Filler arrayed film, method for producing connection structure, and connection structure

Abstract

The present invention provides a filler arrangement film that, when using a filler arrangement film made of conductive particles or the like arranged in an insulating resin layer, connects the connection portion of a tiny first item such as the electrode of a μLED to the connection portion of a second item such as the electrode of a large-screen television substrate via the filler, even if the alignment deviation between the first item and the second item is about ±10%, it can still reliably ensure that the actual capture number of the filler in each connection portion is 1 or more. This invention relates to a filler arrangement film 1 in which fillers 2 are arranged in an insulating resin layer 10. In the insulating resin layer 10, a plurality of first groups 3 formed by a plurality of fillers 2 are aggregated into second groups 4, and the second groups 4 are arranged in a regular manner. The closest distance L1 between the second groups 4 is greater than the closest distance L2 between the first groups, and the closest distance L2 between the first groups is greater than the closest distance L3 between the fillers within the first group.

Description

Technical Field

[0001] This invention relates to a filler arrangement film in which filler is arranged in a resin layer, a method for connecting a tiny first article to a second article such as a substrate using the filler arrangement film, and a connection structure obtained by the method. Here, the tiny first article can be exemplified by, for example, a tiny light-emitting element such as a micro LED or μLED. Prior Technology

[0002] μLED displays, which arrange tiny light-emitting elements (μLEDs) on a substrate, can eliminate the need for backlighting devices required for liquid crystal displays. This enables the display to be made thinner, and it is expected to serve as a display or light source that can also achieve wide color gamut, high resolution, and low power consumption.

[0003] According to Patent Document 1, as a method for manufacturing a display equipped with μLEDs, a red, blue, and green μLED array formed on a carrier substrate is picked up by a transport head and placed on a transfer target substrate such as a display substrate. The μLED array is then bonded to the transfer target substrate by soldering a solder layer, and contact lines are formed on it using ITO or the like.

[0004] Furthermore, Patent Document 2 describes a method in which μLEDs formed on a wafer are disposed on a substrate, and an anisotropic conductive film containing conductive particles dispersed in an adhesive component such as a hydrogenated epoxy compound is used to connect the film to the substrate, and the wafer is then peeled off. By using the anisotropic conductive film method described in Patent Document 2, a display using μLEDs can be easily obtained.

[0005] Patent document 3 describes a two-stage connection method. In this method, when connecting an IC chip and an FPC using an anisotropic conductive film with a conductive particle arrangement layer having a conductive particle area occupancy rate of less than 35% from a top view, a pulse heater type bonding machine is used to temporarily fix the IC chip and FPC in the first stage in order to improve the conductive particle capture efficiency. That is, by pressing the IC chip and FPC into the insulating resin layer of the anisotropic conductive film, the electrodes are brought close to the conductive particle arrangement layer. The formal bonding is then performed in the second stage. [Previous Technical Documents] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-500562 [Patent Document 2] Japanese Patent Application Publication No. 2017-157724 [Patent Document 3] Japanese Patent Application Publication No. 2019-216097 Summary of the Invention

[0007] [The problem that the invention aims to solve]

[0008] If the size of μLEDs is reduced to achieve higher resolution in a display, and the size of the LED electrodes is also reduced accordingly, it becomes difficult to ensure that the electrodes of each μLED can reliably capture the conductive particles when using an anisotropic conductive film containing only conductive particles mixed in an insulating material.

[0009] To address this, we consider using smaller conductive particles to increase the number density of conductive particles in conductive films and anisotropic conductive films.

[0010] However, if the particle size of the conductive particles is reduced, when the μLED is connected to the substrate via the anisotropic conductive film and heated and pressurized, the conductive particles are easily moved by the flow of the resin material constituting the anisotropic conductive film. Furthermore, in high-resolution displays, the gap between electrodes is extremely narrow, so the risk of short circuits caused by the conductive particles between electrodes connecting is worrying.

[0011] In order to suppress the movement of conductive particles during the connection, the pulse heater type bonding machine described in Patent Document 3 was also considered. However, even with this method, the area that can be connected in one crimping is still limited. Therefore, it is not possible to crimp large-area displays such as large-screen TVs in one go using anisotropic conductive films.

[0012] Therefore, the objective of this invention is to provide a filler arrangement film that, when using a filler arrangement film made of conductive particles or the like arranged in an insulating resin layer to connect the connection portion of a tiny first item such as the electrode of a μLED to the connection portion of a second item such as the electrode of a large-screen television substrate via the filler, can reliably ensure that the actual capture number of the filler in each connection portion is 1 or more, even if the alignment deviation between the first item and the second item is about ±10%; and to provide a method for connecting the tiny first item and the second item using this filler arrangement film, and a connection structure obtained using this method. [Technical means to solve the problem]

[0013] The inventors conceived of the following: When using a filler arrangement film made of conductive particles or other fillers arranged in an insulating resin layer, and connecting the connection portion of a tiny first item such as the electrode of a μLED to the connection portion of a second item such as the electrode of a large-screen television substrate via the filler, the filler in the filler arrangement film forms a first group at the position corresponding to the connection portion of the first item, and a plurality of first groups are combined to form a second group corresponding to the shape of the first item. The second group is arranged in accordance with the arrangement of the first item, which can greatly reduce the useless filler that does not participate in the connection. Furthermore, the resin flow during connection passes through the second group without easily affecting the second group. In this way, the filler constituting the first group can be reliably captured between the connection portion of the first item and the connection portion of the second item. In addition, when the first item is a light-emitting element such as a μLED, the filler does not obstruct the emission of light from the light-emitting element, and the luminous efficiency of the light-emitting device with the light-emitting element is improved, thus completing the present invention.

[0014] That is, the present invention provides a filler-arranged membrane, wherein fillers are arranged in an insulating resin layer, and in the insulating resin layer, a plurality of first groups formed by a plurality of fillers are combined into a second group, the second group being regularly arranged, and... The closest distance between the second group is greater than the closest distance between the first group. The closest distance between groups 1 is greater than the closest distance between packing materials within group 1.

[0015] Furthermore, the present invention provides a method for manufacturing a connecting structure, which involves connecting the connecting portions of each first article and the connecting portions of the second article by heating or pressurizing a filler membrane containing fillers arranged in an insulating resin layer, with a plurality of first articles arranged on a second article, thereby connecting them. The manufacturing method of the above-mentioned connecting structure uses the following as the filler-arranged membrane. In the insulating resin layer, at the position corresponding to the connection portion of the first article, a plurality of first groups formed by a plurality of fillers are assembled into a second group corresponding to the shape of the first article. The second group is arranged in accordance with the arrangement of the first article, and... The closest distance between the second group is greater than the closest distance between the first group. The closest distance between groups 1 is greater than the closest distance between packing materials within group 1.

[0016] Furthermore, the present invention provides a connecting structure having a connecting portion, wherein the connecting portion is located in a state where a plurality of first articles are arranged on second articles, and the connecting portion of each first article is connected to the connecting portion of the second article via a filler, and in the above-described connecting structure, The connection point is formed by the packing within the first group, which consists of multiple packing materials. A second group, consisting of multiple first groups, exists corresponding to the mounting location of the first item. The second group is arranged according to the arrangement of the first item, and, The closest distance between the second group is greater than the closest distance between the first group. The closest distance between groups 1 is greater than the closest distance between packing materials within group 1. [Effects of the Invention]

[0017] When the filler arrangement film of the present invention is used, in the case where a filler arrangement film, formed by arranging conductive particles or other fillers on an insulating resin layer, is heated or pressurized to connect a small first item such as an electrode of a large-screen television substrate to the connection portion of the first item, the filler can reliably capture one or more fillers between the connection portions of the first item and the connection portions of the second item, and the risk of fillers connecting to each other in adjacent first item connections or second item connections is low. Therefore, the risk of short circuits when connecting electronic components such as μLEDs to the substrate can be reduced.

[0018] Furthermore, when the first item is a light-emitting element such as a μLED, the second group, corresponding to the shape of the light-emitting element, is arranged in accordance with the arrangement of the light-emitting elements. Therefore, the emission of light from the light-emitting elements is not obstructed in the second group. As a result, the luminous efficiency of the light-emitting device equipped with the light-emitting elements is improved. Simple Explanation of the Diagram

[0019] [Figure 1] is a diagram showing the configuration of the packing in the packing arrangement membrane of the embodiment. [Figure 2] is a diagram showing the correspondence between the packing arrangement in the packing membrane of the embodiment and the connection part of the article connected by the packing membrane. [Figure 3] is an AA cross-sectional view of the packing arrangement membrane of the embodiment in Figure 1. Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings. Furthermore, the same symbols in the drawings represent the same or equivalent constituent elements.

[0021] (Packaging configuration) Figure 1 is a diagram showing the arrangement of fillers in a filler-arrangement film 1 according to one embodiment of the present invention. This filler-arrangement film 1 is formed by arranging conductive particles, which serve as fillers 2, on an insulating resin layer 10. Hereinafter, the filler-arrangement film 1 of the embodiment will be mainly described as an anisotropic conductive film. The filler-arrangement film of the present invention can also be used as a conductive film for electrically connecting articles to each other.

[0022] The filler arrangement membrane of the present invention is used to connect the connecting parts of the first articles and the second articles by heating or pressurizing the first articles and the second articles in a state where a plurality of first articles are arranged on the second articles. In this connected state, the filler is sandwiched between the connecting parts of the first articles and the connecting parts of the second articles, and the opposing surfaces of the first articles and the second articles are bonded to each other by an insulating resin layer.

[0023] In this embodiment, the filler arrangement film 1 serves as an anisotropic conductive film for anisotropically conductively connecting the first and second articles when the first article is configured as a μLED and its electrode is configured as a connecting portion of the first article, and the second article is configured as a substrate having a wiring circuit for the μLED and its electrode is configured as a connecting portion of the second article. The filler arrangement film 1 can also be used as a conductive film.

[0024] As shown in Figure 2, each μLED 20 connected by the filler arrangement film 1 of this embodiment has two electrodes 21 and is arranged in a lattice pattern on the wafer 22.

[0025] Regarding the shape and size of the μLED20, for example, when the shape is rectangular, its long side is less than 200 μm, or less than 150 μm, or less than 50 μm, or less than 20 μm. More specifically, examples include rectangles of 10 μm × 20 μm, 7 μm × 14 μm, and 5 μm × 5 μm. Furthermore, the shape of the μLED20 is not limited to rectangles; for example, it can also be rhomboid.

[0026] Furthermore, the shape and size of the electrode 21 are not particularly limited. For smaller μLEDs, examples include rectangles with a long side of 5 μm to 50 μm and a short side of 3 μm to 40 μm. The distance Ls between electrodes 21 within a single μLED 20 can be appropriately selected based on the application method. For ease of placement, a lower limit of 3 μm or more is preferred, and more preferably 5 μm or more. There is no particular upper limit. When the element is larger than a μLED or microLED and used alone, it can be 3000 μm or less. For display applications, it can be 1000 μm or less, or 500 μm or less, or 150 μm or less, or 20 μm or less.

[0027] In the filler arrangement film 1, a plurality of conductive particles (fillers) 2 disposed at positions corresponding to each electrode (connection portion) 21 of the μLED (first article) 20 form a first group 3. The plurality of first groups 3 are aggregated in accordance with the shape of the μLED 20, thereby forming a second group 4. The second group 4 is regularly arranged in accordance with the arrangement of the μLED 20.

[0028] Here, the so-called first group 3 is positioned at the position corresponding to the electrode 21 of μLED20. This means that when a plurality of μLED20 in a specified arrangement is aligned with the filler arrangement film 1, the electrode 21 of each μLED20 overlaps with the first group 3 when viewed from above, and the gap Ls between the electrodes 21 of each μLED20 overlaps with the gap L2 between the first group 3. Preferably, it means that the electrode 21 is located within the first group 3, or that one or more conductive particles 2 constituting the first group 3 overlap with the electrode 21.

[0029] The so-called arrangement of the second group 4 corresponding to the arrangement of μLED 20 means that, through the above alignment, each μLED 20 overlaps with the second group 4 when viewed from above, and the gap between each μLED overlaps with the gap L1 between the second group 4. Preferably, it means that in each μLED 20, the total area of ​​the conductive particles 2 that are offset from the outer shape of the μLED 20 is within 50% of the outer shape of the μLED 20. More preferably, all the conductive particles 2 that constitute the second group 4 are located within the outer shape of each μLED 20.

[0030] Furthermore, the so-called arrangement of the second group 4 corresponding to the arrangement of μLED20 means that the arrangement direction and spacing of the second group 4 are equal to the arrangement direction and spacing of μLED20.

[0031] In order to reduce the appearance problems caused by the mounting of tiny parts on the filler arrangement membrane 1, it is ideal to have fewer conductive particles 2 between the 4 groups of 2, especially when the particle size of conductive particles 2 is less than 3 μm. It is also ideal to have fewer aggregated or irregular conductive particles between the 4 groups of 2.

[0032] As described above, the first group 3 of the conductive particles in the filler arrangement film 1 corresponds to the electrode 21 of the μLED20, and the second group 4 corresponds to the shape of the μLED20. Therefore, when the closest distance between the second group 4 (i.e., the distance between a conductive particle constituting a certain second group and the conductive particle constituting the group closest to that second group) is set to L1, the closest distance between the first group 3 (i.e., the distance between a conductive particle constituting a certain first group and the conductive particle constituting the group closest to that first group) is set to L2, and the closest distance between the conductive particles 2 within the first group 3 is set to L3, the following condition is satisfied: L1>L2>L3.

[0033] Group 1, 3 corresponds to electrode 21 of μLED20. Therefore, a group of conductive particles of the same shape with two electrodes of μLED can be regarded as a group 2, 4. In the case of this group 2, 4 being arranged side by side, the conductive particles can be regarded as the first group 3 being relatively densely packed at a distance L3, the second group 4 being grouped apart at a distance L2, and the second group 4 being separated by a distance L1. Therefore, the conductive particles (fillers) arranged on the film are not uniformly present on one side, but are present on one side as groups with regularity composed of different distances. Therefore, as mentioned above, L1 is defined as the "closest distance between the second groups", but for practical purposes, it is preferable to have (mixed) the distance between the second groups having a distance greater than this distance.

[0034] When multiple μLEDs 20 arranged on wafer 22 are connected to the substrate by heating and pressurizing the filler arrangement film 1, the resin flow of the insulating resin layer 10 of the filler arrangement film 1 is unlikely to affect the arrangement of the conductive particles 2 in the second group 4. In this respect, L1 and L2 can be appropriately determined according to the shape of the μLED 20, the arrangement spacing, the distance between electrodes, etc. Furthermore, L1 and L2 also depend on the design of the μLED or microLED. For example, in order to adjust the display resolution or the performance as a light source, the lower limit can be above 10 μm, and the upper limit can be set below 3000 μm, or below 1000 μm, or below 500 μm.

[0035] Ideally, the area of ​​the outline shape of the second group 4, which is connected to the outer periphery of the conductive particles 2 constituting the second group 4, should satisfy the following ratio relative to the outer shape of the corresponding μLED 20. That is, if the lower limit of the ratio of the area of ​​the outline shape of the second group 4 to the area of ​​the outer shape of the μLED 20 is reduced, the conductive particles 2 can be easily contained within the outer shape of the μLED 20. In order to facilitate the capture of conductive particles by electrodes, this ratio is preferably 0.1 times or more, more preferably 0.2 times or more, and even more preferably 0.5 times or more. On the other hand, if the upper limit is increased, although the concern of insufficient conductive particles captured by the electrodes can be avoided, there is a risk of damage to transparency or aesthetics. Therefore, it is preferably 1.5 times or less, more preferably 1.3 times or less, and even more preferably 1.2 times or less.

[0036] Furthermore, regarding the allowable deviation of approximately ±10% in the alignment of the first group 3 of the filler arrangement film 1, the electrode 21 of the μLED 20, and the electrode of the substrate, the area of ​​the outline shape of the first group 3, which is connected to the conductive particles 2 constituting the outer periphery of the conductive particles 2, can be 0.5 to 1.8 times the area of ​​the corresponding electrode 21 of the μLED 20, preferably 0.8 to 1.2 times. If it is within this range, there will be just the right number of conductive particles, thereby achieving both preventing short circuits and achieving capture, and it is also easy to obtain a good capture state and easy to confirm the capture state.

[0037] In this invention, a second group 4 may contain a number of first groups 3 corresponding to the number of connecting parts of a first article, and in particular, there may be 3 or fewer first groups 3. In this embodiment, there are 2 first groups 3.

[0038] The relationship between the closest distance L3 between conductive particles in group 1, 3 and the average particle size D of conductive particles 2 is calculated by their ratio L3 / D. The lower limit is preferably 0.3 or more, more preferably 0.5 or more, and the upper limit is preferably 4 or less, more preferably 3 or less.

[0039] The arrangement of the conductive particles 2 in group 1, 3 can be random or regular. To improve the capture efficiency of the conductive particles in each electrode 21, a planar lattice pattern with conductive particles arranged at a predetermined interval along one or more alignment axes in a predetermined direction is preferred. Examples include orthorhombic, hexagonal, cubic, rectangular, and parallel lattices. Alternatively, regions with different planar lattice patterns may also be present.

[0040] On the other hand, in this invention, the average number density of fillers in the entire surface of the filler-arranged membrane 1 and the average number density of fillers in the first group 3 are designed according to the object using the filler-arranged membrane. For example, regarding the lower limit of the average number density in the entire surface, when a sparse state is preferred, it is preferably 500 fillers / mm² or more, and when a dense state is preferred, it is preferably 20,000 fillers / mm² or more, and more preferably 40,000 fillers / mm² or more.

[0041] The lower limit of the average number density of the packing material in Group 1, 3 is preferably 50,000 pieces / mm² or more, and more preferably 500,000 pieces / mm² or more. The upper limit of the average number density is preferably 1,500,000 pieces / mm² or less, and more preferably 1,000,000 pieces / mm² or less.

[0042] The average number density of fillers in the gaps between the second group of 4 is preferably below 1000 per mm², and more preferably practically zero.

[0043] Furthermore, depending on the design of the object, there are also cases where the range exceeds the aforementioned lower and upper limits.

[0044] The average filler area occupancy of the entire surface of the filler-arranged membrane 1 and the average filler area occupancy of the first group 3 are both considered in the same way as the average number density. For example, when it is preferable for the particle size to be small and dense, depending on the object using the filler-arranged membrane 1, the average filler area occupancy of the first group 3 can be set to 5% or more, 8% or more, or 25% or more, or 85% or less, or 50% or less. Here, in this embodiment, the filler area occupancy means the conductive particle area occupancy, which is obtained by multiplying the number density of conductive particles in the filler-arranged membrane 1 under top view (particles / mm²) by the average value of the top view area of ​​one conductive particle (mm² / particle) by 100. When the filler-arranged membrane is made into a very small monolith, it refers to the number density measured in the state before monolithization.

[0045] Furthermore, the number density of conductive particles can be determined not only through observation using a metal microscope, but also by measuring and observing images using image analysis software (such as WinROOF (Mitani Corporation) or A IMAGE KUN (registered trademark) (Asahi Kasei Engineering Co., Ltd.). The number of conductive particles is determined by measuring the number observed on the filler-arranged membrane.

[0046] (filler) In this embodiment, the particle size of the conductive particles 2 used as filler is not particularly limited, but the lower limit of the particle size is preferably 1 μm or more. For example, from the viewpoint of the capture efficiency of conductive particles in the connection structure, the upper limit of the particle size is preferably 50 μm or less, and more preferably 20 μm or less. Depending on the size of the electrode, there may be cases where the particle size of the conductive particles is less than 3 μm, preferably less than 2.5 μm, and more preferably less than 2 μm. When the particle size is less than 1 μm, it can be regarded as an aggregate of particles larger than 1 μm.

[0047] The average particle size can be set as the value measured by an image-based particle size analyzer (e.g., FPIA-3000: manufactured by Malvern Panalytical). In this case, it is preferable to have more than 1,000 particles, preferably more than 2,000.

[0048] Furthermore, regarding the type of conductive particles, appropriate selections can be made from conductive particles used in known anisotropic conductive films. 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 can also be used together. Among these, metal-coated resin particles are superior because the repulsion between the resin particles after connection makes it easier to maintain contact with the terminals, resulting in stable conductivity. Additionally, the surface of the conductive particles can be insulated using known techniques without impairing conductivity.

[0049] Furthermore, in the filler-based membrane of the present invention, the filler can be appropriately selected from the following fillers according to the application of the filler-based membrane and the performance required for the application, such as hardness and optical performance: inorganic fillers (metal particles, metal oxide particles, metal nitride particles, etc.), organic fillers (resin particles, rubber particles, etc.), and fillers in which organic and inorganic materials coexist (e.g., particles whose core is formed of resin material and whose surface is coated with metal (metal-coated resin particles), conductive particles whose surface is attached with insulating microparticles, conductive particles whose surface is treated with insulation, etc.).

[0050] For example, when the filler-arranged membrane is used as a conductive membrane or anisotropic conductive membrane, it contains conductive particles as filler. Fillers other than conductive particles can be used depending on the application of the filler-arranged membrane.

[0051] When filler-coated films are used for color adjustment in micro-optical components such as μLEDs, or for black matrices in color displays, known pigments, dyes, and light-scattering particles can be used as fillers. When the filler-coated film is used as an optical film or matting film, silica fillers, titanium dioxide fillers, styrene fillers, acrylic fillers, melamine fillers, or various titanates can be used. In capacitor films, titanium dioxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate, and mixtures thereof can be used. In adhesive films, polymer-based rubber particles and polysiloxane rubber particles may be included.

[0052] (Cross-sectional structure of a filler-configured membrane) Figure 3 is a cross-sectional view AA of the filler arrangement membrane 1 shown in Figure 1. In the first group 3 region of the filler arrangement membrane 1 in this embodiment, conductive particles 2 are arranged in the insulating resin layer 10.

[0053] The insulating resin layer 10 can be composed of a single insulating resin layer or a laminate of multiple resin layers. The position of the ends of the conductive particles 2 is preferably approximately aligned with one side of the layer. "Approximately aligned" means including, for example, an error of about ±10% in particle size. When the insulating resin layer is made into a laminate of multiple resin layers, for example, as shown in FIG3, a high-viscosity adhesive resin layer 11 holding the conductive particles 2 and an adhesive layer 12 with a lower viscosity than the high-viscosity adhesive resin layer 11 can be formed. The resins constituting the high-viscosity adhesive resin layer 11 and the adhesive layer 12 can, for example, be the same as the adhesive or adhesive layer constituting the insulating resin layer described in Patent Document 3. Different fillers can also be configured in different layers for lamination.

[0054] The insulating resin layer 10 may contain rubber components, inorganic fillers, silane coupling agents, diluent monomers, fillers, softeners, colorants, flame retardants, thixotropic agents, etc., as needed.

[0055] Rubber components can be incorporated to prevent warping or deformation of the connecting structure. The rubber component can be an elastomer with high cushioning (shock absorption) properties, and there are no particular limitations. Specific examples include: acrylic rubber, polysiloxane rubber, butadiene rubber, polyurethane resin (polyurethane elastomer), etc.

[0056] Regarding the thickness of the insulating resin layer 10, when the μLED20 and the substrate are joined by heating and pressurizing using the filler arrangement film 1, no useless resin flow occurs in the insulating resin layer. Furthermore, to prevent resin overflow or agglomeration when the filler arrangement film 1 is rolled into a package, the lower limit of the layer thickness is at least 0.6 times the average particle size of the conductive particles 2, preferably at least 0.9 times, and more preferably at least 1 time, with an upper limit of at least 3 times, preferably at least 2 times, and more preferably at least 1.5 times. If the thickness of the insulating resin layer 10 is less than 0.6 times the average particle size of the conductive particles 2, the conductive particles 2 will be exposed from the insulating resin layer 10. Therefore, when using the filler arrangement film 1 to join the μLED20 and the substrate, it is difficult to achieve temporary adhesion between the filler arrangement film 1 and the μLED20 or the substrate. On the other hand, if it exceeds 3 times, excessive resin flow will occur when μLED20 is connected to the substrate. The resin flow will cause the conductive particles 2 to flow, and the capture of the conductive particles 2 in the electrode will be reduced.

[0057] Furthermore, due to manufacturing reasons such as particle arrangement, the lower limit of the thickness of the insulating resin layer 10 is preferably 2 μm or more, and more preferably 3 μm or more. Considering that excessive thickness may cause deviations during connection, the upper limit is preferably 32 μm or less, more preferably 20 μm or less, and even more preferably 8 μm or less.

[0058] Furthermore, in the case of this invention, the μLED itself is relatively small, and compared to the previous method, the size of the μLED is closer to the size of the conductive particles. μLEDs are prone to deviation, and as a connection structure, it is preferable to avoid this deviation. For these reasons, it is also necessary to keep the thickness of the insulating resin layer 10 within the aforementioned range.

[0059] (Manufacturing method of filler-arranged membrane) Regarding the filler arrangement film 1, except that the conductive particles are configured in a specific way as described above, it can be manufactured in the same manner as known anisotropic conductive films. For example, similar to the manufacturing method of the anisotropic conductive film described in Patent Document 3, firstly, a mold with recesses corresponding to the arrangement pattern of the conductive particles is prepared, conductive particles 2 are filled into the mold, a high-viscosity adhesive resin layer 11 formed on the release film is attached thereon, the conductive particles 2 are pressed into the high-viscosity adhesive resin layer 11 for transfer bonding, and an adhesive layer 12 is applied to the transfer bonding area.

[0060] (Connection method for membranes using filler arrangement) Regarding the method of connecting the electrodes of μLED20 to the electrodes of the substrate when a plurality of μLED20s are regularly arranged on a wafer 22 using a filler arrangement film 1, firstly, the filler arrangement film 1 is aligned and bonded to the electrodes of the substrate, and then the filler arrangement film 1 is aligned and bonded to the μLED20s arranged on the wafer 22. Heating and pressurizing are then applied to connect the electrodes of the μLED20s to the electrodes of the substrate. In this case, as described in Patent Document 3, the connection can be achieved through a two-stage heating and pressurizing process. Furthermore, when the conductive particles are solder particles or the like, the connection can be achieved through reflow soldering.

[0061] During heating and pressurization, the insulating resin layer 10 of the filler arrangement film 1 flows and fills the gap between the opposing surfaces of the μLED20 and the substrate, and is hardened, thereby bonding the μLED20 to the substrate. At this time, the resin flowability is higher between the second group 4 without conductive particles, and lower within the second group 4 than between the groups of 4. Therefore, within the second group 4, the conductive particles 2 of the first group 3, which are arranged corresponding to the electrodes of the μLED20, are not easily affected by the resin flow between the groups of 4, and the electrodes 21 of each μLED20 can reliably capture the conductive particles 2.

[0062] Furthermore, within the second group 4, corresponding to the arrangement of the electrodes 21, the first group 3 are arranged at a distance L2 from each other, thus suppressing short circuits between the electrodes 21 within a μLED 20.

[0063] Furthermore, in the filler array film 1, there are no conductive particles 2 between the second group 4. Therefore, after being connected to the substrate, the light emitted by the μLED 20 will not be blocked by the conductive particles 2. Thus, compared with the case of using a filler array film in which conductive particles are uniformly distributed across the entire film surface, the luminous efficiency of the light-emitting device with μLED installed is improved.

[0064] Furthermore, the filler-arranged membrane can be made into a monolithic shape. The size of the monolithic shape can be designed according to the object, for example, one side can be set to 5 μm or more and 150 μm or less. This allows for applications such as adjusting color or light. That is, the monolithic membrane can be used to connect one article to another, or it can be placed solely on an electrode. Monolithization can be achieved using mechanical methods, chemical methods, laser cutting, etc. Moreover, the cut does not need to penetrate into the substrate; it can be a partial cut.

[0065] The temporary attachment or transfer of filler-filled films and the mounting of μLEDs on substrates can be achieved by the following methods: known methods such as using stamp materials or laser methods (laser peeling), or methods that apply them (e.g., methods described in Japanese Patent Application Publication No. 9-124020, Japanese Patent Application Publication No. 2011-76808, Japanese Patent No. 6636017, Japanese Patent No. 6187665, etc.). There are no particular limitations as long as the method can achieve the effect of the invention.

[0066] (Connection struct) Regarding the connection structure between the μLED20 and the substrate formed by connecting the filler arrangement film 1 in the usage embodiment using the above method, the filler 2 in the first group 3 constitutes the connection portion between the electrode 21 of the μLED20 and the electrode of the substrate. The embodiment is described using a μLED as an example. In this invention, the connection structure can also be a microLED.

[0067] As described above, the resin flow during connection does not easily affect the arrangement of conductive particles 2 within the second group 4. Therefore, similar to before connection, in the planar arrangement of the filler after connection, the second group, composed of multiple first groups, also exists corresponding to the mounting position of the μLEDs, and the second group is arranged corresponding to the arrangement of the μLEDs. Moreover, regardless of whether a connection is formed, when all conductive particles are observed, if the closest distance between the second groups after connection is set as L1', the closest distance between the first groups after connection is set as L2', and the closest distance between conductive particles is set as L3', the following relationship is maintained: L1'>L2'>L3'.

[0068] Compared to the connection structure described above, which uses a filler array film with conductive particles uniformly distributed across the entire film surface to connect μLEDs to the substrate, this connection structure offers improved luminous efficiency. Furthermore, the trapping ability of conductive particles in each electrode is also higher, and the occurrence rate of short circuits is reduced.

[0069] The above describes the connection method using the filler arrangement film of the present invention and the connection structure obtained therefrom, based on the case where the first item is a μLED, the second item is a substrate on which a wiring circuit of a μLED is formed, and the filler of the filler arrangement film is a conductive particle. However, the present invention is not limited thereto.

[0070] For example, the color tone of the connecting structure between the first and second items can be adjusted by setting the first item as a light scattering film or a black matrix layer, setting the second item as a transparent substrate (a substrate equipped with μLEDs), and setting the filler as silicon dioxide or particles colored black. [Example]

[0071] The present invention will now be described in detail based on specific embodiments. Examples 1-3, Comparative Examples 1 and 2

[0072] (Fabrication of anisotropic conductive films) The resin was mixed according to the resin composition in Table 1, coated onto the release film, and dried (60°C, 3 minutes) to obtain the adhesive film.

[0073] [Table 1] resin Product Name Manufacturer Adhesion membrane 1 2 3 Hydrogenated phenoxy resin PKHH Pakistan Industry 35 35 (wt%) Polyvinyl acetal S-LEC KS-10 Sekisui Chemical Industry 50 Bisphenol A type liquid epoxy resin YL-980 Mitsubishi Chemical 40 40 High-purity hydrogenated epoxy resin YX-8000 Mitsubishi Chemical 40 Hydrophobic silicon dioxide microparticles RY200 NIPPON AEROSIL 15 15 cationic polymerization initiator SI-60L Sanxin Chemical Industry 10 10 10 Film thickness 4 4 8 (μm)

[0074] On the other hand, a mold with recesses for filling conductive particles is made in the same manner as described in Japanese Patent No. 6187665, using conductive particles (average particle size 2.2 μm or 3.2 μm, 0.2 μm Ni-plated resin particles, Sekisui Chemicals Co., Ltd.) arranged as shown in Table 2. The conductive particles are filled into the recesses, covered with the adhesive film in Table 1, and the conductive particles are pressed into the adhesive film to produce an anisotropic conductive film.

[0075] [Table 2] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Adhesion membrane 1 2 3 1 1 Particle size (μm) of conductive particles 2.2 2.2 2.2 3.2 2.2 Density of conductive particles in Group 1 (particles / mm²) 100K 100K 100K In the whole film of the face Conductive particle density (particles / mm²) 1.2K 1.2K 1.2K 28K 100K Conductive particle arrangement hexagonal lattice Tongzuo Tongzuo Tongzuo Tongzuo conductive particle configuration The first group of biases exists in the corresponding electrode portion, and the second group of biases exists in the corresponding wafer portion. Tongzuo Tongzuo Uniformly distributed throughout the membrane Tongzuo Distance L3 (μm) between conductive particles 1.2 1.2 1.2 3.2 1.2 Intergroup distance L2 (μm) 5 5 5 The distance between the second group is L1 (μm). 15 15 15 Particle trapping A A A C A insulation A A A A B Visible light transmittance A B B B C

[0076] (Evaluation of anisotropic conductive films) The anisotropic conductive films of Examples 1-3 and Comparative Examples 1 and 2 were used to evaluate particle trapping, insulation, and visible light transmittance in the following manner. The results are shown in Table 2.

[0077] (i) Particle trapping The anisotropic conductive films of Examples 1-3 and Comparative Examples 1 and 2 were laminated onto ITO / NdMo patterned glass, and then heated and pressed onto it (maximum temperature 150°C, pressure 30 MPa, 10 seconds) to obtain a mounting body, mimicking an IC chip for μLED evaluation. This evaluation IC chip has the following electrode layout: two 10 μm × 10 μm bumps (with a 7 μm gap between the bumps) arranged as a group on approximately one surface within a 1.5 cm × 1.5 cm area at a 30 μm spacing.

[0078] The number of conductive particles captured by 100 bumps on the mounting body was measured. The lowest number among the 100 bumps was evaluated according to the following criteria.

[0079] A: 5 or more B: 3-4 C: 1~2 D: 0

[0080] (ii) Insulation The continuity resistance between the 100 bumps of the aforementioned mounting body was measured, and resistance below 10⁷ Ω was considered a short circuit. Based on the number of short circuits, the following criteria were used for evaluation.

[0081] A: No short circuit B: The number of short circuits is 1. C: The number of short circuits is 2 D: The number of short circuits is 3 or more

[0082] (iii) Visible light transmittance The visible light transmittance (400-700 nm) of the anisotropic conductive films of Examples 1-3 and Comparative Examples 1 and 2 was measured, and evaluated according to the following criteria based on their average transmittance (measurement area 10 mm × 10 mm). In this case, as anisotropic conductive films, they were placed on a substrate and placed at 200°C for 1 minute to harden, and the results were measured in this state. This allowed observation of how resin overflowing from the connection structure affected the process.

[0083] A:More than 50% B: 35% or more C: 20% or more D: Less than 20%

[0084] As shown in Table 2, if an anisotropic conductive film is used in an embodiment where conductive particles are biased into bumps on μ wafers or μLEDs, then any one of particle trapping, insulation, and visible light transmittance is rated as excellent (B or above).

[0085] 1: Filler-filled membrane 2: Fillers, conductive particles 3: Group 1 4: Group 2 10: Insulating resin layer 11: High-viscosity adhesive resin layer 12: Adhesive layer 20: Item 1, μLED 21: Electrode (connection part) 22: Wafer L1: Closest distance between groups 2 L2: Closest distance between groups 1 L3: Closest distance between packing materials within group 1 Ls: Electrode spacing of μLED

Claims

1. A filler arrangement film comprising a filler arranged in an insulating resin layer, wherein in the insulating resin layer, a plurality of first groups formed by a plurality of the fillers are combined into a second group, the second group being regularly arranged, and the closest distance between the second group being greater than the closest distance between the first group, the closest distance between the first group being greater than the closest distance between the fillers within the first group, wherein the fillers in the first group are configured as a planar lattice pattern.

2. The membrane with the filler configuration as requested in item 1, wherein, A second group is formed by three or fewer members of the first group.

3. The membrane with the filler configuration as requested in item 1, wherein, The average number density of this filler in the entire membrane is between 20,000 fillers / mm² and 1,500,000 fillers / mm².

4. The membrane with the filler configuration as requested in item 1, wherein, The average area occupied by this filler in the entire membrane is between 25% and 50%.

5. The membrane with the filler configuration as requested in item 1, wherein, The ratio of the closest distance L3 between the packing materials to the average particle size D of the packing material, L3 / D, is between 0.3 and 4.

6. The membrane with the filler configuration as requested in item 1, wherein, The thickness of the insulating resin layer is more than 0.6 times and less than 3 times the average particle size of the filler.

7. The membrane with the filler configuration as requested in item 1, wherein, The filler may be pigments, dyes, light-scattering particles, silica fillers, titanium dioxide fillers, styrene fillers, acrylic fillers, melamine fillers, titanates, lanthanum oxide, polymer-based rubber particles, or polysiloxane rubber particles.

8. Membranes with filler configurations as described in any of requests 1 to 6, wherein, The filler consists of conductive particles.

9. The filler arrangement of any one of the claims 1 to 7 is any one of black matrix, optical film, or matte film.

10. A connecting structure wherein, in a state in which a plurality of first articles are arranged on a second article, the connecting portion of each first article and the connecting portion of the second article are connected by a filler arrangement film in which filler is arranged in an insulating resin layer, and the filler arrangement film of any one of claims 1 to 7 is used as the filler arrangement film.

11. A method for manufacturing a connecting structure, wherein a plurality of first articles are arranged on a second article, and the connecting portions of each of the first articles and the connecting portions of the second article are connected by heating or pressurizing a filler membrane in which fillers are arranged in an insulating resin layer, and the filler membrane of any one of claims 1 to 7 is used as the filler membrane.

12. A method for manufacturing a connecting structure, wherein a plurality of first articles are arranged on a second article, and the connecting portions of each of the first articles and the connecting portions of the second article are connected by heating or pressurizing a filler arrangement film in an insulating resin layer containing fillers, wherein the method for manufacturing the connecting structure uses the filler arrangement film described below, wherein in the insulating resin layer, at the position corresponding to the connecting portion of the first article, a plurality of first groups formed by a plurality of fillers are assembled into a second group corresponding to the shape of the first article, the second group is arranged corresponding to the arrangement of the first articles, and the closest distance between the second group is greater than the closest distance between the first groups, the closest distance between the first groups is greater than the closest distance between the fillers within the first group, and the fillers in the first group are arranged in a planar lattice pattern.

13. A method for manufacturing the connection structure as described in claim 12, wherein, The first item is a μLED, and the second item is a substrate.

14. A method for manufacturing the connection structure as described in claim 13, wherein, The ratio of the area of ​​the outline shape of the second group to the area of ​​the outline shape of the μLED is more than 0.1 times and less than 1.2 times.

15. A method for manufacturing the connection structure as described in claim 13, wherein, The filler is a conductive particle, and the area of ​​the outline shape of the first group, which is connected to the conductive particles on the outer periphery of the first group, is 0.5 to 1.8 times the area of ​​the corresponding electrode of the μLED.

16. A connecting structure having a connecting portion, wherein the connecting portion is located in a state where a plurality of first articles are arranged on a second article, the connecting portion of each first article and the connecting portion of the second article are connected by a filler, and in the connecting structure, the connecting portion is formed by the filler in a first group formed by a plurality of fillers, a second group formed by a plurality of first groups exists corresponding to the mounting position of the first articles, the second group is arranged corresponding to the arrangement of the first articles, and the closest distance between the second groups is greater than the closest distance between the first groups, the closest distance between the first groups is greater than the closest distance between the fillers in the first group, and the fillers in the first group are arranged in a planar lattice pattern.

17. As in the connection constructor of request item 16, wherein, The first item is a μLED, and the second item is a substrate.

18. As in the connection constructor of request item 17, wherein, The ratio of the area of ​​the outline shape of the second group to the area of ​​the outline shape of the μLED is more than 0.1 times and less than 1.2 times.

19. As in the connection constructor of request item 17, wherein, The filler is a conductive particle, and the area of ​​the outline shape of the first group, which is connected to the conductive particles on the outer periphery of the first group, is 0.5 to 1.8 times the area of ​​the corresponding electrode of the μLED.

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