Flexible circuit board, cof module, and electronic device comprising same

Abstract

A flexible circuit board according to an embodiment includes: a substrate; a plurality of circuit patterns arranged on the substrate; and a protective layer arranged on the plurality of circuit patterns and having an opening. The plurality of circuit patterns include a plurality of routing pad parts arranged in the opening and a plurality of routing wiring parts connecting the plurality of routing pad parts to each other. The plurality of routing wiring parts include a first routing wiring part arranged outside the opening, covered by the protective layer, and connecting the plurality of routing pad parts to each other, and a second routing wiring part arranged inside the opening and connecting the plurality of routing pad parts to each other.

Description

Flexible circuit boards, COF modules and electronic devices including the same

[0001] The present invention relates to a flexible circuit board, a COF module and an electronic device including the same.

[0002] Recently, various electronic products are becoming thinner and smaller. Consequently, there is a growing demand for high-density semiconductor chips to be mounted within the narrow spaces of these electronic products.

[0003] A COF (Chip-On-Film) comprises a substrate and a chip on the substrate. The substrate is flexible, meaning the COF is a flexible circuit board. Accordingly, the COF is applicable to flexible displays. For example, the COF can be applied to various wearable electronic devices. Furthermore, the COF has a fine pitch, meaning that the COF is applicable to high-resolution displays.

[0004] The chip includes a semiconductor chip. For example, the chip may be an integrated circuit (IC) chip or a large scale integrated circuit (LSI) chip.

[0005] The chip is connected to an external circuit board and display panel via a circuit pattern. For example, pads are arranged at one end and the other end of the circuit pattern, respectively. One pad is electrically connected to a terminal of the chip. The other pad is connected to a terminal of the circuit board and the display panel. Accordingly, the chip, the circuit board, and the display panel are electrically connected via the COF. As a result, a signal is transmitted to the display panel via the circuit pattern.

[0006] The chips mounted on the above flexible printed circuit board are arranged in a multi-layer structure, each performing a role.

[0007] Recently, Film Level Route (FLR) technology has been adopted. This FLR technology directly places one chip and its associated circuit patterns among multilayer chips on a flexible printed circuit board. Since the routing pattern is placed in the chip mounting area, the size of the chip's layer structure is reduced. Consequently, chip manufacturing costs are reduced.

[0008] The above FLR (Film Level Route) is a power line through which high voltage flows. Accordingly, the FLR (Film Level Route) may be damaged by high voltage. In particular, the outer region of the FLR (Film Level Route) may be more vulnerable to high voltage.

[0009] Therefore, a new structure of flexible circuit board, COF module and electronic device including the same that can solve the above problems are required.

[0010] As a patent related to the above flexible circuit board, Korean registered patent KR10-0618898 (2006.09.01) is disclosed.

[0011] The embodiment provides a flexible circuit board having improved reliability.

[0012] A flexible circuit board according to an embodiment includes a substrate; a plurality of circuit patterns arranged on the substrate; and a protective layer arranged on the plurality of circuit patterns and having an opening, wherein the plurality of circuit patterns include a plurality of routing pad portions arranged within the opening and a plurality of routing wiring portions connecting the plurality of routing pad portions, and the plurality of routing wiring portions include a first routing wiring portion arranged outside the opening and covered with the protective layer, connecting the plurality of routing pad portions, and a second routing wiring portion arranged inside the opening and connecting the plurality of routing pad portions.

[0013] Additionally, the first routing wiring portion is arranged in at least one area among the upper part of the opening, the lower part of the opening, and the side of the opening in the horizontal direction.

[0014] In addition, the first routing wiring section includes a 1-1 routing wiring section and a 1-2 routing wiring section spaced apart from each other, and the 1-2 routing wiring section is arranged to surround the 1-1 routing wiring section on the substrate.

[0015] In addition, the width of the above 1-1 routing wiring section and the width of the above 1-2 routing wiring section are different from each other.

[0016] Additionally, the width of the above 1-1 routing wiring section is larger than the width of the above 1-2 routing wiring section.

[0017] Additionally, the width of the 1-1 routing wiring section is 2 to 10 times the width of the 1-2 routing wiring section.

[0018] Additionally, the second routing wiring portion includes a 2-1 routing wiring portion disposed inside the opening and connected to the 1-1 routing wiring portion, and a 2-2 routing wiring portion spaced apart from the 2-1 routing wiring portion and disposed inside the opening and connected to the 1-2 routing wiring portion.

[0019] In addition, the second routing wiring portion is spaced apart from the 2-1 routing wiring portion and the 2-2 routing wiring portion and is arranged on the inside of the opening, and is not connected to the first routing wiring portion.

[0020] Additionally, the above 2-1 routing wiring section includes areas having different widths.

[0021] In addition, the 2-1 routing wiring section includes a first region having a first width and a second region having a second width smaller than the first width, and the first region of the 2-1 routing wiring section is connected to the 1-1 routing wiring section.

[0022] Additionally, the above 1-1 routing wiring section has a third width that is larger than the second width.

[0023] Additionally, the above-mentioned 2-2 routing wiring section has a fourth width that is smaller than the first width.

[0024] Additionally, the fourth width is smaller than the third width.

[0025] Additionally, the 2-3 routing wiring section has a fifth width that is smaller than the first width.

[0026] Additionally, the fifth width is smaller than the third width.

[0027] Additionally, the first length of the 1-1 routing wiring section is greater than the second length of the first region of the 2-1 routing wiring section.

[0028] Additionally, the first length is 55% to 90% of the sum of the first length and the second length.

[0029] Additionally, the sum of the first length and the second length is 250 μm to 300 μm.

[0030] Meanwhile, a COF module according to an embodiment includes a flexible circuit board; and a chip disposed on the flexible circuit board, wherein the flexible circuit board includes: a substrate; a plurality of circuit patterns disposed on the substrate; and a protective layer disposed on the plurality of circuit patterns and having an opening, wherein the plurality of circuit patterns include a plurality of routing pad portions disposed within the opening and a plurality of routing wire portions connecting the plurality of routing pad portions, wherein the plurality of routing wire portions include a first routing wire portion disposed outside the opening and covered with the protective layer and connecting the plurality of routing pad portions, and a second routing wire portion disposed inside the opening and connecting the plurality of routing pad portions, and wherein the chip is connected to the plurality of routing pad portions.

[0031] A flexible circuit board according to an embodiment includes a fourth circuit pattern. The fourth circuit pattern may be a routing pattern. Accordingly, a high-voltage current may flow through the fourth circuit pattern.

[0032] The fourth circuit pattern includes a plurality of routing wiring portions and a plurality of routing pad portions. The routing wiring portions include a first routing wiring portion positioned outside the open area and a second routing wiring portion positioned inside.

[0033] The size of the first routing wiring section is larger than the sizes of the other wiring sections. Accordingly, the fourth circuit pattern can be prevented from being damaged by high-voltage current.

[0034] Additionally, the length of the first routing wiring portion may have a set size. Accordingly, it is possible to prevent the protective layer from being covered on the wiring portion by the first routing wiring portion.

[0035] Therefore, the size of the open area or chip mounting area can be prevented from increasing by the protective layer.

[0036] Fig. 1 is a top view of a flexible circuit board according to an embodiment.

[0037] Figure 2 is an enlarged view of area A of Figure 1.

[0038] Figure 3 is an enlarged view of area B of Figure 2.

[0039] Figure 4 is a cross-sectional view taken along the BB' area of ​​Figure 3.

[0040] Figures 5 and 6 are cross-sectional views taken along area AA' of Figure 1.

[0041] Fig. 7 is a drawing for explaining the connection of a COF module and other members according to an embodiment.

[0042] FIGS. 8 to 10 are drawings of electronic devices including flexible circuit boards according to embodiments.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the described embodiments, but may be implemented in various different forms. Within the scope of the technical concept of the present invention, one or more of the components of the embodiments may be selectively combined or substituted for use.

[0044] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0045] In addition, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “and (and) at least one (or more) of B, C,” it may include one or more of all combinations that can be combined with A, B, and C.

[0046] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0047] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0048] Additionally, when it is described as being formed or disposed "above or below" each component, above or below includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or disposed between the two components.

[0049] Additionally, when expressed as “upper or lower,” it can include the meaning of not only the upward direction but also the downward direction based on one component.

[0050] In the following description, the first direction (1D) is the direction in which the pad portion of the display panel and the pad portion of the circuit board face each other. In addition, the second direction (2D) is the direction perpendicular to the first direction (1D).

[0051]

[0052] Below, with reference to the drawings, a flexible circuit board and a COF module including the same according to an embodiment are described.

[0053]

[0054]

[0055] Referring to FIG. 1, a flexible circuit board (1000) according to an embodiment includes a substrate (100), a circuit pattern, and a protective layer (300).

[0056] The above-mentioned substrate (100) includes a first surface (1S) and a second surface (2S) opposite to the first surface (1S). The circuit pattern and the protective layer (300) are arranged on the first surface (1S).

[0057] The substrate (100) includes a cutting line (CL). The flexible circuit board (1000) is cut along the cutting line (CL). For example, the circuit pattern, the metal pattern, the protective layer, and the chip are placed on the substrate (100). Thereafter, the substrate (100) is cut along the cutting line (CL). Accordingly, a COF module is manufactured. Accordingly, the edge of the COF module becomes the cutting line (CL).

[0058] The above-mentioned substrate (100) includes an effective area (AA) and an ineffective area (UA). In detail, the first surface (1S) includes the effective area (AA) and the ineffective area (UA).

[0059] The above valid area (AA) and the non-valid area (UA) are separated by the cutting line (CL). The valid area (AA) is an area inside the cutting line (CL). In addition, the non-valid area (UA) is an area outside the cutting line (CL).

[0060] The circuit pattern, the protective layer, and the chip are arranged on the effective area (AA). In addition, a dummy pattern and a sprocket hole (SH) are arranged on the ineffective area (UA). The dummy pattern increases the strength of the substrate (100). In addition, the flexible circuit board (1000) is rolled or unrolled in a roll-to-roll manner by the sprocket hole (SH).

[0061] The above description (100) includes an open area (OA) and a chip mounting area (CHA).

[0062] The open area (OA) is disposed on the effective area (AA). The open area (OA) is disposed inside the substrate (100). The open area (OA) is distinguished by the presence or absence of the protective layer. The protective layer is not disposed on the open area (OA). That is, the open area (OA) may correspond to an opening provided in the protective layer. Therefore, the 'open area (OA)' of the substrate (100) may be referred to as an 'opening' of the protective layer.

[0063] The chip mounting area (CHA) is disposed on the open area (OA). That is, the chip mounting area (CHA) is a portion of the open area (OA). The chip mounting area (CHA) is disposed on the first surface (1S). The chip mounting area (CHA) is disposed on the effective area (AA). The chip (CH) is disposed on the chip mounting area (CHA). In addition, the pad portions of the circuit pattern are disposed inside the chip mounting area (CHA).

[0064]

[0065] The substrate (100) includes a flexible material. For example, the substrate (100) may include polyimide (PI). However, the embodiment is not limited thereto. The substrate (100) may include a polymer material including polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Accordingly, the flexible circuit board can be applied to various electronic devices, including curved display devices.

[0066] The substrate (100) may have a thickness of 20 μm to 100 μm. For example, the substrate (100) may have a thickness of 25 μm to 50 μm. For example, the substrate (100) may have a thickness of 30 μm to 40 μm. When the thickness of the substrate (100) exceeds 100 μm, the overall thickness of the flexible circuit board increases. As a result, the flexible characteristics of the flexible circuit board may be reduced. In addition, when the thickness of the substrate (100) is less than 20 μm, the substrate (100) may be damaged by heat and pressure applied to the substrate when the chip is mounted on the flexible circuit board.

[0067]

[0068] The circuit pattern and the protective layer (300) are disposed on the substrate (100). In detail, the circuit pattern and the protective layer (300) are disposed on the first surface (1S). In detail, the circuit pattern and the protective layer (300) are disposed on at least one of the effective area (AA) and the non-effective area (UA).

[0069] The above circuit pattern includes a first circuit pattern (210), a second circuit pattern (220), a third circuit pattern (230), and a fourth circuit pattern (400).

[0070] Referring to Fig. 1, the first circuit pattern (210) includes a first wiring portion (211), a first pad portion (212a), and a second pad portion (212b). The first wiring portion (211), the first pad portion (212a), and the second pad portion (212b) may include the same material. In addition, the first wiring portion (211), the first pad portion (212a), and the second pad portion (212b) may be formed integrally.

[0071] The first pad portion (212a) is positioned within the chip mounting area (CHA). Accordingly, the first pad portion (212a) is connected to the terminal of the chip. As a result, the first circuit pattern (210) and the chip are connected.

[0072] The second pad portion (212b) is positioned outside the chip mounting area (CHA). The second pad portion (212b) is connected to the pad portion of the circuit board (3000). As a result, the first circuit pattern (210) and the circuit board (3000) are connected.

[0073] The first wiring portion (211) is arranged between the first pad portion (212a) and the second pad portion (212b). The first wiring portion (211) connects the first pad portion (212a) and the second pad portion (212b). Accordingly, the chip (CH) and the circuit board (3000) are connected. Accordingly, a signal generated from the chip (CH) is transmitted to the circuit board (3000).

[0074] The first circuit pattern (210) may further include a test pad portion. Specifically, a first test pad portion (TP1) is arranged in the non-effective area (UA). The first wiring portion (211), the first pad portion (212a), the second pad portion (212b), and the first test pad portion (TP1) may be formed integrally.

[0075] Before connecting the circuit board and the second pad portion (212b), the first circuit pattern (210) can be tested by the first test pad portion (TP1). For example, whether the first circuit pattern is open or shorted can be checked through the first test pad portion (TP1).

[0076]

[0077] The second circuit pattern (220) includes a second wiring portion (221), a third pad portion (222a), and a fourth pad portion (222b). The second wiring portion (221), the third pad portion (222a), and the fourth pad portion (222b) may include the same material. In addition, the second wiring portion (221), the third pad portion (222a), and the fourth pad portion (222b) may be formed integrally.

[0078] The third pad portion (222a) is positioned within the chip mounting area (CHA). Accordingly, the third pad portion (222a) is connected to the terminal of the chip. As a result, the second circuit pattern (220) and the chip (CH) are connected.

[0079] The fourth pad portion (222b) is positioned outside the chip mounting area (CHA). The fourth pad portion (222b) is connected to the pad portion of the external display panel (4000). As a result, the second circuit pattern (220) and the display panel (4000) are connected.

[0080] The second wiring portion (221) is arranged between the third pad portion (222a) and the fourth pad portion (222b). The second wiring portion (221) connects the third pad portion (222a) and the fourth pad portion (222b). Accordingly, the chip (CH) and the display panel (4000) are connected. Accordingly, a signal generated from the chip (CH) is transmitted to the display panel (4000).

[0081] The second circuit pattern (220) may further include a test pad portion. In detail, a second test pad portion (TP2) is arranged in the non-effective area (UA). The second test pad portion (TP2) is arranged outside the cutting line (CL). The second test pad portion (TP2) is arranged on the non-effective area (UA). The second wiring portion (221), the third pad portion (222a), the fourth pad portion (222b), and the second test pad portion (TP2) may be formed integrally.

[0082] Before connecting the circuit board and the fourth pad portion (222b), the second circuit pattern (220) can be tested by the second test pad portion (TP2). For example, whether the second circuit pattern is open or shorted can be checked through the second test pad portion (TP2).

[0083]

[0084] The third circuit pattern (230) includes a third wiring portion (231), a fifth pad portion (232a), and a sixth pad portion (232b). The third wiring portion (231), the fifth pad portion (232a), and the sixth pad portion (232b) may include the same material. In addition, the third wiring portion (231), the fifth pad portion (232a), and the sixth pad portion (232b) may be formed integrally.

[0085] The fifth pad portion (232a) and the sixth pad portion (232b) are positioned outside the chip mounting area (CHA). The fifth pad portion (232a) may be connected to the pad portion of the circuit board (2000). In addition, the sixth pad portion (232b) may be connected to the pad portion of the display panel (4000).

[0086] The third wiring portion (231) is positioned between the fifth pad portion (232a) and the sixth pad portion (232b). The third wiring portion (231) connects the fifth pad portion (232a) and the sixth pad portion (232b). Accordingly, the circuit board (3000) and the display panel (4000) are connected.

[0087] The third circuit pattern (230) may be a bypass circuit. For example, the third circuit pattern (230) may be a power supply pattern. Accordingly, the circuit board and the display panel may be supplied with power by the third circuit pattern (230).

[0088] The third circuit pattern (230) may include a plurality of third circuit patterns spaced apart in the second direction (2D). The line width and spacing of the third circuit pattern (230) may be larger than the line width and spacing of the first circuit pattern (210). In addition, the line width and spacing of the third circuit pattern (230) may be larger than the line width and spacing of the second circuit pattern (220).

[0089]

[0090] The protective layer (300) is disposed on the first surface (1S). Accordingly, the protective layer (300) is disposed on the first circuit pattern (210), the second circuit pattern (220), and the third circuit pattern (230). The protective layer (300) is disposed on the first wiring portion (211), the second wiring portion (221), and the third wiring portion (231). The protective layer (300) is not disposed on the first pad portion (212a), the second pad portion (212b), the third pad portion (222a), the fourth pad portion (222b), the fifth pad portion (232a), and the sixth pad portion (232b). In addition, the protective layer (300) is not disposed on the chip mounting area (CHA).

[0091]

[0092] The fourth circuit pattern (400) is arranged on the effective area (AA). The fourth circuit pattern (400) may be a routing pattern. That is, the fourth circuit pattern (400) may be a routing pattern that serves as one of the layers of a chip having multiple layers arranged on the chip mounting area (CHA).

[0093] That is, the target to which the fourth circuit pattern (400) is connected is different from the target to which the first circuit pattern (210) to the third circuit pattern (230) are connected. The fourth circuit pattern (400) is connected only to the terminal of the chip. The fourth circuit pattern (400) is not connected to the display panel and the circuit board.

[0094] One pad portion of the first circuit pattern (210) to the third circuit pattern (230) is connected to the chip. In addition, the other pad portion of the first circuit pattern (210) to the third circuit pattern (230) is connected to the circuit board or display panel.

[0095]

[0096] The fourth circuit pattern (400) may be a routing circuit pattern. That is, the fourth circuit pattern (400) may have a structure in which a plurality of routing pad portions (420) are arranged within an opening of a protective layer, and the plurality of routing pad portions (420) may be electrically connected through a plurality of routing wiring portions (410) constituting the fourth circuit pattern (400). Hereinafter, the routing circuit pattern will be described as a fourth circuit pattern (400).

[0097] The fourth circuit pattern (400) includes a plurality of routing wiring portions (410) and a plurality of routing pad portions (420). The plurality of routing wiring portions (410) are spaced apart from each other. The routing pad portions (420) are connected to each of the routing wiring portions (410).

[0098] The fourth circuit pattern (400) is disposed inside and outside the open area (OA). The routing wiring portion (410) is disposed inside and outside the open area (OA). In addition, the routing pad portion (420) is disposed inside the open area (OA). The open area (OA) may also be referred to as an opening in the protective layer.

[0099]

[0100] Accordingly, the routing wiring unit (410) includes a first routing wiring unit (411) and a second routing wiring unit (412) that are distinguished according to location. The first routing wiring unit (411) is disposed outside the open area (OA). In addition, the second routing wiring unit (412) is disposed inside the open area (OA).

[0101] The first routing wiring section (411) and the second routing wiring section (412) are connected. The first routing wiring section (411) and the second routing wiring section (412) are formed integrally.

[0102] Accordingly, the protective layer (300) is disposed on the first routing wiring portion (411). In addition, the protective layer (300) is not disposed on the second routing wiring portion (412).

[0103] The first routing wiring section (411) may be positioned at various locations based on the open area (OA). Specifically, the first routing wiring section (411) may be positioned at at least one of the upper, lower, and side portions of the open area (OA) based on the horizontal direction.

[0104] For example, the first routing wiring portion (411) may be arranged at least on one of the upper and lower portions of the open area (OA). The second routing wiring portion (412) extends in multiple directions. Specifically, the second routing wiring portion (412) extends in a first direction (1D) and a second direction (2D). The second routing wiring portion (412) is bent in the second direction (2D) toward the first direction (1D). The first routing wiring portion (411) may be connected to the second routing wiring portion (412) extending in the first direction (1D).

[0105] Alternatively, the first routing wiring portion (411) may be arranged on the side of the open area (OA). The first routing wiring portion (411) may be arranged on at least one of the left and right sides of the open area (OA). The first routing wiring portion (411) may be connected to the second routing wiring portion (412) extending in the second direction (2D).

[0106] The first routing wiring section (411) extends in the first direction (1D) and the second direction (2D) from the outside of the open area (OA).

[0107]

[0108] Hereinafter, an example will be described in which the first routing wiring section (411) is placed above the open area (OA).

[0109] The first routing wiring section (411) may include at least one wiring section. For example, the first routing wiring section (411) may include a plurality of wiring sections spaced apart from each other. The first routing wiring section (411) may include a first-first routing wiring section (411a) and a first-second routing wiring section (411b).

[0110] The above-mentioned 1-1 routing wiring section (411a) is spaced apart from the above-mentioned 1-2 routing wiring section (411b). The above-mentioned 1-1 routing wiring section (411a) is arranged on the inner side of the above-mentioned 1-2 routing wiring section (411b). The above-mentioned 1-2 routing wiring section (411b) surrounds the above-mentioned 1-1 routing wiring section (411a).

[0111] The size of the above-mentioned 1-1 routing wiring section (411a) is different from the size of the above-mentioned 1-2 routing wiring section (411b). Specifically, the width of the above-mentioned 1-1 routing wiring section (411a) is different from the width of the above-mentioned 1-2 routing wiring section (411b). Specifically, the width (W1-1) of the above-mentioned 1-1 routing wiring section (411a) is greater than the width (W1-2) of the above-mentioned 1-2 routing wiring section (411b).

[0112] For example, the width (W1-1) of the 1-1 routing wiring portion (411a) may be at least twice the width (W1-2) of the 1-2 routing wiring portion (411b). In detail, the width (W1-1) of the 1-1 routing wiring portion (411a) may be 2 to 10 times, 3 to 9 times, or 4 to 7 times the width (W1-2) of the 1-2 routing wiring portion (411b).

[0113] The first routing wiring section (411) is arranged outside the off-line area (OA). The fourth circuit pattern (400) is connected to the chip (C). Accordingly, a high-voltage current can flow through the routing wiring section (410). The routing wiring section (410) includes the first-first routing wiring section (411a) having a large width. Accordingly, the first routing wiring section (411) can be prevented from being damaged by the high-voltage current.

[0114] In addition, external electrostatic discharge (ESD) can be effectively blocked by the 1-1 routing wiring section (411a). That is, since the width of the 1-1 routing wiring section (411a) increases, the area of ​​the 1st routing wiring section (411) increases.

[0115] Accordingly, the signal of the chip can be prevented from being interfered with by the static electricity. Accordingly, the electrical characteristics of the COF module are improved.

[0116]

[0117] The second routing wiring section (412) includes a plurality of wiring sections. For example, the plurality of second routing wiring sections (412) are spaced apart from each other. The second routing wiring section (412) may include a second-first routing wiring section (412a), a second-second routing wiring section (412b), and a second-third routing wiring section (412c).

[0118] The above 2-1 routing wiring section (412a) is connected to the 1-1 routing wiring section (411a). The above 2-2 routing wiring section (412b) is connected to the 1-2 routing wiring section (411b). The above 2-3 routing wiring section (412c) is not connected to the 1-1 routing wiring section (411a) and the 1-2 routing wiring section (411b).

[0119] The above 2-1 routing wiring section (412a) includes a first region (1A) and a plurality of second regions (2A). The first region (1A) is connected to the 1-1 routing wiring section (411a). The second region (2A) is connected to the first region (1A). In detail, the first region (1A) is branched into at least two wiring sections, thereby forming a plurality of second regions (2A). Therefore, the first region (1A) and the second region (2A) are formed integrally. In addition, the 1-1 routing wiring section (411a) and the 2-1 routing wiring section (412a) are formed integrally.

[0120] The first region (1A) and the second region (2A) have different sizes. Specifically, the first region (1A) and the second region (2A) have different widths. The width (W2-1) of the first region (1A) is greater than the width (W2-2) of the second region (2A).

[0121] The width (W2-1) of the first region (1A) is equal to or similar to the width (W1-1) of the first-first routing wiring section (411a). Therefore, the width (W2-2) of the second region (2A) is smaller than the width (W1-1) of the first-first routing wiring section (411a).

[0122] The above-mentioned 2-2 routing wiring section (412b) is connected to the above-mentioned 1-2 routing wiring section (411b). The above-mentioned 1-2 routing wiring section (411b) and the above-mentioned 2-2 routing wiring section (412b) are formed integrally.

[0123] The width (W3) of the 2-2 routing wiring portion (412b) is the same as or similar to the width (W1-2) of the 1-2 routing wiring portion (411b). The width (W3) of the 2-2 routing wiring portion (412b) is the same as or similar to the width (W2-2) of the second region (2A). The width (W3) of the 2-2 routing wiring portion (412b) is smaller than the width (W2-1) of the first region (1A). The width (W3) of the 2-2 routing wiring portion (412b) is smaller than the width (W1-1) of the 1-1 routing wiring portion (411a).

[0124] The above 2-3 routing wiring section (412c) is not connected to the 1-1 routing wiring section (411a) and the 1-2 routing wiring section (411b). The 2-3 routing wiring section (412c) is spaced apart from the 2-1 routing wiring section (412a) and the 2-2 routing wiring section (412b).

[0125] The width (W4) of the 2-3 routing wiring portion (412c) is the same as or similar to the width (W1-2) of the 1-2 routing wiring portion (411b). The width (W4) of the 2-3 routing wiring portion (412c) is the same as or similar to the width (W2-2) of the second region (2A). The width (W4) of the 2-3 routing wiring portion (412c) is the same as or similar to the width (W3) of the 2-2 routing wiring portion (412b). The width (W4) of the 2-3 routing wiring portion (412c) is smaller than the width (W2-1) of the 1st region (1A). The width (W4) of the 2-3 routing wiring portion (412c) is smaller than the width (W1-1) of the 1-1 routing wiring portion (411a).

[0126]

[0127] The length of the above-mentioned 1-1 routing wiring section (411a) is different from the length of the above-mentioned 2-1 routing wiring section (412a). Specifically, the first length (L1) of the above-mentioned 1-1 routing wiring section (411a) is longer than the second length (L2) of the first region (1A) of the above-mentioned 2-1 routing wiring section (412a).

[0128] The first length (L1) may be greater than 50% of the sum (L1+L2) of the first length and the second length. In detail, the first length (L1) may be 55% to 90%, 60% to 85%, or 65% to 80% of the sum (L1+L2) of the first length and the second length.

[0129] The sum of the first length and the second length (L1+L2) may be 250 µm to 300 µm. The first length (L1) may be 130 µm to 280 µm, 150 µm to 250 µm, or 180 µm to 240 µm.

[0130] The width of the first area (1A) of the above 1-1 routing wiring section (411a) and the above 2-1 routing wiring section (412a) is larger than the width of the other wiring sections of the 4th circuit pattern.

[0131] The above protective layer (300) is formed by applying a liquid solder resist. Since the width of the first region (1A) of the first-first routing wiring portion (411a) and the second-first routing wiring portion (412a) is large, the movement of the liquid solder resist is restricted by the first region (1A) of the first-first routing wiring portion (411a) and the second-first routing wiring portion (412a).

[0132] Accordingly, the liquid solder resist can be applied to the first-second routing wiring portion (411b) and then flow naturally to cover the wide wiring portion and pad portion. Specifically, the liquid solder resist can flow as much as 130 μm to 280 μm. Accordingly, the protective layer (300) is disposed on the first-first routing wiring portion (411a) and the second wiring portion (221). Accordingly, the first length (L1) is formed as much as the size of the solder resist flowing.

[0133] If the sum of the first and second lengths (L1+L2) exceeds 250 μm to 300 μm, the second length (L2) becomes longer. Accordingly, the wiring portion is not sufficiently covered by the protective layer. Accordingly, the size of the chip mounting area increases, and the size of the COF module may also increase.

[0134]

[0135] Referring to FIGS. 5 and 6, the circuit pattern is formed in a multilayer structure. FIGS. 5 and 6 are described focusing on the first circuit pattern. The following description applies equally to the second and third circuit patterns.

[0136] Referring to Fig. 5, the first circuit pattern is formed in multiple layers. In detail, the first wiring portion (211), the first pad portion (212a), and the second pad portion (212b) include a buffer layer (205), a metal layer (201), and a bonding layer (203).

[0137] The buffer layer (205) may include multiple layers. Specifically, the buffer layer (205) includes a first buffer layer (205a) and a second buffer layer (205b). The first buffer layer (205a) is disposed on the substrate (100). The second buffer layer (205b) is disposed on the first buffer layer (205a).

[0138] The first buffer layer (205a) includes a material having good adhesion to the substrate (100). For example, the first buffer layer (205a) may include nickel (Ni). In addition, the second buffer layer (205b) includes a material having good adhesion to the circuit pattern. For example, the second buffer layer (205b) may include chromium (Cr).

[0139] The above buffer layer (205) may have a thin film thickness in nanometer units. For example, the above buffer layer (205) may have a thickness of 20 nm or less.

[0140] The adhesion between the substrate (100) and the circuit pattern is improved by the buffer layer (205).

[0141] The metal layer (201) is disposed on the buffer layer (205). Specifically, the metal layer (201) is disposed on the second buffer layer (205b). The metal layer (201) includes a metal material. For example, the metal layer (201) may include copper (Cu).

[0142] The above metal layer (201) can be formed by electroplating using the buffer layer as a seed layer. That is, the above metal layer (201) can be a plating layer.

[0143] The thickness of the above metal layer (201) may be 10 µm to 30 µm.

[0144] The above bonding layer (203) is placed on the above metal layer (201).

[0145] The above bonding layer (203) is arranged on the side and upper surface of the metal layer (201). For example, the bonding layer (203) may be arranged to surround the metal layer (201).

[0146] The above bonding layer (203) includes a metal. For example, the bonding layer (203) may include tin (Sn). The bonding layer (203) is formed by a plating process. In detail, the bonding layer (203) may be a plating layer.

[0147] The thickness of the above bonding layer (203) may be 0.3 µm to 0.7 µm. The tin content may increase as it extends from the lower surface to the upper surface of the above bonding layer (203).

[0148] That is, the bonding layer (203) is in contact with the metal layer (201). Therefore, the tin content increases from the lower surface of the bonding layer (203) toward the upper surface. In addition, the copper content decreases from the lower surface of the bonding layer (203) toward the upper surface.

[0149] Accordingly, pure tin may remain in a thickness range of 0.1 µm to 0.3 µm from the upper surface of the bonding layer (203).

[0150] The pad portion can be easily bonded to the terminals of the chip, the circuit board, and the display panel by the bonding layer (203). For example, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer melts. Pure tin remains on the upper surface of the bonding layer. Therefore, the pad portion can be easily bonded to the terminals of the chip, the circuit board, and the display panel.

[0151]

[0152] Referring to Fig. 6, the metal layer (201) may include a first metal layer (201a) and a second metal layer (201b). The first metal layer (201a) is disposed on the buffer layer (205). The second metal layer (201b) is disposed on the first metal layer (201a). The second metal layer (201b) may be formed by electroplating using the first metal layer (201a) as a seed layer. That is, the second metal layer (201b) may be a plating layer.

[0153] The thickness of the first metal layer (201a) may be smaller than the thickness of the second metal layer (201b).

[0154] For example, the thickness of the first metal layer (201a) may be 0.7 µm to 2 µm, and the thickness of the second metal layer (201b) may be 6 µm to 25 µm.

[0155] The first metal layer (201a) and the second metal layer (201b) may include the same metal material. For example, the first metal layer (201a) and the second metal layer (201b) may include copper (Cu).

[0156] The above bonding layer (203) may include a first bonding layer (203a) and a second bonding layer (203b).

[0157] The first bonding layer (203a) is disposed on the metal layer (201). In detail, the first bonding layer (203a) is disposed on the second wiring portion (221), the third pad portion (222a), and the fourth pad portion (222b).

[0158] The second bonding layer (203b) is disposed on the first bonding layer (203a). In detail, the second bonding layer (203b) is disposed on the third pad portion (222a) and the fourth pad portion (222b).

[0159] Accordingly, the second wiring portion (221) includes the buffer layer (205), the metal layer (201), and the first bonding layer (203a). In addition, the third pad portion (222a) and the fourth pad portion (222b) include the buffer layer (205), the metal layer (201), the first bonding layer (203a), and the second bonding layer (203b).

[0160] Accordingly, the layer structure of the second wiring portion (221) is different from the layer structures of the first pad portion (212a) and the second pad portion (212b).

[0161] The first bonding layer (203a) and the second bonding layer (203b) contain metal. In detail, the first bonding layer (203a) and the second bonding layer (203b) may contain tin (Sn).

[0162] The first bonding layer (203a) and the second bonding layer (203b) are arranged with different thicknesses. Specifically, the thickness of the second bonding layer (203b) is greater than the thickness of the first bonding layer (203a).

[0163] For example, the first bonding layer (203a) has a thickness of 0.02 μm to 0.06 μm. In addition, the second bonding layer (203b) has a thickness of 0.2 μm to 0.6 μm.

[0164] Accordingly, the thickness of the first wiring portion (211) is reduced. The flexible circuit board includes a bending area (BA) that is bent in one area. The wiring portion is arranged on the bending area (BA). Accordingly, the thickness of the bonding layer on the wiring portion is formed to be small. Accordingly, when the flexible circuit board is bent, cracks can be prevented from forming in the first wiring portion (211).

[0165] The thickness of the circuit pattern may be greater than 8 μm to 25 μm. Specifically, the thickness of the circuit pattern may be 9 μm to 20 μm. Specifically, the thickness of the circuit pattern may be 10 μm to 15 μm.

[0166] If the thickness of the circuit pattern is less than 8 μm, the resistance of the circuit pattern may increase. Furthermore, when a high current flows through the display panel, the circuit pattern may be damaged. If the thickness of the circuit pattern exceeds 25 μm, it becomes difficult to implement a fine pattern.

[0167]

[0168] Referring to FIG. 7, one end of the COF module (2000) is connected to the display panel (4000), and the other end is connected to the circuit board (3000). For example, the display panel (4000) and the circuit board (3000) are disposed on one surface of the COF module (2000). However, the embodiment is not limited thereto. The display panel (4000) and the circuit board (3000) may be disposed on different surfaces of the COF module (2000). In this case, the COF module (2000) may have circuit patterns disposed on each of both surfaces. For example, the COF module (2000) may include a first circuit pattern and a second circuit pattern disposed on a first surface, and a second circuit pattern and a third circuit pattern disposed on the first surface. The second circuit patterns may be connected to each other through vias.

[0169] Since the COF module (2000) includes a flexible substrate, it has a rigid shape and a bent shape between the display panel (3000) and the circuit board (4000). That is, the COF module (2000) may include a bending area (BA).

[0170] The COF module (2000) connects the display panel (4000) and the circuit board (3000), which are arranged opposite each other, in a curved manner. Therefore, the thickness of the electronic device is reduced. Furthermore, the design freedom of the electronic device is enhanced. Furthermore, the COF module (2000) prevents wiring from breaking even when in a curved configuration. Consequently, the reliability of the electronic device is enhanced.

[0171]

[0172] Since the above COF module is flexible, it can be used in various electronic devices.

[0173] For example, referring to FIG. 8, the COF module can be applied to a flexible touch window. Accordingly, a touch device device including the COF module can be a flexible touch device. Accordingly, the user can bend or fold it by hand. Such a flexible touch window can be applied to wearable touch devices, etc.

[0174] Referring to Fig. 9, the COF module can be applied to various wearable touch devices including curved displays. Accordingly, an electronic device including the COF module can be slimmed down or made lighter.

[0175] Referring to Fig. 10, the COF module can be used in various electronic devices having a display portion, such as a TV, monitor, or laptop. In this case, the COF module can also be used in an electronic device having a curved display portion.

[0176]

[0177] The features, structures, effects, etc. described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0178] In addition, although the above description focuses on embodiments, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. Description; A plurality of circuit patterns arranged on the above description; and A protective layer is disposed on the above plurality of circuit patterns and includes an opening, The above multiple circuit patterns are, It includes a plurality of routing pad sections arranged within the above opening and a plurality of routing wiring sections connecting the plurality of routing pad sections, The above multiple routing wiring sections, A flexible circuit board comprising: a first routing wiring portion arranged on the outside of the opening and covered with the protective layer, the first routing wiring portion connecting the plurality of routing pad portions; and a second routing wiring portion arranged on the inside of the opening and connecting the plurality of routing pad portions.

2. In paragraph 1, A flexible circuit board, wherein the first routing wiring section is arranged in at least one area among the upper part of the opening, the lower part of the opening, and the side of the opening in the horizontal direction.

3. In paragraph 1, The above first routing wiring section includes a 1-1 routing wiring section and a 1-2 routing wiring section which are spaced apart from each other, A flexible circuit board in which the above 1-2 routing wiring section is arranged to surround the above 1-1 routing wiring section on the above substrate.

4. In paragraph 3, A flexible circuit board, wherein the width of the first-first routing wiring section and the width of the first-second routing wiring section are different from each other.

5. In paragraph 4, A flexible circuit board, wherein the width of the above 1-1 routing wiring section is greater than the width of the above 1-2 routing wiring section.

6. In paragraph 5, A flexible circuit board, wherein the width of the first-first routing wiring section is two to ten times the width of the first-second routing wiring section.

7. In paragraph 5, The above second routing wiring section A 2-1 routing wiring section positioned inside the above opening and connected to the 1-1 routing wiring section, and A flexible circuit board comprising a 2-2 routing wiring portion, spaced apart from the 2-1 routing wiring portion and positioned inside the opening and connected to the 1-2 routing wiring portion.

8. In paragraph 7, The above second routing wiring section A flexible circuit board, which is spaced apart from the above-mentioned 2-1 routing wiring portion and the above-mentioned 2-2 routing wiring portion and is arranged on the inside of the opening, and is not connected to the above-mentioned 1st routing wiring portion.

9. In paragraph 8, A flexible circuit board, wherein the above-mentioned 2-1 routing wiring section includes areas having different widths.

10. In paragraph 9, The above 2-1 routing wiring section includes a first region having a first width, and a second region having a second width smaller than the first width, The first region of the above 2-1 routing wiring section is a flexible circuit board connected to the 1-1 routing wiring section.

Images