JP7800181B2 - Adhesive film and method for producing adhesive film - Google Patents

Description

This disclosure relates to an adhesive film and a method for manufacturing an adhesive film.

Conventionally, various adhesives have been used to secure electronic components used in semiconductor devices or to connect circuit components together. One form of adhesive is an adhesive film, which is an adhesive formed into a film. Adhesive films are generally provided with an adhesive layer formed on a release layer known as a separator. When connecting components using an adhesive film, the adhesive layer of the adhesive sheet is attached to one component, the release layer is then peeled off from the adhesive layer, and the other component is superimposed on the adhesive layer attached to the one component.

One known adhesive film is a conductive adhesive film that is made conductive by dispersing conductive particles in the adhesive (see, for example, Patent Document 1). Such conductive adhesive films can be used to effectively connect electronic components together, for example.

Japanese Patent Application Laid-Open No. 2013-207115

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

The present disclosure has been made to solve the above-mentioned problems, and aims to provide an adhesive film and a method for manufacturing an adhesive film that can suppress bending of micro-flakes.

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.

In this adhesive film, the main body of the adhesive layer has strip-shaped microfibers that extend 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. Furthermore, 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. Supporting at least a portion of the microfibers with the support film prevents the microfibers from bending when the adhesive film is wound up during production or when the adhesive film is used.

The release film may be long, and the main portions of the adhesive layer may be arranged spaced apart from one another in the direction in which the release film extends. The main portions of the adhesive layer may also be arranged at regular intervals in the direction in which the release film extends. This configuration allows for continuous use of the adhesive layer, with bending of the micro-flakes suppressed.

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. This more reliably prevents the microfiber from bending. Furthermore, when attaching the microfiber to the adherend, it is possible to reduce variations in pressure at each point on the microfiber.

In the width direction of the adhesive film, the release film may have an overhanging portion that extends outward beyond the adhesive layer. In this case, the overhanging portion of the release film can more reliably protect fine particles. Furthermore, the overhanging portion can be used as a gripping area for the adhesive film when in use, or as an area for locating a positioning marker, thereby improving the convenience of the adhesive film.

A cover film may be laminated on one side of the release film so as to cover the entire adhesive layer including the micro-flakes. In this case, the support film and cover film can provide even more reliable protection for the micro-flakes.

In the width direction of the adhesive film, the cover film may have an overhanging portion that extends outward beyond the adhesive layer. In this case, the cover film can more reliably protect the fine particles.

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

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 at least a portion of the strip-shaped micro-pieces.

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 microfibers, with 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 makes it possible to easily form in the adhesive layer a main body portion and strip-shaped microfibers that extend in the in-plane direction of the release film in the main body portion. In the second lamination process after punching, a support film is laminated on the other side of the release film in an area that overlaps at least a portion of the strip-shaped microfibers, so that at least a portion of the microfibers are supported by the support film. This prevents the microfibers from bending.

This disclosure makes it possible to prevent bending of micro-flakes.

FIG. 1 is a perspective view showing an adhesive film according to an embodiment of the present disclosure. FIG. 2 is a plan view of the adhesive film shown in FIG. 1 . FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. 1 is a flowchart of a method for manufacturing an adhesive film according to an embodiment of the present disclosure. 6 is a schematic diagram showing an example of the configuration of a manufacturing apparatus that is applied to the method for manufacturing the adhesive film shown in FIG. 5. FIG. 2 is a plan view of the adhesive film after the first punching step. FIG. 10 is a plan view showing cutting lines in a second punching step. 10(a) to 10(c) are schematic diagrams showing modified examples of fine particles. 10(a) to 10(c) are schematic diagrams showing other modified examples of the fine pieces. 10(a) to 10(c) are schematic diagrams showing still other modified examples of fine pieces.

Below, 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.

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.
[Configuration of adhesive film]

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

As shown in Figures 1 to 4, adhesive film 1 is composed of release film 2, adhesive layer 3, cover film 4, and support film 5. 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, adhesive film 1 is exemplified as a conductive adhesive film in which conductive particles are contained in adhesive layer 3. Adhesive film 1 is stored in the form of a roll wound around a reel (not shown), for example, as shown in Figure 1. The length of adhesive film 1 is, for example, 1 m to 400 m. The width of adhesive film 1 is determined by the width of release film 2 and is, for example, 5 mm to 300 mm.

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 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 the 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 the adhesive layer 3 and an overhanging portion 2B that overhangs the adhesive layer 3, as shown in Figure 2. As shown in Figures 2 and 3, the main body portion 2A has the same shape as the adhesive layer 3 (the shape of the main body portion 3A and micro-flakes 3B described below) and supports the entire adhesive layer 3.

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 placing a positioning marker. The positioning marker may be, for example, a through hole. There are no particular restrictions on the overhang width of the overhanging portions 2B, but it is, for example, 5 mm to 10 mm. The overhang width of the overhanging portions 2B may be 1 mm to 5 mm, or 10 mm to 20 mm.

The release film 2 may be optically transparent. In this case, when using the adhesive film 1, the position of the adhesive layer 3 can be confirmed from the release film 2 side using an imaging device or the like, allowing the adhesive layer 3 to be attached while being 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 also be 15% to 99%, or 16% to 98%. The transmittance of the release film 2 can be obtained by placing a test piece of the release film 2 cut into a 50 mm x 50 mm square in a haze meter (e.g., NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) and measuring the total light transmittance of the test piece.

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 4% to 99%. The haze value of the release film 2 can be obtained by placing 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.

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 extension 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 example of Figure 2, the main body portions 3A are rectangular in plan view and are arranged at regular intervals in the extension direction of the release film 2. The main body portions 3A may also be arranged at random intervals in the extension direction of the release film 2.

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 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 20 mm to 60 mm.

The distance between the main body portions 3A, 3A in the extension 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.

The microfibers 3B are adhesive portions that correspond to the fine wiring structure of the adherend. The shape, dimensions, and number of the microfibers 3B are appropriately set depending on the type of adherend. In the example of Figure 2, a total of 12 microfibers 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 microfiber 3B is in the shape of a rectangular band. The length of the microfibers 3B is, for example, 1 mm to 5 mm. The width of the microfibers 3B is, for example, 1 mm to 5 mm. The lengths of the microfibers 3B do not need to be the same. For example, microfibers 3B of random lengths may be combined.

The adhesive constituting 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 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.

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 radically 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.

Conductive particles may be, for example, metal particles such as Au, Ag, Ni, Cu, Pd, solder, or carbon particles. Conductive particles may be transition metals such as Ni or Cu coated with precious metals such as Au or Pd. Conductive particles may have a non-conductive core formed from a non-conductive material such as glass, ceramic, or resin (acrylic resin, styrene resin, silicone, etc.), and a conductive layer coating the surface of the core. In this case, the conductive layer may be formed from, 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.

The average particle size of the conductive particles may be, 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.

The conductive particles may be dendritic (also called tree-like) particles. Dendritic conductive particles have a main axis and multiple branches that branch off 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 the oxide film formed on the surface of the electrodes of the circuit components.

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.

Like the release film 2, the cover film 4 is a long film that extends in one direction. 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 faces 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 plasma treatment.

In this embodiment, as shown in Figure 4, the width of the cover film 4 is equal to the width of the release film 2 and 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 sealed 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.

Like the release film 2, the support film 5 is a long film that extends in one direction. The support film 5 is made of a resin material such as polyethylene terephthalate (PET), polyethylene, or polypropylene. To distinguish the support film 5 from the release film 2 and the cover film 4, the support film 5 may be given a color different from the release film 2 and the cover film 4. To ensure strength, the support film 5 may have a thickness of, for example, 20 μm to 100 μm.

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 widthwise center of the support film 5 coincides with the widthwise center of the main body portion 2A of the release film 2 and the widthwise center of the main body portion 3A of the adhesive layer 3. Therefore, the support film 5 is positioned in an area overlapping the entire main body portion 3A and the microfibers 3B of the adhesive layer 3.

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 particles 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 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.
[Method of manufacturing adhesive film]

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

In the first lamination process (step S01), a long adhesive layer 3 is laminated on one surface 2a of a long release film 2. In the first punching process (step S02), the release film 2 and adhesive layer 3 are punched out in a predetermined repeating pattern corresponding to the strip-shaped micro-flakes 3B. In the second punching process (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 extension direction of the release film 2. This forms multiple main body portions 3A arranged at regular intervals in the extension direction of the release film 2, and strip-shaped micro-flakes 3B extending in the in-plane direction of the release film 2 in each main body portion 3A. In the second lamination process (step S04), a support film 5 is laminated on the other surface 2b of the release film 2 in areas that overlap at least a portion of the strip-shaped micro-flakes 3B.

Figure 6 is a schematic diagram showing an example of the configuration of a manufacturing apparatus applicable to the adhesive film manufacturing method shown in Figure 5. The punching device 11 shown in Figure 6 includes, from upstream to downstream, 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 punching cover film K having a width equal to the width of the cover film 4 (shown) is further laminated on the one surface 2a of the release film 2 in the laminate F.

The first punching unit 13 is the part that carries out the first punching step. The first punching unit 13 is composed of a punching blade 21 and a backing member 22. The first punching unit 13 punches (full cuts) the release film 2 and adhesive layer 3 in a predetermined repeating pattern P that corresponds to the strip-shaped micro-flakes 3B. In the example shown in Figure 6, punching by the punching blade 21 of the first punching unit 13 is performed from the punching cover film K side, but punching may also be performed from the release film 2 side.

Figure 7 is a plan view of the adhesive film after the first punching step. For ease of explanation, Figure 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 areas corresponding to both sides of the microfibers 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. Downstream of the first punching section 13, as shown in Figure 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.

The second punching section 14 is the section where the second punching process 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, a half cut is made in the adhesive layer 3 in the extension direction of the release film 2. The punching and half cut by the punching blade 24 of the second punching section 14 is carried out from the adhesive layer 3 side.

Figure 8 is a plan view showing the cutting lines in the second punching process. 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 different in the punching blade 24, 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.

By fully cutting the release film 2 and adhesive layer 3 at line L2, the release film 2 and adhesive layer 3 between the main portions 3A, 3A of the adhesive layer 3 are removed. The removed portions connect with the punched portions formed in the first punching process, 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 Figure 6, a punching cover film K is re-laminated onto 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.

The second take-up roller 16 is located downstream of the first take-up roller 15. The second take-up roller 16 takes up the cut portion 3c (see Figure 8) of the adhesive layer 3 that was half-cut by the second punching section 14 and removes it from one surface 2a of the release film 2. Here, the area of the adhesive layer 3 that is outside the line L1 in the width direction is removed. This forms an overhanging portion 2B in the release film 2 that overhangs outside the adhesive layer 3 in the width direction.

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 Figure 1.
[Action and effect]

As explained above, in adhesive film 1, the main body portion 3A of adhesive layer 3 has strip-shaped microfibers 3B extending in the in-plane direction of release film 2. Having microfibers 3B in adhesive layer 3 allows for suitable connection to complex and miniaturized adherends. Furthermore, in adhesive film 1, support film 5 is laminated on the other surface 2b of release film 2 in an area that overlaps with at least a portion of microfibers 3B. Supporting at least a portion of microfibers 3B by support film 5 prevents microfibers 3B from bending when adhesive film 1 is wound up during production or when adhesive film 1 is used.

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 extension direction of the release film 2. This configuration enables continuous use of the adhesive layer 3 while suppressing bending of the micro-flakes 3B.

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 positioned in an area that overlaps the entire microfiber 3B. With this configuration, the entire microfiber 3B is supported by the support film 5. This more reliably prevents the microfiber 3B from bending. Furthermore, when attaching the microfiber 3B to the adherend, it is possible to reduce variations in pressure at each point on the microfiber 3B.

In this embodiment, the release film 2 has an overhanging portion 2B that overhangs further outward than the adhesive layer 3 in the width direction of the adhesive film 1. This allows the overhanging portion 2B of the release film 2 to more reliably protect the micro-flakes 3B. Furthermore, the overhanging portion 2B can be used as a gripping area for the adhesive film 1 when using it, or as an area for locating a positioning marker, thereby improving the convenience of the adhesive film 1.

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 microfibers 3B. With this configuration, the support film 5 and cover film 4 can more reliably protect the microfibers 3B. Furthermore, in this embodiment, the cover film 4 has a protruding portion 4B that protrudes outward beyond the adhesive layer 3 in the width direction of the adhesive film 1. This allows the cover film 4 to more reliably protect the microfibers 3B.

In this embodiment, the adhesive film 1 is a conductive adhesive film in which conductive particles are contained in the adhesive layer 3. Therefore, the micro-pieces 3B can simultaneously establish physical and electrical connections to complex and miniaturized adherends.

In addition, the adhesive film manufacturing method according to 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, with 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.

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 microfibers 3B extending in the in-plane direction of the release film 2 in each of the main body portions 3A. In the second lamination process (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 microfibers 3B, so that at least a portion of the microfibers 3B is supported by the support film 5. This makes it possible to prevent the microfibers 3B from bending.
[Modification]

The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the release film 2 and the cover film 4 have protruding portions 2B and 4B, respectively, 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.

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

Furthermore, for example, as shown in Figure 11(a), the fine pieces 3Bh may have diamond-shaped extensions at the ends of the band-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 band-shaped portions. As shown in Figure 11(c), the fine pieces 3Bi may be such that only the ends of the band-shaped portions gradually taper. In any of these embodiments, by supporting at least a portion of the fine pieces 3B with 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.

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 extension direction of the release film 2, but the configuration of the adhesive film of the present disclosure is not limited to this. For example, the adhesive film may have a single main body portion 3A in the adhesive layer 3 and fine pieces 3B in the main body portion 3A that extend in the in-plane direction of the release film 2. With this configuration, as in the above embodiment, it is possible to prevent the fine pieces 3B from bending.

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 (10)

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. 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. An adhesive film as described in claim 2, wherein the main body portions of the adhesive layer are arranged at regular intervals in the extension direction of the release film. The adhesive film according to any one of claims 1 to 3, wherein the support film is positioned in an area that overlaps the entirety of the micro-flakes. An adhesive film according to any one of claims 1 to 4, wherein the release film has an overhanging portion that overhangs outward beyond the adhesive layer in the width direction of the adhesive film. An 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 microfibers. An adhesive film as described in claim 6, wherein the cover film has an overhanging portion that overhangs outward beyond the adhesive layer in the width direction of the adhesive film. The adhesive film according to any one of claims 1 to 7, wherein the adhesive film is a conductive adhesive film. The adhesive film of claim 8, wherein the conductive adhesive film contains conductive particles. 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.