Fillers-containing membranes

Abstract

A core film having a through-hole and a filler-containing film in which a filler is held in the through-hole are sandwiched between an insulating base layer and an adhesive layer, and when two members are joined via the filler-containing film by pressure bonding such as thermocompression bonding, resin flow of the core film is suppressed, unintended movement of the filler is restricted, and pressure bonding unevenness during pressure bonding does not occur. The filler-containing membrane satisfies formula (1) 0.95 O1 < = O2 < = 1.05 O1, formula (2) 0.80 Pd < = O1 < = 1.05 Pd, formula (3) 0.08 Pd < = Ct < = 0.40 Pd, and formula (4) S = (L / Pd) * 100 < = 20%. In the formulae, O1 is the opening diameter [[mu] m] of the through-hole in the adhesive layer-side surface of the core film, O2 is the opening diameter [[mu] m] of the through-hole in the insulating base layer-side surface of the core film, Ct is the layer thickness [[mu] m] of the core film, Pd is the average particle diameter [[mu] m] of the filler, and L is the distance [[mu] m] between the center line X of the core film and the center line Y of the filler in the film thickness direction. And S is a position offset ratio [%] of the filler with respect to the core film in the film thickness direction. In addition, with regard to the positive and negative of 'L', the side facing the insulating base layer is set to be positive.

Description

TECHNICAL FIELD

[0001] The present application relates to filler-containing films. BACKGROUND

[0002] Filler-containing films in which a filler is dispersed in a resin layer are used for a wide variety of applications such as matte films, films for capacitors, optical films, films for labels, antistatic films, conductive films, anisotropic conductive films, and the like (Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4). In cases where a filler-containing film is used by being thermally compression-bonded to an article, from the viewpoints of optical properties, mechanical properties, or electrical properties, it is desirable to suppress unnecessary flow of the resin forming the filler-containing film at the time of thermal compression-bonding, and to suppress uneven distribution of the filler. In particular, in cases where electrically conductive particles are contained as a filler, and the filler-containing film is used as an electrically conductive film or an anisotropic conductive film for mounting of electronic components, if the electrically conductive particles are dispersed at a high density in an insulating resin layer to ensure good conductivity so that high-density mounting of electronic components can be dealt with, it is possible that due to excessive resin flow at the time of mounting of electronic components, the electrically conductive particles move unnecessarily and are unevenly distributed between terminals, and short-circuiting occurs, and thus it is required to balance good conductivity and insulating properties.

[0003] In response to such a requirement, an anisotropic conductive film in which electrically conductive particles are filled in the pores of a porous film having pores arranged in a honeycomb shape has been proposed (Patent Document 5). In this anisotropic conductive film, the average pore diameter U L in the surface on the side of the porous film is made larger than the average pore diameter U M in the surface on the other side, further, the average pore diameter U L is set to 1.1 to 1.9 times the average particle diameter d of the electrically conductive particles, and the average pore diameter U M is set to 0.1 to 1.0 times the average particle diameter d of the electrically conductive particles.

[0004] PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: Japanese Patent Application Publication No. 2006-15680 Patent Document 2: Japanese Patent Application Publication No. 2015-138904 Patent Document 3: Japanese Patent Application Publication No. 2013-103368 Patent Document 4: Japanese Patent Application Publication No. 2014-183266 Patent Document 5: Japanese Patent Application Publication No. 2019-114510. SUMMARY

[0005] PROBLEMS TO BE SOLVED BY THE INVENTION However, in the anisotropic conductive film of Patent Document 5, since the average pore diameter U LThe average particle diameter of the conductive particles is 1.1 to 1.9 times the average pore diameter of the porous film, which is very large, and thus the retention of the conductive particles in the pores is reduced. Furthermore, the position of the conductive particles in the depth direction when the conductive particles are filled into the pores of the porous film has not been studied at all. Thus, with the resin flow of the binder resin constituting the porous film during anisotropic conductive connection, there are cases in which the conductive particles are detached from the pores, which can cause uneven distribution of the conductive particles, and in addition, during crimping by a crimping tool during anisotropic conductive connection, uneven crimping such as so-called "partial contact" in which the crimping surface of the crimping tool is tilted with respect to the joint surface to be joined can occur, and there are concerns that it becomes difficult to ensure both conductivity and insulation. Even in the case in which the filler-containing film is used as a conductive film, if uneven crimping such as "partial contact" occurs, the difficulty and complexity of distinguishing between good products and defective products can increase.

[0006] In addition, in the anisotropic conductive film of Patent Document 5, since the porous film thickness is preferably set to 5 μm to 50 μm, and on the other hand, the conductive particle diameter is preferably set to 2 μm to 3 μm, there are cases in which the conductive particles are completely buried in the pores, and there are concerns that the conductive particles cannot be sufficiently flattened by heat crimping during anisotropic conductive connection, and that good conductivity cannot be ensured.

[0007] Note that even in a filler-containing film in which a filler is filled into the pores of a porous film other than an anisotropic conductive film, if the filler is detached from the pores with the resin flow of the binder resin constituting the porous film, the filler becomes unevenly distributed without becoming arranged as intended, and there are concerns that the intended optical, mechanical, or electrical properties of the filler-containing film cannot be ensured.

[0008] The present application aims to solve the problems of the above prior art, and to inhibit resin flow of a core film and limit unintended movement of a filler when two members are joined by crimping (e.g., heat crimping, etc.) using a filler-containing film in which a core film having through-holes is interposed between an insulating base layer and an adhesive layer, and the filler is held in the through-holes, and in addition, to make it possible to avoid uneven crimping during crimping (e.g., heat crimping).

[0009] Means for solving the problem The present inventors have focused on the "proportion of the positional shift of the filler in the film thickness direction of the core film" in addition to the "relationship between the opening diameter of the through-holes on the surface of the core film and the opening diameter of the through-holes on the back surface", the "relationship between the opening diameter of the through-holes on the surface of the core film and the diameter of the filler", and the "relationship between the thickness of the core film and the diameter of the filler", and have found that the above object can be achieved by defining each of these to a specific relationship, and thus the present application has been completed.

[0010] That is, the present application provides a filler-containing film that is a filler-containing film in which a core film having through-holes is interposed between an insulating base layer and an adhesive layer, and a filler is held in the through-holes, satisfy the following formulae (1) to (4): 0.95 < O2 < 1.05 O1 (1) 0.80 < O1 < 1.05 P d 0.80 < O1 < 1.05 P d (2) 0.08 < O1 < 1.05 P d 0.08 < O1 < 1.05 P t 0.08 < O1 < 1.05 P d (3) 0.08 < O1 < 1.05 P d 0.08 < O1 < 1.05 P (4).

[0011] In the above formulae, "O1" is the opening diameter [μm] of the through-hole on the adhesive layer side surface of the core film, "O2" is the opening diameter [μm] of the through-hole on the insulating base layer side surface of the core film, "C t " is the thickness [μm] of the core film, "P d " is the average particle diameter [μm] of the filler, "L" is the distance [μm] between the center line X of the core film and the center line Y of the filler in the film thickness direction, and "S" is the proportion [%] of the distance L [μm] to the average particle diameter P d [μm] of the filler, in other words, the proportion [%] of the positional shift of the filler in the film thickness direction with respect to the core film. Note that the positive and negative of "L" are set as positive toward the insulating base layer side. Note that in the case where a conductive particle is used as the filler, the filler-containing film can be used as a conductive film or an anisotropic conductive film.

[0012] In addition, the present application provides a joint body in which a first member and a second member are joined via the aforementioned filler-containing film of the present application, and preferably provides a connection structure in which a first electronic component is electrically or anisotropically connected to a second electronic component by the filler-containing film used as a conductive film or an anisotropic conductive film. In addition, the present application provides a method for manufacturing a joint body in which the aforementioned filler-containing film is disposed between a first member and a second member and then joined, and preferably provides a method for manufacturing a connection structure in which a first electronic component is electrically or anisotropically connected to a second electronic component by the filler-containing film used as a conductive film or an anisotropic conductive film. In the method for manufacturing, the terminal of the first electronic component and the terminal of the second electronic component are preferably electrically connected by a conductive particle.

[0013] Effects of the Invention In the filler-containing film of the present application, in addition to the "relationship between the opening diameter of the through-hole on the surface of the core film and the opening diameter of the through-hole on the back surface", the "relationship between the opening diameter of the through-hole on the surface of the core film and the diameter of the filler", and the "relationship between the thickness of the core film and the diameter of the filler", the "proportion of the positional shift of the filler in the film thickness direction of the core film" is each defined to a specific range. Therefore, when two members are joined by pressure bonding (e.g., heat pressure bonding, etc.) via the filler-containing film, the flow of the resin of the core film can be suppressed, the unintended movement of the filler can be limited, and in addition, pressure bonding unevenness can be prevented at the time of pressure bonding (e.g., heat pressure bonding) of the film. BRIEF DESCRIPTION OF DRAWINGS

[0014] [ Figure 1A ] Figure 1A is a cross-sectional view of the filler-containing film of the present application.

[0015] [ Figure 1B ] Figure 1B is a partial enlarged cross-sectional view of the filler-containing film of the present application. Figure 1A

[0016] [ Figure 2A ] Figure 2A is a view for explaining the manufacturing method of the filler-containing film of the present application.

[0017] [ Figure 2B ] Figure 2B is a view for explaining the manufacturing method of the filler-containing film of the present application.

[0018] [ Figure 2C ] Figure 2C is a view for explaining the manufacturing method of the filler-containing film of the present application.

[0019] [ Figure 2D ] Figure 2D is a view for explaining the manufacturing method of the filler-containing film of the present application.

[0020] [ Figure 2E ] Figure 2E is a view for explaining the manufacturing method of the filler-containing film of the present application.

[0021] [ Figure 2F ] Figure 2F is a view for explaining the manufacturing method of the filler-containing film of the present application. DETAILED DESCRIPTION

[0022] Hereinafter, one example of the filler-containing film of the present application will be explained in detail with reference to the drawings. Note that in each drawing, the same symbols indicate the same or equivalent constitutional elements.

[0023] <Overall configuration of the filler-containing film 10> Figure 1A ​A sectional view of the filler-containing film 10 of the present application. The filler-containing film 10 is characterized by having a configuration in which the core film 3 having the through-holes th is interposed between the insulating base layer 1 and the adhesive layer 2, and the filler 4 is held in the through-holes th, satisfying the following equations (1) to (4).

[0024] 0.95 < O2 < 1.05 < O1 (1) 0.80 < P d < O1 < 1.05 < P d (2) 0.08 < P d < C t < 0.40 < P d (3) S = (L / P d ) x 100 < 20% (4) Figure 1B A partial enlarged sectional view of the periphery of the filler 4 of the filler-containing film 10 of the present application. As is apparent from Figure 1B , in these equations, "O1" is the opening diameter [μm] of the through-holes th of the adhesive layer 2 side surface of the core film 3, "O2" is the opening diameter [μm] of the through-holes th of the insulating base layer 1 side surface of the core film 3, "C t " is the thickness [μm] of the core film 3, "P d " is the average particle diameter [μm] of the filler 4, "L" is the distance [μm] between the center line X of the core film 3 and the center line Y of the filler 4 in the film thickness direction. "S" is the proportion [%] of the distance L [μm] with respect to the average particle diameter P d [μm] of the filler 4, in other words, the proportion [%] of the positional shift of the filler 4 with respect to the core film 3 in the film thickness direction. Note that, as to the sign of "L", the side toward the insulating base layer is taken as positive.

[0025] Below, the "insulating base layer 1", "adhesive layer 2", "core film 3", and "filler 4", which are specific constituent elements of the filler-containing film 10 of the present application, are described, after which the "equation (1) indicating the relationship between the opening diameter of the through-holes of the core film surface and the opening diameter of the through-holes of the back surface", "equation (2) indicating the relationship between the opening diameter of the through-holes of the core film surface and the filler diameter", "equation (3) indicating the relationship between the core film thickness and the filler diameter", and "equation (4) indicating the proportion of the positional shift of the filler with respect to the core film in the film thickness direction", which are parameter constituent elements that impart characteristics to the filler-containing film 10 of the present application, are described.

[0026] <Specific constituent elements> "Insulating base layer 1" The insulating base layer 1 of the filler-containing film 10 according to the present application is a layer that serves as a base on which the core film is formed when the filler-containing film 10 is manufactured. Such an insulating base layer 1 can be composed of a single insulating resin layer or a laminate of a plurality of insulating resin layers. In addition, the insulating base layer 1 preferably exhibits adhesiveness.

[0027] (Resin composition constituting the insulating base layer 1) The resin composition constituting the insulating base layer 1 can be appropriately selected depending on the use of the filler-containing film, and for example, a thermoplastic resin composition, a high-viscosity adhesive resin composition, or a curable resin composition can be exemplified. For example, in the case where the filler-containing film is used as a conductive film or an anisotropic conductive film, a curable resin composition formed of a polymerizable compound and a polymerization initiator can be used, similarly to the resin composition forming the insulating resin layer of the existing conductive film or anisotropic conductive film. In this case, as the polymerization initiator, a thermal polymerization initiator can be used, a photopolymerization initiator can be used, or they can be used in combination. For example, a thermal cationic polymerization initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermal polymerizable compound, a photoradical polymerization initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound. As the thermal polymerization initiator, a thermal anionic polymerization initiator can also be used. As the thermal anionic polymerization initiator, a microcapsule-type latent curing agent in which an imidazole modifier is used as the core and the surface thereof is coated with a polyurethane is preferably used.

[0028] (Lowest melt viscosity of the insulating base layer 1) In order to suppress unnecessary movement of the filler 4 caused by resin flow when the filler-containing film 10 is pressure-bonded (for example, thermocompression-bonded) to an article, moderate resin flow is induced, and the lowest melt viscosity of the insulating base layer 1 can be 200 Pa s or more, preferably 1500 Pa s or more, more preferably 2000 Pa s or more, particularly preferably 3000 Pa s or more, and preferably 15000 Pa s or less, more preferably 10000 Pa s or less, particularly preferably 8000 Pa s or less. As one example, the lowest melt viscosity can be measured using a rotational rheometer (manufactured by TA Instruments, Inc.) with a pressure of 5 g kept constant, using a measuring plate having a diameter of 8 mm, and more specifically, can be measured by setting a temperature range of 30 to 200°C, a temperature increase rate of 10°C / minute, a measurement frequency of 10 Hz, and a load variation of 5 g with respect to the measuring plate. Note that the adjustment of the lowest melt viscosity can be performed by changing the type or the blending amount of a fine solid that serves as a melt viscosity adjustor, the adjustment conditions of the resin composition, or the like.

[0029] (Thickness of the insulating base layer 1) To stably hold the core film 3 and the filler 4, for example, the layer thickness of the insulating base layer 1 is preferably 0.6 times or more, more preferably 1.2 times or more, and particularly preferably 1.5 times or more the average particle diameter P of the filler 4. In addition, for the upper limit of the layer thickness of the insulating base layer 1, to not cause unnecessary movement of the filler 4 due to resin flow, it is preferably 10 times or less, more preferably 5 times or less the average particle diameter of the filler 4. The layer thickness can be measured by a well-known thickness gauge or film thickness meter. d Preferably, 0.6 times or more, more preferably 1.2 times or more, particularly preferably 1.5 times or more. In addition, for the upper limit of the layer thickness of the insulating base layer 1, to not cause unnecessary movement of the filler 4 due to resin flow, it is preferably 10 times or less, more preferably 5 times or less the average particle diameter of the filler 4. The layer thickness can be measured by a well-known thickness gauge or film thickness meter.

[0030] (Adhesion of the insulating base layer 1) The insulating base layer 1 preferably has adhesion that allows temporary press bonding before press bonding (e.g., heat press bonding) of an article to which the filler-containing film is to be bonded. The adhesion can be measured in accordance with JIS Z 0237, and in addition, can also be measured as a tack force by a probe method in accordance with JIS Z 3284-3 or ASTM D2979-01. The tack force of the insulating base layer 1 that constitutes the filler-containing film 10, for example, when measured by the probe method at a press speed of the probe of 30 mm / min, a press force of 196.25 gf, a press time of 1.0 seconds, a peel speed of 120 mm / min, and a measurement temperature of 23°C ± 5°C, is preferably 1.0 kPa (0.1 N / cm 2 ) or more, more preferably 1.5 kPa (0.15 N / cm 2 ) or more, particularly preferably 3.0 kPa (0.3 N / cm 2 ) or more.

[0031] In addition, the adhesion of the insulating base layer 1 can also be found by the adhesion strength test described in Japanese Patent Application Publication No. 2017-48358. In the adhesion strength test, for example, in a case where the insulating base layer 1 is sandwiched with two glass plates, one of the glass plates is fixed, and the other glass plate is peeled at a peel speed of 10 mm / min and a test temperature of 50°C, the adhesion of the fixed glass plate and the insulating base layer 1 is enhanced so that the adhesion of the peeled glass plate and the surface of the insulating base layer 1 that was bonded to the glass plate can be measured. The adhesion strength (adhesion) thus measured can be preferably set to 1 N / cm 2 (10 kPa) or more, more preferably 10 N / cm 2 (100 kPa) or more. This becomes the adhesion between the surface of the insulating base layer 1 present in the peeling direction and the peeled article.

[0032] Furthermore, the adhesion of the insulating base layer 1 can also be found by a test in which one end of a test piece is aligned and bonded (bonded) and the other end is lifted to peel the test piece. The adhesion measured by this test method can be the same as the adhesion strength test described above (1 N / cm2 (10 kPa) or more). If the adhesive force obtained by the above-mentioned adhesive strength test is sufficiently large (for example, 10 N / cm 2 (100 kPa) or more), the adhesive force obtained by the above-mentioned adhesive strength test is 10% or more of the adhesive force obtained by the above-mentioned adhesive strength test.

[0033] Such an adhesive property can be adjusted by appropriately adjusting the resin composition constituting the insulating base layer, and by improving the smoothness of the insulating base layer forming the outer surface of the filler-containing film through the manufacturing method of the filler-containing film described later.

[0034] "Adhesive layer 2" The adhesive layer 2 constituting the filler-containing film 10 of the present application is a layer for temporarily pressure-bonding and attaching the filler-containing film 10 to an article. The adhesive layer 2 can be constituted by a single insulating resin layer, or can be constituted by a laminate of a plurality of insulating resin layers.

[0035] (Resin composition constituting the adhesive layer 2) The resin composition constituting the adhesive layer 2 is appropriately selected in accordance with the use of the filler-containing film, and for example, a thermoplastic resin composition, a high-viscosity adhesive resin composition, or a curable resin composition can be exemplified. For example, in the case where the filler-containing film is used as a conductive film or an anisotropic conductive film, a curable resin composition formed of a polymerizable compound and a polymerization initiator can be used, as in the case of the resin composition forming the adhesive layer of the existing conductive film or anisotropic conductive film. In this case, as the polymerization initiator, a thermal polymerization initiator can be used, a photopolymerization initiator can be used, or they can be used in combination. For example, a thermal cationic polymerization initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermal polymerizable compound, a photoradical polymerization initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound. As the thermal polymerization initiator, a thermal anionic polymerization initiator can also be used. As the thermal anionic polymerization initiator, a microcapsule-type latent curing agent in which an imidazole modifier is used as the core and the surface thereof is coated with a polyurethane is preferably used.

[0036] (Lowest melt viscosity of the adhesive layer 2) The lowest melt viscosity of the adhesive layer 2 can be the same as that of the above-mentioned insulating base layer 1. It can also be intentionally set to be lower or higher than that of the insulating base layer 1. By adjusting the lowest melt viscosity (and thickness) of the insulating base layer 1 and the adhesive layer 2, the control of the resin flow at the time of pressure-bonding (for example, thermal pressure-bonding) of the filler-containing film 10 to an article can be precisely performed, and application to various uses can be expected. In the case of use for anisotropic conductive connection, the suppression of unnecessary movement of the conductive particles as fillers can be more precisely performed.

[0037] (Thickness of the adhesive layer 2) The thickness of the adhesive layer 2 can be the same as the above-mentioned insulating base layer 1. It can also be intentionally set lower or higher than the insulating base layer 1. Specifically, it is preferably 0.1 μm or more, more preferably 0.5 μm or more. In the case of being used for sticking, it is preferably thinned. In order to fill the filler in the through hole of the core film, it can also be set to 20 μm or more. If it is too thick, there is a concern that the resin will be squeezed out in the case of being made into a roll, and thus it is preferably 50 μm or less. In this way, the upper limit can be appropriately set according to the purpose.

[0038] (Adhesive force of the adhesive layer 2) The adhesive force of the adhesive layer 2 preferably has an adhesive force with which the article to which the filler-containing film is to be heat-welded can be temporarily stuck (it is sufficient to have an adhesive force with which it can be attached to the article). Such an adhesive force of the adhesive layer 2 can be the same as the adhesive force of the insulating base layer 1, can be stronger than the adhesive force of the insulating base layer 1, or can be weaker, in contrast. The adhesive force of the adhesive layer 2 and the adhesive force of the insulating base layer 1 can be optimized, respectively, from the viewpoint of whether the surface to be stuck to the article is the insulating base layer 1 or the adhesive layer 2, and what degree of adhesive force is required for the article to be placed thereon, and the like.

[0039] Such an adhesive property can be adjusted by appropriately adjusting the resin composition constituting the adhesive layer 2, and, in addition, by improving the smoothness of the adhesive layer 2 forming the outer surface of the filler-containing film through the manufacturing method of the filler-containing film described later.

[0040] "Core film 3" The core film 3 constituting the filler-containing film 10 of the present application has a through hole th for filling the filler 4, is a layer for suppressing unintended movement of the filler caused by the flow of the resin of the insulating base layer 1 or the adhesive layer 2, and has a function as a spacer sheet. Such a core film 3 can be constituted by a single insulating resin layer, or can be constituted by a laminate of a plurality of insulating resin layers.

[0041] (Resin composition constituting the core film 3) The resin composition constituting the core film 3 is appropriately selected according to the purpose of the filler-containing film 10, and for example, a thermoplastic resin composition or a high-viscosity adhesive resin composition containing a phenoxy resin, a polyimide resin, a polyamide resin, a polyacetal resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyvinyl chloride resin, a polyvinyl acetate resin, or the like, or a curable resin composition containing an epoxy resin, an acrylic resin, or the like, or a mixture thereof can be exemplified.

[0042] (Melt viscosity of the core film 3) To suppress unnecessary movement of the filler 4 caused by resin flow when the filler-containing film 10 is pressure-bonded (e.g., heat-bonded) to an article, the melt viscosity of the core film 3 is preferably 1.1 times or more, more preferably 1.2 times or more, of the lowest melt viscosity of the insulating base layer 1 in the temperature range at the time of pressure-bonding. As one example, the melt viscosity can be measured using a rotational rheometer (manufactured by TA Instruments, Inc.) with a 8-mm-diameter measuring plate, with the pressure kept constant at 5 g, more specifically, by setting the temperature range to 30 to 250°C, the temperature increase rate to 10°C / min, the measurement frequency to 10 Hz, and the load variation with respect to the measuring plate to 5 g. Note that the adjustment of the melt viscosity can be performed by changing the kind or the blending amount of the fine solid as a melt viscosity adjustor, the adjustment conditions of the resin composition, or the like.

[0043] (Thickness of core film 3) The thickness of the core film 3 is determined in relation to the average particle diameter P d of the filler 4. This will be described later.

[0044] (Through-hole th of core film 3) The core film 3 is formed with through-holes th for filling and holding the filler 4. The through-holes th open on the adhesive layer 2 side and the insulating base layer 1 side, respectively. The planar shape of the opening is preferably circular, but can be other shapes. In the present application, in order to take into account both the filling of the filler into the through-holes and the press-in of the filler, the opening diameter O1 on the adhesive layer 2 side and the opening diameter O2 on the insulating base layer 1 side are preferably made substantially the same. Specifically, the opening diameter O2 on the insulating base layer 1 side is preferably made 0.95 times or more and 1.05 times or less, more preferably 1.0 times, of the opening diameter O1 on the adhesive layer 2 side.

[0045] Such through-holes th can be arranged in a random pattern in the core film 3, or can be arranged in a regular pattern. Such a through-hole pattern is substantially synonymous with the pattern of the presence of the filler in the filler-containing film 10. As examples of a regular pattern, there can be mentioned lattice arrangements such as square lattice, rectangular lattice, diagonal lattice, and the like. Different shapes of lattices can be combined in multiple. By being a regular pattern, there can be mentioned the advantage of being easy to manage the quality. The through-holes th can also be arranged in parallel in a through-hole row at a prescribed interval. The regions where the through-holes th are densely arranged and the regions where the through-holes th are sparsely arranged can also be regularly repeated. In the case where the filler-containing film is an electrically conductive film or an anisotropic conductive film, it is more preferable to form a regular arrangement in which the through-holes th are isolated from each other, since both the capture stability at the terminal and the short-circuit suppression are taken into account. Note that whether the through-holes th are regularly arranged or not can be identified by, for example, observing whether a prescribed arrangement of the through-holes th or the filler repeats in the longitudinal direction of the film (in the case where the filler-containing film is made into a roll body, the winding direction).

[0046] In addition, the packing rate of the fillers to the through holes th can be calculated as {(number of fillers / number of through holes) x 100 (%)}. As with the number density described below, this can be calculated by observation of the film surface field. The packing rate of the fillers is preferably 95% or more, more preferably 98% or more, and even more preferably 99.5% or more. It is desirable that the number of residual through holes (residual rate) in which no filler is packed be small (close to zero), but in practice, the residual rate can be less than 2% of the number of through holes th, preferably less than 1%, and more preferably less than 0.5%. This is because, if the exclusion work is performed in such a way that the residual rate is close to zero, it can become a reason for damage to the film surface.

[0047] The distance between the through holes th can be determined according to the connected article or use, and in addition, the number density of the through holes th is generally 10 to 500,000 / mm 2 The upper limit is preferably 30,000 / mm 2 The upper limit is preferably 500,000 / mm 2 The lower limit is preferably 250,000 / mm 2 The lower limit is more preferably 100,000 / mm 2 The lower limit is more preferably 10,000 / mm 2 The upper limit is preferably 10 mm 2 The upper limit is preferably 10 mm

[0048] The number density of the through holes th (i.e., the fillers) can be calculated by measuring the observed image using image analysis software (e.g., WinROOF (manufactured by San-Ei Gen F.F.I., Inc.) or A image kun (registered trademark) (manufactured by Asahi Kasei Engineering Corporation.)) in addition to observation using a metal microscope. The observation method or measurement method is not limited to the above.

[0049] In the present application, the effect of the application can be more remarkably exhibited by unifying the size of the through holes. For this reason, it is desirable that the size and depth of the opening portion of the through holes satisfy the following conditions. That is, in the filler-containing film, the total of the observation areas is 1 mm 2 The upper limit is preferably 2 mm 2In the above, the size and depth of the opening of 95% or more, preferably 98% or more, more preferably 99.5% or more of the total number of the through holes contained in the region in which the number of the through holes is 1000 or more (preferably 2000 or more) are uniform. Here, "uniform" of the size and depth of the opening means that, taking into account the measurement error, the size and depth of the opening of each through hole are within ±15%, preferably within ±10%, more preferably within ±5% of the average size and average depth of the opening of the through holes contained in the prescribed region. Note that, since there are through holes in which the shape of the opening is different, the size of the opening can be set as the diameter when the area of the opening is converted to a circle.

[0050] "Filler 4" As the filler 4 in the present application, from among publicly known inorganic fillers (metal particles, metal oxide particles, metal nitride particles, etc.), organic fillers (resin particles, rubber particles, etc.), and fillers in which an organic material and an inorganic material are mixed (for example, particles in which the core is formed of a resin material and the surface is plated with a metal (metal-coated resin particles), fillers in which insulating fine particles are attached to the surface of conductive particles, and fillers in which the surface of conductive particles is subjected to insulation treatment), a filler can be appropriately selected according to the performance required by the use, such as the hardness and optical properties. For example, in an optical film or a matte film, a silica filler, a titanium oxide filler, a styrene filler, an acrylic acid filler, a melamine filler, or various titanate fillers, etc. can be used. In a capacitor film, a titanium oxide filler, a magnesium titanate filler, a zinc titanate filler, a bismuth titanate filler, a lanthanum oxide filler, a calcium titanate filler, a strontium titanate filler, a barium titanate filler, a barium zirconate titanate filler, a lead zirconate titanate filler, and a mixed filler thereof can be used. In an adhesive film, polymer-based rubber particles, silicone rubber particles, etc. can be contained. In a conductive film or an anisotropic conductive film, conductive particles are contained. As the conductive particles, 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 in which insulating fine particles are attached to the surface, etc. can be listed. Two or more kinds can be used in combination. Among them, metal-coated resin particles are preferable from the viewpoint of stable conduction performance since the resin particles rebound after connection and thus the contact with the terminal is easily maintained. In addition, an insulation treatment that does not interfere with the conduction properties can be performed on the surface of the conductive particles by publicly known techniques.

[0051] (Average particle diameter of filler 4) In the present application, the average particle diameter P of the filler 4 dThe particle size of the filler 4 is preferably 1 μm or larger, more preferably 1.4 μm or larger, and particularly preferably 2.5 μm or larger, in order to improve the accuracy of filler injection during the manufacture of the filler-containing film. The upper limit is not particularly limited, but in order to suppress the influence of positional displacement of the filler during the manufacture of the filler-containing film, the particle size is preferably 200 μm or smaller, more preferably 50 μm or smaller, and particularly preferably 30 μm or smaller. The average particle size P of the filler 4 is 1 μm or larger, more preferably 1.4 μm or larger, and particularly preferably 2.5 μm or smaller. d The average particle size of the filler-containing film can be determined from a planar image or a cross-sectional image by microscopic observation. Alternatively, the average particle size of the filler, which is the raw material particle size before inclusion in the filler-containing film, can be determined using a wet flow particle size and shape analyzer, FPIA-3000 (manufactured by Malvern Panalytical Ltd.). If fine particles such as insulating fine particles adhere to the filler, the particle size is the diameter without the fine particles.

[0052] The average particle size P of fillers in filler-containing films d The deviation of the CV value (standard deviation / average) is preferably 20% or less. Thus, when the filler-containing film is crimped to the article, the filler-containing film becomes easy to be pressed evenly, which can prevent the pressing force from being locally concentrated. Therefore, when the filler-containing film is constructed as an anisotropic conductive film, the connection stability is improved, and after the connection, the connection state can be accurately evaluated by observing the indentation or the clamping state of the filler. Specifically, in the inspection after the electronic components are anisotropically conductively connected to each other using an anisotropic conductive film, both the components with larger terminal sizes (FOB, etc.) and the smaller components (COG, etc.) can be accurately confirmed by observing the clamping state of the indentation or the conductive particles. Therefore, the inspection after the anisotropic conductive connection becomes easy, and it can be expected to improve the productivity of the connection process.

[0053] On the other hand, in the cross-sectional view of the filler-containing film cut along the film thickness direction ( Figure 1A ), preferably, the apex of each filler in the film thickness direction is flush with the plane parallel to the interface between the insulating base layer 1 and the core film 3. This makes it easy to uniformly press-bond the filler-containing film to the article.

[0054] <Parameter components> The filler-containing membrane 10 of the present invention described above, as described above, limits the "relationship between the opening diameter of the through-holes on the surface of the core membrane and the opening diameter of the through-holes on the back side (Formula (1))", "relationship between the opening diameter of the through-holes on the surface of the core membrane and the filler diameter (Formula (2))", "relationship between the core membrane thickness and the filler diameter (Formula (3))" and "position offset ratio of the filler in the membrane thickness direction of the core membrane (Formula (4))" to specific ranges.

[0055] 0.95 < O2 < 1.05 < O1 (1) 0.80 < P d ≤ O1 < 1.05 < P d (2) 0.08 < P d ≤ C t ≤ 0.40 < P d (3) S = (L / P d ) x 100 < 20% (4) As is apparent from the partial enlarged sectional view of the periphery of the filler 4 of the filler-containing film 10 of the present application as shown in FIG. 1, Figure 1B In these formulas, "O1" is the opening diameter [μm] of the through-hole th on the side surface of the adhesive layer 2 of the core film 3, "O2" is the opening diameter [μm] of the through-hole th on the side surface of the insulating base layer 1 of the core film 3, "C t " is the thickness [μm] of the core film 3, "P d " is the average particle diameter [μm] of the filler 4, and "L" is the distance [μm] between the center line X of the core film 3 and the center line Y of the filler 4 in the film thickness direction. "S" is the ratio [%] of the distance L [μm] to the average particle diameter P d [μm] of the filler 4, in other words, the positional displacement ratio [%] of the filler 4 in the film thickness direction with respect to the core film 3. Note that the positive and negative of "L" are set to be positive toward the insulating base layer side.

[0056] (Meaning of Formula (1)) Formula (1) is a formula that represents the relationship between the opening diameter O1 of the through-hole on the surface of the core film 3 and the opening diameter O2 of the through-hole on the back surface. The reason for focusing on this relationship is to easily arrange the filler at a prescribed position of the through-hole. In the present application, the opening diameter O2 of the back surface (insulating base layer 1 side) of the core film 3 is set to be substantially the same size as the opening diameter O1 of the surface (adhesive layer 2 side), specifically, 0.95 times or more and 1.05 times or less of the opening diameter O1, and preferably the same size. This is because, if the opening diameter O2 of the back surface of the core film 3 is less than 0.95 times or more than 1.05 times the opening diameter O1 of the surface, the degree of invasion into the hole from the adhesive layer or the insulating base layer whose hole becomes the base portion, and the like will slightly change, regardless of whether the opening diameter on the adhesive layer side surface becomes too small or too large.

[0057] (Meaning of Formula (2)) Formula (2) represents the relationship between the opening diameter O1 of the core film 3 and the filler diameter. The reason for focusing on this relationship is to facilitate the filling of the filler into the through-hole and to retain it in the hole. In the present invention, the opening diameter O1 on the surface (adhesive layer side) of the core film 3 is set to the average particle size P of the filler. d This is because if the opening diameter O1 is less than the average particle size P of the filler, d If the ratio is less than 0.80 times the initial density, it becomes difficult for the filler to be filled into the pores, and if it exceeds 1.05 times the initial density, it tends to become difficult for the filler to be retained in the pores.

[0058] (Significance of formula (3)) Formula (3) is a formula that expresses the relationship between the core film thickness and the filler diameter. The reason for focusing on this relationship is the same as above, which is to make it easier for the filler to be filled into the through hole and to be retained in the hole. In the present invention, the core film thickness C t The average particle size P of the filler 4 is set to d 0.08 times or more, preferably 0.12 times or more, 0.40 times or less, preferably 0.36 times or less. This is because if the core film thickness C t Lower than the average particle size P of the filler d If the thickness is less than 0.08 times the film thickness, the filler becomes difficult to retain and tends to fall out easily. If the thickness is greater than 0.40 times the film thickness, the filler tends to be difficult to press into the film due to the small pore size.

[0059] (Significance of formula (4)) Formula (4) is a formula that represents the "position offset ratio of the filler in the film thickness direction of the core film" S. The reason for focusing on this relationship is that since the pressing load from the tool is applied evenly to the entire film, in the present invention where the core film thickness is smaller than the filler diameter, multiple fillers are simultaneously subjected to the load during the load application process. In the present invention, the distance L [μm] between the center line X of the core film 3 and the center line Y of the filler 4 in the film thickness direction is relative to the average particle size P of the filler 4. d The ratio S[%] of [μm] is set to 20% or less, preferably 15% or less. This is because if the ratio S exceeds 20%, the load applied to the filler tends to become uneven, and there is a risk of problems such as filler falling off during press-fitting.

[0060] <Method for producing filler-containing film> The filler-containing film 10 of the present invention can be manufactured as follows. First, an insulating base layer forming composition 1' ( Figure 2A ), and dried by a conventional method, thereby forming an insulating base layer 1 ( Figure 2B ).

[0061] Subsequently, the core film 3 provided with the through holes th by laser processing or photolithography processing, mold processing, or the like is laminated on the insulating base layer 1 by a known method. Figure 2C ).

[0062] Next, the filler 4 is scattered to the core film 3, the filler 4 is filled into the through holes th using a doctor blade or the like, and the filler 4 not filled into the through holes th is removed by blowing or the like Figure 2D ).

[0063] Finally, the adhesive layer-forming composition 2' is applied to the core film 3 Figure 2E ), and after being pressed as necessary with a press tool, it is dried by a conventional method, thereby forming the adhesive layer 2 Figure 2F ). Thus, a filler-containing film provided with the release substrate 20 can be obtained, and if the release substrate 20 is removed, the filler-containing film 10 shown in Figure 1A can be obtained.

[0064] <Method of using the filler-containing film> The filler-containing film of the present application can be used by being attached to an article as with the conventional filler-containing film, and the article to which the filler-containing film is attached is not particularly limited. Therefore, a bonded body in which a first member and a second member are joined via the filler-containing film, and a method of manufacturing a bonded body by disposing the filler-containing film between the first member and the second member and joining them are also part of the present application. For example, in the case where the filler-containing film is configured as a conductive film or an anisotropic conductive film, the conductive film or the anisotropic conductive film can be used for conductive connection or anisotropic conductive connection of a first electronic component such as a semiconductor element using a PN junction (a power generating element such as a solar cell, an image pickup element such as a CCD, a light emitting element, a peltier element), other various semiconductor elements, an IC chip, an IC module, an FPC, and a second electronic component such as an FPC, a glass substrate, a plastic substrate, a rigid substrate, a ceramic substrate, and the like, and in addition, the filler-containing film can be used for electronic components other than conductive connection or anisotropic conductive connection. Note that the surface of the article to which the filler-containing film is to be attached can be smooth, or can have a stepped portion or a convex shape portion.

[0065] The shape, size, use, and the like of the first electronic component and the second electronic component connected by the conductive film or the anisotropic conductive film are not particularly limited. These electronic components can be small and have a small terminal size, or can require high-precision alignment for mounting of the electronic components. For example, the bump area can be several tens of μm 2 to several thousands of μm 2An electronic component (e.g., a submillimeter LED or a micro LED, etc.) that is a subject of the minimization can also be connected. On the other hand, the mounting of an electronic component having a large outer size can be performed using a conductive film or an anisotropic conductive film. In addition, it can be used by being diced to be small. In addition, in the case of a large TV or the like, a filler-containing film of 1 m or more, for example, 4.5 m or more, is sometimes attached on one side. In this case, in addition to the filler-containing film being used as a conductive film or an anisotropic conductive film, it can also be used as a spacer film or the like in which the filler is used as a spacer.

[0066] An IC chip or a wafer can be stacked and multilayered using the conductive film or the anisotropic conductive film of the present application. Note that the electronic component connected by the conductive film or the anisotropic conductive film of the present application is not limited to the above-described examples. In recent years, various electronic components can be used. The present application includes a film-attached body in which the filler-containing film of the present application is attached to various articles, and in particular, a connection structure in which a first electronic component and a second electronic component are connected via an anisotropic conductive film.

[0067] The method of attaching the filler-containing film to an article can be press bonding, such as thermal press bonding, or light irradiation can be used at the time of attachment, depending on the use of the filler-containing film. As one example of using light irradiation, the filler-containing film can be singulated by the laser lift-off method described in Japanese Patent Application Publication No. 2022-151816, and further transferred. As a resin material or an adhesive material to be used for making a filler-containing film suitable for the laser lift-off method, a material described in Japanese Patent Application Publication No. 2022-151816 can be selected and used.

[0068] In the case where the filler-containing film is configured as a conductive film or an anisotropic conductive film, for example, as a more specific method of use, in the case where the first electronic component is an IC chip and the second electronic component is a substrate, for example, the first electronic component is generally placed on the side of a press tool, the second electronic component is placed on a stage opposite to the first electronic component, a conductive film or an anisotropic conductive film is attached to the second electronic component in advance, and the first electronic component and the second electronic component are press bonded, such as thermal press bonding, using the press tool. In this case, a conductive film or an anisotropic conductive film can also be attached to the first electronic component in advance, and the first electronic component is not limited to an IC chip.

[0069] In the case of connecting the first electronic component and the second electronic component by press bonding (e.g., thermal press bonding), as needed, the resin around the conductive particles can be preliminarily excluded before press bonding and temporary press bonding can be performed. By this, the influence of resin flow generated when the conductive film or the anisotropic conductive film is press bonded to the electronic components can be reduced and unnecessary movement of the conductive particles can be suppressed. Specifically, in the case of performing temporary press bonding by attaching one of the electronic components to one face of the conductive film or the anisotropic conductive film and attaching the other electronic component to the other face of the conductive film or the anisotropic conductive film, the electronic components are pressed by a pressing tool, the resin between the electronic components is partially excluded, and then the electronic components are connected to each other by pressing (e.g., thermal pressing) as the formal press bonding (hereinafter, the connection method in which pressing is performed not only at the time of formal press bonding but also at the time of temporary press bonding will be referred to as connection by two-stage press bonding). The connection by two-stage press bonding using the conductive film or the anisotropic conductive film in which the conductive particles are randomly dispersed is described in WO2016 / 143789, but if such connection by two-stage press bonding is performed in the case of connecting the electronic components to each other using the conductive film or the anisotropic conductive film in which the conductive particles are regularly arranged as in the present application, it becomes possible to greatly reduce unnecessary movement of the conductive particles at the time of press bonding (e.g., thermal press bonding). Examples

[0070] Hereinafter, the present application will be described more specifically by examples and comparative examples. The respective formulations of the resin composition for forming the insulating base layer, the resin composition for forming the core film, and the resin composition for forming the adhesive layer used in the examples and comparative examples are shown below.

[0071] <Formula of the resin composition for forming the insulating base layer> Phenoxy resin (YP-50, NIPPON STEEL Chemical & Material Co., Ltd.) 40 parts by mass Silica filler (AEROSIL R 805, NIPPON AEROSIL CO., LTD.) 25 parts by mass Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 30 parts by mass Silane coupling agent (KBM-403, SHIN-ETXU CHEMICAL CO., LTD.) 2 parts by mass Thermal cationic polymerization initiator (SI-60L, SAN-EI CHEMICAL CO., LTD.) 3 parts by mass <Formula of the resin composition for forming the core film> Phenoxy resin (PKFE, BAI INDUSTRIAL CO., LTD.) 70 parts by mass Gas phase silica (RY200, NIPPON AEROSIL CO., LTD.) 30 parts by mass <Formula of the resin composition for the adhesive layer> Phenoxy resin (YP-50, NIPPON STEEL Chemical & Material Co., Ltd.) 40 parts by mass Silica filler (AEROSIL R 805, NIPPON AEROSIL CO., LTD.) 5 parts by mass Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 50 parts by mass Silane coupling agent (KBM-403, SHIN-ETXU CHEMICAL CO., LTD.) 2 parts by mass Thermal cationic polymerization initiator (SI-60L, SAN-EI CHEMICAL CO., LTD.) 3 parts by mass Examples 1 to 4, Comparative Examples 1 to 3 The above resin composition for the insulating base layer was applied to a release film (50 μm thick) made of polyethylene terephthalate on which a release treatment was performed on the surface, and dried by a conventional method, thereby forming an insulating base layer having a layer thickness of 3.0 μm.

[0072] Subsequently, a mold substantially the same as the mold described in paragraph 0111 of Japanese Patent No. 6187665 was prepared using transparent polycarbonate particles on a release film (50 μm thick) made of polyethylene terephthalate on which a release treatment was performed on the surface, and a coating liquid adjusted from the mixture of the above resin composition for the core film was applied to the mold, and dried in a drier at 60°C for 5 minutes, thereby obtaining a core film having a through-hole th having a surface opening diameter (01) on the adhesive layer side and a back surface opening diameter (02) on the insulating base layer side, at the thicknesses of Table 1. In addition, a through-hole th having a surface opening diameter (01) larger than a back surface opening diameter (02) was formed in the same manner (Comparative Examples 1 to 4).

[0073] Subsequently, the core film having a through-hole was peeled from the release film, and the core film was laminated on the previously prepared insulating base layer. Figure 2C ).

[0074] Next, the filler was scattered to the core film, and the filler having an average particle diameter Pd [μm] of Table 1 was filled into the through-hole using a doctor blade, and the filler not filled into the through-hole was removed by air blowing Figure 2D ).

[0075] Finally, the resin composition for forming an adhesive layer was applied to the core film in such a manner that the thickness of the filler-containing film reached about 18 μm Figure 2E , and, after being pressed by a press tool as necessary, it was dried by a conventional method, thereby forming the adhesive layer 2 Figure 2F . Thus, a filler-containing film provided with a release substrate was obtained. If the release substrate was removed, the filler-containing film shown in Figure 1A was obtained. Note that the distance L [μm] between the center line X of the core film and the center line Y of the filler in the thickness direction of the filler-containing film was measured by an optical microscope, and the results are shown in Table 1. Further, the positional shift ratio S [%] of the filler with respect to the core film in the thickness direction of the filler-containing film was calculated, and the results are shown in Table 1.

[0076] <Assessment> With respect to the obtained filler-containing film, the "immobility" of the filler and the "pressing unevenness" in the filler-containing film, and the "conductive property" when the filler-containing film is used as an anisotropic conductive film were evaluated as described below.

[0077] (Immobility) In order to evaluate the immobility of the filler, the particle capturing property was evaluated. Specifically, the filler-containing film of each of the examples and comparative examples was sandwiched between the glass substrate (ITO wiring) corresponding to the IC and the terminal (bump) pattern for evaluating the particle capturing property with an alignment shift of 6 μm, and was heated and pressurized (180°C, 60 MPa, 5 seconds) to produce a connection structure for evaluation. In the connection structure, the number of captured fillers was measured for 100 regions of 6 μm x 66.6 μm in which the bump of the IC for evaluation overlapped with the terminal of the glass substrate, and the lowest number of captured fillers was calculated, and evaluation was performed in accordance with the following particle capturing property evaluation criteria. The results are shown in Table 1. In practical use, an evaluation of A or B is desirable.

[0078] IC for evaluating the particle capturing property Outline: 1.6 x 29.8 mm Thickness: 0.3 mm Bump specifications: size: 12 μm x 66.6 μm, bump pitch: 22 μm (L / S = 12 μm / 10 μm). Bump height: 12 μm.

[0079] Immobility (particle capturing property) evaluation criteria A: lowest number of captured fillers is 5 or more B: lowest number of captured fillers is 3 or more and less than 5 C: lowest number of captured fillers is 1 or more and less than 3 D: lowest number of captured fillers is 0.

[0080] (Compression unevenness) The appearance of the core film having a through-hole in the space between the terminals after compression was observed, and the core film having a large degree of flexure in which the filler was detached from the through-hole was recorded as compression unevenness. Ten spaces between the terminals were observed to investigate the presence or absence of compression unevenness. In practice, there is no problem if the evaluation is C, but an evaluation of B or higher is preferred.

[0081] Compression unevenness evaluation criteria A: The filler was not detached from the through-hole B: The filler detached from the through-hole was 2 or less out of 10 C: The filler detached from the through-hole was 5 or less out of 10 D: The filler detached from the through-hole was 6 or more out of 10.

[0082] (Conductivity) Each of the anisotropic conductive films of the examples and comparative examples as a filler-containing film was sandwiched between an IC and a glass substrate for evaluating the conductivity, heated and pressurized (170°C, 20 MPa, 10 seconds) to produce a connection structure for evaluation, and the initial conduction resistance thereof was measured, and evaluated in accordance with the following conductivity evaluation criteria. The results obtained are shown in Table 1. The initial conduction resistance is required to be A or B in practice.

[0083] Here, the IC and the glass substrate for evaluation corresponded to each other in the terminal (bump) pattern, and had the following dimensions. In addition, when the IC and the glass substrate for evaluation were connected, the long direction of the anisotropic conductive film coincided with the short direction of the bump.

[0084] IC for evaluating the conductivity Outer shape: 1.8 x 20.0 mm Thickness: 0.5 mm Bump specifications: width 30 μm x length 85 μm, distance between bumps 50 μm, bump height 15 μm.

[0085] Glass substrate (Ti / Al wiring) Glass material: 1737F manufactured by Corning Incorporated Outer shape: 30 x 50 mm Thickness: 0.5 mm.

[0086] Conductivity evaluation criteria A: Initial conduction resistance less than 1.0 Ω B: Initial conduction resistance 1.0 Ω or more and less than 2.0 Ω C: Initial conduction resistance 2.0 Ω or more and less than 4.0 Ω D: Initial conduction resistance 4.0 Ω or more.

[0087] [Table 1] <Investigation of results> The anisotropic conductive film of Examples 1 to 4 as the filler-containing film was evaluated as A or B for any evaluation item because it satisfied the formulas (1) to (4). In particular, in the case of Examples 2 and 3 in which the core film layer thickness was about 1.0 μm, any evaluation item was evaluated as A.

[0088] On the other hand, in the case of Comparative Example 1 in which none of the formulas (1) to (4) was satisfied, all evaluation items were evaluated as C. In addition, in the case of Comparative Examples 2 and 3 in which the formulas (3) and (4) were satisfied but the formulas (1) and (2) were not satisfied, the conduction was evaluated as A, but the immobility and the pressure bonding unevenness were evaluated as C.

[0089] Industrial applicability In the filler-containing film of the present application, in addition to the "relationship between the opening diameter of the through hole on the surface of the core film and the opening diameter of the through hole on the back surface", the "relationship between the opening diameter of the through hole on the surface of the core film and the diameter of the filler", and the "relationship between the thickness of the core film and the diameter of the filler", the "position shift ratio of the filler in the film thickness direction of the core film" is each defined to a specific range. Therefore, when two members are joined by pressure bonding (e.g., heat pressure bonding, etc.) via the filler-containing film, the resin flow of the core film can be suppressed, the unintended movement of the filler can be limited, and in addition, the pressure bonding unevenness can be prevented at the time of pressure bonding (e.g., heat pressure bonding) of the film. Therefore, the filler-containing film of the present application is useful when various electronic components are connected to a substrate.

[0090] Explanation of symbols 1 Insulating base layer 1'Composition for forming insulating base layer 2 Adhesive layer 2'Composition for forming adhesive layer 3 Core film 4 Filler 10 Filler-containing film 20 Release substrate th Through hole P d Average particle diameter of filler 01 Opening diameter of through hole on the adhesive layer side surface of the core film 02 Opening diameter of through hole on the insulating base layer side surface of the core film C t Thickness of core film X Center line of core film in the film thickness direction Y Center line of filler in the film thickness direction L Distance between the centerline X of the core film and the centerline Y of the filler.

Claims

1. A filler-containing film comprising a core film having through-holes sandwiched between an insulating base layer and an adhesive layer, wherein a filler is retained in the through-holes. Satisfy the following equations (1) to (4): 0.95O1≤O2≤1.05O1(1) 0.80P d ≤O1≤1.05P d (2) 0.08P d ≤C t ≤0.40P d (3) S=(L / P d )×100≤20% (4) Where, "O1" is the opening diameter of the through hole on the adhesive layer side of the core film [μm], "O2" is the opening diameter of the through hole on the insulating base layer side of the core film [μm], and "C t " is the thickness of the core film [μm], "P d ” is the average particle size of the filler [μm], "L" is the distance between the center line X of the core film and the center line Y of the filler in the film thickness direction [μm], and "S" is the distance L [μm] relative to the average particle size P of the filler d The ratio of [μm] is [%]. In addition, regarding the positive and negative of "L", the positive side is toward the insulating base layer. The filled film according to claim 1 , wherein O1=O2.

3. The filler-containing film according to claim 1 or 2, wherein Average particle size of filler P d 1~200 μm.

4. The filler-containing film according to claim 1 or 2, wherein The through holes are arranged regularly.

5. The filler-containing film according to claim 1 or 2, wherein The filler is conductive particles, and the filler-containing film is used as a conductive film or an anisotropic conductive film.

6. A conjugate, wherein The first member and the second member are bonded together via the filler-containing film according to claim 1 .

7. A method for producing a joined body, wherein: The filler-containing film according to claim 1 is disposed between a first member and a second member and then bonded to each other.

8. A connection structure in which a first electronic component is conductively connected or anisotropically conductively connected to a second electronic component via the filler-containing film according to claim 5 used as a conductive film or an anisotropic conductive film.

9. A method for manufacturing a connection structure, wherein: A first electronic component is conductively connected or anisotropically conductively connected to a second electronic component via the filler-containing film according to claim 5 used as a conductive film or an anisotropic conductive film.

10. The method for manufacturing a connection structure according to claim 9, wherein: The terminals of the first electronic component and the terminals of the second electronic component are electrically connected via the conductive particles.

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