Flexible circuit board, COF module and electronic device including the same

Abstract

A flexible circuit board according to an embodiment includes a substrate having a first surface and a second surface opposite to the first surface, a first circuit pattern and a second circuit pattern disposed on the first surface, and a metal pattern disposed on the second surface, wherein the second surface includes a plurality of first regions and a plurality of second regions, wherein the first pattern is disposed in the first region and the second pattern is disposed in the second region, and the area of ​​the second pattern is larger than the area of ​​the first pattern.

Description

[Technical Field]

[0001] The embodiments relate to a flexible circuit board, a COF module, and an electronic device including the same. [Background technology]

[0002] Recently, various electronic products have become thinner and smaller, which requires semiconductor chips to be mounted at high density in a small area of ​​the electronic product.

[0003] COF (Chip On Film) includes a flexible substrate, which allows it to be used in flexible displays. The COF method can also realize fine pitches, which allows it to be used in high-resolution displays.

[0004] The COF is formed by mounting a semiconductor chip on a thin flexible circuit board, and the semiconductor chip may include an integrated circuit (IC) chip or a large scale integrated circuit (LSI) chip.

[0005] The chip is connected to an external circuit board and a display panel through a circuit pattern. For example, pads are disposed on one end and the other end of the circuit pattern. One of the pads is electrically connected to a terminal of the chip. The other pad is connected to a terminal of the circuit board and a terminal of the display panel. Thus, the chip, the circuit board, and the display panel are electrically connected via the COF. Thus, signals from the chip are transmitted to the display panel through the circuit pattern.

[0006] The flexible circuit board includes a plurality of circuit patterns. The circuit patterns are connected to the chip, the circuit board, and the display panel. The chip is mounted on the flexible circuit board. The signals are transferred to the chip, the circuit board, and the display panel via the circuit patterns. The flexible circuit board is then cut along cutting lines, thereby producing a COF module.

[0007] The chip generates heat during operation, which may increase the internal temperature of the COF module, thereby reducing the reliability of the COF module.

[0008] Therefore, there is a need for a flexible circuit board, a COF module, and an electronic device including the same, each having a new structure that can solve the above problems. Summary of the Invention [Problem to be solved by the invention]

[0009] The embodiment provides a flexible circuit board that can prevent warping.

[0010] The embodiments provide a flexible circuit board with improved heat dissipation. [Means for solving the problem]

[0011] A flexible circuit board according to an embodiment includes a substrate having a first surface and a second surface opposite to the first surface, a first circuit pattern and a second circuit pattern disposed on the first surface, and a metal pattern disposed on the second surface, the second surface including a plurality of first regions and a plurality of second regions, the first pattern being disposed in the first region and the second pattern being disposed in the second region, and the area of ​​the second pattern being larger than the area of ​​the first pattern. [Effects of the Invention]

[0012] The flexible circuit board according to the embodiment includes a first surface and a second surface opposite to the first surface, and a chip is disposed on the first surface.

[0013] The flexible circuit board includes a metal pattern disposed on the first and second surfaces, allowing heat generated by the chip to be dissipated to the outside through the metal pattern, thereby preventing an increase in the internal temperature of the COF module.

[0014] The metal pattern has a predetermined width, which prevents stress from increasing due to the metal pattern, thereby preventing the flexible circuit board from warping, i.e., reducing warpage of the flexible circuit board.

[0015] Therefore, the flexible circuit board according to the embodiment has improved heat dissipation characteristics and reliability.

[0016] A flexible circuit board according to another embodiment includes a plurality of regions. Patterns having different areas are disposed in the plurality of regions. Therefore, the heat dissipation effect is improved by the patterns having larger areas. Furthermore, the flexible circuit board is prevented from warping by the patterns having smaller areas. More specifically, the patterns having smaller areas prevent an increase in stress. Therefore, warpage of the flexible circuit board is reduced.

[0017] Therefore, the flexible circuit board according to the alternative embodiment has improved heat dissipation characteristics and reliability. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a top view of a flexible circuit board according to an embodiment. [Figure 2] FIG. 2 is a bottom view of the flexible circuit board according to the first embodiment. [Figure 3]FIG. 3 is an enlarged view of region A in FIG. [Figure 4] FIG. 4 is an enlarged view of region A in FIG. [Figure 5] FIG. 5 is an enlarged view of region B in FIG. [Figure 6] FIG. 6 is an enlarged view of region C in FIG. [Figure 7] FIG. 7 is a bottom view of the flexible circuit board according to the second embodiment. [Figure 8] FIG. 8 is an enlarged view of region D in FIG. [Figure 9] FIG. 9 is an enlarged view of region E in FIG. [Figure 10] FIG. 10 is another bottom view of the flexible circuit board according to the second embodiment. [Figure 11] FIG. 11 is an enlarged view of region F in FIG. [Figure 12] FIG. 12 is an enlarged view of the G region in FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along the line AA' in FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along the line AA' in FIG. [Figure 15] FIG. 15 is a diagram for explaining a COF module according to an embodiment. [Figure 16] FIG. 16 is a diagram of an electronic device including a flexible circuit board according to an embodiment. [Figure 17] FIG. 17 is a diagram of an electronic device including a flexible circuit board according to an embodiment. [Figure 18] FIG. 18 is a diagram of an electronic device including a flexible circuit board according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical concept of the present invention is not limited to the described embodiments, and may be embodied in various different forms. One or more of the components of the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention.

[0020] Furthermore, unless otherwise clearly and specifically stated, terms (including technical and scientific terms) used in the embodiments of the present invention shall be interpreted as meanings that are commonly understood by a person having ordinary knowledge in the technical field to which the present invention belongs, and commonly used terms, such as terms defined in a dictionary, shall be interpreted in light of the contextual meaning of the relevant technology.

[0021] Furthermore, terms used in the examples of the present invention are intended to describe the examples and are not intended to limit the present invention. In this specification, the singular form can also include the plural form unless otherwise specified in the phrase, and when it is stated as "A and at least one (or one or more) of B and C," it can include one or more of all possible combinations of A, B, and C.

[0022] Furthermore, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. are used to distinguish the components from other components, and the terms do not limit the essence or order of the components.

[0023] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it includes not only the case where the component is directly coupled, coupled, or connected to the other component, but also the case where the component is "coupled," "coupled," or "connected" to the other component by yet another component.

[0024] Furthermore, when a component is described as being formed or positioned "above or below" another component, "above or below" includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or positioned between the two components.

[0025] Furthermore, when the expression "above or below" is used, it can mean not only an upward direction but also a downward direction based on one component.

[0026] In the following description, a first direction 1D is the length direction of the flexible circuit board, and a second direction 2D is the width direction of the flexible circuit board.

[0027] Hereinafter, a flexible circuit board, a COF module, and an electronic device including the same according to embodiments will be described with reference to the drawings.

[0028] Referring to FIGS. 1 and 2, the flexible circuit board 1000 includes a substrate 100, a circuit pattern, a protective layer, and a metal pattern.

[0029] The substrate 100 includes a first surface 1S and a second surface 2S. The first surface 1S and the second surface 2S are opposite surfaces. The circuit pattern, the metal pattern, and the protective layer are disposed on the first surface 1S and the second surface 2S.

[0030] The substrate 100 includes a cutting line CL. The flexible circuit board 1000 is cut along the cutting line CL. Specifically, the circuit pattern, the metal pattern, the protective layer, and the chip are arranged on the substrate 100. Then, the substrate 100 is cut along the cutting line CL. In this way, the COF module 2000 is manufactured.

[0031] The base material 100 includes an effective area AA and a non-effective area UA. Specifically, the first surface 1S includes the effective area AA and the non-effective area UA.

[0032] The effective area AA and the non-effective area UA are divided by the cutting line CL. Specifically, the effective area AA is the area inside the cutting line CL, and the non-effective area UA is the area outside the cutting line CL.

[0033] The circuit pattern, the protective layer, and the chip are disposed on the effective area AA. Dummy patterns and sprocket holes SH are disposed on the non-effective area UA. The dummy patterns increase the strength of the substrate 100. The flexible circuit board 1000 is wound and unwound in a roll-to-roll manner by the sprocket holes SH.

[0034] The substrate 100 includes a chip mounting area CHA. The chip mounting area CHA is arranged on the first surface 1S. The chip mounting area CHA is arranged on the effective area AA. The chip is arranged in the chip mounting area CHA. The pad portion of the circuit pattern is arranged inside the chip mounting area CHA. The protective layer is not arranged on the chip mounting area CHA.

[0035] The substrate 100 includes a flexible material. For example, the substrate 100 may include polyimide (PI), but embodiments are not limited thereto. The substrate 100 may include a polymer material including polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). As a result, the flexible circuit board can be applied to various electronic devices, including curved display devices.

[0036] 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. If the thickness of the substrate 100 exceeds 100 μm, the thickness of the flexible circuit board increases. As a result, the flexibility of the flexible circuit board decreases. If the thickness of the substrate 100 is less than 20 μm, the strength of the substrate decreases. As a result, the substrate may be damaged by heat and pressure generated when mounting the chip.

[0037] The circuit pattern and the protective layer are disposed on the substrate 100. Specifically, the circuit pattern and the protective layer are disposed on the first surface 1S. Specifically, the circuit pattern and the protective layer are disposed on the effective area AA and the non-effective area UA.

[0038] The circuit patterns include a first circuit pattern 210, a second circuit pattern 220, and a third circuit pattern 230.

[0039] 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. The first wiring portion 211, the first pad portion 212a, and the second pad portion 212b may be integrally formed.

[0040] The first pad portion 212a is disposed within the chip mounting area CHA, and is connected to the terminals of the chip, thereby connecting the first circuit pattern 210 to the chip.

[0041] The second pad portion 212b is disposed outside the chip mounting area CHA and is connected to a terminal of an external circuit board, thereby connecting the first circuit pattern 210 to the circuit board.

[0042] The first wiring part 211 is disposed between the first pad part 212a and the second pad part 212b. The first wiring part 211 connects the first pad part 212a and the second pad part 212b. This connects the chip and the circuit board. Therefore, signals generated by the chip are transmitted to the circuit board.

[0043] The first circuit pattern 210 may further include a test pad portion. Specifically, a first test pad portion TP1 is disposed on 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 integrally formed.

[0044] Before connecting the circuit board to the second pad portion 212b, the first circuit pattern 210 is tested. For example, the first circuit pattern 210 can be checked for open and short circuits through the first test pad portion TP1.

[0045] 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. Alternatively, the second wiring portion 221, the third pad portion 222a, and the fourth pad portion 222b may be integrally formed.

[0046] The third pad portion 222a is disposed within the chip mounting area CHA, and is connected to the terminals of the chip, thereby connecting the second circuit pattern 220 to the chip.

[0047] The fourth pad portion 222b is disposed outside the chip mounting area CHA and is connected to an external terminal of a display panel, thereby connecting the second circuit pattern 220 to the display panel.

[0048] The second wiring part 221 is disposed between the third pad part 222a and the fourth pad part 222b. The second wiring part 221 connects the third pad part 222a and the fourth pad part 222b. This connects the chip and the display panel. Therefore, a signal generated by the chip is transferred to the display panel.

[0049] The second circuit pattern 220 may further include a test pad portion. Specifically, a second test pad portion TP2 is disposed 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 integrally formed.

[0050] Before connecting the display panel to the fourth pad portion 222b, the second circuit pattern 220 is tested. For example, the presence or absence of an open or short circuit in the second circuit pattern can be checked through the second test pad portion TP2.

[0051] 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. Alternatively, the third wiring portion 231, the fifth pad portion 232a, and the sixth pad portion 232b may be integrally formed.

[0052] The fifth pad portion 232a and the sixth pad portion 232b are disposed outside the chip mounting area CHA. The fifth pad portion 232a is connected to a terminal of an external circuit board, and the sixth pad portion 232b is connected to a terminal of an external display panel.

[0053] The third wiring portion 231 is disposed 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, thereby connecting the circuit board and the display panel.

[0054] A first protective layer 310 is disposed on the first surface 1S. Thus, the first protective layer 310 is disposed on the first circuit pattern 210, the second circuit pattern 220, and the third circuit pattern 230. The first protective layer 310 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.

[0055] A chip is disposed on the chip mounting area CHA. The chip generates heat during operation, which may increase the internal temperature of the COF module 2000. For this reason, the flexible circuit board according to the embodiment includes a metal pattern.

[0056] The flexible circuit board according to the first embodiment will be described with reference to Figures 2 to 6. For the sake of convenience, the second protective layer is omitted from Figures 3 to 6.

[0057] 2 to 6, the metal pattern is disposed on the substrate 100. Specifically, the metal pattern is disposed on the second surface 2S. The metal pattern is not connected to a chip. The metal pattern may include a 1-1 pattern 411 and a 1-2 pattern 412.

[0058] 2, the second surface 2S includes a plurality of regions. For example, the second surface 2S may include a 1-1 region 1-1A, a 1-2 region 1-2A, and a 1-3 region 1-3A.

[0059] The 1-1 area 1-1A and the 1-2 area 1-2A do not correspond to the chip mounting area CHA, and the 1-3 area 1-3A corresponds to the chip mounting area CHA.

[0060] The 1-2 region 1-2A corresponds to the region on the first surface 1S where the fourth pad portion 222b is arranged.

[0061] Metal patterns are disposed in the 1-1 region 1-1A, the 1-2 region 1-2A, and the 1-3 region 1-3A, respectively. A 1-1 pattern 411 and a 1-2 pattern 412 are disposed in the 1-1 region 1-1A, the 1-2 region 1-2A, and the 1-3 region 1-3A. The 1-1 pattern 411 extends in a first direction 1D. That is, the length direction of the 1-1 pattern 411 is the first direction 1D. Furthermore, the 1-2 pattern 412 extends in a second direction 2D. That is, the length direction of the 1-2 pattern 412 is the second direction 2D.

[0062] 3 and 4, the 1-1 pattern 411 is disposed on the 1-1 region 1-1A. More specifically, a plurality of 1-1 patterns 411 are disposed on the 1-1 region 1-1A. The plurality of 1-1 patterns 411 are spaced apart in the second direction 2D, and the 1-1 patterns 411 are formed with a set width. For example, the width w1 of the 1-1 pattern 411 may be 20 μm or less. For example, the width w1 of the 1-1 pattern 411 may be 5 μm to 20 μm, 6 μm to 15 μm, or 7 μm to 12 μm. Therefore, a pattern having a fine line width is disposed on the 1-1 region 1-1A.

[0063] A first connecting pattern CP1 is disposed on the 1-1 region 1-1A. The first connecting pattern CP1 is connected to a plurality of 1-1 patterns 411. More specifically, the first connecting pattern CP1 is connected to the plurality of 1-1 patterns 411 spaced apart in the second direction 2D. Therefore, the plurality of 1-1 patterns 411 are connected by the first connecting pattern CP1.

[0064] 4, the 1-1 pattern 410 includes a plurality of groups. For example, the 1-1 pattern 411 may include a first group G1 and a second group G2. The first group G1 includes a 1-1a pattern 411a. The second group G2 includes a 1-1b pattern 411b.

[0065] The first group G1 and the second group G2 are spaced apart from each other. The first connecting pattern CP1 is disposed between the first group G1 and the second group G2. Therefore, the first group G1 and the second group G2 are connected by the first connecting pattern CP1.

[0066] Referring to FIG. 5, the 1-2 pattern 412 is disposed on the 1-2 region 1-2A. More specifically, a plurality of 1-2 patterns 412 are disposed on the 1-2 region 1-2A. The plurality of 1-2 patterns 412 are spaced apart in the first direction 1D, and the 1-2 patterns 412 have a predetermined width. For example, the width w2 of the 1-2 pattern 412 may be 20 μm or less. For example, the width w2 of the 1-2 pattern 412 may be 5 μm to 20 μm, 6 μm to 15 μm, or 7 μm to 12 μm. Therefore, a pattern having a fine line width is disposed on the 1-2 region 1-2A.

[0067] The width w1 of the first-first pattern 411 and the width w2 of the first-second pattern 412 may be different. For example, the width w2 of the first-second pattern 412 may be smaller than the width w1 of the first-first pattern 411.

[0068] A second connecting pattern CP2 is disposed on the first-2 region 1-2A. The second connecting pattern CP2 is connected to a plurality of first-2 patterns 412. More specifically, the second connecting pattern CP2 is connected to the plurality of first-2 patterns 412 spaced apart in the first direction 1D. Therefore, the plurality of first-2 patterns 412 are connected by the second connecting pattern CP2.

[0069] A third connecting pattern CP3 is disposed in the boundary region between the 1-1 region 1-1A and the 1-2 region 1-2A. The third connecting pattern CP3 is connected to the 1-1 pattern 411 and the 1-2 pattern 412. Therefore, the 1-1 pattern 411 and the 1-2 pattern 412 are connected by the third connecting pattern CP3.

[0070] 6, the 1-1 pattern 411 and the 1-2 pattern 412 are disposed on the 1-3 region 1-3A. Specifically, a plurality of 1-1 patterns 411 and a plurality of 1-2 patterns 412 are disposed on the 1-3 region 1-3A.

[0071] The 1-3 region 1-3A may include multiple regions. For example, the 1-3 region 1-3A may include a 1-3a region 1-3Aa and a 1-3b region 1-3Ab. The 1-3a region 1-3Aa is disposed on the outer periphery of the 1-3 region 1-3A. The 1-3b region 1-3b is disposed in the center of the 1-3 region 1-3A. Thus, the 1-3b region 1-3b is disposed between the 1-3a regions 1-3Aa.

[0072] The width of the 1-3a region 1-3Aa and the width of the 1-3b region 1-3Ab may be different, for example, the width of the 1-3a region 1-3Aa may be greater than the width of the 1-3b region 1-3Ab.

[0073] The 1-1 pattern 411 is disposed in the 1-3a region 1-3Aa, and the 1-2 pattern 412 is disposed in the 1-3b region 1-3Ab.

[0074] The 1-3 region 1-3A corresponds to the chip mounting region CHA. Therefore, heat generated from the chip is concentrated in the 1-3 region 1-3A. Therefore, the 1-1 pattern 411 and the 1-2 pattern 412 are disposed in the 1-3 region 1-3A. The 1-1 pattern 411 and the 1-2 pattern 412 extend in different directions. As a result, the heat generated in the 1-3 region 1-3A is dispersed in multiple directions. This improves heat dissipation efficiency.

[0075] The flexible circuit board bends in the area between the chip mounting area and the fourth pad portion 222b. Therefore, the 1-1 pattern 411 extending in the bending direction of the flexible circuit board is disposed on the 1-3a area 1-3Aa. Therefore, the flexible circuit board can be easily bent.

[0076] The first connecting pattern CP1, the second connecting pattern CP2, and the third connecting pattern CP3 are arranged on the 1-3 region 1-3A. Thus, the plurality of 1-1 patterns 411 arranged on the 1-3 region 1-3A are connected by the first connecting pattern CP1. The plurality of 1-2 patterns 411 arranged on the 1-3 region 1-3A are connected by the second connecting pattern CP2. The 1-1 pattern 411 and the 1-2 pattern 411 arranged on the 1-3 region 1-3A are connected by the third connecting pattern CP3.

[0077] A second protective layer 320 is disposed on the second surface 2S. Thus, the second protective layer 310 is disposed on the first pattern 411, the second pattern 412, and the connecting patterns CP1, CP2, and CP3. The first protective layer 310 and the second protective layer 320 are disposed with different areas. The second protective layer 320 is also disposed on the chip mounting area CHA and areas corresponding to the pad portions 212a, 212b, 222a, 222b, 232a, and 232b. Therefore, the area of ​​the second protective layer 320 is larger than the area of ​​the first protective layer 310.

[0078] The width of the 1-1 pattern 411 arranged in the 1-1 region 1-1A may be different from the width of the 1-1 pattern 411 arranged in the 1-3 region 1-3A. Specifically, the width of the 1-1 pattern 411 arranged in the 1-1 region 1-1A may be greater than the width of the 1-1 pattern 411 arranged in the 1-3 region 1-3A.

[0079] As a result, the number of 1-1 patterns 411 arranged on the 1-3 region 1-3A increases, and therefore the number of paths through which heat generated on the 1-3 region 1-3A moves increases, thereby improving heat dissipation efficiency.

[0080] The flexible circuit board according to the first embodiment includes a metal pattern on the second surface, so that heat generated by the chip is dissipated to the outside through the metal pattern, thereby preventing an increase in the internal temperature of the COF module.

[0081] In addition, the metal pattern has a predetermined width, which prevents stress from increasing due to the metal pattern, thereby preventing warpage of the flexible circuit board.

[0082] Therefore, the flexible circuit board according to the first embodiment has improved heat dissipation characteristics and reliability.

[0083] A flexible circuit board according to a second embodiment will be described below with reference to Figures 7 to 12. For the sake of convenience, the second protective layer is not shown in Figures 8, 9, 11 and 12.

[0084] 7 to 12, the metal pattern is disposed on the substrate 100. More specifically, the metal pattern is disposed on the second surface 2S. The metal pattern includes a first pattern 410 and a second pattern 420.

[0085] 7 and 10, the second surface 2S includes a plurality of regions. For example, the second surface 2S may include a first region 1A and a second region 2A. In particular, the second surface 2S may include a plurality of first regions 1A and a plurality of second regions 2A.

[0086] The first regions 1A and the second regions 2A are arranged alternately. Therefore, one second region 2A is arranged between a plurality of adjacent first regions 1A. Also, one first region 1A is arranged between a plurality of adjacent second regions 2A.

[0087] Any one of the first areas 1A is disposed in an area corresponding to the chip mounting area CHA. For example, any one of the first areas 1A may be disposed in a central area of ​​the flexible circuit board.

[0088] The first regions 1A extend in the first direction 1D, i.e., the length direction of the first regions 1A is the first direction 1D. The first regions 1A are also spaced apart in the second direction 2D.

[0089] The widths w3 of the first regions 1A may be different from each other. For example, referring to FIG. 10, the widths of the first regions 1A may be gradually reduced from the central region to the outer region of the flexible circuit board.

[0090] The plurality of second areas 2A are not arranged in areas corresponding to the chip mounting areas CHA.

[0091] The second regions 2A extend in the first direction 1D, i.e., the length direction of the second regions 2A is the first direction 1D. The second regions 2A are spaced apart in the second direction 2D.

[0092] The widths w4 of the second regions 2A may be different from each other. For example, referring to Fig. 10, the widths of the second regions 1A may gradually decrease from the central region to the outer region of the flexible circuit board.

[0093] The first region 1A and the second region 2A may have different sizes. Specifically, the areas of the first region 1A and the second region 2A may be different. For example, the total area of ​​the second region 2A may be larger than the total area of ​​the first region 1A.

[0094] Metal patterns are disposed on the first region 1A and the second region 2A, respectively. More specifically, a first pattern 410 and a second pattern 420 are disposed on the first region 1A and the second region 2A.

[0095] The first pattern 410 and the second pattern 420 are different in size. Specifically, the width of the second pattern 420 is larger than the width of the first pattern 410. Also, the area of ​​the second pattern 420 is larger than the area of ​​the first pattern 410. For example, the area of ​​the second pattern 420 may be larger than the area of ​​the chip mounting area CHA.

[0096] In addition, the minimum width of the second pattern 420 is greater than the minimum width of the first pattern 410 .

[0097] 8 and 11, the first pattern 410 is disposed on the first region 1A. The first pattern 410 has a set width. For example, the width of the first pattern 410 may be 20 μm or less. For example, the width of the first pattern 410 may be 5 μm to 20 μm, 6 μm to 15 μm, or 7 μm to 12 μm. Therefore, a pattern having a fine line width is disposed on the first region 1A.

[0098] The first pattern 410 includes a 1-1 pattern 411 and a 1-2 pattern 412. The 1-1 pattern 411 and the 1-2 pattern 412 extend in different directions. The 1-1 pattern 411 extends in a first direction 1D. That is, the length direction of the 1-1 pattern 411 is the first direction 1D. Furthermore, the 1-2 pattern 412 extends in a second direction 2D. That is, the length direction of the 1-2 pattern 412 is the second direction 2D. Therefore, the 1-1 pattern 411 and the 1-2 pattern 412 extend in the length direction of the first region 1A.

[0099] A plurality of 1-1 patterns 411 and a plurality of 1-2 patterns 412 are arranged on the first region 1A, and the plurality of 1-1 patterns 411 are spaced apart in the second direction 2D, and the plurality of 1-2 patterns 412 are spaced apart in the first direction 1D.

[0100] The second pattern 420 is disposed on the second region 2A. The area of ​​the second pattern 420 may be the same as or similar to the area of ​​the second region 2A. That is, the second pattern 420 may be a bulk metal.

[0101] The metal pattern includes a plurality of connection patterns, specifically, a first connection pattern CP1, a second connection pattern CP2, and a third connection pattern CP3.

[0102] The first connecting pattern CP1 is connected to the plurality of 1-1 patterns 411 and the second pattern 420. The plurality of 1-1 patterns 411 are connected by the first connecting pattern CP1. In addition, the plurality of 1-1 patterns 411 and the second pattern 420 are connected by the first connecting pattern CP1.

[0103] The second connecting pattern CP2 is connected to the plurality of first-second patterns 412 and the second pattern 420. The plurality of first-second patterns 412 are connected by the second connecting pattern CP2. In addition, the plurality of first-second patterns 412 and the second pattern 420 are connected by the second connecting pattern CP2.

[0104] The third connecting pattern CP3 is connected to the plurality of 1-1 patterns 412, the plurality of 1-2 patterns 412, and the second pattern 420. The plurality of 1-1 patterns 412, the plurality of 1-2 patterns 412, and the second pattern 420 are connected by the third connecting pattern CP3.

[0105] The metal pattern has an area within a set range. The area of ​​the metal pattern is the sum of the areas of the first pattern 410, the second pattern 420, and the connecting patterns CP1, CP2, and CP3. The metal pattern may occupy 50% or more of the area of ​​the effective area AA. Specifically, the area of ​​the metal pattern may be 50% to 80%, 55% to 75%, or 60% to 70% of the area of ​​the effective area AA.

[0106] If the area of ​​the metal pattern is less than 50% of the area of ​​the effective area AA, the heat dissipation effect of the metal pattern is reduced, resulting in an increase in the internal temperature of the COF module. If the area of ​​the metal pattern is more than 80% of the total area of ​​the effective area AA, the stress transmitted to the flexible circuit board increases, resulting in an increase in the warpage of the COF module.

[0107] 9 and 12, any one of the first areas corresponds to the chip mounting area CHA. The first area corresponding to the chip mounting area CHA includes a plurality of areas.

[0108] For example, the first region corresponding to the chip mounting region CHA may include a region 1a 1Aa and a region 1b 1Ab. The region 1a 1Aa is disposed on the periphery of the first region corresponding to the chip mounting region CHA. The region 1b 1Ab is disposed in the center of the first region corresponding to the chip mounting region CHA. Thus, the region 1b 1Ab is disposed between the regions 1a 1Aa.

[0109] The width of the 1a region 1Aa and the width of the 1b region 1Ab may be different, for example, the width of the 1a region 1Aa may be greater than the width of the 1b region 1Ab.

[0110] The 1-1 pattern 411 is disposed on the 1a region 1Aa, and the 1-2 pattern 412 is disposed on the 1b region 1Ab.

[0111] Therefore, heat generated from the chip is concentrated in the first region corresponding to the chip mounting area CHA. Therefore, the first-1 pattern 411 and the first-2 pattern 412, which extend in different directions, are arranged in the first region corresponding to the chip mounting area CHA. As a result, heat generated in the first region corresponding to the chip mounting area CHA is dispersed in multiple directions. Therefore, heat dissipation efficiency is improved.

[0112] In addition, the flexible circuit board can bend in the area between the chip mounting area and the fourth pad portion 222b. Therefore, the 1-1 pattern 411 extending in the bending direction of the flexible circuit board is disposed on the 1a area 1Aa. Therefore, the flexible circuit board can be easily bent.

[0113] The flexible circuit board according to the second embodiment includes a metal pattern on the second surface, so that heat generated by the chip is dissipated to the outside through the metal pattern, thereby preventing an increase in the internal temperature of the COF module.

[0114] The flexible circuit board also includes a plurality of regions. Patterns having different areas are arranged in the plurality of regions. Therefore, the large-area patterns improve heat dissipation. Furthermore, the small-area patterns prevent warping of the flexible circuit board. Specifically, the small-area patterns prevent stress from increasing. Therefore, warpage of the flexible circuit board is reduced.

[0115] Therefore, the flexible circuit board according to the second embodiment has improved heat dissipation characteristics and reliability.

[0116] Hereinafter, the reduction in internal temperature and warpage due to the metal pattern through the flexible circuit board according to the embodiment and the comparative example will be described.

[0117] Example 1 A metal pattern is disposed on the second surface of the flexible circuit board as shown in Figures 2 to 6. The thickness of the metal pattern is 12 μm.

[0118] Then, a chip is mounted on the flexible circuit board, and the flexible circuit board is cut along the cutting lines to produce a COF module.

[0119] The internal temperature and warpage of the COF module are then measured.

[0120] Example 2 A COF module is manufactured using the flexible circuit boards shown in Figures 7 to 9. The thickness of the metal pattern is 8 μm.

[0121] The internal temperature and warpage of the COF module are then measured.

[0122] Example 3 A COF module is manufactured using the flexible circuit boards shown in Figures 10 to 12. The thickness of the metal pattern is 8 μm.

[0123] Subsequently, the internal temperature and warpage of the COF module are measured.

[0124] (Comparative Example) A metal pattern is disposed over the entire effective area of ​​the second surface of the flexible circuit board, i.e., the entire effective area is covered with the metal pattern, and the thickness of the metal pattern is 8 μm.

[0125] Subsequently, the internal temperature and warpage of the COF module are measured.

[0126] [Table 1]

[0127] Referring to Table 1, the warpage of the COF module according to the embodiment is 3.0 mm or less. In contrast, the warpage of the flexible circuit board according to the comparative example is 4.0 mm. Therefore, the warpage of the COF module according to the embodiment is reduced.

[0128] Moreover, the internal temperature of the flexible circuit boards according to Examples 2 and 3 is 76° C. or less. Therefore, the COF modules according to the examples have improved heat dissipation characteristics.

[0129] That is, the COF module according to the embodiment has improved heat dissipation characteristics and improved warpage.

[0130] The layer structures of the first circuit pattern, the second circuit pattern, and the third circuit pattern will be described below with reference to Figures 13 and 14. For convenience of explanation, the first circuit pattern will be mainly described. The following description also applies to both the second circuit pattern and the third circuit pattern.

[0131] 13, the first circuit pattern is formed in multiple layers. Specifically, the first circuit pattern may include a first metal layer 201 and a second metal layer 202.

[0132] The first metal layer 201 may be a seed layer of the first circuit pattern. For example, the first metal layer 201 may be a seed layer formed on the substrate 100 by electroless plating using a metal material such as copper (Cu).

[0133] The second metal layer 202 may be a plating layer. For example, the second metal layer 202 may be a plating layer formed by electrolytic plating using the first metal layer 201 as a seed layer.

[0134] The thickness of the first metal layer 201 may be less than the thickness of the second metal layer 202 .

[0135] For example, the first metal layer 201 may have a thickness of 0.7 μm to 2 μm, and the second metal layer 202 may have a thickness of 10 μm to 25 μm.

[0136] The first metal layer 201 and the second metal layer 202 may include the same metal material, for example, copper (Cu).

[0137] However, the embodiment is not limited thereto. For example, the first metal layer 201 and the second metal layer 202 may be formed as a single metal layer.

[0138] An adhesive layer 203 is disposed on the second metal layer 201. The adhesive layer 203 is disposed on the side surfaces of the first metal layer 201 and the second metal layer 202 and on the top surface of the second metal layer 202. The adhesive layer 203 is disposed to surround the first metal layer 201 and the second metal layer 202.

[0139] The bonding layer 203 may include a metal. Specifically, the bonding layer 203 may include tin (Sn).

[0140] The bonding layer 203 may be formed to a thickness of 0.3 μm to 0.7 μm, and the tin content of the bonding layer 203 may increase as it extends from the lower surface to the upper surface.

[0141] The bonding layer 203 contacts the second metal layer 202. Therefore, the tin content may increase and the copper content may decrease from the bottom surface of the bonding layer 203 toward the top surface thereof.

[0142] Therefore, only pure tin remains on the upper surface of the bonding layer 203 to a thickness of 0.1 μm to 0.3 μm.

[0143] The bonding layer 203 allows the chip, the circuit board, and the terminals of the display panel to be easily bonded to the pads using heat and pressure. When heat and pressure are applied to the pads, the top surface of the bonding layer melts, leaving pure tin on the top surface of the bonding layer. This allows the chip, the circuit board, and the terminals of the display panel to be easily bonded.

[0144] The first circuit pattern may have a thickness of 2 μm to 25 μm. For example, the first circuit pattern may have a thickness of 5 μm to 20 μm. For example, the first circuit pattern may have a thickness of 7 μm to 15 μm.

[0145] If the thickness of the first circuit pattern is less than 2 μm, the resistance of the second circuit pattern increases, and if the thickness of the first circuit pattern is more than 25 μm, it becomes difficult to realize a fine pattern.

[0146] A buffer layer 205 is disposed between the substrate 100 and the first circuit pattern. The buffer layer 205 improves the adhesion between the substrate 100 and the first circuit pattern.

[0147] The buffer layer 205 has multiple layers. A first buffer layer 205a and a second buffer layer 205b are disposed on the substrate 100. The first buffer layer 205a contacts the substrate 100. The second buffer layer 205b contacts the first circuit pattern 210.

[0148] The first buffer layer 205a may include a material that has excellent adhesion to the substrate 100. For example, the first buffer layer 205a may include nickel (Ni). The second buffer layer 205b may include a material that has excellent adhesion to the second circuit pattern. For example, the second buffer layer 205b may include chromium (Cr).

[0149] The buffer layer 205 may have a thickness in the nanometer range, for example, 20 nm or less.

[0150] The adhesive strength between the substrate 100 and the first circuit pattern is improved by the buffer layer 205. This prevents the first circuit pattern from peeling off.

[0151] 14, the adhesive layer 203 may include a plurality of adhesive layers, for example, a first adhesive layer 203a and a second adhesive layer 203b.

[0152] The first adhesive layer 203a is disposed on the first wiring portion 211, the first pad portion 212a, and the second pad portion 212b.

[0153] The second bonding layer 203b is disposed only on the first pad portion 212a and the second pad portion 212b. The first wiring portion 211 has a layer structure different from the first pad portion 212a and the second pad portion 212b due to the second bonding layer 203b.

[0154] The first and second bonding layers 203a and 203b may contain metal, more specifically, tin (Sn).

[0155] The first adhesive layer 203a and the second adhesive layer 203b may be disposed to have different thicknesses. Specifically, the second adhesive layer 203b may have a thickness greater than that of the first adhesive layer 203a.

[0156] For example, the first adhesive layer 203a may have a thickness of 0.02 μm to 0.06 μm, and the second adhesive layer 203b may have a thickness of 0.2 μm to 0.6 μm.

[0157] If the adhesive layer is disposed thickly between the protective layer 300 and the first wiring portion 211, cracks may occur when the flexible circuit board is bent. Therefore, the first adhesive layer 203a between the protective layer 300 and the first wiring portion 211 is formed to have a thin thickness. This makes it possible to prevent cracks from occurring when the flexible circuit board is bent.

[0158] A chip CH is mounted on the chip mounting area CHA of the flexible circuit board according to the embodiment, and then the flexible circuit board is cut along the cutting lines CL, thereby forming a COF module.

[0159] The COF module 2000 connects a display panel 4000 and a circuit board 3000 .

[0160] 15 , 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 circuit board 3000 and the display panel 4000 may be disposed on one side of the COF module 2000, but the embodiment is not limited thereto. The display panel 4000 and the circuit board 3000 may be disposed on the other side of the COF module 2000.

[0161] The COF module 2000 includes a flexible substrate. Therefore, the COF module 2000 can have both a rigid form and a bending form. That is, the COF module 2000 can include a bending area (BA).

[0162] The COF module 2000 can connect the display panel 4000 and the circuit board 3000 in a bent shape, thereby reducing the thickness of the electronic device. In addition, the wiring pattern of the COF module 2000 will not be broken even when bent, thereby improving the reliability of the electronic device including the COF module.

[0163] The COF module is flexible and therefore applicable to a variety of electronic devices.

[0164] Referring to FIG. 16, the COF module is applied to a flexible touch device.

[0165] Referring to FIG. 17, the COF module is applied to various wearable touch devices.

[0166] Referring to FIG. 18, the COF module is applied to electronic devices such as TVs, monitors or laptops.

[0167] 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 one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, the contents related to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0168] Furthermore, although the above description has focused on the embodiments, these are merely examples and are not intended to limit the present invention. A person skilled in the art to which the present invention pertains may make various modifications and applications not exemplified above within the scope of the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified and implemented. Differences related to such modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims.

Claims

1. a substrate including a first surface and a second surface opposite the first surface; a first circuit pattern and a second circuit pattern disposed on the first surface; a metal pattern disposed on the second surface; the second surface includes a plurality of first regions and a plurality of second regions; a first pattern is disposed in the first region; a second pattern is disposed in the second region; The flexible circuit board, wherein the area of ​​the second pattern is larger than the area of ​​the first pattern.

2. the first surface includes a chip mounting area; The flexible circuit board according to claim 1 , wherein the area of ​​the second pattern is larger than the area of ​​the chip mounting region.

3. The flexible circuit board according to claim 1 , wherein the width of the first pattern is 5 μm to 20 μm.

4. The flexible circuit board of claim 1 , wherein the first pattern includes a plurality of first-1 patterns and a plurality of first-2 patterns extending in different directions.

5. The flexible circuit board of claim 4 , wherein the first-1 pattern and the first-2 pattern extend in a length direction of the first region.

6. The metal pattern is a first connection pattern connected to the plurality of first-1 patterns and the second pattern; a second connection pattern connected to the plurality of first-second patterns and the second pattern; The flexible circuit board according to claim 4 , comprising: a third connecting pattern connected to the plurality of first-1 patterns, a plurality of first-2 patterns, and the second pattern.

7. the substrate has a defined cutting line; the substrate includes an effective area defined by an area inside the cutting line; The flexible circuit board according to claim 1 , wherein the area of ​​the metal pattern is 50% to 80% of the area of ​​the effective region.

8. any one of the plurality of first regions corresponds to the chip mounting region; the first region corresponding to the chip mounting region includes a first region a disposed on the periphery of the first region and a first region b disposed in the center of the first region; The width of the first a region is greater than the width of the first b region, The 1-1 pattern is disposed on the 1a region, The flexible circuit board according to claim 4 , wherein the first-2 pattern is disposed on the first b region.

9. a substrate including a first surface including a chip mounting area and a second surface opposite to the first surface; a first circuit pattern and a second circuit pattern disposed on the first surface; a metal pattern disposed on the second surface; the second surface includes a 1-1 region, a 1-2 region, and a 1-3 region; the first to third regions correspond to the chip mounting region; the metal pattern includes a first-1 pattern and a first-2 pattern disposed on the first-1 region, the first-2 region, and the first-3 region, The first-first pattern and the first-second pattern extend in different directions from each other, A flexible circuit board, wherein the width of the first-1 pattern and the first-2 pattern is 5 μm to 20 μm.

10. The flexible circuit board according to claim 9 , wherein a plurality of first-1 patterns and a first connecting pattern connected to the plurality of first-1 patterns are arranged in the first-1 region.

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