Flexible circuit board, manufacturing method therefor, and electronic device including flexible circuit board

Abstract

Provided is a flexible circuit board manufacturing method wherein raw films are bonded to both sides of a carrier tape and a flexible circuit board is manufactured on the basis of each raw film. The flexible circuit board manufacturing method comprises the steps of: forming a first raw film and a second raw film on both surfaces of a carrier tape, respectively; processing the first raw film to manufacture a first flexible circuit board including a first circuit pattern; processing the second raw film to manufacture a second flexible circuit board including a second circuit pattern; and separating the first flexible circuit board and the second flexible circuit board from the carrier tape.

Description

Flexible circuit board, method of manufacturing the same, and electronic device including said flexible circuit board

[0001] The present invention relates to a flexible circuit board manufactured using a roll-to-roll process, a method for manufacturing the same, and an electronic device including the flexible circuit board.

[0002] Due to the miniaturization and lightweighting of electronic products, flexible circuit boards are being widely used as components. These flexible circuit boards can be manufactured through a roll-to-roll (R2R) process.

[0003] Recently, due to the increasing need for thinner flexible circuit boards, the thickness of the base film used to manufacture flexible circuit boards is becoming increasingly thinner. However, if the thickness of the base film becomes thinner than the standard value, fluidity becomes unstable and creasing or folding may occur. In addition, problems such as bowing, lead delamination, and lead cracking may also occur, which can lead to many difficulties in manufacturing flexible circuit boards.

[0004] The technical problem to be solved by the present invention is to provide a method for manufacturing a flexible circuit board by laminating raw films on both sides of a carrier tape and manufacturing a flexible circuit board based on each raw film.

[0005] In addition, the technical problem to be solved by the present invention is to provide a flexible circuit board produced according to the above manufacturing method, and an electronic device including said flexible circuit board.

[0006] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0007] One aspect of the method for manufacturing a flexible circuit board according to the present invention for achieving the above technical problem comprises: a step of forming a first raw film and a second raw film on each side of a carrier tape; a step of manufacturing a first flexible circuit board including a first circuit pattern by processing the first raw film; a step of manufacturing a second flexible circuit board including a second circuit pattern by processing the second raw film; and a step of separating the first flexible circuit board and the second flexible circuit board from the carrier tape.

[0008] One side of the flexible circuit board of the present invention for achieving the above technical problem is characterized by being manufactured according to the above manufacturing method.

[0009] One aspect of the electronic device of the present invention for achieving the above technical problem is characterized by including a flexible circuit board manufactured according to the above manufacturing method.

[0010] Specific details of other embodiments are included in the detailed description and drawings.

[0011] According to the present invention, the following effects can be obtained.

[0012] First, productivity can be increased by simultaneously manufacturing multiple flexible circuit boards on both sides of the carrier tape.

[0013] Second, by providing a balance of structural and material properties on both sides of the carrier tape, deformation can be prevented during processes such as heat treatment during process flow.

[0014] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0015] FIG. 1 is a flowchart for explaining, step by step, a method for manufacturing a flexible circuit board according to some embodiments of the present invention.

[0016] FIG. 2 is a first example diagram for explaining the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0017] FIG. 3 is a first example diagram for explaining the product production method in step S110 of the manufacturing method of a flexible circuit board.

[0018] Figure 4 is a second example diagram illustrating a product production method in step S110 of a method for manufacturing a flexible circuit board.

[0019] FIG. 5 is a third example diagram illustrating the product production method in step S110 of the manufacturing method of a flexible circuit board.

[0020] Figure 6 is a second example diagram illustrating the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0021] FIG. 7 is a third example diagram illustrating the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0022] Figure 8 is an example diagram illustrating the product structure at step S130 of the method for manufacturing a flexible circuit board.

[0023] FIG. 9 is an example diagram illustrating a product production method in step S120 of a method for manufacturing a flexible circuit board.

[0024] FIG. 10 is an example diagram illustrating a product production method in step S130 of a method for manufacturing a flexible circuit board.

[0025] Figure 11 is an example diagram illustrating the product structure at step S140 of the method for manufacturing a flexible circuit board.

[0026] FIG. 12 is an example diagram illustrating the product structure at step S150 of the method for manufacturing a flexible circuit board.

[0027] FIG. 13 is a fourth example diagram illustrating the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0028] FIG. 14 is a flowchart for explaining, step by step, a method for manufacturing a flexible circuit board according to some other embodiments of the present invention.

[0029] Embodiments of the present invention will be described in detail below with reference to the attached drawings. Identical components in the drawings are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0030] Flexible circuit boards can be manufactured using a roll-to-roll (R2R) process. Flexible circuit boards can be manufactured by bonding raw films to both sides of a carrier tape and based on each raw film. Flexible circuit boards can be provided as chip-on-film (COF). Flexible circuit boards can be provided as substrates for mounting electronic components for display driving.

[0031] Hereinafter, a method for manufacturing a flexible circuit board is described. FIG. 1 is a flowchart for explaining, step by step, a method for manufacturing a flexible circuit board according to some embodiments of the present invention.

[0032] When the carrier tape and the raw film are prepared, the raw film can be formed on both sides of the carrier tape (S110). Referring to FIG. 2, a first raw film (220) can be formed on the first side (210a) of the carrier tape (210). Then, a second raw film (230) can be formed on the second side (210b) of the carrier tape (210). For example, the first raw film (220) and the second raw film (230) can be provided as a flexible copper clad laminate (FCCL).

[0033] The first surface (210a) and the second surface (210b) may be different planes of the carrier tape (210). The first surface (210a) and the second surface (210b) may be opposing planes of the carrier tape (210). The first surface (210a) may be the upper surface of the carrier tape (210), and the second surface (210b) may be the lower surface of the carrier tape (210). FIG. 2 is a first example diagram for explaining the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0034] The first direction (D1) and the second direction (D2) can form a two-dimensional plane. The first direction (D1) may be the X-axis direction and the second direction (D2) may be the Y-axis direction. The first direction (D1) may be the left-right direction and the second direction (D2) may be the front-back direction. Alternatively, the first direction (D1) may be the front-back direction and the second direction (D2) may be the left-right direction. The third direction (D3) can form a three-dimensional solid with the first direction (D1) and the second direction (D2). The third direction (D3) is a direction perpendicular to the plane formed by the first direction (D1) and the second direction (D2). The third direction (D3) may be the Z-axis direction. The third direction (D3) may be the up-down direction.

[0035] A first raw film (220) may be formed on the first surface (210a) of the carrier tape (210), and a second raw film (230) may not be formed on the second surface (210b) of the carrier tape (210). Alternatively, a second raw film (230) may be formed on the second surface (210b) of the carrier tape (210), and a first raw film (220) may not be formed on the first surface (210a) of the carrier tape (210). That is, the raw film may be formed only on one surface of the carrier tape.

[0036] The first raw film (220) and the second raw film (230) may include a base film. However, in accordance with the need for thinning of flexible circuit boards, a technological change is underway to thin the thickness of the base film. Conventionally, the thickness of the base film has mainly been 34㎛ to 38㎛, but recently, it is required that the thickness of the base film be 25㎛ or less.

[0037] However, if the thickness of the base film is formed in this way, wrinkles, folds, cracks, etc. may occur during the roll-to-roll process due to the thin thickness of the base film, and the fluidity may become unstable. In addition, the thickness of the carrier tape can be reinforced to secure a thickness suitable for roll-to-roll flow, but in this case, a bowing phenomenon may occur due to differences in physical properties and thermal shrinkage between the carrier tape and the base film. Accordingly, in the present invention, when manufacturing a flexible circuit board, a first raw film (220) and a second raw film (230) can be formed on both sides of the carrier tape (210) (S110).

[0038] Referring to FIG. 3, the first raw film (220) and the second raw film (230) can be formed simultaneously on each side (210a, 210b) of the carrier tape (210). That is, the formation of the first raw film (220) on the first side (210a) of the carrier tape (210) and the formation of the second raw film (230) on the second side (210b) of the carrier tape (210) can be performed simultaneously. FIG. 3 is a first example diagram for explaining a product production method in step S110 of a method for manufacturing a flexible circuit board.

[0039] Referring to FIGS. 4 and 5, a first raw film (220) and a second raw film (230) may be formed sequentially on each side (210a, 210b) of a carrier tape (210). Referring to FIG. 4, the first raw film (220) may first be formed on the first side (210a) of the carrier tape (210), and then the second raw film (230) may be formed on the second side (210b) of the carrier tape (210). FIG. 4 is a second example diagram for explaining a product production method in step S110 of a method for manufacturing a flexible circuit board.

[0040] Alternatively, referring to FIG. 5, a second raw film (230) may first be formed on the second side (210b) of the carrier tape (210), and then a first raw film (220) may be formed on the first side (210a) of the carrier tape (210). FIG. 5 is a third example diagram for explaining a product production method in step S110 of a method for manufacturing a flexible circuit board.

[0041] Referring again to Fig. 2, the explanation will be provided.

[0042] A carrier tape (210) may be formed between a first raw film (220) and a second raw film (230). The carrier tape (210) may be placed below the first raw film (220). The carrier tape (210) may be placed on top of the second raw film (230).

[0043] The carrier tape (210) may be made of an insulating resin. For example, the carrier tape (210) may be made of at least one synthetic resin selected from polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). However, the synthetic resin constituting the carrier tape (210) is not limited to these, and any synthetic resin having insulating properties is possible.

[0044] The carrier tape (210) may be provided with a certain thickness. In the present invention, the flexible circuit board may be manufactured using a roll-to-roll process. However, for raw materials to flow through the roll-to-roll, the thickness of the raw materials must satisfy a reference range. The raw materials may include a carrier tape (210), a first raw film (220), and a second raw film (230). Preferably, the carrier tape (210) may be provided with a thickness of 25 μm to 75 μm.

[0045] A first raw film (220) may be formed on a carrier tape (210). The first raw film (220) may be formed on a first surface (210a) of the carrier tape (210). For example, the first raw film (220) may be laminated to the first surface (210a) of the carrier tape (210). In this case, the carrier tape (210) may be provided as a stiffener. The first raw film (220) may include a first substrate layer (221) and a first metal layer (222).

[0046] The first substrate layer (221) may be provided as a base film having a constant thickness. The first substrate layer (221) may be made of an insulating resin. For example, the first substrate layer (221) may be made by including at least one polymer material selected from polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), epoxy, and glass fiber. However, the polymer material constituting the first substrate layer (221) is not limited thereto, and any material is possible as long as it is a polymer material with insulating properties.

[0047] The first substrate layer (221) may be made of an insulating resin, similar to the carrier tape (210). The first substrate layer (221) may be made of a synthetic resin different from that of the carrier tape (210). For example, the first substrate layer (221) may be made of polyimide (PI) resin, and the carrier tape (210) may be made of polyethylene terephthalate (PET) resin. However, it is not limited thereto, and it is also possible for the first substrate layer (221) to be made of a synthetic resin of the same type as that of the carrier tape (210).

[0048] The first substrate layer (221) may be provided with a certain thickness. The first substrate layer (221) may be provided with a specified thickness so that the thickness of the raw material is suitable for flow through roll-to-roll. The first substrate layer (221) may be provided with a thickness thinner than that of the carrier tape (210). Alternatively, the first substrate layer (221) may be provided with a thickness equivalent to that of the carrier tape (210). The first substrate layer (221) may be provided with a thickness of 25 μm or less. In order for the first substrate layer (221) to support the circuit pattern obtained from the first metal layer (222), mechanical properties such as rigidity and the coefficient of thermal expansion (CTE) are required. However, if the first substrate layer (221) is provided with a thickness of less than 5 μm, the mechanical properties may be insufficient. Accordingly, preferably, the first substrate layer (221) may be provided with a thickness of 5 μm to 25 μm.

[0049] A first metal layer (222) may be formed on a first substrate layer (221). The first substrate layer (221) may be formed on a carrier tape (210), and the first metal layer (222) may be formed on the first substrate layer (221). The first metal layer (222) may be made of an electrically conductive material. For example, the first metal layer (222) may be formed from any one metal selected from conductive metals such as nickel (Ni), chromium (Cr), copper (Cu), gold (Au), silver (Ag), platinum (Pt), aluminum (Al), palladium (Pd), titanium (Ti), and tin (Sn). Alternatively, the first metal layer (222) may be formed by alloying a plurality of metals selected from the conductive metals.

[0050] The carrier tape (210) may further include an adhesive layer thereon. Referring to FIG. 6, the first adhesive layer (240) may be formed between the carrier tape (210) and the first raw film (220). Specifically, the first adhesive layer (240) may be formed between the carrier tape (210) and the first substrate layer (221). In the present invention, the carrier tape (210) having the first adhesive layer (240) formed thereon is defined as a detach carrier. FIG. 6 is a second example diagram for explaining the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0051] The first adhesive layer (240) may be provided with a certain thickness. The first adhesive layer (240) may be provided with a certain thickness considering the adhesive force between the carrier tape (210) and the first raw film (220). The first adhesive layer (240) may be provided with a thickness thinner than the carrier tape (210). The first adhesive layer (240) may be provided with a thickness thinner than the first substrate layer (221). However, it is not limited thereto, and it is also possible for the first adhesive layer (240) to be provided with a thickness equivalent to that of the first substrate layer (221). For example, the first adhesive layer (240) may be provided with a thickness of 8㎛ to 10㎛.

[0052] A detach carrier can be separated from a flexible circuit board after forming a circuit pattern on a first substrate layer (221) based on a first metal layer (222). In the present invention, a flexible circuit board is defined as including the first substrate layer (221) and the circuit pattern formed thereon. The adhesive strength of the first adhesive layer (240) constituting the detach carrier must be able to prevent separation between the carrier tape (210) and the first raw film (220) during a roll-to-roll manufacturing process. Additionally, the adhesive strength of the first adhesive layer (240) must be able to smoothly separate the flexible circuit board from the detach carrier after the manufacturing process. Accordingly, the adhesive strength of the first adhesive layer (240) is preferably 15gf / cm to 40gf / cm when in the raw material state before the manufacturing process, and preferably 15gf / cm to 60gf / cm when in the finished product state after the manufacturing process.

[0053] The first raw film (220) may further include a first tiecoat layer (223). Referring to FIG. 7, the first tiecoat layer (223) may be provided as a seed layer between the first substrate layer (221) and the first metal layer (222). The first tiecoat layer (223) may be provided as a conductive layer in the form of a thin film. For example, the first tiecoat layer (223) may be formed from any one metal selected from conductive metals such as nickel (Ni), chromium (Cr), copper (Cu), gold (Au), aluminum (Al), and palladium (Pd). Alternatively, the first tiecoat layer (223) may be formed from an alloy comprising a plurality of metals selected from the conductive metals. The first tiecoat layer (223) may be formed by physical methods such as deposition, adhesion, or plating, or by chemical methods. The first tie-coat layer (223) can increase the bonding between the first substrate layer (221) and the first metal layer (222). FIG. 7 is a third example diagram for explaining the product structure at step S110 of the method for manufacturing a flexible circuit board.

[0054] Referring again to Fig. 2, the explanation will be provided.

[0055] A second raw film (230) may be formed under the carrier tape (210). The second raw film (230) may be formed on the second surface (210b) of the carrier tape (210). For example, the carrier tape (210) may be provided as a stiffener, and the second raw film (230) may be laminated with the carrier tape (210). The second raw film (230) may include a second substrate layer (231) and a second metal layer (232).

[0056] The second substrate layer (231) may be formed on the second surface (210b) of the carrier tape (210). The second substrate layer (231) may be made of a resin equivalent to that of the first substrate layer (221) and may be provided with a thickness equivalent to that of the first substrate layer (221), but the present embodiment is not necessarily limited thereto.

[0057] The second metal layer (232) may be formed on the second substrate layer (231). When arranged in a stacking order, the second metal layer (232) may be located at the bottom, the second substrate layer (231) may be stacked on the second metal layer (232), the carrier tape (210) may be stacked on the second substrate layer (231), the first substrate layer (221) may be stacked on the carrier tape (210), and the first metal layer (222) may be stacked on the first substrate layer (221). The second metal layer (232) may be formed by including a metal equivalent to that of the first metal layer (222), but the present embodiment is not necessarily limited thereto.

[0058] A second adhesive layer (250) may be provided between the carrier tape (210) and the second substrate layer (231). Referring to FIG. 6, a first adhesive layer (240) may be provided between the carrier tape (210) and the first substrate layer (221), and a second adhesive layer (250) may be provided between the carrier tape (210) and the second substrate layer (231). However, the present invention is not limited thereto. Although not shown in FIG. 6, a first adhesive layer (240) may be provided between the carrier tape (210) and the first substrate layer (221), and a second adhesive layer (250) may not be provided between the carrier tape (210) and the second substrate layer (231). Alternatively, a second adhesive layer (250) may be provided between the carrier tape (210) and the second substrate layer (231), and a first adhesive layer (240) may not be provided between the carrier tape (210) and the first substrate layer (221).

[0059] A second tie coat layer (233) may be provided between the second substrate layer (231) and the second metal layer (232). Referring to FIG. 7, a first tie coat layer (223) may be provided between the first substrate layer (221) and the first metal layer (222), and a second tie coat layer (233) may be provided between the second substrate layer (231) and the second metal layer (232). However, the present invention is not limited thereto. Although not shown in FIG. 7, a first tie coat layer (223) may be provided between the first substrate layer (221) and the first metal layer (222), and a second tie coat layer (233) may not be provided between the second substrate layer (231) and the second metal layer (232). Alternatively, a second tie coat layer (233) may be provided between the second substrate layer (231) and the second metal layer (232), and a first tie coat layer (223) may not be provided between the first substrate layer (221) and the first metal layer (222).

[0060] Meanwhile, although not illustrated in FIGS. 6 and 7, a first tie coat layer (223) and a second tie coat layer (233) may be provided, and a first adhesive layer (240) and a second adhesive layer (250) may not be provided. That is, a first tie coat layer (223) may be provided between a first substrate layer (221) and a first metal layer (222), a second tie coat layer (233) may be provided between a second substrate layer (231) and a second metal layer (232), a first adhesive layer (240) may not be provided between a carrier tape (210) and a first substrate layer (221), and a second adhesive layer (250) may not be provided between a carrier tape (210) and a second substrate layer (231).

[0061] Referring again to Fig. 1, the explanation will be provided.

[0062] When the first raw film (220) and the second raw film (230) are formed on both sides of the carrier tape (210) (S110), the first raw film (220) and the second raw film (230) are processed (S120) to form a circuit pattern on each of them (S130). Referring to FIG. 8, a first flexible circuit board (310) can be formed from the first raw film (220) on the first side (210a) of the carrier tape (210), and a second flexible circuit board (320) can be formed from the second raw film (230) on the second side (210b) of the carrier tape (210). The first flexible circuit board (310) can be formed by forming a first circuit pattern (311) on the first substrate layer (221). The second flexible circuit board (320) can be created by forming a second circuit pattern (321) on the second substrate layer (231). FIG. 8 is an example diagram illustrating the product structure at step S130 of the method for manufacturing a flexible circuit board.

[0063] The first circuit pattern (311) and the second circuit pattern (321) can be created from the first metal layer (222) and the second metal layer (232). The first circuit pattern (311) and the second circuit pattern (321) can be created using an etching method. For example, the first circuit pattern (311) and the second circuit pattern (321) can be created using photo etching. The first metal layer (222) and the second metal layer (232) can be provided with a certain thickness to accommodate the fine pitch of the circuit. Preferably, the first metal layer (222) and the second metal layer (232) can be provided with a thickness of 5 μm to 10 μm.

[0064] The first metal layer (222) and the second metal layer (232) may be provided as a seed layer or an under layer. In this case, a first circuit pattern (311) and a second circuit pattern (321) may be formed on the first metal layer (222) and the second metal layer (232). In this case, a first tie coat layer (223) and a second tie coat layer (233) may not be formed under the first metal layer (222) and the second metal layer (232). The first circuit pattern (311) and the second circuit pattern (312) may be created using a plating method. For example, the first circuit pattern (311) and the second circuit pattern (312) may be created using an additive, semi-additive, printing, coating, etc. The first metal layer (222) and the second metal layer (232) may be provided with a certain thickness to serve as a seed layer or an under layer. Preferably, the first metal layer (222) and the second metal layer (232) may be provided with a thickness of 0.5 μm to 3 μm. The first metal layer (222) and the second metal layer (232) may be removed after forming the first circuit pattern (311) and the second circuit pattern (321).

[0065] The first raw film (220) and the second raw film (230) can be processed simultaneously. Referring to FIG. 9, processing the first raw film (220) and processing the second raw film (230) can be done simultaneously. However, this is not limited thereto, and the first raw film (220) and the second raw film (230) can also be processed sequentially. The first raw film (220) can be processed first, and then the second raw film (230) can be processed. Alternatively, the second raw film (230) can be processed first, and then the first raw film (220) can be processed. FIG. 9 is an example diagram for explaining a product production method in step S120 of a method for manufacturing a flexible circuit board.

[0066] The first circuit pattern (311) and the second circuit pattern (321) may be provided with the same design. In the present invention, multiple flexible circuit boards having the same circuit pattern can be produced at once. Referring to FIG. 10, the first circuit pattern (311) and the second circuit pattern (321) may be formed symmetrically at 180 degrees around the first reference line (410) and the second reference line (420). FIG. 10 is an illustrative diagram for explaining the product production method in step S130 of the method for manufacturing a flexible circuit board.

[0067] The first reference line (410) and the second reference line (420) may be positioned in a mutually corresponding manner with respect to the carrier tape (210). The first reference line (410) and the second reference line (420) may overlap in a third direction (D3). The second circuit pattern (321) may have a design equivalent to the first circuit pattern (311) rotated 180 degrees in the horizontal direction (D1 and D2). The second circuit pattern (321) may be equivalent to a design obtained by reversing the first circuit pattern (311) front and back or left and right.

[0068] Referring again to Fig. 1, the explanation will be provided.

[0069] When a first circuit pattern (311) and a second circuit pattern (321) are formed on the first substrate layer (221) and the second substrate layer (231) (S130), a first protective layer (312) and a second protective layer (322) are formed on the first circuit pattern (311) and the second circuit pattern (321) (S140).

[0070] Referring to FIG. 11, the first protective layer (312) may cover the first circuit pattern (311). The first protective layer (312) may cover the top surface and the side surface of the first circuit pattern (311). Alternatively, the first protective layer (312) may cover only the top surface of the first circuit pattern (311). The first protective layer (312) may not cover the first circuit pattern (311) within some areas. The first protective layer (312) may not cover the first circuit pattern (311) within the inner lead area and the first circuit pattern (311) within the outer lead area.

[0071] Likewise, the second protective layer (322) may cover the second circuit pattern (321). The second protective layer (322) may cover the upper surface and the side surface of the second circuit pattern (321). Alternatively, the second protective layer (322) may cover only the upper surface of the second circuit pattern (321). The second protective layer (322) may not cover the second circuit pattern (321) within some areas. The second protective layer (322) may not cover the second circuit pattern (321) within the inner lead area and the second circuit pattern (321) within the outer lead area. FIG. 11 is an example diagram for explaining the product structure at step S140 of the method for manufacturing a flexible circuit board.

[0072] The first protective layer (312) and the second protective layer (322) may be formed as insulating resin layers including solder resist. The first protective layer (312) and the second protective layer (322) may be formed using various methods such as printing, bonding, coating, and photolithography. In the case of printing or coating, they may be formed by printing or coating a liquid solder resist. In the case of bonding, they may be formed by bonding a coverlay film using a lamination method.

[0073] Referring again to Fig. 1, the explanation will be provided.

[0074] When a first flexible circuit board (310) and a second flexible circuit board (320) are formed on each side (210a, 210b) of the carrier tape (210), the first flexible circuit board (310) and the second flexible circuit board (320) are peeled off from the carrier tape (210) (S150). Referring to FIG. 12, the first flexible circuit board (310) may include a first substrate layer (221), a first circuit pattern (311), and a first protective layer (312). Likewise, the second flexible circuit board (320) may include a second substrate layer (231), a second circuit pattern (321), and a second protective layer (322). Step S150 may be performed after Step S140. FIG. 12 is an illustrative diagram for explaining the product structure at Step S150 of the method for manufacturing a flexible circuit board.

[0075] When separating the first flexible circuit board (310) and the second flexible circuit board (320) from the carrier tape (210), light or heat may be used. If light is used, a laser lift-off process may be applied. In this process, light may be irradiated toward the product to weaken the adhesive strength of the first adhesive layer (240) and the second adhesive layer (250), after which the first flexible circuit board (310) and the second flexible circuit board (320) may be separated from the carrier tape (210). The first adhesive layer (240) and the second adhesive layer (250) may be formed using a photoreactive adhesive.

[0076] When heat is used, heat is applied to the product to weaken the adhesive strength of the first adhesive layer (240) and the second adhesive layer (250), after which the first flexible circuit board (310) and the second flexible circuit board (320) can be separated from the carrier tape (210). The first adhesive layer (240) and the second adhesive layer (250) may be formed using a heat-reactive adhesive. The first adhesive layer (240) and the second adhesive layer (250) may be provided as a high-temperature detachable adhesive that is easily detached at high temperatures.

[0077] The first flexible circuit board (310) may include a first substrate layer (221) and a first circuit pattern (311) and may not include a first protective layer (312). Likewise, the second flexible circuit board (320) may include a second substrate layer (231) and a second circuit pattern (321) and may not include a second protective layer (322). Step S150 may be performed after Step S130. Step S140 may be omitted. Alternatively, Step S140 may be performed after Step S150.

[0078] In this embodiment, a first raw film (220) and a second raw film (230) can be bonded and processed to the surface (210a) and back surface (210b) of a carrier tape (210), respectively, to simultaneously manufacture a first flexible circuit board (310) and a second flexible circuit board (320). According to this embodiment, the effect of increasing productivity can be obtained by simultaneously producing a plurality of flexible circuit boards. In addition, in this embodiment, a first raw film (220) and a second raw film (230) having the same physical properties and thermal shrinkage rate can be laminated to both sides (210a, 210b) of the carrier tape (210). According to the present embodiment, a film thickness suitable for a roll-to-roll process can be secured, and by balancing the surface (210a) and the back side (210b), problems such as creasing, folding, and bowing can be improved, and risks such as lead peeling, lead cracking, and accumulated pitch due to stretching caused by contact during process flow can also be reduced. In addition, by adjusting the detach carrier thickness, it becomes possible to manufacture flexible circuit boards of various thicknesses that meet customer needs, such as 5㎛, 10㎛, 12.5㎛, 20㎛, and 25㎛.

[0079] Meanwhile, referring to FIGS. 13 and 14, a first metal layer (222) may be provided on one side of the first substrate layer (221), and a first metal foil layer (224) may be provided on the other side of the first substrate layer (221). When the first raw film (220) is bonded to the carrier tape (210), the first metal foil layer (224) may be located between the first adhesive layer (240) and the first substrate layer (221). The first metal foil layer (224) may be removed after the first flexible circuit board (310) is separated from the carrier tape (210) (S160). The first metal foil layer (224) may be removed from the first flexible circuit board (310) by a method such as metal etching.

[0080] Likewise, a second metal layer (232) may be provided on one side of the second substrate layer (231), and a second metal foil layer (234) may be provided on the other side of the second substrate layer (231). When the second raw film (230) is bonded to the carrier tape (210), the second metal foil layer (234) may be located between the second adhesive layer (250) and the second substrate layer (231). The second metal foil layer (234) may be removed after the second flexible circuit board (320) is separated from the carrier tape (210). The second metal foil layer (234) may be removed from the second flexible circuit board (320) by a method such as metal etching. FIG. 13 is a fourth example diagram illustrating the product structure at step S110 of the method for manufacturing a flexible circuit board. FIG. 14 is a flowchart illustrating the method for manufacturing a flexible circuit board according to several other embodiments of the present invention step by step.

[0081] Although embodiments of the present invention have been described above with reference to the attached drawings, the present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0082] The present invention may be applied to circuit boards and devices including the same. For example, the present invention may be applied to circuit boards manufactured by a roll-to-roll method. For example, the present invention may be applied to chip-on-films installed in display devices.

Claims

A step of forming a first raw film and a second raw film on each side of a carrier tape, respectively; A step of manufacturing a first flexible circuit board including a first circuit pattern by processing the first raw film; A step of manufacturing a second flexible circuit board including a second circuit pattern by processing the second raw film; and A method for manufacturing a flexible circuit board comprising the step of separating the first flexible circuit board and the second flexible circuit board from the carrier tape. In Article 1, A method for manufacturing a flexible circuit board in which the step of manufacturing the first flexible circuit board and the step of manufacturing the second flexible circuit board are performed simultaneously. In Article 1, The above-mentioned first raw film is, A first substrate layer made of an insulating material; and It includes a first metal layer formed on the first substrate layer, A method for manufacturing a flexible circuit board in which the first substrate layer is provided with a thickness equivalent to that of the carrier tape or a thickness thinner than that of the carrier tape. In Paragraph 3, A method for manufacturing a flexible circuit board, wherein the first substrate layer is provided with a thickness of 5 μm to 25 μm. In Paragraph 3, The above first circuit pattern is a method for manufacturing a flexible circuit board formed from the above first metal layer. In Article 5, A method for manufacturing a flexible circuit board, wherein the first metal layer is provided with a thickness of 5 μm to 10 μm. In Paragraph 3, The first circuit pattern is formed on the first metal layer, and A method for manufacturing a flexible circuit board in which the first metal layer is removed after forming the first circuit pattern. In Article 7, A method for manufacturing a flexible circuit board in which the first metal layer is provided with a thickness of 0.5 μm to 3 μm. In Article 1, The carrier tape further comprises a first adhesive layer provided between it and the first raw film, and A method for manufacturing a flexible circuit board in which light or heat is provided to the first adhesive layer in the above separation step. In Article 9, A method for manufacturing a flexible circuit board in which the adhesive strength of the first adhesive layer is 15 gf / cm to 40 gf / cm before providing light or heat, and 15 gf / cm to 60 gf / cm after providing light or heat. In Article 1, A step of forming a first metal layer on one surface of a first substrate layer included in the first raw film and forming a first metal foil layer on the other surface of the first substrate layer; and A method for manufacturing a flexible circuit board, further comprising the step of removing the first metal foil layer provided between the first raw film and the carrier tape. In Article 11, The above removal step is performed after the above separation step, and is a method for manufacturing a flexible circuit board removed from the first flexible circuit board. In Article 1, A method for manufacturing a flexible circuit board in which the second circuit pattern is formed in a direction parallel to the length direction of the carrier tape and is inverted from the first circuit pattern. A flexible circuit board manufactured by a manufacturing method according to any one of claims 1 to 13. An electronic device comprising a flexible circuit board according to claim 14.

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