Flexible printed circuit board, cof module and electronic device including the same

Abstract

A flexible circuit board according to an embodiment includes: a substrate including a chip mounting area; and a circuit pattern disposed on the substrate. The circuit patterns include a first circuit pattern, a second circuit pattern, and a third circuit pattern. The first circuit pattern includes a first pad portion disposed inside the chip mounting area, a second pad portion disposed outside the chip mounting area, and a first wiring portion connected to the first pad portion and the second pad portion. The second circuit pattern includes a third pad portion disposed inside the chip mounting area, a fourth pad portion disposed outside the chip mounting area, and a second wiring portion connected to the third pad portion and the fourth pad portion. The third circuit pattern includes a third wiring portion and a fifth pad portion disposed inside the chip mounting area. A width of the third wiring portion is larger than a width of the fifth pad portion.

Description

Technical Field

[0001] Embodiments relate to a flexible printed circuit board, a COF module, and an electronic device including the COF module. Background Art

[0002] Recently, various electronic products have become thinner and thinner. In addition, electronic products have become smaller and lighter. Therefore, it is necessary to mount semiconductor chips in a narrow area of ​​electronic products with high density.

[0003] The Chip On Film (COF) method uses a flexible substrate. Therefore, the COF method is applied to flexible displays. For example, the COF method can be applied to various wearable electronic devices. The COF method can form a fine pitch. Therefore, the COF method is applied to high-resolution displays.

[0004] The COF method is a method of mounting a semiconductor chip on a flexible circuit board in the form of a thin film. For example, the semiconductor chip may include an integrated circuit (IC) chip or a large-scale integrated circuit (LSI) chip.

[0005] The chip is connected to a printed circuit board (PCB) and a display panel through a circuit pattern. For example, a pad portion is provided at one end and the other end of the circuit pattern, respectively. One pad portion is electrically connected to a terminal of the chip. In addition, another pad portion is connected to a terminal of the printed circuit board and a terminal of the display panel. Thus, the chip, the PCB, and the display panel are electrically connected through the COF. Therefore, the signal is transmitted to the display panel through the circuit pattern.

[0006] The chip is mounted on a flexible circuit board. The chip has a multi-layer structure. Each layer performs a corresponding function.

[0007] Recently, the film level routing FLR (Film Level Route, FLR) technology has been applied. The FLR technology directly sets a part of the multilayer structure and the circuit pattern connected to the partial layer on the flexible circuit board. Since the wiring pattern is set in the chip mounting area of ​​the flexible circuit board, the size of the chip is reduced. Therefore, the manufacturing cost of the chip is reduced.

[0008] The process of bonding the wiring pattern and the chip is performed at high temperature and high pressure. Therefore, stress may be generated during the process. Therefore, the stress may be transferred to the wiring pattern. Therefore, cracks may occur in one area of ​​the wiring pattern. Therefore, the reliability of the COF module may be reduced.

[0009] Therefore, there is a need for a flexible circuit board, a COF module and an electronic device including the COF module having a novel structure capable of solving the above problems. Summary of the invention

[0010] Technical issues

[0011] The embodiment provides a flexible circuit board capable of ensuring reliability by preventing cracks in a wiring pattern.

[0012] Embodiments provide a COF module with improved electrical characteristics.

[0013] Technical Solution

[0014] According to an embodiment, a flexible circuit board includes: a substrate, the substrate includes a chip mounting area; and a circuit pattern, the circuit pattern is arranged on the substrate, wherein the circuit pattern includes a first circuit pattern, a second circuit pattern and a third circuit pattern, wherein the first circuit pattern includes a first pad portion arranged inside the chip mounting area, a second pad portion arranged outside the chip mounting area, and a first wiring portion connected to the first pad portion and the second pad portion, the second circuit pattern includes a third pad portion arranged inside the chip mounting area, a fourth pad portion arranged outside the chip mounting area, and a second wiring portion connected to the third pad portion and the fourth pad portion, the third circuit pattern includes a third wiring portion and a fifth pad portion arranged inside the chip mounting area, and a width of the third wiring portion is greater than a width of the fifth pad portion.

[0015] Beneficial Effects

[0016] The flexible circuit board according to the embodiment includes a third circuit pattern (wiring pattern) arranged in the chip mounting area. When the third circuit pattern is joined with the chip, stress is generated. The third circuit pattern is formed into various sizes. Therefore, the third circuit pattern is prevented from being damaged or deformed due to stress.

[0017] The stress may vary based on the position. Therefore, the width of the wiring portion of the third circuit pattern is formed to various sizes based on the position. Therefore, the third circuit pattern is prevented from being damaged or deformed.

[0018] Therefore, the flexible circuit board and the COF module have a small size. In addition, the flexible circuit board and the COF module have improved electrical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a top view of a COF module including a flexible circuit board according to an embodiment.

[0020] Figure 2 It is used to illustrate Figure 1 Graph of area A.

[0021] Figure 3 and Figure 4 It is along Figure 2 A cross-sectional view taken along the area AA'.

[0022] Figure 5 yes Figure 2 Magnified view of area B.

[0023] Figure 6 It is used to illustrate Figure 3 Graph of various shapes of area C.

[0024] Figure 7 It is used to illustrate Figure 1 Another picture of region A.

[0025] Figure 8 yes Figure 7 Magnified view of area D.

[0026] Fig. 9 It is used to illustrate Figure 1 Another picture of region A.

[0027] Fig.10 yes Fig. 9 Magnified view of area E.

[0028] Fig.11 It is used to illustrate Figure 1 Another picture of region A.

[0029] Fig.12 yes Fig.11 Magnified view of area F.

[0030] Fig.13 It is used to illustrate Figure 1 Another picture of region A.

[0031] Fig.14 It is along Fig.13 A cross-sectional view taken along area BB'.

[0032] Fig.15 is a top view of a COF module according to an embodiment.

[0033] Fig.16 is a cross-sectional view illustrating a connection relationship of a COF module including a flexible circuit board according to an embodiment.

[0034] Figures 17 to 19 is a diagram of an electronic device including a flexible circuit board according to an embodiment. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the spirit and scope of the present disclosure are not limited to a part of the described embodiments, and can be implemented in various other forms, and within the spirit and scope of the present disclosure, more than one element of the embodiment can be selectively combined and rearranged.

[0036] In addition, unless otherwise explicitly defined and described, the terms (including technical terms and scientific terms) used in the embodiments of the present disclosure may be interpreted as having the same meaning as that commonly understood by ordinary technicians in the field to which the present disclosure belongs, and these terms (for example, those defined in commonly used dictionaries) may be interpreted as having a meaning consistent with their meaning in the context of the relevant technology.

[0037] In addition, the terms used in the embodiments of the present disclosure are used to describe the embodiments and are not intended to limit the present disclosure. In this specification, unless specifically stated in a phrase, a singular form may also include a plural form, and when described as "at least one (or more) of A (and) B and C", it may include at least one of all combinations that can be combined among A, B and C.

[0038] In addition, when describing the elements of the embodiments of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish an element from other elements, and these terms do not limit the nature, order, or sequence of the elements.

[0039] In addition, when an element is described as being “connected,” “combined” or “contacting” other elements, this may include not only the case where the element is directly “connected,” “combined” or “contacting” the other elements, but also the case where the element is “connected,” “combined” or “contacting” through another element located between the element and the other elements.

[0040] In addition, when described as being formed or arranged "on" or "under" each element, "on..." or "under..." may include not only the case where two elements are directly connected to each other, but also the case where one or more other elements are formed or arranged between the two elements.

[0041] Furthermore, when expressed as “on” or “under”, this may include not only an upward direction based on one element but also a downward direction based on the one element.

[0042] 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 accompanying drawings.

[0043] Figure 1 is a top view of a flexible circuit board according to an embodiment.

[0044] Reference Figure 1 , the flexible circuit board 1000 includes a substrate 100 , a circuit pattern 200 disposed on the substrate 100 , and a protection layer 300 disposed on the circuit pattern 200 .

[0045] The substrate 100 may include a flexible substrate. For example, the substrate 100 may be a polyimide (PI) substrate. However, the embodiment is not limited thereto. The substrate 100 may include a polymer material, for example, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Therefore, the flexible circuit board is applied to various electronic devices including a curved display device. For example, the flexible circuit board can be applied to a wearable electronic device.

[0046] The substrate 100 has 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 may increase. Therefore, the flexibility of the flexible circuit board is reduced. In addition, if the thickness of the substrate 100 is less than 20 μm, the substrate 100 may be damaged when the chip is mounted on the flexible circuit board.

[0047] The substrate 100 includes an active area UA and a non-active area UA. For example, the active area AA may be a central area of ​​the substrate 100. In addition, the non-active area UA may be an edge area of ​​the substrate 100.

[0048] The active area AA includes a chip mounting area CA. The chip mounting area CA is an area where a chip connected to a circuit pattern is mounted. The protective layer 300 is not provided in the chip mounting area CA. Therefore, a pad portion of the circuit pattern provided in the chip mounting area CA is exposed. Therefore, the pad portion of the circuit pattern is connected to a terminal portion of the chip.

[0049] A plurality of circuit patterns 210, 220 and 230 are disposed on the active area AA. In detail, the plurality of circuit patterns are spaced apart from each other. In addition, the plurality of circuit patterns extend in a plurality of directions.

[0050] The active area AA is an area actually used in the flexible circuit board 1000. That is, when the flexible circuit board is in contact with another panel or the like, the active area AA is an area in contact with the panel.

[0051] No circuit pattern is provided in the unactive area UA.

[0052] The unactive area UA includes a plurality of holes. Specifically, the unactive area UA includes a plurality of sprocket holes H. The flexible circuit board is rolled or unrolled through the sprocket holes H in a roll-to-roll manner.

[0053] The unactive area UA is an area not actually used in the flexible circuit board 1000. When the flexible circuit board is brought into contact with another panel or the like, the unactive area UA is removed.

[0054] In detail, the flexible circuit board 1000 includes a cutting line CL as a boundary between the unactive area UA and the active area AA. The COF module is manufactured by cutting the cutting line CL.

[0055] The circuit pattern includes a wiring portion and a pad portion. In addition, a plurality of circuit patterns are provided in the active area AA. The circuit pattern includes a first circuit pattern 210 , a second circuit pattern 220 , and a third circuit pattern 230 .

[0056] In detail, the first circuit pattern 210 and the second circuit pattern 220 are disposed in an inner region of the chip mounting area CA and an outer region of the chip mounting area CA.

[0057] In addition, the third circuit pattern 230 is disposed in an inner region of the chip mounting area CA. Figure 1 and Figure 2 , the first circuit pattern 210 includes a first wiring portion 211, a first pad portion 212a, and a second pad portion 212b. The first pad portion 212a is disposed inside the chip mounting area CA. The second pad portion 212b is disposed outside the chip mounting area CA. The first wiring portion 211 is disposed between the first pad portion 212a and the second pad portion 212b. The first pad portion 212a and the second pad portion 212b are connected through the first wiring portion 211.

[0058] The first wiring portion 211 , the first pad portion 212 a , and the second pad portion 212 b may be integrally formed.

[0059] The first wiring portion 211 extends in the first direction based on the chip mounting area CA.

[0060] The first pad portion 212a is electrically connected to the chip. The second pad portion 212b is electrically connected to the printed circuit board. The first wiring portion 211 transmits signals between the chip and the printed circuit board.

[0061] The protective layer 300 is disposed on the first circuit pattern 210. The protective layer 300 is disposed on the first wiring portion 211. The protective layer 300 surrounds the first wiring portion 211. In addition, the protective layer 300 is not disposed on the first pad portion 212a and the second pad portion 212b. Therefore, the first pad portion 212a and the second pad portion 212b are exposed to the outside.

[0062] The second circuit pattern 220 includes a second wiring portion 221, a third pad portion 222a, and a fourth pad portion 222b. The third pad portion 222a is disposed inside the chip mounting area CA. The fourth pad portion 222b is disposed outside the chip mounting area CA. The second wiring portion 221 is disposed between the third pad portion 222a and the fourth pad portion 222b. The third pad portion 222a and the fourth pad portion 222b are connected by the second wiring portion 221.

[0063] The second wiring portion 221 , the third pad portion 222 a , and the fourth pad portion 222 b may be integrally formed.

[0064] The second wiring portion 221 extends in a second direction based on the chip mounting area CA. The second direction is opposite to the first direction.

[0065] The third pad portion 222a is electrically connected to the chip. In addition, the fourth pad portion 222b is electrically connected to the display panel. In addition, the second wiring portion 221 transmits signals between the chip and the display panel.

[0066] The protective layer 300 is disposed on the second circuit pattern 220. The protective layer 300 is disposed on the second wiring portion 221. The protective layer 300 surrounds the second wiring portion 221. In addition, the protective layer 300 is not disposed on the third pad portion 222a and the fourth pad portion 222b. Therefore, the third pad portion 222a and the fourth pad portion 222b may be exposed to the outside.

[0067] The third circuit pattern 230 includes a third wiring portion 231 and a plurality of fifth pad portions 232. The third wiring portion 231 and the fifth pad portion 232 are disposed inside the chip mounting area CA.

[0068] The third circuit pattern 230 is connected to the chip. The fifth pad portion 232 is electrically connected to the chip. The third circuit pattern 230 includes a plurality of third circuit patterns. Each third circuit pattern 230 includes at least one fifth pad portion. Each fifth pad portion is electrically connected to the chip.

[0069] The third circuit pattern 230 may be a wiring pattern. The third circuit pattern 230 may be an FLR (film level wiring) pattern. The wiring pattern has the function of a chip. Therefore, a part of the layer of the chip is rearranged with the wiring pattern.

[0070] The third circuit pattern 230 is connected to the chip through the fifth pad portion. Therefore, the signal of the first circuit pattern 210 is transmitted to the third circuit pattern 230. In addition, the signal is transmitted to the chip and the second circuit pattern 220 through the third circuit pattern 230. Therefore, the signal is transmitted to the display panel.

[0071] At least one of the first circuit pattern 210, the second circuit pattern 220, and the third circuit pattern 230 may include a metal material having high conductivity. In detail, at least one of the first circuit pattern 210, the second circuit pattern 220, and the third circuit pattern 230 may include copper (Cu).

[0072] However, the embodiment is not limited thereto. At least one of the first circuit pattern 210, the second circuit pattern 220, and the third circuit pattern 230 may include at least one metal of copper (Cu), aluminum (Al), chromium (Cr), nickel (Ni), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and alloys thereof.

[0073] Reference Figure 3 and Figure 4 To describe the layer structure of the circuit pattern. Figure 3 and Figure 4 The description of the layer structure described in 20 is applicable to at least one of the first circuit pattern 210, the second circuit pattern 220, and the third circuit pattern 230. Hereinafter, for convenience of explanation, the first circuit pattern will be described.

[0074] Reference Figure 3 , the first circuit pattern 210 is formed of multiple layers. In detail, the first wiring portion 211 and the first pad portion 212a include a first metal layer 201 and a second metal layer 202. In addition, the second pad portion 212b also includes the first metal layer 201 and the second metal layer 202.

[0075] The first metal layer 201 is a seed layer of the first circuit pattern 210. The first metal layer 201 may include copper (Cu). The first metal layer 201 is formed by electroless plating.

[0076] The second metal layer 202 is a plated layer. The second metal layer 202 is formed by electrolytic plating. The second metal layer 202 is formed using the first metal layer 201 as a seed layer.

[0077] The thickness of the first metal layer 201 is smaller than that of the second metal layer 202. For example, the thickness of the first metal layer 201 may be 0.7 μm to 2 μm, and the thickness of the second metal layer 202 may be 10 μm to 25 μm.

[0078] The first metal layer 201 and the second metal layer 202 may include the same metal material. For example, the first metal layer 201 and the second metal layer 202 may include copper (Cu).

[0079] In addition, a bonding layer 203 is disposed on the second metal layer 201. The bonding layer 203 is disposed on the side of the first metal layer 201, the side of the second metal layer 202, and the upper surface of the second metal layer 202. The bonding layer 203 surrounds the first metal layer 201 and the second metal layer 202.

[0080] The bonding layer 203 includes a metal. For example, the bonding layer 203 may include tin (Sn).

[0081] The thickness of the bonding layer 203 may be 0.3 μm to 0.7 μm.

[0082] The content of tin may increase as extending from the lower surface of the bonding layer 203 toward the upper surface of the bonding layer 203. In addition, the content of copper may decrease as extending from the lower surface toward the upper surface. The lower surface is a surface where the bonding layer 203 contacts the second metal layer 202.

[0083] Therefore, pure tin may remain only within a thickness range of 0.1 μm to 0.3 μm from the upper surface of the bonding layer 203 .

[0084] The terminals of the chip, the pad portion of the printed circuit board, and the pad portion of the display panel can be easily bonded by heat and pressure via the bonding layer 203. That is, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer where pure tin is retained melts. Therefore, the chip, the printed circuit board, and the display panel can be easily bonded.

[0085] The first circuit pattern 210 may have a thickness of 2 μm to 25 μm. For example, the first circuit pattern 210 may have a thickness of 5 μm to 20 μm. For example, the first circuit pattern 210 may have a thickness of 7 μm to 15 μm.

[0086] Flash etching is performed to separate the first circuit pattern during the manufacturing process. Thus, the first metal layer 201 is etched. Therefore, the first circuit pattern 210 finally manufactured is smaller than the sum of the thicknesses of the first metal layer 201, the second metal layer 202, and the bonding layer 203 formed during the manufacturing process.

[0087] If the thickness of the first circuit pattern 210 is less than 2 μm, the resistance of the first circuit pattern 210 may increase. If the thickness of the first circuit pattern 210 exceeds 25 μm, it may be difficult to form a fine pattern.

[0088] A buffer layer 205 may be disposed between the substrate 100 and the first circuit pattern 210. The buffer layer 205 improves adhesion between the substrate 100 and the first circuit pattern 210.

[0089] The buffer layer 205 may be formed of a plurality of layers. The buffer layer 205 may include a first buffer layer 205a and a second buffer layer 205b located on the first buffer layer 205a. The first buffer layer 205a contacts the substrate 100. The second buffer layer 205b contacts the first circuit pattern 210.

[0090] The first buffer layer 205a may include 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 may include a material having good adhesion to the first circuit pattern 210. For example, the second buffer layer 205b may include chromium (Cr).

[0091] The buffer layer 205 may have a film thickness of nanometer units. For example, the buffer layer 205 may have a thickness of 20 nm or less.

[0092] The buffer layer 205 increases adhesion between the substrate 100 and the first circuit pattern 210 .

[0093] Reference Figure 4 The bonding layer 203 includes a plurality of bonding layers. The bonding layer 203 may include a first bonding layer 203a and a second bonding layer 203b.

[0094] The first bonding layer 203a is disposed on the first wiring portion 211 and the first pad portion 212a. In addition, the first bonding layer 203a is also disposed on the second pad portion 212b. That is, the first bonding layer 203a is disposed on the first circuit pattern 210.

[0095] Furthermore, the second bonding layer 203 b is provided only on the first pad portion 212 a and the second pad portion 212 b .

[0096] The first bonding layer 203a and the second bonding layer 203b include a metal. In detail, the first bonding layer 203a and the second bonding layer 203b may include tin (Sn).

[0097] The first bonding layer 203a and the second bonding layer 203b have different thicknesses. The thickness of the second bonding layer 203b is greater than that of the first bonding layer 203a.

[0098] For example, the first bonding layer 203a may have a film thickness of 0.02 μm to 0.06 μm. In addition, the second bonding layer 203b may have a thickness of 0.2 μm to 0.6 μm.

[0099] If the bonding layer between the protective layer 300 and the first wiring portion 211 becomes thicker, the bending characteristics of the flexible circuit board are reduced. That is, when the flexible circuit board is bent, cracks may be generated. Therefore, the first bonding layer 231 between the protective layer 300 and the first wiring portion 211 is formed with a thin thickness. Therefore, the bending characteristics of the flexible circuit board are improved.

[0100] The tin content may increase as it extends from the lower surface of the second bonding layer 203b to the upper surface. In addition, the copper content may decrease as it extends from the lower surface to the upper surface. The lower surface is the surface where the second bonding layer 203b contacts the first bonding layer 203a.

[0101] Therefore, pure tin may remain only within a thickness range of 0.1 μm to 0.3 μm from the upper surface of the second bonding layer 203 b .

[0102] The terminals of the chip, the pad portion of the printed circuit board, and the pad portion of the display panel can be easily bonded by heat and pressure via the second bonding layer 203b. That is, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer that retains pure tin melts. Therefore, it is easy to bond the chip, the printed circuit board, and the display panel.

[0103] The protective layer 300 is disposed on the wiring portions of the first and second circuit patterns 210 and 220. The protective layer 300 surrounds the first and second wiring portions 211 and 221. The protective layer 300 is disposed in a region other than the first, second, third, and fourth pad portions.

[0104] The protective layer 300 may include solder paste. For example, the solder paste may include a thermosetting resin, a thermoplastic resin, a filler, a curing agent, or a curing accelerator.

[0105] In the above description, the first circuit pattern 210 and the second circuit pattern 220 are disposed on the same surface of the substrate 100 , but the embodiment is not limited thereto.

[0106] For example, the first circuit pattern 210 and the second circuit pattern 220 may be disposed on different surfaces of the substrate 100. For example, the first circuit pattern 210 may be disposed on one surface of the substrate 100. Also, the second circuit pattern 220 may be disposed on another surface of the substrate 100.

[0107] Therefore, the display panel is connected to the chip on one surface of the substrate 100. In addition, the printed circuit board is connected to the chip on the other surface of the substrate 100.

[0108] The third circuit pattern 230 is disposed inside the chip mounting area CA.

[0109] The chip is bonded to the pad portions of the first circuit pattern, the second circuit pattern, and the third circuit pattern under a high temperature and high pressure environment. Therefore, stress may be generated when the chip is bonded to the pad portions of the circuit pattern.

[0110] A protective layer is disposed on the wiring portions of the first circuit pattern and the second circuit pattern. Therefore, even if stress is transmitted to the wiring portions of the first circuit pattern and the second circuit pattern, the first circuit pattern and the second circuit pattern can be prevented from being deformed or cracked.

[0111] However, the third circuit pattern is not provided with a protective layer, so if stress is transmitted to the wiring portion of the third circuit pattern, deformation or cracking of the third circuit pattern may occur.

[0112] Therefore, the shape of the third circuit pattern may be changed. Therefore, adjacent third circuit patterns may be short-circuited. Or, cracks may occur in one area of ​​the third circuit pattern. Therefore, the electrical characteristics of the COF module may be degraded.

[0113] Hereinafter, a flexible circuit board and a COF module capable of solving the above-mentioned problems will be described.

[0114] Reference Figure 2 , Figure 5 and Figure 6 , the third circuit pattern 230 includes regions having different sizes. In detail, the third circuit pattern 230 may include regions having different widths. In detail, the width w1 of the third wiring portion 231 is different from the width w2 of the fifth pad portion 232 .

[0115] The width w1 of the third wiring portion 231 is greater than the width w2 of the fifth pad portion 232. The width w1 of the third wiring portion 231 is the maximum width of the third wiring portion. The width w2 of the fifth pad portion 232 is the maximum width of the fifth pad portion 232.

[0116] The terminal portion 400 of the chip is disposed on the fifth pad portion 232. Since the width w2 of the fifth pad portion 232 is smaller than the width w1 of the third wiring portion 231, the third circuit pattern 230 can be prevented from increasing the spacing due to the terminal portion 400. Therefore, the size of the flexible circuit board can be prevented from increasing. In addition, the number of third circuit patterns disposed on the chip mounting area CA can be increased.

[0117] The width w1 of the third wiring portion 231 is greater than the width w2 of the fifth pad portion 232. Therefore, when the fifth pad portion 232 is bonded to the terminal portion 400, the third wiring portion 231 can be prevented from being damaged. In detail, the fifth pad portion 232 is bonded to the terminal portion 400 at a high temperature and high pressure. Therefore, stress may be generated during the bonding process. The stress moves toward the third wiring portion 231.

[0118] The width w1 of the third wiring portion 231 is greater than the width w2 of the fifth pad portion 232. Therefore, the strength of the third wiring portion 231 is increased. In detail, since the width w1 of the third wiring portion 231 is increased, the area of ​​the third wiring portion 231 is increased. Therefore, the magnitude of the stress per unit area of ​​the third wiring portion 231 is reduced. Therefore, the shape of the third wiring portion 231 can be prevented from being changed due to the stress. In addition, cracks in the third wiring portion 231 can be prevented.

[0119] For example, the width w1 of the third wiring portion 231 may be three times or less than the width w2 of the fifth pad portion 232. In detail, the width w1 of the third wiring portion 231 may be greater than one time the width w2 of the fifth pad portion 232 and less than or equal to three times the width w2 of the fifth pad portion 232. In more detail, the width w1 of the third wiring portion 231 may be 1.5 times to 3 times or 2 times to 2.5 times the width w2 of the fifth pad portion 232.

[0120] If the width w1 of the third wiring portion 231 exceeds 3 times the width w2 of the fifth pad portion 232, the spacing between the third circuit patterns becomes narrower. Therefore, adjacent third circuit patterns may be short-circuited. In addition, the number of third circuit patterns provided in the chip mounting area is reduced. Therefore, the number of layers of the chip increases, and the size of the chip increases.

[0121] In addition, the width w1 of the third wiring portion 231 may be greater than or equal to the distance G between the third wiring portion 231 and the terminal portion 400. In addition, the width w1 of the third wiring portion 231 may be less than or equal to the length L of the terminal portion 400. In addition, the width w1 of the third wiring portion 231 may be greater than or less than the width w3 of the terminal portion 400.

[0122] For example, the width w1 of the third wiring portion 231 may be 20 μm to 30 μm. In addition, the width w2 of the fifth pad portion 232 may be 9 μm to 20 μm. In addition, the distance G between the third wiring portion 231 and the terminal portion 400 may be 10 μm to 30 μm. In addition, the length L of the terminal portion 400 may be 30 μm to 50 μm. In addition, the width w3 of the terminal portion 400 may be 15 μm to 50 μm.

[0123] In the drawing, the third wiring portion 231 is shown to have a square shape. However, the embodiment is not limited thereto.

[0124] Reference Figure 6 , the third wiring portion 231 may be formed in various shapes. Figure 6 (a), the third wiring portion 231 may be formed in a hexagonal shape. Figure 6 (b), the width of the third wiring portion 231 may decrease from the center to the periphery. Figure 6 (c), the third wiring portion 231 may include a curved surface. Therefore, it is possible to prevent the width of the pattern from suddenly changing in the boundary region between the third wiring portion 231 and the fifth pad portion 232. Thus, it is possible to prevent stress from being concentrated in the boundary region between the fifth pad portion 232 and the third wiring portion 231. Therefore, cracks in the boundary region between the fifth pad portion 232 and the third wiring portion 231 can be prevented.

[0125] Alternatively, refer to Figure 6 (d), the third wiring portion 231 can protrude in one direction. Therefore, the spacing of the third circuit pattern can be easily controlled. In detail, the spacing between adjacent third circuit patterns can be narrowed by the third wiring portion having a large width. Therefore, the position of the third wiring portion can be controlled according to the space of the chip mounting area. Therefore, the spacing of the third circuit pattern can be easily controlled.

[0126] The flexible circuit board according to the embodiment forms the third circuit pattern of different widths for each region. In detail, the width of the fifth pad portion is formed to be smaller than the width of the wiring portion. Therefore, the terminal portion of the chip arranged on one fifth pad portion can be prevented from interfering with another fifth pad portion. In addition, in order to prevent the interference of the terminal portion, the spacing of the third circuit pattern can be prevented from increasing.

[0127] In addition, the width of the wiring portion of the third circuit pattern is greater than the fifth pad portion. Therefore, the wiring portion of the third circuit pattern can be prevented from being deformed or cracked due to stress.

[0128] In addition, the width of the wiring portion of the third circuit pattern is increased. Therefore, when the chip is installed, heat can be effectively dissipated. Alternatively, the heat generated after the chip is installed can be effectively dissipated. That is, the wiring portion of the third circuit pattern can be a heat dissipation pattern. Therefore, the internal temperature of the flexible circuit board or COF module is reduced.

[0129] Therefore, the flexible circuit board has a small size. In addition, the flexible circuit board has improved electrical characteristics. In addition, the heat inside the flexible circuit board is effectively dissipated.

[0130] In the following, reference will be made to Figures 7 to 14 A flexible circuit board according to another embodiment will be described.

[0131] Reference Figure 7 and Figure 8 The third wiring portion 231 includes regions having different widths. For example, the third wiring portion 231 may include a 3-1st wiring portion 231a and a 3-2nd wiring portion 231b.

[0132] The 3-1 wiring portion 231a is adjacent to the fifth pad portion 232. Specifically, the 3-1 wiring portion 231a is connected to the fifth pad portion 232. In addition, the 3-2 wiring portion 231b is connected to the 3-1 wiring portion 231a. Specifically, the 3-1 wiring portion 231a is connected to the end of the 3-2 wiring portion 231b. That is, the 3-1 wiring portion 231a is provided between the fifth pad portion 232 and the 3-2 wiring portion 231b.

[0133] When the fifth pad portion 232 is bonded to the terminal portion 400, stress may be generated. The width w1-1 of the 3-1 wiring portion 231a and the width w-2 of the 3-2 wiring portion 231b may be greater than the width w2 of the fifth pad portion 232. Therefore, the unit area of ​​the third wiring portion is increased. Therefore, the shapes of the 3-1 wiring portion 231a and the 3-2 wiring portion 231b are prevented from being deformed or cracked due to stress.

[0134] In addition, the width w1-1 of the 3-1 wiring portion 231a and the width w1-2 of the 3-2 wiring portion 231b may be different. Specifically, the width w1-1 of the 3-1 wiring portion 231a is greater than the width w1-2 of the 3-2 wiring portion 231b. That is, the width of the third wiring portion 231 adjacent to the fifth pad portion 232 is greater than the width of the third wiring portion 231 away from the fifth pad portion 232.

[0135] The stress may be greatest in the region adjacent to the fifth pad portion 232. Therefore, the width w1-1 of the 3-1st wiring portion 231a is formed to be greater than the width w1-2 of the 3-2nd wiring portion 231b in consideration of the distribution of the stress transferred to the third wiring portion 231. Therefore, when the third circuit pattern is bonded to the chip, the third circuit pattern can be prevented from being deformed or cracked.

[0136] Therefore, the flexible circuit board has improved electrical characteristics.

[0137] Reference Figures 9 to 12 A plurality of third circuit patterns are disposed in the chip mounting area CA. For example, the third circuit pattern may include a 3-1st circuit pattern 230a, a 3-2nd circuit pattern 230b, and a 3-3rd circuit pattern 230c.

[0138] The 3-1st circuit pattern 230a and the 3-2nd circuit pattern 230b are adjacent to each other. In addition, the 3-2nd circuit pattern 230b and the 3-3rd circuit pattern 230c are adjacent to each other. For example, the 3-1st circuit pattern 230a may be disposed at the center of the chip mounting area CA. In addition, the 3-2nd circuit pattern 230b and the 3-3rd circuit pattern 230c may be disposed between the center and the outside of the chip mounting area CA.

[0139] Reference Fig. 9 and Fig.10 , among the 3-1st circuit pattern 230a, the 3-2nd circuit pattern 230b, and the 3-3rd circuit pattern 230c, the width of the wiring portion of one circuit pattern may be different from the widths of the wiring portions of the other circuit patterns. For example, the width w4 of the wiring portion of the 3-1st circuit pattern 230a may be greater than the width w5 of the wiring portion of the 3-2nd circuit pattern 230b and the width w5 of the wiring portion of the 3-3rd circuit pattern 230c. Therefore, the width of the wiring portion of the circuit pattern disposed in the central portion of the chip mounting area CA may be greater.

[0140] In addition, the 3-1st circuit pattern 230a, the 3-2nd circuit pattern 230b, and the 3-3rd circuit pattern 230c may be arranged at different intervals. For example, the first interval d1 between the 3-1st circuit pattern 230a and the 3-2nd circuit pattern 230b and the second interval d2 between the 3-2nd circuit pattern 230b and the 3-3rd circuit pattern 230c may be different from each other. For example, the first interval d1 may be smaller than the second interval d2.

[0141] Alternatively, refer to Fig.11 and Fig.12 , the widths of the circuit patterns of the 3-1st circuit pattern 230a, the 3-2nd circuit pattern 230b, and the 3-3rd circuit pattern 230c may be different. In detail, the width w4 of the wiring portion of the 3-1st circuit pattern 230a may be greater than the width w5 of the wiring portion of the 3-2nd circuit pattern 230b and the width w5 of the wiring portion of the 3-3rd circuit pattern 230c. In addition, the width w5 of the wiring portion of the 3-2nd circuit pattern 230b may be greater than the width w5 of the wiring portion of the 3-3rd circuit pattern 230c. Therefore, the width of the wiring portion of the 3-1st circuit pattern disposed in the center portion of the chip mounting area is the largest. In addition, the width of the wiring portion of the third circuit pattern becomes smaller as it is away from the center portion.

[0142] That is, the width of the wiring portions of the plurality of third circuit patterns may become smaller as they extend to the outer region of the chip mounting area. Alternatively, the pitch of the wiring portions of the plurality of third circuit patterns may increase as they extend to the outer region of the chip mounting area.

[0143] The pad portions of the first circuit pattern, the second circuit pattern, and the third circuit pattern may be bonded to the terminal portion of the chip under high temperature and high pressure. At this time, the temperature and pressure of the central area of ​​the chip mounting area CA may be greater than the temperature and pressure of other areas. Therefore, the third circuit pattern disposed in the central part of the chip mounting area may be subjected to greater stress than the third circuit pattern disposed in other positions.

[0144] Therefore, the width of the wiring portion of the third circuit pattern arranged in the central portion of the chip mounting area is greater than the width of the wiring portions of other third circuit patterns. Alternatively, the width of the wiring portion of the third circuit pattern becomes smaller as it extends from the central portion of the chip mounting area toward the outside.

[0145] Therefore, even if different stresses are generated at respective positions, deformation and cracking of the third circuit pattern can be effectively prevented.

[0146] Reference Fig.13 and Fig.14 , the width of the third wiring portion 231 and the width of the fifth pad portion 232 may be the same or similar. In addition, the thickness T1 of the third wiring portion and the thickness T2 of the fifth pad portion 232 may be different.

[0147] In detail, the thickness T1 of the third wiring portion may be greater than the thickness T2 of the fifth pad portion 232 .

[0148] Since the thickness T1 of the third wiring portion is greater than the thickness T2 of the fifth pad portion 232, the third wiring portion 231 can be prevented from being damaged when the fifth pad portion 232 is bonded to the terminal portion 400. In detail, by increasing the thickness T1 of the third wiring portion, it is possible to increase the strength of the third wiring portion 231. Therefore, it is possible to prevent the shape of the third wiring portion 231 from being changed or cracks from being formed due to stress generated during bonding of the chip to the fifth pad portion.

[0149] In addition, the width of the third wiring portion and the width of the fifth pad portion 232 may be the same or similar. Therefore, the gap between the third circuit patterns is widened. Therefore, the third circuit pattern can be prevented from short-circuiting. Alternatively, the size of the chip mounting area can be reduced. Therefore, a small-sized flexible circuit board can be manufactured. Alternatively, the number of third circuit patterns provided in the chip mounting area can be increased.

[0150] Fig.15 is a diagram showing a top view of a COF module according to an embodiment.

[0151] Reference Fig.15 , the COF module according to the embodiment includes the flexible circuit board as described above. In addition, the COF module may include a chip CH disposed on the chip mounting area CA.

[0152] In addition, the flexible circuit board 1000 may include the protection layer 300 as described above.

[0153] In addition, the COF module is manufactured by cutting the flexible circuit board 1000 and mounting the chip CH. In detail, the flexible circuit board 1000 is cut along the cutting line CL. Subsequently, the driving chip is mounted on the chip mounting area.

[0154] The COF module is disposed between the display panel and the printed circuit board and can transmit signals.

[0155] Reference Fig.16 , one end portion of the COF module 2000 according to the embodiment is connected to the display panel 3000 . In addition, the other end portion of the COF module 2000 is connected to the printed circuit board 4000 .

[0156] The COF module 2000 includes a flexible substrate, and thus, may have a rigid form or a bent form between the display panel 3000 and the printed circuit board 4000 .

[0157] The COF module 2000 can connect the display panel 3000 and the printed circuit board 4000 in a bent form. Therefore, the thickness of the electronic device is reduced and the degree of freedom of design is improved. In addition, since the COF module 2000 includes a flexible substrate, the wiring will not be damaged even in a bent form. Therefore, the reliability of the electronic device is improved.

[0158] The COF module can be applied to various electronic devices.

[0159] For example, refer to Fig.17 , COF module is applied to a flexible touch window that can be bent. Therefore, the user can bend the touch device with his hands.

[0160] Reference Fig.18 , COF modules are applied to various wearable touch devices including curved displays. Therefore, electronic devices can be made slim or lightweight.

[0161] Reference Fig.19 , COF modules are applied to various electronic devices with displays, such as TVs, monitors, and notebook computers. COF modules can also be used in electronic devices that apply curved displays.

[0162] The characteristics, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present disclosure, but are not limited to one embodiment. In addition, those skilled in the art can combine or modify the characteristics, structures, and effects shown in the various embodiments for other embodiments. Therefore, it should be understood that such combinations and modifications are included within the scope of the present disclosure.

[0163] In addition, the above mainly describes the embodiment, but the embodiment is only an example and does not limit the present disclosure. It can be understood by those skilled in the art that various changes and applications not presented above can be made without departing from the basic features of the embodiment. For example, the various components specifically shown in the embodiment can be changed. In addition, it should be understood that the differences related to such changes and such applications are included in the scope defined in the appended claims of the present disclosure.

Claims

1. A flexible circuit board, comprising: a substrate including a chip mounting area; as well as a circuit pattern, wherein the circuit pattern is arranged on the substrate, Wherein, the circuit pattern includes a first circuit pattern, a second circuit pattern and a third circuit pattern, wherein the first circuit pattern includes a first pad portion disposed inside the chip mounting area, a second pad portion disposed outside the chip mounting area, and a first wiring portion connected to the first pad portion and the second pad portion, wherein the second circuit pattern includes a third pad portion disposed inside the chip mounting area, a fourth pad portion disposed outside the chip mounting area, and a second wiring portion connected to the third pad portion and the fourth pad portion, wherein the third circuit pattern includes a third wiring portion and a fifth pad portion disposed inside the chip mounting area, and Wherein, the width of the third wiring portion is greater than the width of the fifth pad portion.

2. The flexible circuit board according to claim 1, wherein: The width of the third wiring portion is greater than 1 times the width of the fifth pad portion and less than or equal to 3 times the width of the fifth pad portion.

3. The flexible circuit board according to claim 1, wherein: The third wiring portion includes a 3-1 wiring portion connected to the fifth pad portion and a 3-2 wiring portion connected to the 3-1 wiring portion, and The width of the 3-1 wiring portion is different from the width of the 3-2 wiring portion.

4. The flexible circuit board according to claim 3, wherein: The width of the 3-1 wiring portion is greater than the width of the 3-2 wiring portion.

5. The flexible circuit board according to claim 1, wherein: the third circuit pattern includes a 3-1st circuit pattern, a 3-2nd circuit pattern, and a 3-3rd circuit pattern which are disposed in the chip mounting region and are adjacent to each other, wherein the 3-1st circuit pattern is arranged in the center portion of the chip mounting area, wherein the 3-2nd circuit pattern and the 3-3rd circuit pattern are arranged between the central portion and the outer portion of the chip mounting area, and The width of one of the 3-1st circuit pattern, the 3-2nd circuit pattern and the 3-3rd circuit pattern is different from the width of the other circuit patterns of the 3-1st circuit pattern, the 3-2nd circuit pattern and the 3-3rd circuit pattern.

6. The flexible circuit board according to claim 5, wherein: The width of the wiring portion of the 3-1 circuit pattern is larger than the widths of the wiring portions of the 3-2 circuit pattern and the 3-3 circuit pattern.

7. The flexible circuit board according to claim 1, wherein: The third circuit pattern includes a 3-1st circuit pattern, a 3-2nd circuit pattern, and a 3-3rd circuit pattern which are disposed in the chip mounting region and are adjacent to each other, and Herein, a width of the wiring portion of the third circuit pattern decreases as extending from a central portion of the chip mounting region toward an outer portion of the chip mounting region.

8. A COF module, comprising: The flexible circuit board according to any one of claims 1 to 7; as well as a chip, the chip being disposed in the chip mounting area, and The chip is connected to the first pad portion, the third pad portion and the fifth pad portion.

9. The COF module according to claim 8, wherein: The width of the third wiring portion is greater than or equal to the distance between the third wiring portion and the terminal portion of the chip, and Wherein, the width of the third wiring portion is less than or equal to the length of the terminal portion.

10. An electronic device comprising: The COF module according to claim 8; a printed circuit board connected to the first circuit pattern; as well as A display panel is connected to the second circuit pattern.

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