Connection film, connection structure, and method for manufacturing the same

Abstract

The present invention provides a method for manufacturing a bonding membrane with high productivity. This invention involves printing an adhesive into a predetermined shape on a release film, thereby forming a connecting film of the predetermined shape on the release film. Furthermore, a plurality of connecting films of the predetermined shape are formed along the width direction of the release film. The release film is then cut along its length direction to a predetermined width, and the plurality of release films of the predetermined width are joined together along its length. The joined release film of the predetermined width is then rolled into a core. This method achieves higher productivity.

Description

Technical Field

[0001] This technology relates to a method for manufacturing a bonding film for connecting electronic components. Prior Technology

[0002] In recent years, components in smartphones and other devices have become increasingly dense, leading to limitations in space within the casing. In particular, in camera modules, cameras (image sensors) are becoming larger and more multi-lens, requiring sufficient space in the assembly section.

[0003] Figure 24 is a perspective view schematically showing an example of a substrate for a camera module. Figure 24(A) is a perspective view schematically showing an example of a substrate with a recess (cavity) on the mounting surface. Figure 24(B) is a perspective view schematically showing an example of a substrate with a polygonal mounting surface. As shown in Figures 24(A) and 24(B), in order to ensure space, excess parts are removed, for example, the corner 101 of the substrate or FPC (Flexible Printed Circuits) is removed, and a recess 102 is provided on the mounting surface.

[0004] Substrates with such complex shapes are difficult to handle using conventional bonding films. One method for mounting complex-shaped substrates is to apply conductive paste using a distributor, but this method is difficult to control in terms of positional accuracy and overflow, and it is also difficult to achieve uniform thickness, resulting in unstable conductive connections. Furthermore, applying paste using a distributor is too time-consuming in the process, which affects yield, making it quite challenging.

[0005] Furthermore, Patent Document 1 discloses a method in which the support membrane is halved and the unwanted connecting membrane portion is removed, thereby monolithizing the connecting membrane. However, the technology described in Patent Document 1 involves material loss or an increase in the number of processes, and there is still room for improvement in terms of the manufacturability of the connecting membrane. [Previous Technical Documents] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2020-198422 Summary of the Invention

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

[0008] This technology is proposed in view of the existing situation and provides a method for manufacturing a bonding membrane that can achieve good productivity. [Technical means to solve the problem]

[0009] The manufacturing method of the bonding film in this technology involves printing an adhesive onto a release film in a specified shape, thereby forming a bonding film of a specified shape on the release film. [Effects of the Invention]

[0010] According to this technology, material loss or the increase in the number of processes can be suppressed, and good productivity of the connecting film can be obtained. Simple Explanation of the Diagram

[0011] [Figure 1] is a perspective view schematically illustrating one example of the printing step in the manufacturing method of the connecting film. [Figure 2] is a perspective view schematically illustrating one example of the drying step in a method for manufacturing a connecting membrane. [Figure 3] is a perspective view schematically showing one example of the temporary attachment step of temporarily attaching the connecting film to the substrate. [Figure 4] is a top view illustrating the cutting steps of cutting a connecting film of a specified shape. Figure 4(A) is a top view illustrating the cutting steps of obtaining a linear connecting film. Figure 4(B) is a top view illustrating the cutting steps of obtaining a single-piece connecting film. [Figure 5] is a top view illustrating the cutting steps of a connecting film without cutting a film of a specified shape. Figure 5(A) is a top view illustrating the cutting steps of a connecting film to obtain a linear shape. Figure 5(B) is a top view illustrating the cutting steps of a connecting film to obtain a single-piece shape. [Figure 6] is a top view illustrating Example 1 of manufacturing a connecting membrane with a width smaller than the longitudinal width. [Figure 7] is a top view illustrating Example 2 of manufacturing a connecting membrane with a width smaller than the longitudinal section width. [Figure 8] is a schematic diagram of the connected film stack manufactured in Manufacturing Example 2. Figure 8(A) is a top view and Figure 8(B) is a cross-sectional view. [Fig. 9](A) is a top view of one example of the connected film laminate manufactured in Manufacturing Example 2, and Fig. 9(B) is a top view of another example of the connected film laminate manufactured in Manufacturing Example 2. [Figure 10] is a top view used to illustrate another manufacturing example of the connecting membrane. [Figure 11] is a schematic perspective view of a membrane roll. [Figure 12] is a top view of the mounting surface of the camera module. [Figure 13] is a cross-sectional view at the cut line II-II shown in Figure 12. [Figure 14] is a top view of a unit region of a membrane structure. [Figure 15] is a cross-sectional view at the cut line IV-IV shown in Figure 14. [Figure 16] is a cross-sectional view showing the steps of attaching the connecting film to the camera module. [Figure 17] is a cross-sectional view showing the state of the substrate after it has been peeled off from the bonding film during the bonding step. [Figure 18] is a cross-sectional view showing the mounting steps of the flexible substrate onto the camera module. [Figure 19] is a cross-sectional view showing the connection steps of connecting the terminals of the camera module to the terminals of the flexible substrate via the connecting film. [Figure 20] is a cross-sectional view of the connection structure on which the camera module is installed. [Figure 21] is a cross-sectional view showing an example of the configuration of a connection structure with a camera module installed. [Figure 22] is a top view illustrating the fabrication of the anisotropic conductive film in the embodiment. [Figure 23] is a top view used to illustrate the fabrication of anisotropic conductive film in a conventional example. [Fig. 24] is a perspective view schematically showing an example of a substrate of a camera module. Fig. 24(A) is a perspective view schematically showing an example of a substrate with a recess (cavity) on the mounting surface. Fig. 24(B) is a perspective view schematically showing an example of a substrate with a polygonal mounting surface. Implementation

[0012] Hereinafter, with reference to the drawings, embodiments of the present invention will be described in detail in the following order. 1. Manufacturing method of the connecting membrane 2. Membrane roll 3. Manufacturing method of connecting structures 4. Example

[0013] <1. Manufacturing method of the connecting membrane> The method for manufacturing the bonding film in this embodiment involves printing an adhesive into a predetermined shape on a release film, thereby forming a bonding film of the predetermined shape on the release film. This method, compared to forming a bonding film of the predetermined shape by cutting off unwanted portions, reduces material waste and the number of processes, resulting in better manufacturability of the bonding film. Furthermore, it prevents a decrease in the strength of the release film due to cutting.

[0014] Connecting films are used to connect various electronic components. Examples include: filler films containing fillers; conductive films such as anisotropic conductive films (ACF) and isotropic conductive films; and non-conductive films (NCF).

[0015] Examples of printing methods include screen printing using a screen mask and inkjet printing using a blower to coat the adhesive. Screen printing is suitable for adhesives with insulating adhesives (ADH), and it is also suitable for paste adhesives regardless of whether solvents are used. It offers greater freedom in the design and selection of adhesive components. Inkjet printing, on the other hand, allows for direct patterning based on available data without the need for a screen. The choice between screen printing and inkjet printing can be made by considering factors such as the substrate, the properties of the adhesive, and the turnaround time. The following example of screen printing will be used to illustrate this.

[0016] Figure 1 is a perspective view schematically illustrating an example of the printing step in the manufacturing method of the bonding film. As shown in Figure 1, in the printing step, the adhesive 2 is forced through the mesh of the screen 3 by pressure generated by a squeegee or the like, and printed (coated) onto the release film 1.

[0017] As described below, the release film 1 is, for example, a substrate obtained by peeling polysiloxane. Examples of substrates include PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), and PTFE (Polytetrafluoroethylene).

[0018] Adhesive 2 can be appropriately selected from insulating adhesives such as self-curing type, light-curing type, light-heat curing type, and hot-melt type, depending on the purpose. Furthermore, adhesive 2 may also contain fillers such as conductive particles in the insulating adhesive.

[0019] The mesh cover 3 uses a screen made of synthetic fibers such as polyester, or stainless steel or various metal fibers. When the adhesive 2 contains conductive particles, it is sufficient to make the mesh size larger than the maximum diameter of the conductive particles.

[0020] Figure 2 is a perspective view schematically illustrating an example of the drying step in a method for manufacturing a bonding film. As shown in Figure 2, in the drying step, an adhesive 2 of a predetermined shape is dried, thereby forming a bonding film 4 of a predetermined shape on the release film 1. It is preferable to use an oven or dryer for drying. Furthermore, in the printing and drying steps, it is preferable to form a plurality of bonding films of predetermined shapes in the width direction of the release film 1. This allows for the efficient manufacture of strip films, as described below.

[0021] Furthermore, when a filler-containing film or conductive film of a predetermined shape is formed on the release film 1, the adhesive containing the filler or conductive particles can be printed into the predetermined shape, or the filler or conductive particles can be positioned within the film's field of view at predetermined positions on the connecting film of the predetermined shape formed by printing the insulating adhesive into the predetermined shape. The arrangement can be intentionally random or a regular arrangement. For example, a transfer method can be used for this arrangement. For example, a transfer method can be used where conductive particles are attached to a micro-adhesive layer of a transfer body, the attachment surface of the conductive particles of the transfer body is overlapped with the connecting film of the predetermined shape and pressed, thereby transferring the conductive particles to the connecting film of the predetermined shape. The transfer method is not limited to this. Furthermore, arrangement methods other than transfer are not excluded.

[0022] In this way, by using printing to uniformly coat the adhesive onto the release film in a shape that conforms to a specific design, bonding films capable of handling substrates with complex shapes can be manufactured efficiently.

[0023] Figure 3 is a perspective view schematically illustrating one example of the temporary attachment step of the connecting film to the substrate. As shown in Figure 3, the connecting film 4 of a predetermined shape is aligned and temporarily attached (attached) to the substrate 5, thereby allowing the connecting film 4 to be installed without overflowing from the substrate 5, thus enabling stable production of the mount. Furthermore, by setting alignment marks required for temporarily attaching the connecting film 4 (e.g., printing on the release film 1), the alignment accuracy can be further improved.

[0024] [Variation Example 1] As shown in Figures 1 and 2, by forming a plurality of connecting films 4 of a predetermined shape in the width direction of the release film 1, connecting films 4 of a predetermined shape can be efficiently manufactured on a long strip of release film 1. Specifically, the manufacturing method of the connecting film preferably includes the following steps: a cutting step, in which the release film 1 is cut in the length direction with a predetermined width; a connecting step, in which a plurality of release films 1 of a predetermined width are connected in the length direction; and a winding step, in which the connected release films 1 of a predetermined width are wound onto a roll core. This allows for the efficient production of film rolls.

[0025] Here, Figures 4 and 5 are used to explain the cutting steps in the modified example. Figure 4 is a top view illustrating the cutting steps of cutting a connecting film of a specified shape. Figure 4(A) is a top view illustrating the cutting steps of obtaining a linear connecting film. Figure 4(B) is a top view illustrating the cutting steps of obtaining a single-piece connecting film.

[0026] As shown in Figures 4(A) and 4(B), during the cutting step, the first-shaped connecting film 4 and the release film 1 can be cut together to form a second-shaped connecting film 4 with a width of 1 / 2 of the first shape. Alternatively, multiple of these can be arranged along the width of a single sheet. Because the sides of the elongated release film overlap with the sides of the connecting film, the connecting film 4 obtained by cutting the connecting film of the specified shape is effective for applications such as the adjacent mounting of electronic components.

[0027] Figure 5 is a top view illustrating the cutting steps of a connecting film without cutting a film of a specified shape. Figure 5(A) is a top view illustrating the cutting steps of a connecting film to obtain a linear shape. Figure 5(B) is a top view illustrating the cutting steps of a connecting film to obtain a single-piece shape.

[0028] As shown in Figures 5(A) and 5(B), in the cutting step, the release film 1 can be cut without cutting the connecting film of the specified shape, thus forming the connecting film 4 of the specified shape. Since the side of the strip release film 1 does not overlap with the side of the connecting film, it can, for example, prevent a portion of the connecting film from overflowing from the side when it is rolled into a strip and wound onto a core.

[0029] The side of the connecting film 4 can be aligned with the side of the release film 1 (the connecting film 4 and the release film 1 can be longitudinally cut simultaneously), or the connecting film 4 can be housed inside the release film 1. In this embodiment, the connecting film 4 is formed solely by printing, but it can also have a cut surface along the side of the release film 1. Regarding the cut surface along the side of the release film 1, as described above, the side of the connecting film 4 is substantially aligned with the side of the release film 1. When the connecting film 4 is formed by printing, the resin end of the connecting film 4 inside the release film 1 has a protrusion or becomes blurred. Furthermore, regarding the case of the connecting film 4 being formed by printing, this can be confirmed by the fact that the resin side of the connecting film 4 is not straight relative to the side of the release film 1. Moreover, the term "blurred" refers to the appearance characteristic of printing, such as the side of the connecting film 4 appearing meandering or the thickness of the end being uneven when viewed from above. It also possesses the characteristics observed under a microscope.

[0030] [Variation Example 2] Furthermore, by creating gaps in the width direction of the release film and forming a rectangular connecting film in the length direction, and then cutting the release film in the length direction with a specified width, a conductive film with a width less than a specified width can be obtained. In particular, in conventional methods such as half-cutting, it is difficult to consider productivity and elongation in the construction of the cutting blade to manufacture a connecting film with a width of less than 0.5 mm. However, by combining printing and slitting, a connecting film with a width of less than 0.5 mm can be easily manufactured. This is especially useful when manufacturing in long strips.

[0031] Figure 6 is a top view illustrating Example 1 of manufacturing a connecting film with a width smaller than the longitudinal cut width. As shown in Figure 6, in Example 1, an adhesive is printed on a release film 51 in the longitudinal direction with a width smaller than the longitudinal cut width s to form a connecting film 52, and the release film 51 that forms the gaps between the connecting films 52 is longitudinally cut into S1 to S5.

[0032] According to Manufacturing Example 1, a connecting film smaller than the longitudinal cut width can be manufactured in a single longitudinal cut step, and narrow connecting films can be manufactured more simply than the conventional method of using both half-cut and longitudinal cut. Furthermore, in Manufacturing Example 1, since the longitudinal cut is performed along the length direction with release film 51 at both ends of the longitudinal cut width s, curling or wrinkling during longitudinal cutting can be prevented. Also, since the connecting film does not contact the longitudinal cutter, adhesion problems are expected to be easily avoided. Here, "curling" refers to the state where the connecting film separates from the release film, and "wrinkling" refers to the state where lines caused by curling or other defects are observed in the connecting film.

[0033] Figure 7 is a top view illustrating manufacturing example 2 of a connecting film with a width smaller than the longitudinal section width. As shown in Figure 7, in manufacturing example 2, an adhesive is printed on a release film 53 with a specified width in the length direction, and longitudinal sections S1 to S5 are made on the adhesive and the release film 53 which becomes a void, to form a connecting film 54 with a width smaller than the longitudinal section width s.

[0034] Compared to Manufacturing Example 1, in Manufacturing Example 2, for example, the printing width of the adhesive can be increased to twice the longitudinal cutting width. Furthermore, in Manufacturing Example 2, the film is cut along its length with one end of the longitudinal cutting width s serving as the release film 53 as a gap and the other end as the adhesive. Here, the width of the connecting film 54 relative to the longitudinal cutting width s is preferably 0.125 to 0.75, more preferably 0.25 to 0.6. This suppresses warping or wrinkling during longitudinal cutting. Also, since the width of the adhesive film can be adjusted so that a portion of the printing width overlaps with the longitudinal cutting width, it is possible to obtain an adhesive film with a narrower width than in Manufacturing Example 1. Thus, through Manufacturing Examples 1 and 2, a connecting film with a narrower width than the release film 1 that is longitudinally cut and rolled onto a roll can be obtained.

[0035] Figure 8 schematically illustrates the laminated connecting film manufactured in Manufacturing Example 2. Figure 8(A) shows a top view, and Figure 8(B) shows a cross-sectional view. As shown in Figures 8(A) and 8(B), the side surface of the connecting film 54 manufactured in Manufacturing Example 2 is composed of a printed side 55 and a longitudinally cut side 56. The printed side 55 and the longitudinally cut side 56 can be observed under a microscope, and differences can be identified based on the following: for example, the resin end of the printed side has a protrusion or is blurred, while the longitudinally cut side is a cut surface and is relatively sharp. Furthermore, if the thickness of the connecting film is compared, the thickness of the printed end has a larger difference, while the thickness of the longitudinally cut end has a smaller and more stable difference. Therefore, it can be seen that when compared using observation under a microscope, the printed end is relatively rough, while the longitudinally cut end is relatively smooth.

[0036] Figure 9(A) and Figure 8(A) are both top views showing one example of the bonding film laminate manufactured in Manufacturing Example 2, and Figure 9(B) is a top view showing another example of the bonding film laminate manufactured in Manufacturing Example 2. As shown in Figure 9(A), the longitudinally cut side 56 of the bonding film 54 coincides with the side of the release film 53. Here, the longitudinally cut bonding film 54 can also be rewound onto another release film 57. In this way, as shown in Figure 9(B), the bonding film 54 can be positioned at the center of the width direction of the release film 57. By rewinding the bonding film in this way, the position of the release film in the width direction can be changed. In this way, for example, it can be prevented that a portion of the bonding film overflows from the side when it is stretched into a strip and wound onto a core.

[0037] Figure 10 is a top view illustrating another manufacturing example of the connecting film. As shown in Figure 10, for example, adhesive can be printed on the release film 58 along its length at a first predetermined width of connecting films 59-61, a second predetermined width of connecting films 62-63, and a third predetermined width of connecting films 64-66. The release film 58 is then longitudinally cut S1-S5, thereby forming connecting films 59-66 of different widths from a single sheet. Alternatively, these connecting films of different widths can be halved at predetermined lengths to create individual sheets of connecting films of different widths. These individual sheets are then transferred to predetermined positions on another release film and combined to form a connecting film of a predetermined shape on the release film. While a complex form is used here as an example, even for simpler forms or combinations, individual sheets can be formed simultaneously during rewinding by halving and reattaching to another release film at predetermined intervals. Thus, by combining printing and slitting, connecting films of different widths can be easily produced. Therefore, the manufacturing process for connecting films with different designs or connecting films of shapes formed by combining individual pieces is simpler than conventional half-cutting methods, which can reduce material waste and achieve good productivity.

[0038] <2. Membrane roll packaging> Figure 11 is a schematic perspective view of a membrane roll. As shown in Figure 11, the membrane roll system is formed by rolling a membrane structure onto a core 20. The membrane structure includes a strip substrate 21 and connecting membranes 22 and 23 formed on the substrate 21. The core 20 has a shaft hole for inserting a rotating shaft for rotating the roll, and connects to one end of the membrane structure along its length to wind the membrane structure. There is no particular limitation on the length of the membrane structure rolled onto the membrane roll, but suitable lengths are 5 m or more, 10 m or more, 50 m or more, and 5000 m or less, 500 m or less, 300 m or less, and 100 m or less. For example, in cases where the length exceeds 300 m, it can also be connected to form a longer strip.

[0039] The substrate 21 is a support film formed by molding the release film 1 into a strip and supporting the connecting films 22 and 23. Examples of substrate 21 include PET, PMP, and PTFE. Furthermore, the substrate 21 may be obtained by peeling at least the surface of the connecting films 22 and 23 with, for example, polysiloxane.

[0040] There is no particular limitation on the thickness of the substrate. For separation purposes, the lower limit of the substrate thickness is preferably 10 μm or more, more preferably 25 μm or more, and even more preferably 38 μm or more. Regarding the upper limit of the substrate thickness, if it is too thick, there is a concern that it may exert excessive pressure on the bonding membrane; therefore, it is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 75 μm or less. It can also be set to 50 μm or less.

[0041] Furthermore, there is no particular limitation on the width of the substrate. The lower limit of the substrate width can be 0.5 mm or more, and for the purpose of rewinding, it is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 4 mm or more. Regarding the upper limit of the substrate width, if it is too large, there are concerns that it will be difficult to handle and process, so it is preferably 500 mm or less, more preferably 250 mm or less, and even more preferably 120 mm or less.

[0042] The following example illustrates the use of anisotropic conductive films containing conductive particles in insulating adhesives as connecting films. The lower limit of the thickness of the anisotropic conductive film can be, for example, the same as the diameter of the conductive particles, preferably 1.3 times or more the diameter of the conductive particles, or 2 μm or more, with 10 μm or more being preferred. Furthermore, the upper limit of the thickness of the anisotropic conductive film can be, for example, 40 μm or less, or less than twice the diameter of the conductive particles. Additionally, an adhesive layer or layer without conductive particles can be laminated onto the anisotropic conductive film; the number of layers or the number of laminated layers can be appropriately selected according to the object or purpose. Furthermore, the insulating resin used as the adhesive layer or layer can be the same as that used in the anisotropic conductive film. The conductive particles can be dispersed in the resin or arranged in the resin. Furthermore, when the conductive particles are dispersed in the resin, they can also be separated without contact. The thickness of the anisotropic conductive film is not particularly limited, similar to that of conventional adhesive films. The lower limit can be 2 μm or more, preferably 5 μm or more, and the upper limit can be 200 μm or less, preferably 100 μm or less. Furthermore, the anisotropic conductive film can also be further laminated with adhesive films or bonding films. Here, the connecting film refers to a film that is placed on a release film and then bonded to an object to be connected, thus separating the connecting film into a single unit.

[0043] As conductive particles, those used in known anisotropic conductive films can be appropriately selected. Examples include: metal particles such as nickel, copper, silver, gold, and palladium; alloy particles such as solder; and metal-coated resin particles obtained by coating the surface of resin particles such as polyamide and polybenzoguanamine with metals such as nickel. Insulation treatment of the surface can also be performed to a degree that does not impede conductivity. Furthermore, protrusions can be incorporated into the surface shape.

[0044] There is no particular limitation on the particle size of the conductive particles. The lower limit of the particle size can be 1 μm or more, preferably 2 μm or more. For example, from the viewpoint of the capture efficiency of conductive particles in the connecting structure, the upper limit of the particle size is preferably 50 μm or less, and even more preferably 20 μm or less. Furthermore, the particle size of the conductive particles can be set as the value obtained by measuring with an image-type particle size analyzer (for example, FPIA-3000: manufactured by Malvern Instruments Ltd). The number is preferably 1000 or more, and more than 2000 is preferred.

[0045] Insulating adhesives (insulating resins) can be made from known insulating adhesives. Examples of curing types include thermosetting, photosetting, and combined photo-thermal curing types. Examples include: photoradical polymerization resin compositions containing (meth)acrylate compounds and photoradical polymerization initiators; thermoradical polymerization resin compositions containing (meth)acrylate compounds and thermoradical polymerization initiators; thermocationic polymerization resin compositions containing epoxy compounds and thermocationic polymerization initiators; and thermoanionic polymerization resin compositions containing epoxy compounds and thermoanionic polymerization initiators. Furthermore, known adhesive compositions can also be used. In the case of hot-melt adhesives, compositions disclosed in Japanese Patent Application Publication No. 2014-060025 can be used.

[0046] The following example illustrates a thermally free radical polymerized insulating adhesive containing a film-forming resin, an elastomer, a (meth)acrylic acid monomer, a polymerization initiator, and a silane coupling agent. Furthermore, the term "(meth)acrylic acid monomer system" encompasses either acrylic acid monomers or methacrylic acid monomers.

[0047] There are no particular limitations on the type of film-forming resin used; examples include phenoxy resins, unsaturated polyester resins, saturated polyester resins, urethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefin resins. One type of film-forming resin can be used alone, or two or more can be used in combination. Phenoxy resins are particularly preferred in terms of film-forming properties, processability, and bonding reliability. Phenoxy resins are resins synthesized from bisphenol A and epichlorohydrin; appropriately synthesized resins or commercially available products can be used. There are no particular limitations on the content of the film-forming resin; however, a content of 10% to 60% by mass is preferred.

[0048] There are no particular limitations on what can be used as an elastomer; examples include polyurethane resin (polyurethane-based elastomer), acrylic rubber, polysiloxane rubber, butadiene rubber, etc.

[0049] There are no particular limitations on the (meth)acrylic acid monomer; for example, it can be a monofunctional (meth)acrylic acid monomer or a polyfunctional (meth)acrylic acid monomer with two or more functions. From the viewpoint of stress relief of the polymer, it is preferable that at least 80% by mass of the (meth)acrylic acid monomer in the insulating adhesive is a monofunctional (meth)acrylic acid monomer. Furthermore, from the viewpoint of adhesion, the monofunctional (meth)acrylic acid monomer is preferably carboxylic acid-containing. Also, the molecular weight of the carboxylic acid-containing monofunctional (meth)acrylic acid monomer is preferably 100-500, more preferably 200-350. Furthermore, the content of the carboxylic acid-containing monofunctional (meth)acrylic acid monomer in the insulating adhesive is preferably 3%-20% by mass, more preferably 5%-10% by mass.

[0050] There are no particular limitations on the polymerization initiator, as long as it can cure the (meth)acrylic acid monomer at the specified temperature during hot pressing. Examples of organic peroxides include lauryl peroxide, butyl peroxide, benzyl peroxide, dilauryl peroxide, dibutyl peroxide, dicarbonate peroxide, and benzoyl peroxide. One of these can be used alone, or two or more can be used in combination. There are no particular limitations on the content of the polymerization initiator in the insulating adhesive, but it is preferably 0.5% to 15% by mass.

[0051] There are no particular limitations on the silane coupling agent used; examples include epoxy-based silane coupling agents, acrylic-based silane coupling agents, thiol-based silane coupling agents, and amine-based silane coupling agents. The content of the silane coupling agent in the insulating adhesive is not particularly limited, but is preferably 0.1% to 5.0% by mass.

[0052] <3. Manufacturing Method of Connecting Structures> The manufacturing method of the connecting structure according to this embodiment includes the following steps: an attachment step, in which a connecting film having a unit area having a predetermined length in the length direction of the substrate and a predetermined width in the width direction of the substrate is attached to a first electronic component or a second electronic component having a plurality of terminal rows from a membrane structure having a strip substrate and a connecting film formed on the substrate; and a connection step, in which the terminals of the first electronic component and the terminals of the second electronic component are connected via the connecting film; and the membrane structure has non-attached portions in the unit area other than the corresponding portions of the plurality of terminal rows, where the connecting film is not attached. Therefore, existing mounting equipment can be used to mount electronic components with a plurality of terminal rows on the mounting surface. Furthermore, in the attachment step, the connecting film can be attached once instead of attaching the connecting film multiple times for each plurality of terminal rows.

[0053] Here, "unit area" refers to an area with a specified length along the length of the substrate, such as a rectangular area. "Non-attached area" refers to the area within the unit area where the bonding film is not attached to the electronic component; for example, a gap where the bonding film is absent.

[0054] Examples of first electronic components include: mounting surfaces composed of a plurality of protrusions with terminal rows on the protrusions; mounting surfaces with a plurality of terminal rows on a flat surface; and mounting surfaces with a recess in the center and terminal rows formed on the periphery. A first electronic component with a recess in the center of the mounting surface may have the following characteristics: for example, a rectangular mounting surface, and terminal rows on two opposing sides, two adjacent sides (L-shaped), or three sides (U-shaped, C-shaped) of the periphery of the recess. Furthermore, the terminal rows may also be located around the entire periphery. The periphery of these recesses and the terminal rows may be configured only in a parallel or perpendicular manner, but are not limited to this and can be appropriately adjusted according to the object. Therefore, the shape of the unit area of ​​the connecting film is also appropriately adjusted accordingly.

[0055] Furthermore, the shape of the mounting surface can be not only rectangular, but also, for example, curved shapes, circles, polygons, etc. Curved shapes, in particular, are easier to form by printing compared to post-film processing, and are therefore sometimes preferred. Also, the mounting surface may have holes that expose the substrate, partially separated from the periphery of the outer shape. Furthermore, the shape of the holes can be not only rectangular, but also, for example, curved shapes, circles, polygons, etc. Such shapes are required when the design involves other parts in the mounting surface not being in contact with the connecting film. Furthermore, the shape of the mounting part having the mounting surface can be the same as the mounting surface, or it can be a different shape. It can be either the first electronic component or the second electronic component, or both (not shown).

[0056] When the first electronic component has a recess at the center of the mounting surface, the membrane structure may have a non-attached portion in the direction from the periphery of the unit area to the center of the unit area. This prevents the recess from filling with gas, which could reduce the reliability of the connection.

[0057] When the unit area of ​​the membrane structure is rectangular, the non-attached portion can be formed in the direction from the center of at least one side of the unit area to the center of the unit area. In this way, a first electronic component having a mounting surface with terminal rows formed on three sides (U-shape) around the periphery of the recess can be installed.

[0058] Furthermore, when the unit area of ​​the membrane structure is rectangular, the non-attached portion can also be formed in the unit area from the center of the substrate in the width direction to the length direction of the substrate. In this way, a first electronic component having a mounting surface with terminal rows formed on two opposing sides of the periphery of the recess can be installed.

[0059] Furthermore, within a unit area of ​​the membrane structure, a connecting film composed of the following attachment portions can also be printed: such as hexagonal, octagonal, dodecagonal, or other polygonal shapes; U-shaped shapes; or U-shaped, C-shaped, or cylindrical shapes composed of curves. The attachment portions of the connecting film can also be shapes that combine straight lines and curves. As mentioned above, in cases involving complex shapes, the film can be segmented and discontinuous. The segmentation point can be identified based on the presence of characteristics substantially similar to the longitudinally cut end. It is distinguished from films formed solely by printing by having both a printed end and a longitudinally cut end.

[0060] Preferably, in a unit area, at least a portion of the attachment portion of the membrane structure has the same shape as the mounting surface of the first or second electronic component. That is, the attachment portion of the connecting membrane conforms to the shape of the mounting surface; for example, it can be rectangular, curved, circular, polygonal, or a partially missing U-shaped, C-shaped, or other similar shape. By conforming the shape of the attachment portion of the connecting membrane to the shape of the mounting surface, excessive overflow of the connecting membrane from the mounting surface can be prevented. This facilitates the handling of the electronic components to be mounted, improves workability, prevents obstruction of subsequent steps, and ultimately reduces overall manufacturing costs.

[0061] There are no particular restrictions on the first and second electronic components; they can be selected appropriately according to the purpose. Examples of first electronic components include: ceramic substrates, rigid substrates, flexible printed circuits (FPCs), glass substrates, plastic substrates, resin multilayer substrates, IC (Integrated Circuit) modules, and IC chips. Similarly, examples of second electronic components include: ceramic substrates, rigid substrates, flexible printed circuits (FPCs), glass substrates, plastic substrates, and resin multilayer substrates.

[0062] In functional modules such as camera modules, ceramic substrates are sometimes used due to their excellent electrical and thermal insulation properties. Ceramic substrates have advantages such as excellent dimensional stability when miniaturized (e.g., below 1 cm²).

[0063] There are no particular limitations on the type of bonding film; examples include anisotropic conductive films (ACF) and non-conductive films (NCF). Furthermore, there are no particular limitations on the curing type of the bonding film; examples include thermosetting types, photosetting types, and photothermal curing types. Additionally, the bonding film can also be a thermoplastic resin-based hot-melt type.

[0064] Furthermore, this technology can be used in the manufacturing methods of all electronic machines that use electrical connections, such as semiconductor devices (including driver ICs and all devices that utilize semiconductors such as optical elements, thermoelectric conversion elements, and photoelectric conversion elements), display devices (monitors, televisions, head-mounted displays, etc.), mobile devices (tablet terminals, smartphones, wearable terminals, etc.), game consoles, audio-visual equipment, camera devices (devices that use image sensors such as camera modules), electrical installations for vehicles (mobile devices), medical devices, sensor devices (touch sensors, fingerprint verification, iris verification, etc.), and home appliances.

[0065] The following is a specific example of a method for manufacturing a connection structure for mounting a camera module. The method for manufacturing the connection structure shown in the specific example includes: an attachment step of attaching a connection film to the camera module, a mounting step of mounting a flexible substrate on the camera module, and a connection step of connecting the terminals of the camera module to the terminals of the flexible substrate via the connection film.

[0066] [Camera Module] Figure 12 is a top view of the mounting surface of the camera module, and Figure 13 is a cross-sectional view at the cut line II-II shown in Figure 12. As shown in Figures 12 and 13, the camera module 10 includes: a ceramic substrate 11 having a recess (cavity) in a rectangular mounting surface; a first terminal row 12 and a second terminal row 13 formed on two opposing sides of the periphery of the recess in the rectangular mounting surface; and an image sensor 14 housed in the recess. Furthermore, in the cross-section at cut line II-II, the camera module 10 has a mounting surface with a predetermined width of 12W where the first terminal row 12 is formed and a mounting surface with a predetermined width of 13W where the second terminal row 13 is formed.

[0067] [Membrane Structures] Figure 14 is a top view of a unit region of the membrane structure, and Figure 15 is a cross-sectional view at the cut line IV-IV shown in Figure 14. As shown in Figures 14 and 15, the membrane structure includes a strip-shaped substrate 21 and connecting membranes 22 and 23 formed on the substrate 21, and has a rectangular unit region with a predetermined length 21L in the length direction and a predetermined width 21W in the width direction of the substrate 21 when viewed from above. In the unit region, the membrane structure 20 has a gap 24, which serves as a non-attached portion, from the center of the width direction of the substrate 21 to the length direction of the substrate 21. The gap 24 can be formed, for example, by masking from the center of the width direction of the substrate 21 to the length direction of the substrate 21 during screen printing. That is, the non-attached portion is formed in the unit area from the center of the substrate in the width direction and in the length direction of the substrate, and the connecting film 22 with a specified width of 22W and the connecting film 23 with a specified width of 23W are formed separately in the length direction of the substrate 21, corresponding to the first terminal row 12 and the second terminal row 13 of the ceramic substrate 11.

[0068] The widths 22W and 23W of the connecting film 22 and the connecting film 23, respectively, can be narrower, the same, or wider than the widths 12W and 13W of the mounting surface of the first terminal row 12 and the second terminal row 13, respectively.

[0069] When the width of the connecting film is narrower than the width of the mounting surface of the terminal block, excessive resin overflow from the film connector can be prevented. Therefore, excessive resin overflow can be prevented from contacting the camera module or other mounted parts, thereby improving assembly workability.

[0070] [Attachment Steps] Figure 16 is a cross-sectional view showing the attachment step of the connecting film to the camera module, and Figure 17 is a cross-sectional view showing the state after the substrate is peeled off from the connecting film during the attachment step. As shown in Figures 16 and 17, in the attachment step, the connecting films 22 and 23 of a unit area of ​​the membrane structure 20 are transferred to the camera module 10. For example, using an attachment device, the connecting films 22 and 23 of a unit area are pressed from the substrate side of the membrane structure to attach them at once to the mounting surface of the camera module 10 on the platform. After the connecting films 22 and 23 are transferred, the membrane structure is rolled up only as a substrate.

[0071] [Installation Steps] 18 is a cross-sectional view representing the mounting step of mounting a flexible substrate on the camera module. 18 , the reactive substrate 30 corresponds to the first terminal row 12 and the second terminal row 13 of the camera module 10 , and has a first terminal row 32 and a second terminal row 33 on the substrate 31 . In the mounting step, the 1st terminal row 32 and the 2nd terminal row 33 of the reactive substrate 30 are aligned with the 1st and 2nd terminal row 13 of the camera module 10 , and the reflexive substrate 30 is mounted on the camera module 10 .

[0072] [Connection Steps] 19 is a cross-sectional view representing the connection step of connecting the terminals of the camera module to the terminals of the reflex substrate via a connecting membrane. As shown in FIG. Also, according to the hardened type of the connecting membrane, heating, light irradiation, etc., harden the connecting membrane.

[0073] [Camera Module Mount] 20 represents a cross-sectional view of a connected construct mounted with a camera module. As shown in FIG. The second terminal row 13 of the camera module 10 and the second terminal row 33 of the reactive substrate 30 are further connected by means of a hardened film 23A which is hardened by the connecting film 23 . Furthermore, in the case of a hot-melt type connected film, the hardened film 23

[0074] 21 represents a cross-sectional view of a constituent of a connected construct mounted with a camera module. Mark the same symbols for configurations with the same configuration as those shown in Figures 12~20 and omit the explanation. 21 , the connection construct has: a camera module 10 having a 1st terminal row 12 and a 2nd terminal row 13 , a reactive substrate 30 having a 1st terminal row 32 and a 2nd terminal row 33 , a hardened film 22 A hardened by linking film 22 between the 1st terminal row 12 Further, the connecting construct has: a protective glass 15 fixed on a ceramic substrate 11 , and a lens 16 configured on an image sensor 14 and disposed in the housing. Also, at the flexible substrate 30 , an IC 17 for the camera module driver may be mounted in addition to a camera module mounting section.

[0075] With this type of connection structure, the distance T2 between the image sensor 14 and the lens 16 is difficult to shorten optically, but the distance T1 between the lens 16 and the flexible substrate 30 can be shortened, thereby enabling thinning. Furthermore, in the rectangular mounting surface of the connection structure, two opposing sides of the periphery of the recess of the ceramic substrate 11 are fixed by hardening films 22A and 23A, while a portion of the other two sides is not fixed. Therefore, it is possible to prevent the recess of the ceramic substrate 11 from being blocked by the substrate 31 of the flexible substrate 30, thus preventing the flexible substrate 30 from expanding due to gas influence. [Example]

[0076] <4-1. First Embodiment> The first embodiment of this technology will be described below. Anisotropic conductive paste, an evaluation substrate, and an evaluation FPC are prepared.

[0077] (Anisotropic conductive paste) Anisotropic conductive paste is prepared by adding 5 parts by weight of resin core conductive particles (Ni (substrate) / Au (surface), resin core) with an average particle size of 20 μm and 95 parts by weight of insulating adhesive to a planetary mixing device (product name: Defoaming Mixer Taro, manufactured by THINKY Corporation) and stirring for 1 minute.

[0078] The insulating adhesive is a mixed solution of ethyl acetate and toluene. This mixed solution contains, in a solids composition of 50% by mass, 47 parts by mass of phenoxy resin (trade name: YP-50, manufactured by NSCC Epoxy Manufacturing Co., Ltd.), 3 parts by mass of a monofunctional monomer (trade name: M-5300, manufactured by Toa Synthetic Co., Ltd.), 25 parts by mass of an amine ester resin (trade name: UR-1400, manufactured by Toyobo Co., Ltd.), 15 parts by mass of a rubber component (trade name: SG80H, manufactured by Nagase Chemical Co., Ltd.), 2 parts by mass of a silane coupling agent (trade name: A-187, manufactured by Momentive Advanced Materials Japan Co., Ltd.), and 3 parts by mass of an organic peroxide (trade name: Nyper BW, manufactured by Nippon Oil Co., Ltd.).

[0079] (Evaluation substrate) Alumina ceramic substrate, substrate thickness: 0.4 mm, width: 6.0 mm, terminal mounting surface: 1.0 mm × 6.0 mm, tungsten wiring, wire-to-space ratio: 100 μm / 100 μm, terminal height: 10 μm, wire-to-space ratio: 100 μm / 100 μm, with cavity structure, terminal rows located on opposite sides.

[0080] (Evaluation using FPC) Copper wiring, wire spacing = 100 μm / 100 μm, terminal height 12 μm, polyimide film thickness: 25 μm

[0081] [Example 1] In the screen printing of a mesh cover shaped to mate with the mounting surface of the evaluation substrate (within the unit area (21W, 21L: 6.0 mm) shown in Figures 14 and 15, the connecting films 22 and 23 (22W, 23W: 1.2 mm) are designated as paste passage portions), anisotropic conductive paste is applied to a release film and dried to create a monolithic anisotropic conductive film. After the monolithic anisotropic conductive film is bonded to the evaluation substrate, an evaluation FPC is mounted on it and thermo-pressed (temperature: 140°C, pressure: 1 MPa, time: 6 sec) to create the connection structure.

[0082] For the connection structure, microscopic observation of the indentation of conductive particles on the terminals from the FPC side revealed a trapping count of 25.5 conductive particles for the terminal (connection area: 200,000 μm²). Furthermore, the production of monolithic anisotropic conductive films showed good manufacturability. Additionally, linear anisotropic conductive films with a width of approximately 100 μm can also be fabricated.

[0083] [Comparative Example 1] Anisotropic conductive paste is applied to the entire surface of the release film using a coating machine and allowed to dry, forming anisotropic conductive film. Following the shape required to mate with the mounting surface of the evaluation substrate (the connecting films 22 and 23 in the unit area (21W, 21L: 6.0 mm) shown in Figures 14 and 15, with portions of 22W and 23W: 1.2 mm), the anisotropic conductive film is halved, and unwanted portions are removed, thereby creating a monolithic anisotropic conductive film. This monolithic anisotropic conductive film is then bonded to the evaluation substrate, mounted on an evaluation FPC, and hot-pressed (temperature: 140°C, pressure: 1 MPa, time: 6 sec) to create the connection structure.

[0084] For the connection structure, the indentation of conductive particles on the terminals was observed under a microscope from the FPC side. The results showed that the number of conductive particles captured for the terminal (connection area: 200,000 μm²) was 26.1. Furthermore, compared to the embodiment, the fabrication of a monolithic anisotropic conductive film requires the removal of unwanted portions, resulting in more processing steps or material loss, and thus lower productivity. Additionally, if a linear anisotropic conductive film with a width of approximately 100 μm is fabricated, the desired portions are also peeled off from the release liner during the removal of unwanted portions.

[0085] [Reference Example 1] In the screen printing of a mesh cover shaped to mate with the mounting surface of the evaluation substrate (with the connecting films 22 and 23 (22W, 23W: 1.2 mm) in the unit area (21W, 21L: 6.0 mm) shown in Figures 14 and 15, the paste passage portion is set as the connecting film portion), anisotropic conductive paste is applied to the evaluation substrate. The evaluation FPC is mounted on it and thermo-pressed (temperature: 140°C, pressure: 1 MPa, time: 6 sec) to create the connection structure.

[0086] For the connection structure, the indentation of conductive particles on the terminals was observed under a microscope from the FPC side. The results showed that the number of conductive particles captured for the terminal (connection area: 200,000 μm²) was 15.2. It is believed that this is because conductive particles entered the wiring area during coating, resulting in uneven particle density and a reduced number of particles on the terminal.

[0087] The evaluation results of Example 1, Comparative Example 1, and Reference Example 1 are shown in Table 1.

[0088] [Table 1] Example 1 Comparative Example 1 Reference Example 1 Formation method Screen printing Half cut Screen printing Forming surface Release film Release film substrate Number of particles captured [number] 25.5 26.1 15.2 Productivity good Difference -

[0089] <4-2. Second Example> In the second embodiment, a strip-shaped anisotropic conductive film with a width smaller than the slit width was fabricated using a slitting machine, and the shape of the anisotropic conductive film was evaluated. The anisotropic conductive paste used was the same as in the first embodiment, and the slitting machine used had a slit width with a lower limit of 0.4 mm.

[0090] [evaluate] The strip-shaped anisotropic conductive film was observed under a microscope and evaluated using the following indicators. Here, "curling" refers to the state in which the anisotropic conductive film separates from the release film, and "wrinkling" refers to the state in which lines caused by curling or other factors are observed in the anisotropic conductive film. A: No warping or wrinkling was found in any of the anisotropic conductive films. B: For some anisotropic conductive films, either warping or wrinkling can be observed. C: It is impossible to fabricate strip-shaped anisotropic conductive films.

[0091] [Example 11] Using a screen with multiple openings in the shape of strips with a line width of 0.1 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged on the release film, each with a line width of 0.1 mm, a length of 150 mm, and a thickness of 25 μm.

[0092] Figure 22 is a top view illustrating the fabrication of the anisotropic conductive film in the embodiment. As shown in Figure 22, in Embodiment 11, a strip-shaped anisotropic conductive film is formed by ensuring a width b of 0.35 mm on both sides of the release film portion as a gap in the width direction with a line width (a+a) of 0.1 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cut width of 0.4 mm to fabricate anisotropic conductive films with a width a of 0.05 mm and a length of 150 mm. The fabrication of this anisotropic conductive film is performed 5 times. Although some peeling was observed in some anisotropic conductive films, anisotropic conductive films with a width of 0.05 mm can be fabricated in one longitudinal cut process (Evaluation B).

[0093] [Example 12] Using a screen with multiple openings in the shape of strips with a line width of 0.2 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged on the release film, each with a line width of 0.2 mm, a length of 150 mm, and a thickness of 25 μm.

[0094] As shown in Figure 22, in Example 12, a strip-shaped anisotropic conductive film is formed by ensuring a 0.3 mm width b on both sides of the release film portion as a gap in the width direction where the line width (a+a) is 0.2 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cutting width of 0.4 mm to produce anisotropic conductive films with a width a of 0.1 mm and a length of 150 mm. This anisotropic conductive film is produced 5 times. No warping or wrinkling occurred in any of the anisotropic conductive films, and an anisotropic conductive film with a width of 0.1 mm can be produced in a single longitudinal cutting process (Evaluation A).

[0095] [Example 13] Using a screen with multiple openings in the shape of strips with a line width of 0.32 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged on the release film, each with a line width of 0.32 mm, a length of 150 mm, and a thickness of 25 μm.

[0096] As shown in Figure 22, in Example 13, a strip-shaped anisotropic conductive film is formed by ensuring a width b of 0.24 mm on both sides of the release film portion as a gap in the width direction where the line width (a+a) is 0.32 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cutting width of 0.4 mm to produce anisotropic conductive films with a width a of 0.16 mm and a length of 150 mm. This process of producing the anisotropic conductive film is repeated 5 times. No warping or wrinkling occurred in any of the anisotropic conductive films, demonstrating that anisotropic conductive films with a width of 0.16 mm can be produced in a single longitudinal cutting process (Evaluation A).

[0097] [Example 14] Using a screen with multiple openings in the shape of strips with a line width of 0.4 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged on the release film, each with a line width of 0.4 mm, a length of 150 mm, and a thickness of 25 μm.

[0098] As shown in Figure 22, in Example 14, a strip-shaped anisotropic conductive film is formed by ensuring a 0.2 mm width b on both sides of the release film portion as a gap in the width direction where the line width (a+a) is 0.4 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cut width of 0.4 mm to produce anisotropic conductive films with a width a of 0.2 mm and a length of 150 mm. This process of producing the anisotropic conductive film is repeated 5 times. No warping or wrinkling occurred in any of the anisotropic conductive films, demonstrating that anisotropic conductive films with a width of 0.2 mm can be produced in a single longitudinal cut process (Evaluation A).

[0099] [Example 15] Using a screen with multiple openings in the shape of strips with a line width of 0.48 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged with a line width of 0.48 mm, a length of 150 mm, and a thickness of 25 μm on the release film.

[0100] As shown in Figure 22, in Example 15, a strip-shaped anisotropic conductive film is formed by ensuring a 0.16 mm width b on both sides of the release film portion as a gap in the width direction where the line width (a+a) is 0.48 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cut width of 0.4 mm to produce anisotropic conductive films with a width a of 0.24 mm and a length of 150 mm. This process of producing the anisotropic conductive film is repeated 5 times. No warping or wrinkling occurred in any of the anisotropic conductive films, demonstrating that anisotropic conductive films with a width of 0.24 mm can be produced in a single longitudinal cut process (Evaluation A).

[0101] [Example 16] Using a screen with multiple openings in the shape of strips with a line width of 0.6 mm, anisotropic conductive paste is applied to the release film by screen printing and then dried, thereby forming anisotropic conductive film with multiple rectangular strips arranged on the release film, each with a line width of 0.6 mm, a length of 150 mm, and a thickness of 25 μm.

[0102] As shown in Figure 22, in Example 16, a strip-shaped anisotropic conductive film is formed by ensuring a 0.1 mm width b on both sides of the release film portion as a gap in the width direction where the line width (a+a) is 0.6 mm. Then, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and the gap width (b+b) with a longitudinal cut width of 0.4 mm to produce anisotropic conductive films with a width a of 0.3 mm and a length of 150 mm. This anisotropic conductive film is produced 5 times. Although some warping / wrinkling was observed in some of the anisotropic conductive films, anisotropic conductive films with a width of 0.3 mm can be produced in a single longitudinal cut process (Evaluation B).

[0103] [Example from Xi Zhi] Figure 23 is a top view illustrating the fabrication of the anisotropic conductive film in the conventional example. Anisotropic conductive paste is applied to the entire surface of a release film using a coating machine and allowed to dry, forming the anisotropic conductive film. Then, as shown in Figure 23, after halving H1 to H6 with a width a of 0.1 mm, longitudinal cuts S1 to S5 are made at the center of the line width (a+a) and gap width (b+b) with a longitudinal cut width of 0.4 mm, removing the anisotropic conductive film with a width b of 0.3 mm. This process is repeated five times to fabricate anisotropic conductive films with a width a of 0.1 mm and a length of 150 mm. As a result, it is not possible to fabricate the film in a single longitudinal cut process as in the example, and peeling occurs when removing unwanted portions, making it impossible to fabricate strip-shaped anisotropic conductive films (Evaluation C).

[0104] The evaluation results of Examples 11-16 and conventional examples are shown in Table 2.

[0105] [Table 2] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 1 (learned) Production method Printing + Slitting Half cut + Longitudinal section Membrane width a [μm] 50 100 160 200 240 300 100 The gap width b [μm] 350 300 240 200 160 100 300 Longitudinal width c [μm] 400 400 400 400 400 400 400 a / c 0.125 0.25 0.4 0.5 0.6 0.75 0.25 evaluate B A A A A B C

[0106] In conventional examples, it is impossible to manufacture the film using a single slitting process as in the embodiments, and peeling occurs when removing unwanted portions, making it impossible to produce strip-shaped anisotropic conductive films. On the other hand, in embodiments 11-16, by having the ratio of the width 'a' of the anisotropic conductive film to the slitting width 'c' be between 0.125 and 0.75, anisotropic conductive films with a width smaller than the slitting width can be manufactured in a single slitting process after printing. Furthermore, in embodiments 12-15, by having the ratio of the width 'a' of the anisotropic conductive film to the slitting width 'c' be between 0.25 and 0.6, peeling and wrinkling can be prevented. Moreover, although anisotropic conductive films were used for manufacturing and evaluation in the embodiments, it is presumed that the same effect can be expected for adhesive films and conductive films as well.

[0107] 1: Release film 2: Adhesive 3: Mesh cover 4: Connecting membrane 5:Substrate 10: Camera Module 11: Ceramic substrate 12: Terminal 1 13: Second terminal column 14: Image Sensor 15: Protective Glass 16: Lens 17: Camera module driver IC 20: Roll core 21: Substrate 22: Connecting membrane 23: Connecting membrane 24: Gap 30:Flexible substrate 31: Substrate 32: Terminal 1 33: Second terminal column 41: Buffer material 42: Crimping tool 43: Crimping tools 51: Release film 52: Connecting membrane 53: Release film 54: Connecting membrane 55: Printed side 56: Longitudinal section of the side 57: Release film 58: Release film 59~66: Connecting membrane 101: Corner 102: concave part

Claims

1. A method for manufacturing a bonding film, wherein an adhesive is printed onto a release film in a predetermined shape selected from at least one of a rectangle, a curved shape, a circle, a polygon, and a line shape, thereby forming a bonding film of a predetermined shape on the release film, and gaps are provided in the width direction of the release film to form a plurality of bonding films of the predetermined shape, and the release film is cut in the length direction with a predetermined width such that the ratio of the width of the bonding film to the predetermined width is 0.125 or more and 0.75 or less.

2. The method for manufacturing the connecting film as claimed in claim 1, wherein a plurality of release films of the specified width are connected in the length direction, and the release film of the specified width formed by the connection is rolled into a core.

3. The method for manufacturing the connecting film as claimed in claim 2, wherein the connecting film of the specified shape is cut when the release treatment film is cut along the length direction with a specified width.

4. The method for manufacturing the connecting film as claimed in claim 2, wherein when the release treatment film is cut along the length direction with a specified width, the connecting film of the specified shape is not cut.

5. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The adhesive contains conductive particles and forms a conductive film of a specified shape on the release film.

6. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The adhesive contains conductive particles and forms an anisotropic conductive film of a specified shape on the release film.

7. A method for manufacturing a connecting film according to any one of claims 1 to 4, wherein conductive particles are disposed at a predetermined position on a connecting film of a predetermined shape, and an anisotropic conductive film of a predetermined shape is formed on the release treatment film.

8. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The above printing is either screen printing or inkjet printing.

9. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The aforementioned connecting membrane is strip-shaped.

10. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The length of the aforementioned connecting membrane is between 5 m and 5000 m.

11. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The connecting membrane of the above-specified shape is continuous in the length direction.

12. A method for manufacturing the connecting membrane as described in any of claims 1 to 4, wherein, The connecting membrane of the above-mentioned shape is broken along its length.

13. The method for manufacturing the connecting film as claimed in claim 1, wherein a gap is provided in the width direction of the release treatment film and a rectangular connecting film is formed in the length direction, and the release treatment film is cut in the length direction with a predetermined width.

14. The method for manufacturing the connecting membrane as claimed in claim 13, wherein the membrane is cut along its length with one end of the specified width becoming the aforementioned gap and the other end becoming the aforementioned connecting membrane.

15. A method for manufacturing the connecting membrane as described in claim 13 or 14, wherein, The width specified above does not reach 0.5 mm.

16. A connecting membrane manufactured by any one of the manufacturing methods of claims 1 to 15.

17. A bonding film in which an adhesive is printed on a release film in a predetermined shape selected from at least one of a rectangle, a curved shape, a circle, a polygon, and a line shape, and a gap is provided in the width direction of the release film, wherein the ratio of the width of the bonding film to the width of the release film is 0.125 or more and 0.75 or less.

18. The connecting film of claim 17 has one side portion that coincides with the side portion of the release treatment film and is formed with a width smaller than the width of the release treatment film.

19. The connecting film of claim 17, which is housed inside the release film, with two sides of the release film exposed.

20. The connecting film of claim 17 has two sides that coincide with the two sides of the release treatment film, and the central portion of the release treatment film is exposed throughout the length direction.

21. The connecting membrane of claim 17 contains conductive particles.

22. The connecting membrane of claim 17 has conductive particles disposed at specified positions.

23. The connecting membrane, as in claim 17, is strip-shaped.

24. The connecting membrane of claim 17 has a length of 5 m or more and 5000 m or less.

25. The connecting membrane as claimed in claim 17, wherein, The connecting membrane of the above-specified shape is continuous in the length direction.

26. The connecting membrane as claimed in claim 17, wherein, The connecting membrane of the above-mentioned shape is broken along its length.

27. A connection structure comprising: a first electronic component having a first terminal, a second electronic component having a second terminal, and a hardened film formed by hardening the connection film of any one of claims 17 to 26, wherein the first terminal and the second terminal are connected by the hardened film.

28. A method for manufacturing a connecting structure, wherein a terminal of a first electronic component is connected to a terminal of a second electronic component via a connecting film of any one of claims 17 to 26.

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