Adhesive film and method for producing adhesive film

Abstract

To provide an adhesive film that can prevent a micro piece from being bent and a method for manufacturing adhesive film.SOLUTION: An adhesive film 1 is provided with a release film 2, and an adhesive layer 3 laminated on one surface 2a side of the release film 2. The adhesive layer 3 comprises a body portion 3A, and a strip-shaped micro piece 3B protruding from the body portion 3A in an in-plane direction of the release film 2. On the other surface 2b side of the release film 2, a support film 5 is laminated on a region overlapping with at least a part of the micro piece 3B.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to adhesive films and methods for making adhesive films. [Background technology]

[0002] Conventionally, various adhesives have been used to fix electronic components used in semiconductor devices or to connect circuit components together. One form of adhesive is an adhesive film formed from an adhesive in a film form. The adhesive film is generally provided in a state in which an adhesive layer is formed on a release layer called a separator. When connecting components using an adhesive film, the adhesive layer of an adhesive sheet is attached to one component, the release layer is peeled off from the adhesive layer, and the other component is superimposed on the adhesive layer attached to the one component.

[0003] Known adhesive films include conductive adhesive films that are made conductive by dispersing conductive particles in the adhesive (see, for example, Patent Document 1). Such conductive adhesive films can be used to suitably connect electronic components together electrically. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-207115 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been an increasing demand for semiconductor devices with higher functionality, higher integration, and higher speed. Accordingly, the shapes of the bonded parts of electronic components (e.g., semiconductor chips, wiring boards, etc.) connected using adhesive films have become more complex and finer. As the bonded parts become more complex and finer, the adhesive film may be provided with minute, strip-shaped pieces protruding from the main body of the adhesive layer in order to precisely position the adhesive layer at a desired location. However, when such minute pieces are provided on the adhesive film, there is a problem in that the minute pieces are easily bent when the adhesive film is wound up during production or when the adhesive film is used.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an adhesive film that can suppress bending of fine particles and a method for manufacturing an adhesive film. [Means for solving the problem]

[0007] An adhesive film according to one aspect of the present disclosure comprises a release film and an adhesive layer laminated on one side of the release film, the adhesive layer having a main body portion and strip-shaped micro-flakes extending in the in-plane direction of the release film in the main body portion, and a support film laminated on the other side of the release film in an area overlapping at least a portion of the micro-flakes.

[0008] In this adhesive film, the main body of the adhesive layer has strip-shaped microfibers extending in the in-plane direction of the release film. The presence of microfibers in the adhesive layer allows for suitable connection to complex and miniaturized adherends. In addition, in this adhesive film, a support film is laminated on the other side of the release film in an area that overlaps with at least a portion of the microfibers. Because at least a portion of the microfibers are supported by the support film, bending of the microfibers can be prevented when the adhesive film is wound up during production or when the adhesive film is used.

[0009] The release film may be long, and the main portions of the adhesive layer may be arranged spaced apart from each other in the extending direction of the release film. The main portions of the adhesive layer may be arranged at regular intervals in the extending direction of the release film. This configuration enables continuous use of the adhesive layer with the bending of the micro-pieces suppressed.

[0010] The support film may be positioned in an area that overlaps the entire microfiber. In this case, the entire microfiber is supported by the support film. Therefore, bending of the microfiber can be more reliably suppressed. Furthermore, when the microfiber is attached to the adherend, it is possible to suppress variations in pressure at each part of the microfiber.

[0011] In the width direction of the adhesive film, the release film may have a protruding portion that protrudes outward beyond the adhesive layer. In this case, the protruding portion of the release film can more reliably protect the fine particles. Furthermore, by using the protruding portion as a gripping area for the adhesive film when using the adhesive film or as an area for arranging a positioning marker, the convenience of the adhesive film can be improved.

[0012] A cover film may be laminated on one side of the release film so as to cover the entire adhesive layer including the fine particles, in which case the fine particles can be more reliably protected by the support film and cover film.

[0013] The cover film may have a protruding portion that protrudes outward beyond the adhesive layer in the width direction of the adhesive film, in which case the cover film can more reliably protect the fine particles.

[0014] The adhesive film may be a conductive adhesive film. The conductive adhesive film may contain conductive particles. In this case, the minute particles can simultaneously establish physical and electrical connections to complex and minute adherends.

[0015] A method for manufacturing an adhesive film according to one aspect of the present disclosure comprises a first lamination step of laminating an adhesive layer on one side of a release film; a first punching step of punching the release film and adhesive layer in a predetermined pattern corresponding to the strip-shaped micro-pieces; a second punching step of punching the release film and adhesive layer between the patterns and half-cutting the adhesive layer to form a main body portion and strip-shaped micro-pieces extending in the in-plane direction of the release film in the main body portion in the adhesive layer; and a second lamination step of laminating a support film on the other side of the release film in an area that overlaps with at least a portion of the strip-shaped micro-pieces.

[0016] This adhesive film manufacturing method combines a first punching process in which the release film and adhesive layer are punched out in a predetermined pattern corresponding to the strip-shaped micro-pieces, and a second punching process in which the release film and adhesive layer are punched out between the patterns and the adhesive layer is half-cut. This allows for the simple formation of a main body portion and strip-shaped micro-pieces extending in the in-plane direction of the release film in the main body portion in the adhesive layer. In the second lamination process after punching, a support film is laminated on the other side of the release film in an area overlapping at least a portion of the strip-shaped micro-pieces, so that at least a portion of the micro-pieces are supported by the support film. This prevents the micro-pieces from bending. [Effects of the Invention]

[0017] According to the present disclosure, bending of the micro-flakes can be suppressed. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing an adhesive film according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of the adhesive film shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] 1 is a flowchart of a method for manufacturing an adhesive film according to an embodiment of the present disclosure. [Figure 6] 6 is a schematic diagram showing an example of the configuration of a manufacturing apparatus that can be used in the method for manufacturing the adhesive film shown in FIG. 5. FIG. [Figure 7] FIG. 2 is a plan view of the adhesive film after the first punching step. [Figure 8] FIG. 10 is a plan view showing cutting lines in the second punching step. [Figure 9] 10(a) to 10(c) are schematic diagrams showing modified examples of fine particles. [Figure 10] 10(a) to 10(c) are schematic diagrams showing other modified examples of fine pieces. [Figure 11] 10(a) to 10(c) are schematic diagrams showing still other modified examples of fine pieces. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of an adhesive film and a method for manufacturing an adhesive film according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0020] In the following description, the same elements are designated by the same reference numerals, and redundant explanations are omitted. Dimensions and dimensional ratios in the drawings are for convenience only and do not necessarily reflect actual dimensions. In this specification, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. The upper or lower limit of a numerical range described in stages in this specification may be replaced with the upper or lower limit of a numerical range of another stage. [Adhesive film composition]

[0021] Fig. 1 is a perspective view showing an adhesive film according to one embodiment of the present disclosure. Fig. 2 is a plan view showing the adhesive film. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2, and Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. For ease of explanation, Fig. 2 shows the configuration of the adhesive film with the cover film removed.

[0022] As shown in FIGS. 1 to 4, the adhesive film 1 is composed of a release film 2, an adhesive layer 3, a cover film 4, and a support film 5. The adhesive film 1 is a joining member used, for example, to fix electronic components used in semiconductor devices or to connect circuit components together. In this embodiment, the adhesive film 1 is exemplified by a conductive adhesive film in which conductive particles are contained in the adhesive layer 3. The adhesive film 1 is stored in a roll state wound around a reel (not shown), for example, as shown in FIG. 1. The length of the adhesive film 1 is, for example, 1 m to 400 m. The width of the adhesive film 1 is determined by the width of the release film 2 and is, for example, 5 mm to 300 mm.

[0023] Here, the release film 2 is a long film extending in one direction. The release film 2 is made of a resin material such as polyethylene terephthalate (PET), polyethylene, or polypropylene. One surface 2a of the release film 2 may be subjected to a surface treatment such as a release treatment or a plasma treatment. The width of the release film 2 is greater than the width of the adhesive layer 3 (the length of the long side of a main body portion 3A described below). As a result, in the width direction of the adhesive film 1, the release film 2 has a main body portion 2A that overlaps with the adhesive layer 3 and an overhanging portion 2B that overhangs beyond the adhesive layer 3, as shown in FIG. 2. As shown in FIGS. 2 and 3, the main body portion 2A has the same shape as the adhesive layer 3 (the shapes of the main body portion 3A and the fine pieces 3B described below) and supports the entire adhesive layer 3.

[0024] As shown in Figures 2 and 4, the overhanging portions 2B overhang on both sides of the adhesive layer 3 in the width direction of the adhesive film 1. The overhanging portions 2B have the function of enhancing the protective effect of the adhesive layer 3. The overhanging portions 2B can also be used as a gripping area for the adhesive film 1 when using it, or as an area for arranging a positioning marker. The positioning marker may be, for example, a through hole. The overhanging width of the overhanging portions 2B is not particularly limited, but is, for example, 5 mm to 10 mm. The overhanging width of the overhanging portions 2B may be 1 mm to 5 mm, or 10 mm to 20 mm.

[0025] The release film 2 may be optically transparent. In this case, when using the adhesive film 1, it becomes possible to check the position of the adhesive layer 3 from the release film 2 side using an imaging device or the like, and the adhesive layer 3 can be attached in a state where it is positioned with high precision relative to the adherend. The transmittance of the release film 2 can be, for example, 15% to 100%. The transmittance of the release film 2 may be 15% to 99%, or may be 16% to 98%. The transmittance of the release film 2 can be obtained by setting a test piece of the release film 2 cut into a 50 mm x 50 mm square in a haze meter (for example, NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) and measuring the total light transmittance of the test piece.

[0026] The haze value of the release film 2 can be, for example, 3% to 100%. The haze value of the release film 2 may be 3% to 99%, or may be 4% to 99%. The haze value of the release film 2 can be obtained by setting a test piece of the release film 2 cut into a 50 mm x 50 mm square in a haze meter (for example, NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) and measuring the haze value of the test piece.

[0027] The adhesive layer 3 is laminated on one surface 2a of the release film 2. Here, the adhesive layer 3 has a plurality of main body portions 3A arranged at a distance from each other in the extending direction of the release film 2, and strip-shaped fine pieces 3B extending in the in-plane direction of the release film 2 in each of the main body portions 3A. In the example of FIG. 2, the main body portions 3A are rectangular in plan view and are arranged at regular intervals in the extending direction of the release film 2. The main body portions 3A may also be arranged at random intervals in the extending direction of the release film 2.

[0028] The long sides of the main body portion 3A extend in the width direction of the adhesive film 1, and the short sides of the main body portion 3A extend in the length direction of the adhesive film 1. The length of the long sides of the main body portion 3A is the width of the release film 2 minus the width of the two overhanging portions 2B, 2B. The length of the long sides of the main body portion 3A is, for example, 30 mm to 40 mm. The length of the long sides of the main body portion 3A may be 5 mm to 30 mm, or may be 40 mm to 60 mm. The length of the short sides of the main body portion 3A is, for example, 10 mm to 20 mm. The length of the short sides of the main body portion 3A may be 5 mm to 10 mm, or may be 20 mm to 60 mm.

[0029] The distance between the main body portions 3A, 3A in the extending direction of the release film 2 is, for example, 0.1 mm to 30 mm. The distance between the main body portions 3A, 3A may be 0.5 mm or more, 0.8 mm or more, 1.0 mm or more, or 3.0 mm or more. The distance between the main body portions 3A, 3A may be 5.0 mm or less, 8.0 mm or less, 10 mm or less, or 30 mm or less. The distances between all of the main body portions 3A, 3A may be equal to each other or may be different from each other.

[0030] The fine pieces 3B are adhesive portions corresponding to fine wiring structures in the adherend. The shape, dimensions, and number of the fine pieces 3B are appropriately set according to the mode of the adherend. In the example of FIG. 2, twelve fine pieces 3B are provided, three at each center of the long and short sides of the main body portion 3A. Here, the long and short sides of the main body portion 3A are cut out in a comb-like shape toward the center of the main body portion 3A, and each fine piece 3B has a rectangular band shape. The length of the fine pieces 3B is, for example, 1 mm to 5 mm. The width of the fine pieces 3B is, for example, 1 mm to 5 mm. The lengths of the fine pieces 3B do not need to be the same. For example, fine pieces 3B of random lengths may be combined.

[0031] The adhesive constituting the adhesive layer 3 may be a conductive adhesive. The conductive adhesive may contain conductive particles. The conductive adhesive may have anisotropic conductivity or non-anisotropic conductivity (e.g., isotropic conductivity). The conductive adhesive may be an anisotropic conductive adhesive film or a non-anisotropic conductive adhesive film. The adhesive component may be, for example, a thermosetting adhesive component. The thermosetting adhesive component contains, for example, a thermosetting resin such as an epoxy resin and a curing agent. The thermosetting adhesive component may contain a thermoplastic resin, a coupling agent, a filler, etc., as necessary.

[0032] The adhesive component may be, for example, a photocurable adhesive component. The photocurable adhesive component may be, for example, a radical curable adhesive component. The radical curable adhesive component contains, for example, a radical polymerizable compound and a radical polymerization initiator. The radical curable adhesive component may contain a thermoplastic resin, a coupling agent, a filler, etc., as necessary. The content of the adhesive component may be 75 to 98% by volume based on the total volume of the adhesive.

[0033] Examples of conductive particles include metal particles such as Au, Ag, Ni, Cu, Pd, solder, and carbon particles. Conductive particles may be made of transition metals such as Ni and Cu coated with precious metals such as Au and Pd. Conductive particles may have a non-conductive core made of a non-conductive material such as glass, ceramic, or resin (acrylic resin, styrene resin, silicone, etc.), and a conductive layer covering the core. In this case, the conductive layer may be made of, for example, gold, silver, copper, nickel, palladium, or an alloy thereof. Conductive particles may have an outermost layer made of precious metals, or may use heat-fusible metal particles.

[0034] The conductive particles may have an average particle size of, for example, 1 to 30 μm. The average particle size can be measured using a particle size distribution measuring device (e.g., Microtrac manufactured by Nikkiso Co., Ltd.) that uses a laser diffraction / scattering method. The content of the conductive particles in the adhesive may be 2 to 20% by volume based on the total volume of the adhesive.

[0035] The conductive particles may be dendritic (also called tree-like) particles. Dendritic conductive particles have a main axis and multiple branches branching two-dimensionally or three-dimensionally from the main axis. In dendritic conductive particles, each of the multiple branches forms a pointed protrusion. Because the protrusions are pointed, when the adhesive film 1 is used to connect circuit components, etc., the protrusions can penetrate an oxide film formed on the surface of the electrode of the circuit component.

[0036] The conductive adhesive may be any adhesive that is conductive and does not necessarily contain conductive particles. In this case, examples of conductive adhesives include those containing metal oxides such as indium tin oxide, indium oxide, and tin oxide, and conductive fibers. Examples of conductive fibers include metal fibers such as gold, silver, and platinum, and carbon fibers such as carbon nanotubes.

[0037] The cover film 4 is a long film extending in one direction, similar to the release film 2. The cover film 4 is made of a resin material such as polyethylene terephthalate (PET), polyethylene, or polypropylene. In this embodiment, as shown in Figures 3 and 4, the cover film 4 is laminated on one surface 2a of the release film 2 so as to cover the entire adhesive layer 3 including the microfibers 3B. The one surface 2a of the cover film 4 is the surface facing the release film 2 and the adhesive layer 3. The one surface 2a of the cover film 4 may be subjected to a surface treatment such as a release treatment or a plasma treatment.

[0038] 4, in this embodiment, the width of the cover film 4 is equal to the width of the release film 2 and is greater than the width of the adhesive layer 3. As a result, in the width direction of the adhesive film 1, the cover film 4 has a main portion 4A that overlaps with the adhesive layer 3 and an overhanging portion 4B that overhangs further outward than the adhesive layer 3. The adhesive layer 3 is sandwiched between the main portion 4A of the cover film 4 and the main portion 2A of the release film 2, and both sides of the adhesive layer 3 are blocked by the overhanging portions 4B of the cover film 4 and the overhanging portions 2B of the release film 2, thereby firmly protecting the entire adhesive layer 3 including the microfibers 3B.

[0039] The support film 5 is a long film extending in one direction, similar to the release film 2. The support film 5 is made of a resin material such as polyethylene terephthalate (PET), polyethylene, or polypropylene. The support film 5 may be given a color different from the release film 2 and the cover film 4 in order to distinguish it from the release film 2 and the cover film 4. The thickness of the support film 5 may be, for example, 20 μm to 100 μm in order to ensure strength.

[0040] The support film 5 is laminated on the other surface 2b of the release film 2 in an area overlapping at least a portion of the microfibers 3B. In this embodiment, as shown in Figure 4, the width of the support film 5 is equal to the length of the long side of the main body portion 3A of the adhesive layer 3. Furthermore, the center of the width of the support film 5 coincides with the center of the width of the main body portion 2A of the release film 2 and the center of the width of the main body portion 3A of the adhesive layer 3. Therefore, the support film 5 is arranged in an area overlapping with the entire main body portion 3A and the microfibers 3B of the adhesive layer 3.

[0041] In this embodiment, as described above, the main body portion 2A of the release film 2 has the same shape as the main body portion 3A and the fine pieces 3B in the adhesive layer 3, and the main body portion 2A of the release film 2 is not disposed between the main body portions 3A, 3A of the adhesive layer 3 (see FIGS. 2 and 3). Therefore, when the cover film 4 is peeled off from the release film 2 and the adhesive layer 3, the support film 5 laminated on the other surface 2b of the release film 2 can be seen from the one surface 2a of the release film 2 between the main body portions 3A, 3A. [Adhesive film manufacturing method]

[0042] Next, a method for manufacturing the above-mentioned adhesive film will be described. Fig. 5 is a flowchart of a method for manufacturing an adhesive film according to an embodiment of the present disclosure. As shown in the figure, this method for manufacturing an adhesive film includes a first laminating step (step S01), a first punching step (step S02), a second punching step (step S03), and a second laminating step (step S04).

[0043] In the first lamination step (step S01), a long adhesive layer 3 is laminated on one surface 2a of a long release film 2. In the first punching step (step S02), the release film 2 and adhesive layer 3 are punched out in a predetermined repeating pattern corresponding to the strip-shaped micro pieces 3B. In the second punching step (step S03), the release film 2 and adhesive layer 3 are punched out between the repeating patterns, and the adhesive layer 3 is half-cut in the extending direction of the release film 2. This forms a plurality of main body portions 3A arranged at regular intervals in the extending direction of the release film 2, and strip-shaped micro pieces 3B extending in the in-plane direction of the release film 2 in each main body portion 3A. In the second lamination step (step S04), a support film 5 is laminated on the other surface 2b of the release film 2 in an area overlapping at least a portion of the strip-shaped micro pieces 3B.

[0044] FIG. 6 is a schematic diagram showing an example of the configuration of a manufacturing apparatus that can be used in the manufacturing method of the adhesive film shown in FIG. 5. The punching device 11 shown in FIG. 6 includes, in order from the upstream side, a first payout roller 12, a first punching section 13, a second punching section 14, a first take-up roller 15, a second take-up roller 16, a third take-up roller 17, a second pay-out roller 18, and a third pay-out roller 19. A laminate F is paid out from the first pay-out roller 12, in which an adhesive layer 3 is laminated on one surface 2a of a release film 2. In the laminate F, the width of the adhesive layer 3 on the one surface 2a of the release film 2 is equal to the width of the release film 2. In this embodiment, a cover film K for punching, having a width equal to the width of the cover film 4 (shown in the figure), is further laminated on the one surface 2a of the release film 2 in the laminate F.

[0045] The first punching unit 13 is a section where the first punching step is carried out. The first punching unit 13 is composed of a punching blade 21 and a backing member 22. The first punching unit 13 performs punching (full cut) of the release film 2 and the adhesive layer 3 in a predetermined repeating pattern P corresponding to the strip-shaped micro pieces 3B. In the example of FIG. 6, punching by the punching blade 21 of the first punching unit 13 is carried out from the side of the punching cover film K, but the punching may also be carried out from the side of the release film 2.

[0046] FIG. 7 is a plan view of the adhesive film after the first punching step. For ease of explanation, FIG. 7 illustrates the laminate F from the adhesive layer 3 side with the punching cover film K removed. As shown in the figure, in the first punching section 13, rectangular band-shaped regions corresponding to both sides of the fine pieces 3B formed on the long and short sides of the main body portion 3A of the adhesive layer 3 are punched out of both the release film 2 and the adhesive layer 3. On the downstream side of the first punching section 13, as shown in FIG. 6, the punching cover film K is temporarily peeled off from the laminate F by auxiliary rollers 23, 23. The laminate F from which the punching cover film K has been peeled off is then transported to the second punching section 14.

[0047] The second punching section 14 is a section where the second punching step is carried out. The second punching section 14 is composed of a punching blade 24 and a backing member 25. In addition to punching (full cutting) the release film 2 and adhesive layer 3 between the repeating patterns P, P, half cutting of the adhesive layer 3 in the extending direction of the release film 2 is carried out. The punching and half cutting by the punching blade 24 of the second punching section 14 are carried out from the adhesive layer 3 side.

[0048] 8 is a plan view showing the cutting lines in the second punching step. As shown in the figure, the second punching section 14 fully cuts the release film 2 and adhesive layer 3 along a widthwise line L1 corresponding to the long side of the main body portion 3A of the adhesive layer 3, and cuts only the adhesive layer 3 along a lengthwise line L2 along the short side of the main body portion of the adhesive layer 3. By making the blade length corresponding to line L1 and the blade length corresponding to line L2 of the punching blade 24 different, it is possible to fully cut the release film 2 and adhesive layer 3 along line L1 and half-cut the adhesive layer 3 along line L2 simultaneously.

[0049] By fully cutting the release film 2 and the adhesive layer 3 at line L2, the release film 2 and the adhesive layer 3 between the main portions 3A, 3A of the adhesive layer 3 are removed. The removed portions connect to the punched portions formed in the first punching step, thereby forming fine pieces 3B on the long side of the main portion 3A of the adhesive layer 3. Downstream of the second punching section 14, as shown in FIG. 6, a punching cover film K is re-laminate on the laminate F by auxiliary rollers 26, 27. The punching cover film K laminated on the laminate F is taken up by the first take-up roller 15 downstream of the auxiliary rollers 26, 27 and removed from the laminate F.

[0050] The second winding roller 16 is located downstream of the first winding roller 15. The second winding roller 16 takes up the cut portion 3c (see FIG. 8) of the adhesive layer 3 that was half-cut in the second punching section 14 and removes it from one surface 2a of the release film 2. Here, the region of the adhesive layer 3 that is outward in the width direction from the line L1 is removed. As a result, an overhanging portion 2B is formed in the release film 2 that overhangs outward in the width direction from the adhesive layer 3.

[0051] After the cut portion 3c is removed, the laminate F is taken up by the third take-up roller 17 downstream of the second take-up roller 16. When the laminate F is taken up by the third take-up roller 17, the cover film 4 that is paid out from the second pay-out roller 18 and the support film 5 that is paid out from the third pay-out roller 19 are laminated onto the laminate F. The cover film 4 is laminated onto one surface 2a of the release film 2, and the support film 5 is laminated onto the other surface 2b of the release film 2, thereby obtaining the roll of adhesive film 1 shown in FIG. 1. [Action and effect]

[0052] As explained above, in the adhesive film 1, the main body portion 3A of the adhesive layer 3 has strip-shaped fine pieces 3B extending in the in-plane direction of the release film 2. The presence of the fine pieces 3B in the adhesive layer 3 allows for suitable connection to complex and fine adherends. Furthermore, in the adhesive film 1, a support film 5 is laminated on the other surface 2b of the release film 2 in an area that overlaps with at least a portion of the fine pieces 3B. Because at least a portion of the fine pieces 3B are supported by the support film 5, bending of the fine pieces 3B can be prevented when the adhesive film 1 is wound up during production or when the adhesive film 1 is used.

[0053] In this embodiment, the release film 2 is long, and the main body portions 3A of the adhesive layer 3 are arranged at regular intervals in the extending direction of the release film 2. This configuration enables continuous use of the adhesive layer 3 with the bending of the micro-pieces 3B suppressed.

[0054] In this embodiment, the width of the support film 5 is equal to the length of the long side of the main body portion 3A of the adhesive layer 3, and the support film 5 is arranged in an area that overlaps the entire fine piece 3B. With this configuration, the entire fine piece 3B is supported by the support film 5. Therefore, bending of the fine piece 3B can be more reliably suppressed. Furthermore, when attaching to the adherend, it is possible to suppress variations in pressure at each part of the fine piece 3B.

[0055] In this embodiment, the release film 2 has an overhanging portion 2B that overhangs outward beyond the adhesive layer 3 in the width direction of the adhesive film 1. This allows the micro-flakes 3B to be more reliably protected by the overhanging portion 2B of the release film 2. Furthermore, the convenience of the adhesive film 1 can be improved by using the overhanging portion 2B as a gripping area for the adhesive film 1 when using it, or as an area for arranging a positioning marker.

[0056] In this embodiment, a cover film 4 is laminated on one surface 2a of the release film 2 so as to cover the entire adhesive layer 3 including the fine pieces 3B. With this configuration, the support film 5 and cover film 4 can more reliably protect the fine pieces 3B. Furthermore, in this embodiment, in the width direction of the adhesive film 1, the cover film 4 has a protruding portion 4B that protrudes outward beyond the adhesive layer 3. Therefore, the cover film 4 can more reliably protect the fine pieces 3B.

[0057] In this embodiment, the adhesive film 1 is a conductive adhesive film containing conductive particles in the adhesive layer 3. Therefore, the fine pieces 3B can simultaneously establish physical and electrical connections to the adherend, which is complicated and fine.

[0058] In addition, the adhesive film manufacturing method of this embodiment combines a first punching process (step S02) in which the release film 2 and adhesive layer 3 are punched out in a predetermined repeating pattern P corresponding to the strip-shaped micro-pieces 3B, and a second punching process (step S03) in which the release film 2 and adhesive layer 3 are punched out between the repeating patterns P, P and the adhesive layer 3 is half-cut in the extension direction of the release film 2.

[0059] This makes it possible to easily form a plurality of main body portions 3A arranged at regular intervals in the extension direction of the release film 2, and strip-shaped fine pieces 3B extending in the in-plane direction of the release film 2 in each of the main body portions 3A. In the second lamination step (step S04) after punching, a support film 5 is laminated on the other surface 2b of the release film 2 in an area that overlaps with at least a portion of the strip-shaped fine pieces 3B, so that at least a portion of the fine pieces 3B is supported by the support film 5. This makes it possible to prevent the fine pieces 3B from bending. [Variations]

[0060] The present disclosure is not limited to the above-described embodiment. For example, in the above-described embodiment, the release film 2 and the cover film 4 are provided with the protruding portions 2B and 4B, but one or both of the protruding portions 2B and 4B may be omitted. The cover film 4 may be omitted, and does not necessarily have to be laminated on the one surface 2a of the release film 2.

[0061] The shape of the microfibers 3B of the adhesive layer 3 shown in FIG. 2 is merely an example, and various modifications are possible. For example, as shown in FIG. 9(a), the microfibers 3Ba may have a circular extension at the tip of a strip-shaped portion, or as shown in FIG. 9(b), the microfibers 3Bb may have a rectangular extension at the tip of a strip-shaped portion. As shown in FIG. 9(c), the microfibers 3Bc may have a triangular extension at the tip of a strip-shaped portion. Furthermore, as shown in FIG. 10(a), the microfibers 3Bd may have an inverted triangular extension at the tip of a strip-shaped portion, or as shown in FIG. 10(b), the microfibers 3Be may have a triangular shape that gradually tapers as a whole. As shown in FIG. 10(c), the microfibers 3Bf may have an inverted trapezoidal shape that gradually tapers as a whole.

[0062] Furthermore, for example, as shown in Figure 11(a), the fine pieces 3Bh may have diamond-shaped extensions at the ends of the strip-shaped portions, or as shown in Figure 11(b), the fine pieces 3Bh may have multiple rectangular extensions at the ends and middle of the strip-shaped portions. As shown in Figure 11(c), the fine pieces 3Bi may be gradually tapered only at the ends of the strip-shaped portions. In either of these embodiments, since at least a portion of the fine pieces 3B is supported by the support film 5, bending of the fine pieces 3B can be prevented when the adhesive film 1 is wound up during production or when the adhesive film 1 is used.

[0063] In the above embodiment, an adhesive film 1 was exemplified in which the release film 2 was long and the main body portions 3A of the adhesive layer 3 were arranged at regular intervals in the extending direction of the release film 2, but the configuration of the adhesive film of the present disclosure is not limited to this. For example, an adhesive film may be one in which the adhesive layer 3 has a single main body portion 3A and fine pieces 3B in the main body portion 3A that extend in the in-plane direction of the release film 2. Even with this configuration, as in the above embodiment, it is possible to prevent the fine pieces 3B from bending. [Explanation of symbols]

[0064] 1...adhesive film, 2...release film, 2B...extending portion, 2a...one side, 2b...other side, 3...adhesive layer, 3A...main body portion, 3B...fine pieces, 4...cover film, 4B...extending portion, 5...support film.

Claims

1. A release film; an adhesive layer laminated on one side of the release film, the adhesive layer has a main body portion and strip-shaped fine pieces extending in an in-plane direction of the release film in the main body portion, An adhesive film in which a support film is laminated on the other side of the release film in an area overlapping at least a portion of the fine pieces.

2. The release film is long, The adhesive film according to claim 1 , wherein the main portions of the adhesive layer are arranged spaced apart from each other in the extending direction of the release film.

3. 3. The adhesive film according to claim 2, wherein the main portions of the adhesive layer are arranged at regular intervals in the extending direction of the release film.

4. 4. The adhesive film according to claim 1, wherein the support film is disposed in an area that overlaps the entirety of the micro-pieces.

5. 5. The adhesive film according to claim 1, wherein the release film has a protruding portion that protrudes outward beyond the adhesive layer in the width direction of the adhesive film.

6. The adhesive film according to any one of claims 1 to 5, wherein a cover film is laminated on one side of the release film so as to cover the entire adhesive layer including the fine particles.

7. 7. The adhesive film according to claim 6, wherein the cover film has a protruding portion that protrudes outward beyond the adhesive layer in the width direction of the adhesive film.

8. The adhesive film according to any one of claims 1 to 7, wherein the adhesive film is a conductive adhesive film.

9. The adhesive film according to claim 8 , wherein the conductive adhesive film contains conductive particles.

10. a first lamination step of laminating an adhesive layer on one side of a release film; a first punching step of punching the release film and the adhesive layer in a predetermined pattern corresponding to the strip-shaped micro-pieces; a second punching step of punching the release film and the adhesive layer between the patterns and half-cutting the adhesive layer to form a main body portion and minute strip-shaped pieces extending in an in-plane direction of the release film in the main body portion; A method for manufacturing an adhesive film, comprising a second lamination step of laminating a support film on the other side of the release film in an area that overlaps at least a portion of the strip-shaped micro-pieces.

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