000 to 40,000 pieces / mm 2 Further preferred is 15,000 to 35,000 pieces / mm 2 .

[0079] The number density of the filler can be determined not only by observation using a metal microscope as described above, but also by measuring and observing images using image analysis software (e.g., WinROOF, Mitani Corporation, etc.). The observation or measurement methods are not limited to those described above.

[0080] In addition, the average top-view area of ​​a single filler is determined by measuring images of the membrane surface using observations based on metal microscopy or electron microscopy such as SEM. Image analysis software can also be used. The observation and measurement methods are not limited to those described above.

[0081] As described above, the area occupancy rate is preferably 35% or less, more preferably 30% or less, for the following reasons. Specifically, in conventional anisotropic conductive films, to cope with fine pitch, the interparticle distance of conductive particles is narrowed and the particle density is increased within a range that does not cause short circuits. However, if the number of terminals of electronic components increases and the total connection area of ​​each electronic component increases, and the particle density of conductive particles is increased, the thrust required for the pressing clamp used to heat-press the anisotropic conductive film onto the electronic component will increase, raising concerns that existing pressing clamps may result in insufficient pressing. This problem of the necessary thrust for the pressing clamp is not limited to anisotropic conductive films but is common to all filler-containing films. In contrast, in this invention, by preferably setting the area occupancy rate to 35% or less, more preferably 30% or less, as described above, the thrust required for the pressing clamp used to heat-press the filler-containing film onto the article is suppressed.

[0082] <Packaging>

[0083] In this invention, filler 1 is selected appropriately from 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 (e.g., particles with a core formed of resin material and a surface plated with metal (metal-coated resin particles), fillers with insulating microparticles attached to the surface of conductive particles, fillers with insulating treatment on the surface of conductive particles, etc.), based on the performance requirements of the application, such as hardness and optical properties. For example, silica fillers, titanium dioxide fillers, styrene fillers, acrylic fillers, melamine fillers, or various titanates can be used in optical films or matting films. Titanium oxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate, and mixtures thereof can be used in capacitor films. Adhesive films may contain polymer-based rubber particles, silicone rubber particles, etc. Anisotropic conductive films may 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 microparticles attached to their surface. Two or more types may be used in combination. Among these, metal-coated resin particles are preferred from the perspective of easy maintenance of contact between the resin particles and the terminals after connection, and stable conductivity. Furthermore, the surface of the conductive particles can be insulated using known techniques without impairing conductivity. The fillers listed above according to their intended use are not limited to this application; filler-containing films for other applications may also contain fillers as needed. Additionally, in filler-containing films for each application, two or more fillers may be used in combination as needed.

[0084] The shape of the filler is appropriately selected from spherical, ellipsoidal, columnar, needle-shaped, and combinations thereof, depending on the application of the filler-containing membrane. From the perspective of facilitating the confirmation of filler configuration and maintaining a uniform state, a spherical shape is preferred. In particular, in anisotropic conductive films, the conductive particles are preferably approximately spherical. By using approximately spherical particles as conductive particles, for example, as described in Japanese Patent Application Publication No. 2014-60150, when manufacturing an anisotropic conductive film with conductive particles arranged in a transfer mold, the conductive particles are smoothly transferred onto the transfer mold, thus allowing for high-precision filling of conductive particles at predetermined positions on the transfer mold. Therefore, the conductive particles can be precisely configured.

[0085] Here, an approximate sphere is defined as a sphericity of 70 to 100 calculated using the following formula.

[0086] Sphericity = {1 - (So - Si) / So} × 100

[0087] In the above formula, So is the area of ​​the circumcircle of the packing in the planar image of the packing, and Si is the area of ​​the incircle of the packing in the planar image of the packing.

[0088] In this calculation method, planar images of the filler are taken in both a planar field of view and a cross-section of the filler-containing membrane. The circumscribed and inscribed areas of any 100 or more (preferably 200 or more) fillers are measured in each planar image. The average circumscribed and inscribed areas are calculated and preferably used as So and Si as described above. Furthermore, the sphericity is preferably within the aforementioned range in both the planar field of view and the cross-section. The difference in sphericity between the planar field of view and the cross-section is preferably within 20, more preferably within 10. Inspection during the production of the filler-containing membrane is primarily done in the planar field of view, and detailed quality assessment after hot-pressing is performed in both the planar field of view and the cross-section; therefore, the smaller difference in sphericity is preferred. It should be noted that if it is a filler monomer, the sphericity can also be determined using a wet flow cytometry particle size and shape analyzer FPIA-3000 (Malvern).

[0089] The particle size D of the filler is appropriately determined according to the application of the filler-containing membrane. For example, in anisotropic conductive films, in order to cope with deviations in wiring height, suppress the increase in on-resistance, and suppress the occurrence of short circuits, it is preferable to have a particle size of 1 μm or more and 30 μm or less, more preferably 2.5 μm or more and 9 μm or less. Depending on the object to be connected, fillers larger than 9 μm are sometimes suitable.

[0090] It should be noted that the particle size D of the filler dispersed before resin layer 2 can be measured using a common particle size distribution measuring device. Additionally, the average particle size can also be determined using a particle size distribution measuring device. An example of such a device is the FPIA-3000 (Malvern). On the other hand, the particle size D of the filler in a filler-containing membrane can be determined by observation using an electron microscope such as SEM. In this case, it is desirable to set the number of samples for which the particle size D is to be measured to be 200 or more. Furthermore, if the filler is not spherical, the maximum length or the diameter that mimics a spherical shape can be denoted as the particle size D of the filler.

[0091] In this invention, the CV value (standard deviation / average) of the deviation of the particle size D of the filler in the filler-containing membrane is set to 20% or less. By setting the CV value to 20% or less, the filler-containing membrane is easily and uniformly pressed when it is pressed onto an article. This is especially beneficial in cases where filler is arranged, as it prevents localized pressure concentration and contributes to the stability of the connection. Furthermore, the connection status can be accurately evaluated based on the indentation after connection. Specifically, when the filler-containing membrane is constructed as an anisotropic conductive membrane, the connection status can be accurately confirmed based on the indentation during the inspection of the anisotropic conductive membrane after anisotropic conductive connection with an electronic component, regardless of whether the terminal size is large (FOG, etc.) or small (COG, etc.). Therefore, the inspection after anisotropic conductive connection becomes easier, and it is expected to improve the productivity of the connection process.

[0092] Here, the particle size deviation can be calculated using an image-based particle size analyzer or similar device. The particle size of the filler particles, which are not present in the filled membrane but are used as raw material particles for the membrane, can also be determined using the aforementioned wet flow cytometry particle size and shape analyzer FPIA-3000 (Malvern). In this case, as long as the number of filler particles measured is 1000 or more, preferably 3000 or more, more preferably 5000 or more, the deviation of the individual filler particles can be accurately determined. When filler is present in the filled membrane, the sphericity can be determined using planar or cross-sectional images, similar to the above method.

[0093] <Resin Layer>

[0094] (Resin viscosity)

[0095] In this invention, the minimum melt viscosity of the resin layer 2 is not particularly limited and can be appropriately determined according to the application of the filler-containing film or the manufacturing method of the filler-containing film. For example, within the range where the aforementioned tilt 2b or undulation 2c can be formed, it can be set to about 1000 Pa·s by the manufacturing method of the filler-containing film. On the other hand, as a manufacturing method of the filler-containing film, when performing a method of holding the filler on the surface of the resin layer in a prescribed configuration and pressing the filler into the resin layer, from the perspective of film forming of the resin layer, it is preferable to set the minimum melt viscosity of the resin to 1100 Pa·s or more.

[0096] Furthermore, as explained in the method for manufacturing the filler-containing membrane described later, from such Figure 1B As shown, an inclined 2b is formed around the exposed portion of the filler 1 pressed into the resin layer 2, or as shown in the figure. Figure 4 and Figure 6 Considering the angle of undulation 2c formed on the surface of the resin layer directly above the filler 1 pressed into the resin layer 2, the minimum melt viscosity is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, further preferably 3000 to 15000 Pa·s, and particularly preferably 3000 to 10000 Pa·s. As an example, this minimum melt viscosity can be determined using a rotational rheometer (manufactured by TA Instruments) with a constant measuring pressure of 5g and a measuring plate with a diameter of 8mm. More specifically, it can be determined by setting the heating rate to 10°C / min, the measuring frequency to 10Hz, and the load variation on the measuring plate to 5g within a temperature range of 30 to 200°C.

[0097] By setting the minimum melt viscosity of the resin layer 2 to a high viscosity of 1500 Pa·s or more, unnecessary movement of the filler can be suppressed during hot pressing of the filler-containing film onto the article. In particular, when the filler-containing film is used as an anisotropic conductive film, it can prevent the conductive particles 1 that should be held between the terminals during anisotropic conductive connection from flowing due to resin flow.

[0098] Furthermore, when a filler dispersion layer 3 containing a filler film 10A is formed by pressing filler 1 into resin layer 2, regarding resin layer 2 when filling 1 is pressed in, when filling 1 is pressed into resin layer 2 and exposed from resin layer 2, resin layer 2 undergoes plastic deformation, resulting in resin layer 2 around filling 1 forming an inclined 2b ( Figure 1B The high-viscosity viscous body, or, when the filler 1 is pressed in so that it is not exposed from the resin layer 2 but embedded in the resin layer 2, forms an undulation 2c on the surface of the resin layer 2 directly above the filler 1. Figure 4 , Figure 6 The resin layer 2 is a highly viscous material. Therefore, the lower limit of the viscosity of the resin layer 2 at 60°C is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. This determination can be performed using the same method as for the minimum melt viscosity, by taking the value at a temperature of 60°C.

[0099] Regarding the specific viscosity of the resin layer 2 when the filler 1 is pressed into it, depending on the shape or depth of the slope 2b, undulation 2c to be formed, the lower limit is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. Furthermore, such a viscosity is obtained preferably at 40–80°C, more preferably 50–60°C.

[0100] As described above, by forming an inclined 2b around the filler 1 exposed from the resin layer 2 ( Figure 1B When the filler-containing membrane is pressed onto an article, the flattening of the filler 1 reduces the resistance from the resin layer 2 compared to the case without the tilt 2b. Therefore, when the filler-containing membrane is used as an anisotropic conductive membrane, the clamping of conductive particles in the terminals becomes easier during anisotropic conductive connections, thereby improving conductivity and the trapping ability of conductive particles in the terminals.

[0101] Inclined 2b is preferably aligned with the shape of the exposed portion of the filler. This is because, in addition to making the inclination effect in the connection easier to observe, it also makes the filler easier to identify, thereby facilitating product inspection during the manufacturing of filler-containing membranes.

[0102] Furthermore, an undulation 2c is formed on the surface of the resin layer 2 directly above the filler 1, which is embedded without being exposed from the resin layer 2. Figure 4 , Figure 6 Similar to the inclined case, it is easier to apply pressing pressure from the article to the filler when pressing it onto the article. Furthermore, due to the undulating depressions, the amount of resin directly above the filler is reduced compared to a flat resin surface, thus making it easier to expel the resin directly above the filler during pressing, resulting in a better connection between the article and the filler. In particular, when the filler-containing film is used as an anisotropic conductive film, the terminals easily contact the conductive particles during anisotropic conductive connections, thereby improving the trapping ability of conductive particles in the terminals and increasing the reliability of conductivity.

[0103] The tilt 2b and undulation 2c may sometimes disappear partially due to hot pressing or other processes on the resin layer, and this invention covers such cases. Additionally, the filler may sometimes be exposed at a point on the surface of the resin layer, with tilt or undulation present around that point; this invention also covers such cases. These options are appropriately selected depending on the application of the filler-containing membrane or the article to be hot-pressed. In other words, the filler-containing membrane of this invention offers high design flexibility, allowing for the reduction of the degree of tilt or undulation as needed, or for the use of the membrane after a portion of the tilt or undulation has disappeared.

[0104] (Resin layer thickness)

[0105] In the filler-containing membrane of the present invention, the ratio (La / D) of the thickness La of the resin layer 2 to the particle size D of the filler 1 is preferably 0.6 to 10. Here, the particle size D of the filler refers to its average particle size. If the thickness La of the resin layer 2 is too large, the filler is prone to displacement when the filler-containing membrane is pressed onto an article. Therefore, when the filler-containing membrane is used as an optical membrane, optical properties will deviate. In addition, when the filler-containing membrane is used as an anisotropic conductive membrane, the capture of conductive particles in terminals that have been anisotropically conductively connected to electronic components decreases. This tendency is significant if La / D exceeds 10. Therefore, La / D is more preferably 8 or less, and even more preferably 6 or less. Conversely, if the thickness La of the resin layer 2 is too small, resulting in La / D being less than 0.6, it is difficult to maintain the filler 1 in a specified particle dispersion state or a specified arrangement through the resin layer 2. In particular, when the filler film is used as an anisotropic conductive film, and the terminal to be connected is a high-density COG, the ratio (La / D) of the thickness La of the insulating resin layer 2 to the particle size D of the conductive particles is preferably 0.6 to 3, more preferably 0.8 to 2. On the other hand, when the filler film is an anisotropic conductive film, if the risk of short circuit is considered low due to the bump layout of the electronic components to be connected, the lower limit of the ratio (La / D) can also be set to 0.25 or more.

[0106] (Composition of the resin layer)

[0107] In this invention, the resin layer 2 may be formed from a thermoplastic resin composition, a high-viscosity adhesive resin composition, or a curable resin composition. The resin composition constituting the resin layer 2 is appropriately selected according to the application of the filler-containing membrane. In addition, whether the resin layer 2 is to be insulating also depends on the application of the filler-containing membrane.

[0108] Here, the curable resin composition may, for example, be formed from a thermopolymerizable composition containing a thermopolymerizable compound and a thermopolymerizable initiator. A photopolymerizable initiator may also be included in the thermopolymerizable composition as needed.

[0109] When using both thermal polymerization initiators and photopolymerization initiators, compounds that function as both thermal and photopolymerizable compounds can be used, or compounds that contain photopolymerizable compounds in addition to thermal polymerization compounds can be used. It is preferable to contain photopolymerizable compounds in addition to thermal polymerization compounds. For example, cationic curing initiators are used as thermal polymerization initiators, epoxy resins are used as thermal polymerization compounds, photoradical polymerization initiators are used as photopolymerization initiators, and acrylate compounds are used as photopolymerizable compounds.

[0110] As a photopolymerization initiator, it can also contain multiple light-reacting wavelengths. Therefore, in the manufacture of filler-containing films, the wavelengths used for photocuring the resin used to film the resin layer and for photocuring the resin used when pressing the filler-containing film onto the article can be used separately.

[0111] When photocuring is performed during the manufacturing of the filler-containing film, all or part of the photopolymerizable compounds contained in the resin layer can be photocured. Through this photocuring, the configuration of the filler 1 in the resin layer 2 is maintained or even fixed. Therefore, when the filler-containing film is used as an anisotropic conductive film, short-circuit suppression and improved trapping of conductive particles in the terminals are observed. Furthermore, through this photocuring, the viscosity of the resin layer in the manufacturing process of the filler-containing film can be appropriately adjusted.

[0112] The amount of photopolymerizable compound in the resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably less than 2% by mass. This is because if there is too much photopolymerizable compound, the force required to press the filler-containing film into the article will increase.

[0113] Examples of thermopolymerizable compositions include: thermopolymerizable acrylate compositions containing (meth)acrylate compounds and thermopolymerizable initiators, and thermopolymerizable epoxy compositions containing epoxy compounds and thermopolymerizable cationic initiators. Thermopolymerizable anionic epoxy compositions containing thermopolymerizable anionic initiators can also be used instead of thermopolymerizable cationic epoxy compositions containing thermopolymerizable cationic initiators. Furthermore, multiple polymerizable compounds can be used in combination, provided that no particular obstacles are encountered. Examples of parallel applications include the combined use of thermopolymerizable cationic compounds and thermopolymerizable compounds.

[0114] Here, conventionally known thermopolymerizable (meth)acrylate monomers can be used as (meth)acrylate compounds. For example, monofunctional (meth)acrylate monomers or difunctional or more polyfunctional (meth)acrylate monomers can be used.

[0115] Examples of initiators for thermal free radical polymerization include organic peroxides and azo compounds. In particular, organic peroxides that do not generate nitrogen that leads to bubble formation are preferred.

[0116] Regarding the amount of thermal free radical polymerization initiator used, if too little is used, the curing will be poor, and if too much is used, the product life will be reduced. Therefore, relative to 100 parts by weight of (meth)acrylate compound, it is preferred to be 2 to 60 parts by weight, and more preferably 5 to 40 parts by weight.

[0117] Examples of epoxy compounds include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic varnish type epoxy resin, their modified epoxy resins, alicyclic epoxy resins, etc., and two or more of them can be used in combination. In addition to epoxy compounds, oxetane compounds can also be used in combination.

[0118] As a thermal cationic polymerization initiator, compounds known as thermal cationic polymerization initiators for epoxy compounds can be used, such as iodonium salts, sulfonium salts, phosphonium salts, ferrocene salts, etc., which generate acids by heat. In particular, aromatic sulfonium salts with good latency to temperature are preferred.

[0119] Regarding the amount of thermal cationic polymerization initiator used, too little will tend to result in poor curing, while too much will tend to reduce product life. Therefore, relative to 100 parts by weight of epoxy compound, it is preferred to be 2 to 60 parts by weight, and more preferably 5 to 40 parts by weight.

[0120] As a thermal anionic polymerization initiator, commonly used and known curing agents can be used. Examples include organic acids such as dihydrazides, dicyandiamide, amine compounds, polyamide amine compounds, cyanate compounds, phenolic resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, Brønsted salts, polythiol-based curing agents, urea resins, melamine resins, isocyanate compounds, and terminally capped isocyanate compounds. One or more of these can be used alone. Among these, a microcapsule-type latent curing agent formed by coating a polyurethane core with an imidazole modifier is preferred.

[0121] The thermopolymerizable composition preferably contains a film-forming resin or a silane coupling agent. Examples of film-forming resins include phenoxy resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, polyurethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefin resins; two or more of these can be used in combination. Among these, phenoxy resins are preferred from the perspectives of film-forming properties, processability, and bonding reliability. The weight-average molecular weight is preferably 10,000 or higher. Examples of silane coupling agents include epoxy-based silane coupling agents and acrylic-based silane coupling agents. These silane coupling agents are primarily alkoxysilane derivatives.

[0122] In the thermopolymerizable composition, in order to adjust the melt viscosity, an insulating filler may be included in addition to filler 1 described above. Examples of such fillers include silica powder and alumina powder. The insulating filler is preferably a microfiller with a particle size of 20 to 1000 nm. Furthermore, the amount of the filler is preferably set to 5 to 50 parts by mass relative to 100 parts by mass of the thermopolymerizable compound (photopolymerizable compound) such as the epoxy compound. The insulating filler included in addition to filler 1 is preferably used when the purpose of the filler-containing film is an anisotropic conductive film, but it may not be insulating depending on the application; for example, conductive microfillers may also be included. When the filler-containing film is used as an anisotropic conductive film, an even smaller insulating filler (so-called nanofiller) different from filler 1 may be appropriately included in the resin layer forming the filler dispersion layer, as needed.

[0123] In addition to the insulating or conductive fillers mentioned above, the filler membrane of the present invention may also contain fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion scavengers, etc.

[0124] (The position of the filler in the thickness direction of the resin layer)

[0125] In the filler-containing membrane of the present invention, as described above, the position of the filler 1 in the thickness direction of the resin layer 2 may be that the filler 1 is exposed from the resin layer 2 or it may be embedded in the resin layer 2 without being exposed. However, the ratio of the distance Lb between the deepest part of the filler and the cross-section 2p of the center between adjacent fillers (hereinafter referred to as the embedment amount) to the particle size D of the filler (Lb / D) (hereinafter referred to as the embedment rate) is preferably 60% or more and 105% or less.

[0126] By setting the embedment ratio (Lb / D) to 60% or more, the filler 1 is maintained in a specified particle dispersion state or a specified arrangement by the resin layer 2. In addition, by setting it to 105% or less, the amount of resin in the resin layer that causes the filler to move unnecessarily when the filler-containing membrane is pressed with the article can be reduced.

[0127] It should be noted that, in this invention, the embedment ratio (Lb / D) refers to a value where 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of fillers contained in the filler membrane constitutes the embedment ratio (Lb / D). Therefore, an embedment ratio of 60% or more and 105% or less means that an embedment ratio of 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of fillers contained in the filler membrane is 60% or more and 105% or less.

[0128] Thus, by ensuring a uniform embedment ratio (Lb / D) across all fillers, the pressing load (weight) when the filler-containing film is pressed onto the article is applied evenly to the filler. Therefore, the film-bonded assembly formed by pressing the filler-containing film onto the article ensures uniformity in optical and mechanical properties. Furthermore, when the filler-containing film is used as an anisotropic conductive film, the trapping state of conductive particles in the terminals during anisotropic conductive connections becomes better, improving the reliability of conductivity.

[0129] The embedment ratio (Lb / D) can be measured by randomly sampling more than 10 locations with an area of ​​30 mm² from the filler membrane. 2 The above area is determined by observing a portion of the membrane cross-section in an SEM image and measuring a total of more than 50 fillers. To further improve accuracy, the measurement can be performed on more than 200 fillers.

[0130] Alternatively, the embedment ratio (Lb / D) can be measured by adjusting the focus in a planar field-of-view image and calculating the number of elements at a certain level. Alternatively, the embedment ratio (Lb / D) can also be measured using a laser-based discrimination displacement sensor (manufactured by Keyence, etc.).

[0131] (Solutions with an embedment rate of 60% or more but less than 100%)

[0132] For a more specific embedment scheme of filler 1 with an embedment ratio (Lb / D) of 60% or more and 105% or less, the following can be listed first: Figure 1B As shown in the filler-containing membrane 10A, the filler 1 is embedded in a manner that exposes from the resin layer 2 with an embedment rate of 60% or more and less than 100%. In this filler-containing membrane 10A, the portion of the surface of the resin layer 2 that contacts the filler 1 exposed from the resin layer 2 and the cross-section 2p of the surface 2a of the nearby resin layer relative to the central portion between adjacent fillers have a recessed inclination 2b, which forms an ridge line that generally follows the shape of the filler.

[0133] Such inclination 2b or undulation 2c ( Figure 4 , Figure 6 When manufacturing a filler-containing membrane by pressing filler 1 into resin layer 2, the lower limit of the viscosity of resin layer 2 when filler 1 is pressed in is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. Furthermore, such viscosity is preferably obtained at 40–80°C, more preferably 50–60°C.

[0134] (A solution with a 100% embedment rate)

[0135] Secondly, in the filler-containing membrane of the present invention, examples of schemes with an embedment ratio (Lb / D) of 100% include: Figure 2 As shown in the filler membrane 10B, the filler 1 has a surrounding surface with... Figure 1B The filler-containing membrane 10A shown is similarly formed with an inclination 2b approximately along the ridge of the filler's shape, and the exposed diameter Lc of the filler 1 exposed from the resin layer 2 is smaller than the particle size D of the filler 1; as shown Figure 3A As shown in the filler membrane 10C, the slope 2b around the exposed portion of the filler 1 is steeply present near the filler 1, and the exposed diameter Lc of the filler 1 is approximately equal to the particle size D of the filler; such as Figure 4 As shown in the filler-containing membrane 10D, the surface of the resin layer 2 has shallow undulations 2c, and the filler 1 is exposed from the resin layer 2 at its top 1a.

[0136] It should be noted that small protrusions 2q may also be formed adjacent to the inclined resin layer 2 2 around the exposed portion of the filler, or the undulation 2c of the resin layer 2 directly above the filler. One example is shown below. Figure 3B 10C' of filler membrane.

[0137] The embedment rate of these filler membranes 10B, 10C, 10C', and 10D is 100%, therefore the top 1a of filler 1 is aligned with the surface 2a of resin layer 2 on one surface. If the top 1a of filler 1 is aligned with the surface 2a of resin layer 2 on one surface, then... Figure 1B Compared to the case where the filler 1 protrudes from the resin layer 2, during the hot pressing of the filler-containing film and the article, the amount of resin in the film thickness direction around each filler is less likely to become uneven, thus reducing filler movement caused by resin flow. It should be noted that even if the embedment rate is not strictly 100%, this effect can still be achieved if the top of the filler 1 embedded in the resin layer 2 is aligned with the surface of the resin layer 2 to the extent that they form a single plane. In other words, when the embedment rate (Lb / D) is approximately 80–105%, particularly 90–100%, the top of the filler 1 embedded in the resin layer 2 and the surface of the resin layer 2 can be considered as a single plane, which can reduce filler movement caused by resin flow.

[0138] Of these filler films 10B, 10C, 10C', and 10D, in the case of 10D, because the amount of resin around the filler 1 is unlikely to become uneven, filler movement caused by resin flow can be eliminated. Furthermore, even at the top 1a, the filler 1 is exposed from the resin layer 2, thus facilitating bonding between the filler and the article. In the case of the filler film as an anisotropic conductive film, good trapping of conductive particles 1 in the terminals and minimal movement of conductive particles are expected. Therefore, this solution is particularly effective in cases of fine pitch or narrow spacing between bumps.

[0139] It should be noted that, as described later, the filler-containing membrane 10B with different shapes or depths, such as the inclined 2b and undulating 2c, is... Figure 2 ), 10C ( Figure 3A ), 10D ( Figure 4 It can be manufactured by changing the viscosity of the resin layer 2 when the filler 1 is pressed in.

[0140] (Solutions with an embedment rate exceeding 100%)

[0141] In the filler-containing membrane of the present invention, when the embedment rate exceeds 100%, examples include: Figure 5 As shown in the filler-containing membrane 10E, the filler 1 is exposed, and the resin layer 2 surrounding the exposed portion has an inclination 2b relative to the cross-section 2p; or, as... Figure 6 As shown in the filler-containing membrane 10F, the surface of the resin layer 2 directly above the filler 1 has a undulation 2c relative to the cross section 2p.

[0142] It should be noted that there is a filler-containing membrane 10E with an inclined 2b in the resin layer 2 surrounding the exposed portion of filler 1. Figure 5 ) and a filler-containing membrane 10F with undulations 2c in the resin layer 2 directly above filler 1 ( ) and a filler-containing membrane 10F ( ) Figure 6 They can be manufactured by changing the viscosity of the resin layer 2 when the filler 1 is pressed in during their manufacture.

[0143] If crimping Figure 5 The illustrated filler membrane 10E and article are shown, where the filler 1 is directly pressed by the article, thus facilitating bonding between the article and the filler. When the filler membrane is used as an anisotropic conductive membrane, the trapping ability of conductive particles in the terminals is improved. Furthermore, if crimping... Figure 6 The illustrated article contains a filler membrane 10F and an article. The filler 1 does not directly press the article, but rather presses it through the resin layer 2. However, the amount of resin present in the pressing direction is different from that in the other case. Figure 8 Compared to the state where filler 1 is embedded at a rate exceeding 100%, filler 1 is not exposed from resin layer 2, and the surface of resin layer 2 is flat, there are fewer filler particles, making it easier to apply pressure to the filler. Therefore, when using a filler-containing film as an anisotropic conductive film, it hinders the unnecessary movement of conductive particles 1 between terminals due to resin flow during anisotropic conductive connections.

[0144] The inclined 2b of the resin layer 2 around the exposed portion of the filler described above is easily obtained. Figure 1B , Figure 2 , Figure 3A , Figure 3B , Figure 5 ), or the undulation 2c of the resin layer 2 directly above the filler ( Figure 4 , Figure 6From the perspective of the effect, the ratio of the maximum depth Le of the inclined 2b around the exposed part of the filler 1 to the particle size D of the filler 1 (Le / D) is preferably less than 50%, more preferably less than 30%, and even more preferably 20-25%. The ratio of the maximum diameter Ld of the inclined 2b around the exposed part of the filler 1 to the particle size D of the filler 1 (Ld / D) is preferably more than 100%, more preferably 100-150%. The ratio of the maximum depth Lf of the undulation 2c in the resin directly above the filler 1 to the particle size D of the filler 1 (Lf / D) is greater than 0, preferably less than 10%, and more preferably less than 5%.

[0145] It should be noted that the exposed diameter (i.e., the diameter of the exposed portion) Lc of packing 1 can be set to be less than or equal to the particle size D of packing 1, preferably 10% to 90% of the particle size D of the packing. For example... Figure 4 As shown, it can be set to expose a point at the top of the filler 1, or it can be set to completely embed the filler 1 in the resin layer 2, with an exposed diameter Lc of 0.

[0146] On the other hand, if there are areas where the top of the filler 1 embedded in the resin layer 2 is approximately the same surface as the surface of the resin layer 2, and the depth of the depression (the distance from the deepest part of the depression to the cross-section of the center between adjacent fillers) caused by the inclination 2b or undulation 2c is locally concentrated (hereinafter, referred to only as "filler with a depression depth of 10% or more on the same surface as the resin layer"), then even if the performance or quality of the filler-containing membrane is not problematic, the appearance may sometimes be damaged. Furthermore, if the inclination 2b or undulation 2c of such areas is oriented towards the article and the filler-containing membrane is bonded to the article, the inclination 2b or undulation 2c may sometimes cause bulging after bonding. For example, in the case where the filler-containing membrane is an anisotropic conductive membrane, if conductive particles with a depression depth of 10% or more on the same surface as the insulating resin layer 2 are concentrated at a single protrusion, bulging may sometimes occur after bonding to the protrusion, resulting in a decrease in conductivity. Therefore, in the region where any filler that forms a surface with the resin layer 2 and has a depression depth of 10% or more is within 200 times the filler particle size, the ratio of the number of fillers forming a surface with the resin layer and having a depression depth of 10% or more relative to the total number of fillers is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. In contrast, in regions where this ratio exceeds 50%, it is preferable to apply resin or the like to the surface containing the filler film to reduce the depressions caused by the tilt 2b or undulation 2c. In this case, the applied resin preferably has a lower viscosity than the resin forming the resin layer 2, and it is desirable that the concentration of the applied resin is diluted to a level where the depressions in the resin layer 2 can be confirmed after application. By reducing the depressions caused by the tilt 2b or undulation 2c in this way, the aforementioned problems of appearance or bulging can be improved.

[0147] It should be noted that, as Figure 7As shown, in the filler-containing membrane 10G with an embedment ratio (Lb / D) of less than 60%, the filler 1 easily rolls on the resin layer 2. Therefore, when the filler-containing membrane is pressed with the article, the connection between the filler and the article becomes good. So, especially when the filler-containing membrane is used as an anisotropic conductive membrane, from the perspective of improving the capture rate of conductive particles in the terminals during anisotropic conductive connection, it is preferable to set the embedment ratio (Lb / D) to 60% or more.

[0148] Additionally, in schemes with an embedment ratio (Lb / D) exceeding 100%, such as... Figure 8 In the comparative example shown, where the surface of the resin layer 2 of the filler-containing membrane 10X is flat, the amount of resin between the filler 1 and the terminal becomes excessive during the hot pressing of the filler-containing membrane and the article. In addition, the filler 1 is not pressed directly onto the article, but rather through the resin layer, and the filler becomes easy to flow due to the resin flow.

[0149] In this invention, the presence of tilt 2b and undulation 2c on the surface of resin layer 2 can be confirmed by observing the cross-section of the filler-containing film using a scanning electron microscope, or by observing in a planar field of view. Tilting 2b and undulation 2c can also be observed using an optical microscope or a metal microscope. Furthermore, the size of tilt 2b and undulation 2c can be confirmed by adjusting the focus during image observation, etc. As described above, even after reducing the tilt or undulation through hot pressing, residual tilt or undulation can be confirmed using the same method as described above.

[0150] <Modification scheme for membranes containing fillers>

[0151] (Second resin layer)

[0152] The filler-containing membrane of the present invention can also be as follows Figure 9 As shown in the filler-containing membrane 10H, a second resin layer 4, preferably with a minimum melt viscosity lower than that of the resin layer 2, is laminated on the surface where the resin layer 2 of the filler dispersion layer 3 is formed with an inclined 2b. The second resin layer and the third resin layer (described later) are layers in which the resin layer itself does not contain the filler 1 dispersed in the filler dispersion layer 3. Alternatively, it can be as follows: Figure 10 As shown in the filler-containing membrane 10I, a second resin layer 4 with a minimum melt viscosity lower than that of the resin layer 2 is stacked on the surface of the resin layer 2 of the filler dispersion layer 3 where the inclination 2b is not formed. The same applies when an undulation 2c is formed instead of the inclination 2b.

[0153] The second resin layer 4 can also be made insulating or conductive depending on the application of the filler-containing film. If the second resin layer 4 is laminated, the adhesion between two opposing articles can be improved when they are heat-pressed together via the filler-containing film. In particular, when the filler-containing film is used as an anisotropic conductive film with an insulating resin layer as the second resin layer, and electronic components are anisotropically conductively connected, the second resin layer can fill the space formed by the electrodes or bumps of the electronic components, thereby improving the adhesion between the electronic components.

[0154] When using a filler-containing film with a second resin layer 4 to join opposing articles, it is preferable that the second resin layer 4 is located on the side of the article being pressed by a thermoforming tool, regardless of whether the second resin layer 4 is located on the forming surface of the inclined 2b. When the filler-containing film is used as an anisotropic conductive film, it is preferable that the second resin layer 4 is located on the side of the first electronic component, such as an IC chip, being pressed by a thermoforming tool (in other words, the resin layer 2 is located on the side of the second electronic component, such as a substrate supported on a stage). By operating in this way, unintentional movement of the filler can be avoided, and the trapping ability of conductive particles during anisotropic conductive bonding can be improved in anisotropic conductive films. This also applies even if the inclined 2b is undulating 2c. It should be noted that when using anisotropic conductive film to connect the first electronic component and the second electronic component, the first electronic component, such as the IC chip, is usually positioned as the pressing clamp side, and the second electronic component, such as the substrate, is positioned as the stage side. After temporarily pressing the anisotropic conductive film to the second electronic component, the first electronic component and the second electronic component are then formally pressed together. However, depending on the size of the pressing area of ​​the second electronic component, the first electronic component and the second electronic component may be formally pressed together after temporarily attaching the anisotropic conductive film to the first electronic component.

[0155] The greater the difference in minimum melt viscosity between resin layer 2 and the second resin layer 4, the easier it is for the second resin layer 4 to fill the space between two items connected via a filler-containing film. Therefore, when anisotropically conductive connections are made between the first and second electronic components, the space formed by the electrodes or bumps of the electronic components is easily filled by the second insulating resin layer 4, which is expected to improve the adhesion between the electronic components. Furthermore, the greater this difference, the smaller the amount of movement of the insulating resin layer 2, which holds the conductive particles in the conductive particle dispersion layer, relative to the second resin layer 4, thus improving the trapping ability of conductive particles in the terminal.

[0156] The minimum melt viscosity ratio of resin layer 2 to second resin layer 4 practically depends on the ratio of the thicknesses of resin layer 2 to second resin layer 4, but is preferably 2 or more, more preferably 5 or more, and even more preferably 8 or more. On the other hand, if this ratio is too large, there is a concern that resin overflow or adhesion may occur when the long strip of filler-containing film is rolled into a package, so it is practically preferred to be 15 or less. More specifically, the preferred minimum melt viscosity of second resin layer 4 satisfies the above-mentioned ratio and is 3000 Pa·s or less, more preferably 2000 Pa·s or less, and particularly preferably 100 to 2000 Pa·s.

[0157] It should be noted that the second resin layer 4 can be formed by adjusting the viscosity in the same resin composition as the resin layer 2.

[0158] The thickness of the second resin layer 4 can be appropriately set according to the application of the filler-containing film. Since this thickness is affected by the article to be heat-pressed or the heat-pressing conditions, it is not particularly limited. From the perspective of not excessively increasing the difficulty of the lamination process of the second resin layer 4, it is generally preferred to set it to 0.2 to 50 times the filler particle size. In addition, when the filler-containing film is used as an anisotropic conductive film 10H, 10I, the thickness of the second resin layer 4 is preferably 4 to 20 μm, and even more preferably 1 to 8 times the diameter of the conductive particles.

[0159] Furthermore, the minimum melt viscosity of the filler-containing membrane 10H, 10I, which combines the resin layer 2 and the second resin layer 4, is determined according to the application of the filler-containing membrane or the ratio of the thickness of the resin layer 2 to the thickness of the second resin layer 4. In the case where the filler-containing membrane is used as an anisotropic conductive membrane, it is practically set to 8000 Pa·s or less. In order to facilitate filling between the bumps, it can be set to 200 to 7000 Pa·s, preferably 200 to 4000 Pa·s.

[0160] (Third resin layer)

[0161] In the filler-containing membrane of the present invention, a third resin layer may also be provided on the opposite side of the second resin layer 4, sandwiching the resin layer 2. The third resin layer may also be made insulating or conductive depending on the intended use of the filler-containing membrane. For example, in the case where the filler-containing membrane is used as an anisotropic conductive membrane with an insulating third resin layer, the third resin layer can function as an adhesive layer. In the case where the filler-containing membrane is used as an anisotropic conductive membrane, similar to the second resin layer, the third resin layer may also be provided to fill the space formed by electrodes or bumps of electronic components.

[0162] The resin composition, viscosity, and thickness of the third resin layer can be the same as or different from those of the second resin layer. There is no particular limitation on the minimum melt viscosity of the filler-containing film in which the resin layer 2, the second resin layer 4, and the third resin layer are stacked together; it can be set to below 8000 Pa·s, 200–7000 Pa·s, or 200–4000 Pa·s.

[0163] (Other stacking schemes)

[0164] Depending on the application of the filler membrane, filler dispersion layers can be stacked, or layers without fillers can be placed between the stacked filler dispersion layers, such as a second resin layer. A second or third resin layer can also be provided on the outermost layer.

[0165] <Method for manufacturing membranes containing fillers>

[0166] The method for manufacturing a filler-containing membrane of the present invention includes a step of forming a filler dispersion layer in which filler is dispersed in a resin layer. The step of forming the filler dispersion layer includes: a step of maintaining the filler on the surface of the resin layer with a specific area occupancy ratio; and a step of pressing the filler held in the resin layer into the resin layer.

[0167] In the process of holding the filler on the surface of the resin layer, the CV value of the filler particle size held on the surface of the resin layer is set to 20% or less. Furthermore, the filler is held on the surface of the resin layer, dispersed on the surface, and the area occupancy of the filler, calculated by the following formula, is 0.3% or more.

[0168] Area occupancy (%) = [number density of fillers in top view] × [average area of ​​1 filler in top view] × 100 On the other hand, in the process of pressing the filler held in the resin layer into the resin layer, the filler held on the surface of the resin layer is pressed into the resin layer in such a way that the surface of the resin layer near the filler is inclined or undulated relative to the cross section of the resin layer at the center between adjacent fillers.

[0169] The resin layer into which the filler is pressed can form the aforementioned inclined 2b or undulating 2c, without particular limitation. Preferably, the minimum melt viscosity is 1100 Pa·s or more, and the viscosity at 60°C is 3000 Pa·s or more. Among these, the minimum melt viscosity is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, further preferably 3000 to 15000 Pa·s, and particularly preferably 3000 to 10000 Pa·s. The lower limit of the viscosity at 60°C is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and further preferably 10000 Pa·s or less.

[0170] When the filler-containing membrane is formed from a single layer of filler dispersion layer 3, the filler-containing membrane of the present invention can be manufactured, for example, by holding the filler 1 on the surface of the resin layer 2 in a prescribed arrangement and then pressing the filler 1 into the resin layer using a plate or roller. It should be noted that, when manufacturing a filler-containing membrane with an embedding rate of more than 100%, a pressure plate having protrusions corresponding to the arrangement of the filler can also be used for pressing.

[0171] Here, the amount of filler 1 embedded in the resin layer 2 can be adjusted by the pressing pressure, temperature, etc. when pressing the filler 1. In addition, the shape and depth of the tilt 2b and undulation 2c can be adjusted by the viscosity of the resin layer 2, the pressing speed, temperature, etc. during pressing.

[0172] Known methods can be used to retain filler 1 on resin layer 2. For example, filler 1 can be directly sprinkled onto resin layer 2; or, filler 1 can be attached as a monolayer to a biaxially stretchable film, the film can be biaxially stretched, and the stretched film can be pressed against resin layer 2 to transfer the filler to resin layer 2, thereby retaining filler 1 on resin layer 2. Alternatively, filler 1 can also be retained on resin layer 2 by filling filler in a transfer mold and transferring the filler to resin layer 2.

[0173] When using a transfer mold to hold the filler 1 in the resin layer 2, the transfer mold can be, for example, formed by known opening-forming methods such as photolithography on inorganic materials such as silicon, various ceramics, glass, and stainless steel, or organic materials such as various resins; or a transfer mold using a printing method. Furthermore, the transfer mold can be formed into shapes such as a plate or a roller. It should be noted that the present invention is not limited to the methods described above.

[0174] Alternatively, a second resin layer with a lower viscosity than the resin layer can be laminated on the surface of the pressed-in side of the resin layer containing the filler, or on the opposite side thereof.

[0175] To economically bond filler-containing films to articles on an industrial production line, the filler-containing film is preferably manufactured in a certain length. Therefore, the length of the filler-containing film is preferably 5m or more, more preferably 10m or more, and even more preferably 25m or more. On the other hand, if the filler-containing film is too long, it becomes difficult to use existing crimping devices, resulting in poor operability. Therefore, the length of the filler-containing film is preferably 5000m or less, more preferably 1000m or less, and even more preferably 500m or less. Furthermore, from the perspective of excellent operability, this long filler-containing film is preferably manufactured as a roll wound around a core.

[0176] <Instructions for use of membranes containing fillers>

[0177] The filler-containing film of the present invention can be bonded to articles in the same way as conventional filler-containing films, and there are no particular limitations on the articles as long as the filler-containing film can be bonded. Depending on the intended use, the filler-containing film can be bonded to various articles by pressing, preferably by heat pressing. This bonding can be performed using light irradiation, or a combination of heat and light. For example, if the resin layer of the filler-containing film has sufficient adhesion to the article to which it is to be bonded, a film-bonded body formed by gently pressing the resin layer of the filler-containing film onto the article surface can be obtained. In this case, the surface of the article is not limited to a flat surface; it can be uneven or curved as a whole. When the article is in film or flat shape, a pressing roller can also be used to bond the filler-containing film to the article. Thus, the filler of the filler-containing film can also be directly bonded to the article.

[0178] Alternatively, the filler-containing membrane can be placed between two opposing first and second articles, and the two opposing articles can be connected using a hot-pressing roller or pressing tool, so that the filler is held between the articles. Alternatively, the filler can be inserted into the articles without direct contact with them.

[0179] Furthermore, when using a filler-containing film as an anisotropic conductive film, a thermoforming tool can be used to apply the anisotropic conductive film for anisotropic conductive connections between first electronic components such as IC chips, IC modules, and FPCs, and second electronic components such as FPCs, glass substrates, plastic substrates, rigid substrates, and ceramic substrates. The anisotropic conductive film of this invention can also be used to stack IC chips or wafers for multilayering. It should be noted that the electronic components connected using the anisotropic conductive film of this invention are not limited to the aforementioned electronic components. In recent years, it has been used in a wide variety of electronic components.

[0180] Therefore, the present invention includes: an adhesive body obtained by hot-pressing the filler-containing film of the present invention onto various articles, and a method for manufacturing the adhesive body. In particular, when the filler-containing film is used as an anisotropic conductive film, it further includes a method for manufacturing a connection structure for anisotropically conductively connecting a first electronic component and a second electronic component using the anisotropic conductive film, and the resulting connection structure, i.e., a connection structure obtained by anisotropically conductively connecting the first electronic component and the second electronic component through the anisotropic conductive film of the present invention.

[0181] As a method for connecting electronic components using anisotropic conductive films, when the anisotropic conductive film is composed of a single layer of conductive particle dispersion layer 3, for various substrates and other second electronic components, temporary bonding and pressing are performed on the side of the anisotropic conductive film where the conductive particles 1 are embedded in the surface. Then, an IC chip and other first electronic components are assembled on the side of the temporarily pressed anisotropic conductive film where the conductive particles 1 are not embedded in the surface, and thermal bonding is performed. This allows for manufacturing. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerization compound, but also a photopolymerization initiator and a photopolymerization compound (which may also be the same as the thermal polymerization compound), a bonding method using both light and heat can be used. By operating in this way, unintentional movement of the conductive particles can be minimized. Alternatively, the side where the conductive particles are not embedded can be temporarily bonded to the second electronic component for use. It should also be noted that the anisotropic conductive film can be temporarily bonded to the first electronic component instead of the second electronic component.

[0182] Furthermore, when the anisotropic conductive film is formed by a laminate of a conductive particle dispersion layer 3 and a second insulating resin layer 4, the conductive particle dispersion layer 3 is temporarily adhered to various substrates or other second electronic components and temporarily pressed together. The second insulating resin layer 4 side of the temporarily pressed anisotropic conductive film is aligned with a first electronic component such as an IC chip and placed thereon, and then heat-pressed together. Alternatively, the second insulating resin layer 4 side of the anisotropic conductive film can be temporarily adhered to the first electronic component. Alternatively, the conductive particle dispersion layer 3 side can be temporarily adhered to the first electronic component for use.

[0183] Example

[0184] Hereinafter, through examples, an anisotropic conductive film, which is one embodiment of the filler-containing film of the present invention, will be specifically described.

[0185] Examples 1-11, Comparative Examples 1-2

[0186] (1) Fabrication of anisotropic conductive films

[0187] Resin compositions for forming an insulating resin layer and a second insulating resin layer were prepared according to the mixing methods shown in Table 1.

[0188] A resin composition to form an insulating resin layer is applied to a PET film with a film thickness of 50 μm using a doctor blade coater. The mixture is then dried in an oven at 80°C for 5 minutes to form an insulating resin layer on the PET film. Figure 12 An insulating resin layer of the thickness shown. The same procedure is followed to... Figure 12 The thickness shown forms a second insulating resin layer on the PET film.

[0189] [Table 1]

[0190]

[0191] On the other hand, a mold is made so that the conductive particle 1 appears as a top-down view. Figure 1A In the square lattice arrangement shown, the distance between particles is equal to the particle size of the conductive particles, and the number density of conductive particles reaches 28,000 / mm. 2 That is, a mold is made in which the convex pattern is a square grid arrangement, the spacing between the convex parts on the grid axis is twice the average diameter of the conductive particles (3μm), and the angle θ between the grid axis and the short side direction (long side direction of the terminal) of the anisotropic conductive film is 15°. Particles of a known transparent resin are injected into the mold in a molten state, cooled, and solidified, thereby forming the depressions. Figure 1A The resin mold with the arrangement pattern shown.

[0192] As conductive particles, metal-coated resin particles (Sekisui Chemicals Co., Ltd., AUL703, average particle size 3 μm) were prepared. These conductive particles were filled into the recesses of a resin mold, and the aforementioned insulating resin layer was coated on top. The particles were then pressed together at 60°C and 0.5 MPa. The insulating resin layer was then peeled off the mold, and the conductive particles on the insulating resin layer were pressed into the insulating resin layer under pressure (pressing conditions: 60–70°C, 0.5 MPa) to create an anisotropic conductive film consisting of a single layer of conductive particle dispersion (Examples 6–11 and Comparative Example 2). The embedding state of the conductive particles was controlled by the pressing conditions. It should be noted that the CV value of the metal-coated resin particles used was less than 20% when measured using an FPIA-3000 (Malvern) with a particle count of 1000 or more.

[0193] The area occupancy of conductive particles in the anisotropic conductive film manufactured in this manner is as follows: 28,000 particles / mm² 2 ×(1.5×1.5×3.14×10 -6 ) × 100 = 19.8%.

[0194] In addition, a second insulating resin layer is stacked on the conductive particle dispersion layer that was also prepared, thereby creating a bilayer anisotropic conductive film (Examples 1-5, Comparative Example 1).

[0195] (2) Embedded state

[0196] The anisotropic conductive films of Examples 1-11 and Comparative Examples 1-2 were cut with a cutting line passing through the conductive particles, and their cross-sections were observed using a metal microscope. In addition, for Examples 4-11 and Comparative Example 2, where the conductive particles were exposed on the surface of the anisotropic conductive film or the conductive particles were located near the surface of the anisotropic conductive film, the film surface was observed using a metal microscope. Figure 11AA photograph of the upper surface of Example 4 is shown. Figure 11B A photograph of the upper surface of Example 8 is shown.

[0197] In Examples 1-6, 9-11, and Comparative Example 1, conductive particles were exposed from the insulating resin layer. In Examples 1-6 and 9-11, an inclination 2b was observed on the surface of the insulating resin layer surrounding the conductive particles, and the surrounding surface portion ( Figure 11A The outer portion of the dashed line is flat. On the other hand, in Comparative Example 1, no tilt was observed around the conductive particles.

[0198] In Example 8, the conductive particles were completely embedded in the insulating resin layer, and the conductive particles did not protrude from the insulating resin layer. However, undulations 2c were observed on the surface of the insulating resin layer directly above the conductive particles, and the surrounding surface portion was also observed. Figure 11B The outer part of the dashed line is flat. In Comparative Example 2, the embedment rate is slightly greater than 100%, the conductive particles are not exposed from the resin layer, but the surface of the resin layer is flat, and no undulations are observed on the surface of the resin layer directly above the conductive particles.

[0199] It should be noted that the anisotropic conductive film of Example 7 is an example of a mixture of the tilt 2b of Example 6 and the undulation 2c of Example 8. The tilt 2b is observed on the surface of the insulating resin layer surrounding the conductive particles exposed from the insulating resin layer, and the surface around it is observed to be partially flat. On the other hand, the undulation 2c is observed on the surface of the insulating resin layer directly above the conductive particles completely embedded in the insulating resin layer, and the surface around it is observed to be partially flat.

[0200] (3) Evaluation

[0201] For the anisotropic conductive films of the examples and comparative examples prepared in (1), the following procedures were performed to measure or evaluate (a) initial on-resistance, (b) on-resistance, and (c) particle trapping properties. The results are shown in […]. Figure 12 .

[0202] (a) Initial on-resistance

[0203] The anisotropic conductive films of each embodiment and comparative example were cut to a sufficient area for connection, sandwiched between an IC for evaluating conductivity characteristics and a glass substrate, and heated and pressurized (180°C, 60 MPa, 5 seconds) to obtain various evaluation connectors. The on-resistance of the obtained evaluation connectors was measured using the four-terminal method. In practical applications, an initial on-resistance rating of B or higher is preferred, and an A rating is more preferable. Even a C rating is acceptable as long as it is below 2Ω.

[0204] Here, regarding the evaluation IC and the glass substrate, their terminal patterns correspond, and their dimensions are as follows. Furthermore, when connecting the evaluation IC and the glass substrate, the long side direction of the anisotropic conductive film and the short side direction of the bumps are aligned.

[0205] IC for evaluating conduction characteristics

[0206] Dimensions: 1.8 × 20.0 mm;

[0207] Thickness: 0.5mm;

[0208] Bump specifications: size 30×85μm, distance between bumps 50μm, bump height 15μm.

[0209] Glass substrate (ITO wiring)

[0210] Glass material: Corning 1737F;

[0211] Dimensions: 30×50mm;

[0212] Thickness: 0.5mm;

[0213] Electrode: ITO wiring.

[0214] Initial On-Resistance Evaluation Standard

[0215] A: Below 0.3Ω;

[0216] B: Greater than 0.3Ω and less than 1Ω;

[0217] C: 1Ω or higher.

[0218] (b) Conductivity

[0219] Similar to the initial on-resistance, the on-resistance of the evaluation connector prepared in (a) was measured after 500 hours in a constant temperature bath at 85°C and 85% RH. In practical applications, a conduction reliability rating of B or higher is preferred, and A is more preferable. Even a C rating is acceptable as long as it is below 6Ω.

[0220] Conductivity Reliability Evaluation Standard

[0221] A: Below 2.5Ω;

[0222] B: Exceeding 2.5Ω and less than 5Ω;

[0223] C: 5Ω or higher.

[0224] (c) Particle trapping properties

[0225] Using an IC for evaluating particle trapping performance, the alignment of the IC with the glass substrate (ITO wiring) corresponding to the terminal pattern is offset by 6 μm. Heating and pressurizing (180°C, 60 MPa, 5 seconds) are applied. The number of conductive particles trapped in 100 6 μm × 66.6 μm areas where the bumps of the IC overlap with the terminals of the substrate is measured. The minimum trapping number is determined, and evaluation is performed according to the following criteria. Practically, a rating of B or higher is preferred.

[0226] Evaluation of particle trapping performance using IC

[0227] Dimensions: 1.6 × 29.8 mm;

[0228] Thickness: 0.3mm;

[0229] Bump specifications: size 12×66.6μm, bump spacing 22μm (L / S=12μm / 10μm), bump height 12μm.

[0230] Particle trapping performance evaluation criteria

[0231] A: 5 or more;

[0232] B: 3 or more but less than 5;

[0233] C: Less than 3.

[0234] Depend on Figure 12 It can be seen that in Examples 1-7 and 9, where the conductive particle embedment rate is 60-105%, the conductive particles are exposed from the insulating resin layer, and have a tilt 2b, and in Example 8, where the conductive particles are completely embedded in the insulating resin layer and have undulations 2c, the initial conduction resistance and conduction reliability are both rated A, and the particle trapping performance is also good. However, in Comparative Example 1, where even the embedment rate is within this range, the conductive particles are exposed from the insulating resin layer but do not have a tilt 2b, and in Comparative Example 2, where the conductive particles are completely embedded in the insulating resin layer with an embedment rate of approximately 100% and do not have undulations 2c, the particle trapping performance is rated C. The conductive particles cannot be retained during connection, and fine-pitch connections cannot be handled. It can be inferred that if the surface of the insulating resin layer 2 is flat around or directly above the conductive particles 1, the conductive particles are easily affected by resin flow during anisotropic conductive connections, and the pressure of the conductive particles into the terminals is insufficient.

[0235] In addition, it was clarified that in the above Examples 1 to 7 and 9, the minimum melt viscosity of the insulating resin layer was 2000 Pa·s or more and the melt viscosity at 60°C was 3000 Pa·s or more. However, in Comparative Examples 1 and 2, the minimum melt viscosity was 1000 Pa·s and the melt viscosity at 60°C was 1500 Pa·s. By adjusting the pressing conditions of the conductive particles, the viscosity during pressing was reduced, so the tilt 2b and undulation 2c were not formed.

[0236] As can be seen from Examples 4, 5 and Examples 6, 9, the particle capture performance is good in both the case of forming a bilayer type of anisotropic conductive film with a conductive particle dispersion layer and a second insulating resin layer, and the case of forming a single layer of conductive particle dispersion layer.

[0237] As can be seen from Examples 3, 4, and 5, when the anisotropic conductive film is formed into a double-layer type with a conductive particle dispersion layer and a second insulating resin layer, the particle capture performance is good in practical applications, whether the second insulating resin layer is stacked on the surface of the insulating resin layer where conductive particles are pressed in or on the opposite side.

[0238] It should be noted that when the surface of the anisotropic conductive film exposed by the conductive particles in Examples 4 and 5 was sprayed with the same diluted resin composition to make the surface slightly flat, the results obtained were substantially the same when the products were evaluated in the same way.

[0239] In all embodiments where initial conductivity was measured, when the same method for determining the number of short circuits as described in the embodiment of Japanese Patent Application Publication No. 2016-085983 was performed to confirm the number of short circuits between 100 bumps, no short circuits were found. Furthermore, for all embodiments of the anisotropic conductive film, when the short circuit occurrence rate was determined according to the method for determining the short circuit occurrence rate described in the embodiment of Japanese Patent Application Publication No. 2016-085982, the results were all less than 50 ppm, confirming that it is practically feasible. It should be noted that in the case of anisotropic conductive films where conductive particles are randomly dispersed in an insulating resin, a higher number of short circuit occurrence rates were obtained. This can be confirmed by referring to Comparative Example 2 of Patent Document 2 or Comparative Example 2 of Patent Document 3, etc.

[0240] It should be noted that the anisotropic conductive film of Example 7, with its mixed tilt and undulation, yielded the same results as Examples 6 and 8. This demonstrates that the effect is achieved by the presence of tilt or undulation near the conductive particles. Furthermore, the fact that the same effect was obtained in Examples 6-8 indicates a wide range of possibilities in the manufacturing conditions of anisotropic conductive films. This suggests various benefits such as reduced manufacturing costs and rapid design changes for anisotropic conductive films, and also indicates high industrial value.

[0241] Experimental Examples 1-4

[0242] (Fabrication of anisotropic conductive films)

[0243] For the anisotropic conductive film used for COG connections, to investigate the effect of the resin composition of the insulating resin layer on the film-forming ability and conductivity, resin compositions for forming the insulating resin layer and the second insulating resin layer were prepared by blending as shown in Table 2. In this case, the minimum melt viscosity of the resin composition was adjusted according to the preparation conditions of the insulating resin composition. Using the obtained resin composition, the same operation as in Example 1 was performed to form the insulating resin layer. An anisotropic conductive film consisting of a single layer of conductive particle dispersion was prepared by pressing conductive particles into the insulating resin layer. Then, a second insulating resin layer was stacked on the side of the insulating resin layer where the conductive particles were pressed in, to prepare the anisotropic conductive film shown in Table 3. In this case, the arrangement of the conductive particles was the same as in Example 1. In addition, by appropriately adjusting the pressing conditions of the conductive particles, the conductive particles were embedded in the state shown in Table 3.

[0244] In the fabrication process of this anisotropic conductive film, after the conductive particles were pressed into the insulating resin layer, the film shape was not maintained in Experiment 4 (film shape evaluation: NG), while the film shape was maintained in the other experimental examples (film shape evaluation: OK). Therefore, for the anisotropic conductive films in the experimental examples other than Experiment 4, the embedding state of the conductive particles was observed and measured using a metal microscope before subsequent evaluation.

[0245] It should be noted that, in all experimental examples except for Experiment 4, tilting, or both tilting and undulation, were observed. Table 3 shows the measurements of the experimental example in which tilting was most clearly observed. The observed embedment state satisfies the preferred range described above.

[0246] [Table 2]

[0247]

[0248] [Table 3]

[0249]

[0250] (evaluate)

[0251] (a) Initial on-resistance and on-reliability

[0252] The same procedures as in Example 1 were performed, and the initial on-resistance and on-reliability were evaluated at three levels. The evaluation criteria were also the same as in Example 1. The results are shown in Table 3.

[0253] (b) Particle trapping ability

[0254] The same procedures as in Example 1 were performed to evaluate particle trapping performance.

[0255] As a result, all three experimental examples received a rating of B or higher.

[0256] (c) Short circuit occurrence rate

[0257] The same procedure as in Example 1 was performed, and the short-circuit occurrence rate was evaluated.

[0258] As a result, the values ​​in Experiments 1-3 were all less than 50 ppm, confirming that there are no practical problems.

[0259] Table 3 shows that if the minimum melt viscosity of the insulating resin layer is below approximately 1000 Pa·s, it is difficult to form a tilted film in the insulating resin layer near the conductive particles. On the other hand, if the minimum melt viscosity of the insulating resin layer is above 1500 Pa·s, by adjusting the conditions for embedding the conductive particles, a tilt can be formed on the surface of the insulating resin layer near the conductive particles. The anisotropic conductive film obtained by this operation exhibits good conductivity when used in COG.

[0260] Experimental Examples 5-8

[0261] (Fabrication of anisotropic conductive films)

[0262] For anisotropic conductive films used in FOG connections, to investigate the effect of the resin composition of the insulating resin layer on film-forming ability and conductivity, resin compositions for forming the insulating resin layer and the second insulating resin layer were mixed and modulated as shown in Table 4. In this case, the conductive particle configuration was set to a number density of 15,000 particles / mm². 2 The hexagonal lattice arrangement was such that one of its lattice axes was tilted at 15° relative to the long side of the anisotropic conductive film. Furthermore, the minimum melt viscosity of the resin composition was adjusted according to the preparation conditions of the insulating resin composition. Using the obtained resin composition, the same operation as in Example 1 was performed to form an insulating resin layer. An anisotropic conductive film consisting of a single layer of conductive particle dispersion was created by pressing conductive particles into the insulating resin layer. A second insulating resin layer was then laminated onto the side of the insulating resin layer where the conductive particles were pressed in, thus creating the anisotropic conductive film shown in Table 5. In this case, by appropriately adjusting the pressing conditions of the conductive particles, the conductive particles were embedded in the state shown in Table 5.

[0263] In the fabrication process of this anisotropic conductive film, after the conductive particles were pressed into the insulating resin layer, the film shape was not maintained in Experiment 8 (film shape evaluation: NG), while the film shape was maintained in the other experimental examples (film shape evaluation: OK). Therefore, for the anisotropic conductive films in the experimental examples other than Experiment 8, the embedding state of the conductive particles was observed and measured using a metal microscope before subsequent evaluation.

[0264] It should be noted that, in all experimental examples except Experimental Example 8, tilting, or both tilting and undulation, were observed. Table 5 shows the measurements of the experimental example in which tilting was most clearly observed. The observed embedment state satisfies the preferred range described above.

[0265] [Table 4]

[0266]

[0267] [Table 5]

[0268]

[0269] (evaluate)

[0270] (a) Initial on-resistance and on-reliability

[0271] The following operations were performed to evaluate (i) the initial on-resistance and (ii) the on-reliability. The results are shown in Table 5.

[0272] (i) Initial on-resistance

[0273] The anisotropic conductive films obtained in each experimental example were cut to a sufficient area for connection and sandwiched between an FPC for evaluating conductivity characteristics and an alkali-free glass substrate. They were then heated and pressurized (180°C, 4.5 MPa, 5 seconds) using a thermoforming tool with a tool width of 1.5 mm to obtain the evaluation connectors. The on-resistance of the obtained evaluation connectors was measured using the four-terminal method, and the measured values ​​were evaluated according to the following standards.

[0274] The conduction characteristics are evaluated using an FPC:

[0275] Terminal spacing: 20μm;

[0276] Terminal width / terminal spacing: 8.5μm / 11.5μm;

[0277] Polyimide film thickness (PI) / copper foil thickness (Cu) = 38 / 8, Sn plating.

[0278] Alkali-free glass substrate:

[0279] Electrode: ITO wiring;

[0280] Thickness: 0.7mm.

[0281] Evaluation criteria for initial on-resistance

[0282] OK: Less than 2.0Ω;

[0283] NG: 2.0Ω or higher.

[0284] (ii) Conductivity reliability

[0285] The evaluation connector prepared in (i) was placed in a constant temperature bath at 85°C and 85%RH for 500 hours. Its on-resistance after placement was measured in the same manner as the initial on-resistance, and its measured value was evaluated according to the following criteria.

[0286] Evaluation criteria for conduction reliability

[0287] OK: Less than 5.0Ω;

[0288] NG: 5.0Ω or higher.

[0289] (b) Particle trapping ability

[0290] For the 100 terminals of the evaluation connector made in (i), the number of conductive particles captured is measured, and the minimum capture number is determined. If the minimum capture number is 10 or more, there is no practical problem.

[0291] The minimum number of captures in Experiments 5-7 was all above 10.

[0292] (c) Short circuit occurrence rate

[0293] The number of short circuits in the evaluation connectors fabricated in (i) was measured, and the short circuit rate was determined by the measured number of short circuits and the number of gaps in the evaluation connectors. The short circuit rates in Experiments 5-7 were all less than 50 ppm, confirming that they are practically feasible.

[0294] Table 5 shows that if the minimum melt viscosity of the insulating resin layer is below approximately 1000 Pa·s, it is difficult to form a tilted film on the surface of the insulating resin layer near the conductive particles. On the other hand, if the minimum melt viscosity of the insulating resin layer is above 1500 Pa·s, a tilt can be formed on the surface of the insulating resin layer near the conductive particles by adjusting the conditions when the conductive particles are embedded. The anisotropic conductive film obtained by this operation has good conductivity when used in FOG.

[0295] Symbol Explanation

[0296] 1: Filler, conductive particles;

[0297] 1a: Top of the packing;

[0298] 2: Resin layer, insulating resin layer;

[0299] 2a: The surface of the resin layer;

[0300] 2b: Inclined;

[0301] 2c: fluctuations;

[0302] 2f: Flat surface portion;

[0303] 2p: Cross-section;

[0304] 2q: The highlighted part;

[0305] 3: Filler dispersion layer, conductive particle dispersion layer;

[0306] 4: Second resin layer, second insulating resin layer;

[0307] 10A, 10B, 10C, 10C', 10D, 10E, 10F, 10G, 10H, 10I: films containing fillers, anisotropic conductive films of the embodiments;

[0308] 20: terminal;

[0309] A: Lattice axis;

[0310] D: Diameter of conductive particles, particle size of filler;

[0311] La: Thickness of the resin layer;

[0312] Lb: Embedding depth (the distance from the deepest part of the packing to the cross-section of the center between adjacent packings);

[0313] Lc: Exposed diameter;

[0314] Ld: Maximum diameter of the inclination;

[0315] Le: Maximum depth of inclination;

[0316] Lf: Maximum depth of undulation;

[0317] θ: The angle between the long side of the terminal and the lattice axis of the conductive particles.

Claims

1. A filler-containing membrane, which is a filler-containing membrane having a filler dispersion layer in which filler is dispersed in a resin layer. The amount of resin around or directly above the filler is reduced because the resin layer near the filler is dragged into the interior by the filler's embedment, relative to the cross-section of the resin layer at the center between adjacent fillers. The filler is positioned uniformly along the film thickness direction. The ratio of the distance Lb from the deepest part of the packing to the aforementioned cross-section to the particle size D of the packing, Lb / D, is 60% or more and 105% or less. The aforementioned resin layer is a pre-cured resin layer formed from a curable resin composition. The above-mentioned curable resin composition contains a polymerizable compound and a polymerization initiator. The polymerizable compound is a thermopolymerizable compound that functions as both a thermal polymerizable compound and a photopolymerizable compound. The polymerization initiator is a thermal polymerization initiator, or a mixed polymerization initiator of thermal polymerization initiator and photopolymerization initiator. The CV value of the filler particle size is below 20%. The packing material is arranged regularly.

2. A filler-containing membrane, which is a filler-containing membrane having a filler dispersion layer in which filler is dispersed in a resin layer. The surface of the resin layer near the filler is inclined or undulating relative to the cross-section of the resin layer in the center between adjacent fillers. In this tilt, the surface of the resin layer surrounding the filler is defective relative to the aforementioned cross-section. In this undulation, the amount of resin in the resin layer directly above the filler is less than when the surface of the resin layer directly above the filler is located at the aforementioned cross-section. The amount of resin around or directly above the filler is reduced because it is dragged into the interior by the embedded filler. The filler is positioned uniformly along the film thickness direction. The ratio of the distance Lb from the deepest part of the packing to the aforementioned cross-section to the particle size D of the packing, Lb / D, is 60% or more and 105% or less. The aforementioned resin layer is a pre-cured resin layer formed from a curable resin composition. The above-mentioned curable resin composition contains a polymerizable compound and a polymerization initiator. The polymerizable compound is a thermopolymerizable compound that functions as both a thermal polymerizable compound and a photopolymerizable compound. The polymerization initiator is a thermal polymerization initiator, or a mixed polymerization initiator of thermal polymerization initiator and photopolymerization initiator. The CV value of the filler particle size is below 20%, and the tilted or undulating portion disappears. The packing material is arranged regularly.

3. The filler-containing membrane according to claim 1 or 2, wherein, The packing materials are configured so that they do not come into contact with each other.

4. The filler-containing membrane according to claim 1 or 2, wherein, The packing density is set at 100 on one side of any five or more locations within the measurement area. μ A rectangular area larger than m is measured, and the total area of ​​the measurement area is set to 2 mm. 2 The above refers to the number density.

5. The filler-containing membrane according to claim 1 or 2, wherein, The filler area occupancy rate calculated by the following formula is above 0.3% and below 35%: Area occupancy rate (%) = [number density of packing material under top view] × [average area of ​​1 packing material under top view] × 100.

6. The filler-containing membrane according to claim 1 or 2, wherein, The filler is a metal particle or a metal-coated resin particle.

7. The filler-containing membrane according to claim 6, wherein, The filler has an insulated surface.

8. The filler-containing membrane according to claim 1 or 2, wherein, The filler is exposed from the resin layer.

9. The filler-containing membrane according to claim 1 or 2, wherein, The filler is not exposed from the resin layer but is embedded within it.

10. The filler-containing membrane according to claim 2, wherein, The ratio of the depth Le of the aforementioned inclination or undulation from the aforementioned cross-section to the particle size D of the filler, Le / D, is less than 50%.

11. The filler-containing membrane according to claim 2, wherein, The ratio of the maximum diameter Ld of the aforementioned tilt or undulation to the particle size D of the filler, Ld / D, is 100% or more.

12. The filler-containing membrane according to claim 1 or 2, wherein, The ratio of the resin layer thickness La to the filler particle size D, La / D, is 0.6 to 10.

13. The filler-containing membrane according to claim 1 or 2, wherein, The closest distance between packing particles is more than 0.5 times the particle size of the packing.

14. The filler-containing membrane according to claim 2, wherein, A second resin layer is laminated on the surface opposite to the surface on which the resin layer of the filler dispersion layer is formed, which has an inclined or undulating surface.

15. The filler-containing membrane according to claim 2, wherein, A second resin layer is stacked on the inclined or undulating surface of the resin layer in the filler dispersion layer.

16. The filler-containing membrane according to claim 14 or 15, wherein, The minimum melt viscosity of the second resin layer is lower than that of the resin layer in the filler dispersion layer.

17. The filler-containing membrane according to claim 1 or 2, wherein, The resin layer of the filler dispersion layer is an insulating resin layer, and the filler is a conductive particle.

18. The filler-containing membrane according to claim 1 or 2, wherein, The filler-containing membrane is configured as a strip with a length of 5m or more, or as a roll wound on a winding core.

19. Membrane adhesive, wherein, The filler-containing membrane as described in any one of claims 1 to 18 is affixed to the article.

20. Connecting structures, where, The first article and the second article are joined together via a filler-containing membrane as described in any one of claims 1 to 18.

21. Connecting structures, where, In the case where the filler in the filler-containing membrane according to any one of claims 1 to 18 is a conductive particle, the first article and the second article are connected via the filler-containing membrane.

22. A method for manufacturing a connecting structure, wherein, The first article and the second article are pressed together using the filler-containing membrane according to any one of claims 1 to 18.

23. A method for manufacturing a connecting structure, wherein, In the case where the filler in the filler-containing membrane according to any one of claims 1 to 18 is a conductive particle, the first article and the second article are pressed together via the filler-containing membrane, thereby connecting the first article and the second article.

24. A method for manufacturing a filler-containing membrane, comprising the step of forming a filler dispersion layer in which filler is dispersed in a resin layer, wherein, The process of forming the filler dispersion layer includes: a process of maintaining fillers with a particle size CV value of 20% or less on the surface of the resin layer; and The process of pressing the filler held on the surface of the resin layer into the resin layer. In the process of holding the filler on the surface of the resin layer, the filler is dispersed on the surface of the resin layer, and the position of the filler is consistent in the film thickness direction. In the process of pressing the filler into the resin layer, the pressing pressure, the viscosity of the resin layer, the pressing speed or temperature are adjusted so that the surface of the resin layer near the filler is lower than the cross section of the resin layer at the center between adjacent fillers. The amount of resin around the filler or directly above the filler is reduced due to the drag of the filler being embedded. The ratio of the distance Lb of the deepest part of the filler from the aforementioned cross section to the particle size D of the filler, Lb / D, is 60% or more and 105% or less. The aforementioned resin layer is a pre-cured resin layer formed by a curable resin composition containing a polymerizable compound and a polymerization initiator. The polymerizable compound is a thermally polymerizable compound that functions as both a thermally polymerizable compound and a photopolymerizable compound. The polymerization initiator is a thermally polymerizable initiator or a mixed polymerization initiator of thermally polymerizable initiator and photopolymerizable initiator. The filler is arranged regularly.

25. The method for manufacturing a filler-containing membrane according to claim 24, wherein, The filler is composed of conductive particles.

26. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, The packing materials are configured so that they do not come into contact with each other.

27. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, A second resin layer is laminated on the surface opposite to the surface on which the resin layer of the filler dispersion layer is formed, which has an inclined or undulating surface.

28. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, A second resin layer is stacked on the inclined or undulating surface of the resin layer in the filler dispersion layer.

29. The method for manufacturing a filler-containing membrane according to claim 27, wherein, The minimum melt viscosity of the second resin layer is lower than that of the resin layer in the filler dispersion layer.

30. The method for manufacturing a filler-containing membrane according to claim 28, wherein, The minimum melt viscosity of the second resin layer is lower than that of the resin layer in the filler dispersion layer.

31. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, In the process of holding the filler on the surface of the resin layer, the filler is held on the surface of the resin layer in a predetermined arrangement. In the process of pressing the filler into the resin layer, a plate or roller is used to press the filler into the resin layer.

32. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, In the process of holding the filler on the surface of the resin layer, the filler is filled into a transfer mold and transferred to the resin layer, thereby holding the filler on the surface of the resin layer in a specified configuration.

33. The method for manufacturing a filler-containing membrane according to claim 24 or 25, wherein, The resin layer uses an insulating resin layer as the filler dispersion layer.

34. A method for manufacturing a filler-containing membrane, comprising the step of forming a filler dispersion layer in which filler is dispersed in a resin layer, wherein, The process of forming the filler dispersion layer includes: a process of maintaining fillers with a particle size CV value of 20% or less on the surface of the resin layer; and The process of pressing the filler held on the surface of the resin layer into the resin layer. In the process of holding the filler on the surface of the resin layer, the filler is dispersed on the surface of the resin layer, and the position of the filler is consistent in the film thickness direction. In the process of pressing the filler into the resin layer, the surface of the resin layer near the filler is inclined or undulating relative to the cross-section of the resin layer at the center between adjacent fillers. By adjusting the pressing pressure, the viscosity of the resin layer, the pressing speed, or the temperature, the surface of the resin layer around the filler is damaged relative to the aforementioned cross-section in the inclination, and the amount of resin in the resin layer directly above the filler is less than when the surface of the resin layer directly above the filler is at the aforementioned cross-section in the undulation. The amount of resin around the filler or the amount of resin directly above the filler... The amount of resin decreases due to the dragging effect of the filler embedded in the interior. The ratio of the distance Lb from the deepest part of the filler to the aforementioned cross-section to the particle size D of the filler, Lb / D, is 60% or more and 105% or less, and the inclined or undulating portion disappears. The aforementioned resin layer is a resin layer before curing formed by a curable resin composition containing a polymerizable compound and a polymerization initiator. The polymerizable compound is a thermally polymerizable compound that functions as both a thermally polymerizable compound and a photopolymerizable compound. The polymerization initiator is a thermally polymerizable initiator or a mixed polymerization initiator of thermally polymerizable initiator and photopolymerizable initiator, and the filler is arranged regularly.

35. The method for manufacturing a filler-containing membrane according to claim 34, wherein, The filler is composed of conductive particles.

36. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, The packing materials are configured so that they do not come into contact with each other.

37. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, A second resin layer is laminated on the surface opposite to the surface on which the resin layer of the filler dispersion layer is formed, which has an inclined or undulating surface.

38. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, A second resin layer is stacked on the inclined or undulating surface of the resin layer in the filler dispersion layer.

39. The method for manufacturing a filler-containing membrane according to claim 37, wherein, The minimum melt viscosity of the second resin layer is lower than that of the resin layer in the filler dispersion layer.

40. The method for manufacturing a filler-containing membrane according to claim 38, wherein, The minimum melt viscosity of the second resin layer is lower than that of the resin layer in the filler dispersion layer.

41. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, In the process of holding the filler on the surface of the resin layer, the filler is held on the surface of the resin layer in a predetermined arrangement. In the process of pressing the filler into the resin layer, a plate or roller is used to press the filler into the resin layer.

42. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, In the process of holding the filler on the surface of the resin layer, the filler is filled into a transfer mold and transferred to the resin layer, thereby holding the filler on the surface of the resin layer in a specified configuration.

43. The method for manufacturing a filler-containing membrane according to claim 34 or 35, wherein, The resin layer uses an insulating resin layer as the filler dispersion layer.

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