Flexible Circuit Board and its Manufacturing Method

Abstract

This invention provides a flexible circuit board and a method for manufacturing the same. The flexible circuit board includes a flexible substrate, wherein the flexible substrate includes a first portion, two second portions, two third portions, two first bending portions, and two second bending portions. The flexible circuit board includes a first connection circuit layer extending from the upper surface of the first portion of the flexible substrate, penetrating the first portion to the upper surface of the second portion, a second connection circuit layer extending from the lower surface of the second portion, penetrating the third portion to the lower surface of the third portion, a first circuit layer on the upper surface of the first portion, and a second circuit layer on the lower surface of the third portion. Therefore, the flexible circuit board of this invention utilizes connection circuit layers to connect the bent flexible substrate, achieving a hole-free effect and realizing high-density circuit board manufacturing.

Description

Technical Field

[0001] This invention relates to a flexible circuit board and a method for manufacturing the same, and more particularly to a flexible circuit board that can be bent and a method for manufacturing the same. Background Technology

[0002] In recent years, with the rapid development of various electronic devices, the application of flexible printed circuit boards (PCBs) has become increasingly widespread, with high-density PCBs representing a major development trend. However, high-density PCBs have higher requirements for hole size, circuit width, and number of layers. Compared to ordinary PCBs, high-density PCBs must reduce the number of vias to increase the circuit distribution area and the number of electronic components. Summary of the Invention

[0003] One aspect of the present invention is to provide a flexible circuit board that uses a connecting circuit layer to connect a bent flexible substrate to achieve a hole-free effect and realize high density of the circuit board.

[0004] Another aspect of the present invention is to provide a method for manufacturing a flexible circuit board.

[0005] According to one aspect of the present invention, a flexible circuit board is provided. The flexible circuit board includes a flexible substrate, wherein the flexible substrate includes a first portion, two second portions, two third portions, two first bends, and two second bends, with the second portions above the third portions and the first portions above the second portions. The two first bends respectively connect the first portion and the two second portions, and the first portion and the second portion are located between the two first bends. The two second bends respectively connect the two second portions and the two third portions, and the two second bends are located between the second portions. The flexible circuit board includes a plurality of first connection circuit layers configured to extend from the upper surface of the first portion of the flexible substrate, penetrating the first portion to the upper surface of the second portion; a plurality of second connection circuit layers configured to extend from the lower surface of the second portion of the flexible substrate, penetrating the third portion to the lower surface of the third portion; a plurality of first circuit layers disposed on the upper surface of the first portion of the flexible substrate; and a plurality of second circuit layers disposed on the lower surface of the third portion of the flexible substrate.

[0006] According to one embodiment of the present invention, the flexible circuit board further includes a third circuit layer and at least one embedded electronic component disposed on the third circuit layer. The third circuit layer is disposed on the lower surface of the first portion of the flexible substrate and between the two second bends.

[0007] According to one embodiment of the present invention, the flexible circuit board further includes a plurality of third circuit layers and a plurality of embedded electronic components disposed on the third circuit layers. The plurality of third circuit layers are respectively disposed on the lower surface of the first portion of the flexible substrate and on the two second bending portions.

[0008] According to an embodiment of the present invention, the flexible circuit board further includes at least one electronic component disposed on the first circuit layer and / or on the second circuit layer of the flexible substrate.

[0009] According to an embodiment of the present invention, the flexible circuit board further includes a plurality of fixed terminals, which are respectively disposed on the second portion of the flexible substrate near the ends of the first bending portion and the second bending portion.

[0010] According to another aspect of the present invention, a method for manufacturing a flexible circuit board is provided. The method includes providing a substrate, wherein the substrate includes a flexible substrate, an upper metal layer, and a lower metal layer, the upper metal layer and the lower metal layer being respectively located on an upper surface and a lower surface of the flexible substrate; depositing a first conductive layer and a second conductive layer on the upper metal layer and the lower metal layer, respectively; patterning the upper metal layer, the lower metal layer, the first conductive layer, and the second conductive layer to form a first connection circuit layer and a second circuit layer on the lower surface of the flexible substrate, and forming a second connection circuit layer and a first circuit layer on the upper surface of the flexible substrate; performing a laser drilling operation on the flexible substrate to form a plurality of openings in the flexible substrate; performing a first bending operation on the flexible substrate to insert the first connection circuit layer into a portion of the plurality of openings; and performing a second bending operation on the flexible substrate to insert the second connection circuit layer into the remaining plurality of openings.

[0011] According to one embodiment of the present invention, after the laser drilling operation is performed on the flexible substrate and before the first bending operation is performed, the method further includes attaching a cover film onto a portion of the flexible substrate, a portion of the upper metal layer and a portion of the lower metal layer.

[0012] According to one embodiment of the present invention, the method further includes bonding at least one electronic component on the first circuit layer and / or the second circuit layer.

[0013] According to one embodiment of the present invention, patterning the upper metal layer, the lower metal layer, the first conductive layer, and the second conductive layer includes forming a third circuit layer on the lower surface of the flexible substrate. After the laser drilling operation on the flexible substrate and before the first bending operation, the method further includes bonding at least one embedded electronic component on the third circuit layer.

[0014] According to an embodiment of the present invention, when performing the first bending operation and the second bending operation, the method further includes filling a plurality of adhesive layers between the flexible substrate and the first connection circuit layer and the second connection circuit layer.

[0015] The flexible circuit board and its manufacturing method of the present invention utilize bending of the flexible substrate to achieve electrical connection between the connecting circuit layers, thereby achieving hole-free and high-density circuit boards, and improving the reliability and design freedom of the circuit boards. Attached Figure Description

[0016] A better understanding of the features disclosed herein will be achieved by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, for clarity of discussion, the dimensions of many features may be arbitrarily scaled.

[0017] Figure 1 A cross-sectional view of a flexible circuit board according to some embodiments of the present invention is shown.

[0018] Figures 2A to 2H A cross-sectional view illustrating an intermediate stage of a method for manufacturing a flexible circuit board according to some embodiments of the present invention.

[0019] Figure 3A and Figure 3B A cross-sectional view of a flexible circuit board according to some embodiments of the present invention is shown. Detailed Implementation

[0020] The following disclosure provides numerous different embodiments or illustrations to implement various features of the invention. The specific examples of components and configurations described below are for the purpose of simplifying this disclosure. These are, of course, merely illustrative and are not intended to be limiting. For example, a description of a first feature formed on or above a second feature includes embodiments where the first and second features are in direct contact, as well as embodiments where other features are formed between the first and second features such that the first and second features are not in direct contact. Furthermore, element symbols and / or letters are repeated in various specific examples in this disclosure. This repetition is for the purpose of simplifying and clarifying the description and does not imply a relationship between the various discussed embodiments and / or configurations.

[0021] Furthermore, spatially relative terms, such as "below," "below," "lower," "above," and "upper," are used to facilitate the description of the relationship between a part or feature depicted in the accompanying drawings and other parts or features. In addition to the directions depicted in the drawings, spatially relative terms also include different orientations of the elements during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used in this disclosure can also be interpreted in this way.

[0022] Existing multilayer circuit boards require vias to electrically connect the circuits of each layer. This involves creating blind or through vias, followed by copper plating or filling with copper paste to form conductive vias. However, the presence of conductive vias occupies layout space on the circuit board, thus hindering the fabrication of high-density circuit boards and limiting the flexibility of the board design. Furthermore, conductive vias created using either copper plating or copper paste do not allow for bending of flexible circuit boards, and the connection method of the conductive vias affects the reliability of the circuit board.

[0023] Therefore, as described above, the present invention provides a flexible circuit board and its manufacturing method, which utilizes the bending of a flexible substrate to achieve electrical connection between multiple circuit layers, thereby achieving hole-free and high-density circuit boards, and improving the reliability and design freedom of the circuit boards.

[0024] Please see Figure 1 , Figure 1 A cross-sectional view of a flexible circuit board 100 according to some embodiments of the present invention is illustrated. The flexible circuit board 100 includes a flexible substrate 110, wherein the flexible substrate 110 includes a first portion 111, two second portions 115, two third portions 119, two first bends 113, and two second bends 117. The second portions 115 are located above the third portions 119, and the first portions 111 are located above the second portions 115.

[0025] The first bend 113 connects the first portion 111 and the two second portions 115 respectively, and along the direction X, the first portion 111 and the second portion 115 are located between the two first bends 113. The second bend 117 connects the two second portions 115 and the two third portions 119 respectively, and along the direction X, the two second bends 117 are located between the two second portions 115 (and / or between the two third portions 119). In some embodiments, both second bends 117 are located between the two first bends 113.

[0026] The flexible circuit board 100 further includes a first connection circuit layer 120 and a second connection circuit layer 130. The first connection circuit layer 120 is configured to extend from the upper surface 111A of a first portion 111 of the flexible substrate 110 through the first portion 111 to the upper surface 115A of a second portion 115. In some embodiments, the first connection circuit layer 120 includes conductive posts 121 penetrating the first portion 111 and a metal layer 125 on the upper surface 115A of the second portion 115. In some embodiments, the first connection circuit layer 120 further includes a plating layer 128 disposed above the conductive posts 121.

[0027] The second connection circuit layer 130 is configured to extend from the lower surface 115B of the second portion 115 of the flexible substrate 110 through the third portion 119 to the lower surface 119B of the third portion 119. In some embodiments, the second connection circuit layer 130 includes conductive pillars 131 penetrating the third portion 119 and a metal layer 135 on the lower surface 115B of the second portion 115. In some embodiments, the second connection circuit layer 130 further includes a plating layer 138 disposed above the conductive pillars 131. Therefore, the present invention does not require the use of existing electrical connection methods such as vias, conductive adhesives, and / or tin, but achieves the effect of interlayer interconnection by utilizing the first connection circuit layer 120 and the second connection circuit layer 130.

[0028] The flexible circuit board 100 further includes a first circuit layer 140 and a second circuit layer 150. The first circuit layer 140 is disposed on the upper surface 111A of a first portion 111 of the flexible substrate 110. In some embodiments, the first circuit layer 140 includes a metal layer 145 disposed on the upper surface 111A of the first portion 111 and a plating gold layer 148 disposed on the metal layer 145. The second circuit layer 150 is disposed on the lower surface 119B of a third portion 119 of the flexible substrate 110. In some embodiments, the second circuit layer 150 includes a metal layer 155 disposed on the lower surface 119B of the third portion 119 and a plating gold layer 158 disposed on the metal layer 155.

[0029] In some embodiments, the flexible circuit board 100 further includes a third circuit layer 160, wherein the third circuit layer 160 is disposed on the lower surface 111B of the first portion 111 of the flexible substrate 110, and the third circuit layer 160 is located between two second bends 117. Similarly, the third circuit layer 160 includes a metal layer and a plating layer (not shown). In some embodiments, the flexible circuit board 100 further includes embedded electronic components 165 disposed on the third circuit layer 160. In other words, the third circuit layer 160 may be configured to electrically connect to the embedded electronic components 165. In some embodiments, the embedded electronic components 165 may be components such as capacitors, resistors, or inductors. It should be understood that, although Figure 1Only one embedded electronic component 165 is shown. The present invention does not limit the number of embedded electronic components 165, which can be adjusted according to application requirements.

[0030] In some embodiments, the flexible circuit board 100 includes an adhesive layer 170. The adhesive layer 170 fills the space between a first portion 111 and a second portion 115, between the second portion 115 and a third portion 119, and between two second bends 117 of the flexible substrate 110. The adhesive layer 170 can be used to shape the flexible circuit board 100.

[0031] In some embodiments, the flexible circuit board 100 includes fixed terminals 180A to 180D, each of which includes a conductive post 181 extending through the flexible substrate 110 and a metal layer 185 on the flexible substrate. The fixed terminals 180A to 180D are configured to precisely position the flexible substrate 110 at the bending point.

[0032] In some embodiments, the fixing terminal 180A is configured to extend through the first portion 111 of the flexible substrate 110 to the upper surface 115A of the second portion 115, and is located at the end of the second portion 115 near the first bend 113; the fixing terminal 180B is configured to extend through the first portion 111 of the flexible substrate 110 to the upper surface 115A of the second portion 115, and is located at the end of the second portion 115 near the second bend 117; the fixing terminal 180C is configured to extend through the third portion 119 of the flexible substrate 110 to the lower surface 115B of the second portion 115, and is located at the end of the second portion 115 near the second bend 117; the fixing terminal 180D is configured to extend through the third portion 119 of the flexible substrate 110 to the lower surface 115B of the second portion 115, and is located at the end of the second portion 115 near the first bend 113 (or near the end of the third portion 119).

[0033] In some embodiments, the flexible circuit board 100 includes a cover film 190 for protection and insulation. In some embodiments, the cover film 190 is disposed on the first bend 113 and the second bend 117 of the flexible substrate 110 to cover metal layers 113M and 117M respectively, and to cover the conductive posts 181 of the fixing terminals 180A to 180C. In some embodiments, the cover film 190 is disposed on the upper surface 111A of the first portion 111 and the lower surface 119B of the third portion 119 of the flexible substrate 110 to cover the metal layer 111M on the first portion 111 respectively.

[0034] In some embodiments, the flexible circuit board 100 further includes electronic components 101 and / or electronic components 103. Electronic component 101 is disposed on the upper surface 111A of the first portion 111 of the flexible substrate 110 and electrically connected to the first circuit layer 140 and / or the first connection circuit layer 120. In some embodiments, electronic component 101 is a module component, such as a screen module, a camera module, or a speaker module. Electronic component 103 is disposed on the lower surface 119B of the third portion 119 of the flexible substrate 110 and electrically connected to the second circuit layer 150 and / or the second connection circuit layer 130. In some embodiments, electronic component 103 may be a connector or a system-in-package (SiP) component. It should be understood that, although... Figure 1 The illustration shows one electronic component 101 and two electronic components 103. The present invention does not limit the number of electronic components 101 and 103, which can be adjusted according to application requirements.

[0035] Figures 2A to 2H A cross-sectional view illustrating an intermediate stage of a method for manufacturing a flexible circuit board 100 according to some embodiments of the present invention is shown below. Figures 2A to 2H This describes the manufacturing process of the flexible circuit board 100. First, please refer to... Figure 2A A substrate 201 is provided. In some embodiments, the substrate 201 includes a flexible substrate 110, an upper metal layer 210A disposed on an upper surface 110A of the flexible substrate 110, and a lower metal layer 210B disposed on a lower surface 110B of the flexible substrate 110. In some embodiments, the substrate 201 is a double-sided flexible copper clad laminate (FCCL).

[0036] Please see Figure 2B A first conductive layer 220A and a second conductive layer 220B are deposited on specific regions of the upper metal layer 210A and the lower metal layer 210B, respectively. In some embodiments, Figure 2B The structure is formed by two copper plating operations on the substrate 201 to form a first conductive layer 220A and a second conductive layer 220B that are not completely flat.

[0037] Figures 2C to 2E For sequential pair Figure 2B The structure is patterned to form a first connection circuit layer 120, a second connection circuit layer 130, a first circuit layer 140, and a second circuit layer 150 (see reference). Figure 1 First, please refer to Figure 2CThe upper metal layer 210A and the lower metal layer 210B are patterned to form a first patterned metal layer 230A and a second patterned metal layer 230B, respectively. In some embodiments, the first patterned metal layer 230A and the second patterned metal layer 230B are substantially asymmetrical patterns, i.e., they are not aligned with each other. In some embodiments, the first patterned metal layer 230A includes a first circuit layer 140, while the second patterned metal layer 230B includes a second circuit layer 150.

[0038] Next, please refer to Figure 2D The first conductive layer 220A and the second conductive layer 220B are patterned to form conductive pillars 181. In some embodiments, the remaining first conductive layer 220A or second conductive layer 220B is separated from the conductive pillars 181 by a groove R1, and the groove R1 exposes the flexible substrate 110. In some embodiments, the conductive pillars 181 on the upper surface 110A of the flexible substrate 110 are substantially arranged to intersect with the conductive pillars 181 on the lower surface 110B of the flexible substrate 110.

[0039] Then, please see Figure 2E The remaining first conductive layer 220A or second conductive layer 220B is patterned to form conductive pillars 131 of the second connection circuit layer 130 on the upper surface 110A of the flexible substrate 110 and conductive pillars 121 of the first connection circuit layer 120 on the lower surface 110B of the flexible substrate 110, respectively. In some embodiments, the conductive pillars 131 and 121 are staggered, with the conductive pillar 131 located between two adjacent conductive pillars 121.

[0040] Please see Figure 2F A laser drilling operation is performed on the flexible substrate 110 to form a plurality of openings O1 and O2. Openings O1 are located between the conductive pillars 131 on both sides, while openings O2 are located on opposite sides of the flexible substrate 110. In some embodiments, the number of openings O1 is the same as the total number of conductive pillars 181 and 121 located on the lower surface 110B of the flexible substrate 110, and the number of openings O2 is the same as the total number of conductive pillars 181 and 131 located on the upper surface 110A of the flexible substrate 110.

[0041] Please also refer to Figure 2G The first patterned metal layer 230A and the second patterned metal layer 230B (refer to...) Figure 2D It also includes a metal layer 111M. In some embodiments, the second patterned metal layer 230B further includes a third circuit layer 160. Figure 2GIn the process, a cover film 190 is laminated to cover one end of a specific opening O1 and one end of a specific opening O2 of the flexible substrate 110, both of the metal layer 111M and the flexible substrate 110. Next, a plating gold process is performed to form a plating gold layer 128 on the conductive pillar 121; a plating gold layer 138 on the conductive pillar 131; a plating gold layer 148 on the first patterned metal layer 230A not covered by the cover film 190; and a plating gold layer 158 on the second patterned metal layer 230B. Then, embedded electronic components 165 can be bonded to the third circuit layer 160.

[0042] Please also refer to Figure 2G and Figure 2H ,right Figure 2G The structure undergoes two bending operations to form Figure 2H The structure is as follows: First, a first bending operation is performed on the flexible substrate 110 so that the conductive post 121 and the conductive post 181 located on the upper surface 110A of the flexible substrate 110 are respectively inserted into the opening O1, thereby forming the first connection circuit layer 120 and the fixed terminals 180A and 180B respectively. In addition, the first bending operation allows the two first bending portions 113 of the flexible substrate 110 to connect the first portion 111 and the remaining flexible substrate 110 respectively.

[0043] Then, a second bending operation is performed on the flexible substrate 110 so that the conductive post 131 and the conductive post 181 located on the lower surface 110B of the flexible substrate 110 are respectively inserted into the opening O2, thereby forming the second connection circuit layer 130 and the fixing terminals 180C and 180D respectively. The second bending operation allows the second bent portion 117 of the flexible substrate 110 to connect the second portion 115 and the third portion 119. In some embodiments, both the opening O1 and the opening O2 into which the conductive post 181 is inserted have an end covered by the cover film 190. At this point, the fabrication of the flexible circuit board 100 is substantially completed. Next, different electronic components (e.g., Figure 1 The electronic components 101 and / or 103 shown in the figure are disposed on the first circuit layer 140 or the second circuit layer 150, and thus can be manufactured. Figure 1 The flexible circuit board 100 shown.

[0044] In addition, such as Figure 3A and Figure 3B As shown, more embedded electronic components 165 can be placed in the flexible circuit board. Figure 3A and Figure 3B Cross-sectional views of flexible circuit boards 300 and 400 according to some embodiments of the present invention are shown respectively. For simplification purposes, Figure 3A and Figure 3B Several components are omitted, such as the first connection circuit layer and the second connection circuit layer.

[0045] In some embodiments, please refer to Figure 3A The flexible circuit board 300 includes a third circuit layer 360A, a third circuit layer 360B, and a third circuit layer 360C. The third circuit layer 360A is disposed on the lower surface 311B of the first portion 311 of the flexible substrate 310, while the third circuit layers 360B and 360C are respectively disposed on the outer surface 317A of the second bent portion 317 of the flexible substrate 310. Therefore, the flexible circuit board 300 can accommodate three embedded electronic components. For example, embedded electronic component 365 can be electrically connected to the third circuit layer 360A, embedded electronic component 361 can be electrically connected to the third circuit layer 360B, and embedded electronic component 363 can be electrically connected to the third circuit layer 360C.

[0046] In some embodiments, please refer to Figure 3B The flexible circuit board 400 includes a third circuit layer 460A, a third circuit layer 460B, a third circuit layer 460C, a third circuit layer 460D, and a third circuit layer 460E. The third circuit layer 460A is disposed on the lower surface 411B of the first portion 411 of the flexible substrate 410. The third circuit layers 460B and 460C are respectively disposed on the outer surface 417A of the second bending portion 417 of the flexible substrate 410, while the third circuit layers 460D and 460E are respectively disposed on the inner surface 417B of the second bending portion 417 of the flexible substrate 410. Therefore, the flexible circuit board 400 may be provided with three embedded electronic components, for example, embedded electronic component 465 is electrically connected to the third circuit layer 460A, embedded electronic component 461 is electrically connected to the third circuit layer 460B, embedded electronic component 463 is electrically connected to the third circuit layer 460C, embedded electronic component 467 is electrically connected to the third circuit layer 460D, and embedded electronic component 469 is electrically connected to the third circuit layer 460E.

[0047] Based on the above, the present invention provides a flexible circuit board and its manufacturing method. It utilizes bending of a flexible substrate to replace conductive vias with connecting circuit layers to achieve electrical connections between layers, and uses positioning terminals for precise positioning, thereby achieving a hole-free and high-density circuit board, and improving the reliability of the circuit board. Furthermore, the flexible circuit board of the present invention can also encapsulate multiple electronic components in a single package, thus improving design freedom.

[0048] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0049] [Symbol Explanation]

[0050] 100: Flexible Circuit Board

[0051] 101: Electronic Components

[0052] 103: Electronic Components

[0053] 110:Soft substrate

[0054] 110A: Upper surface

[0055] 110B: Lower surface

[0056] 111: Part One

[0057] 111A: Upper surface

[0058] 111B: Lower surface

[0059] 111M: Metallic layer

[0060] 113: First bend

[0061] 113M: Metallic layer

[0062] 115: Part Two

[0063] 115A: Top surface

[0064] 115B: Lower surface

[0065] 117: Second bend

[0066] 117M: Metallic layer

[0067] 119: Part Three

[0068] 119B: Lower surface

[0069] 120: First connection circuit layer

[0070] 121: Conductive post

[0071] 125: Metal layer

[0072] 128:Gold layer

[0073] 130: Second connection circuit layer

[0074] 131: Conductive post

[0075] 135: Metal layer

[0076] 138:Gold layer

[0077] 140: First Circuit Layer

[0078] 145: Metal layer

[0079] 148:Gold layer

[0080] 150: Second Circuit Layer

[0081] 155: Metal layer

[0082] 158:Gold layer

[0083] 160: Third Circuit Layer

[0084] 165: Embedded electronic components

[0085] 170: Adhesive layer

[0086] 180A, 180B, 180C, 180D: Fixed terminals

[0087] 181: Conductive post

[0088] 185: Metal layer

[0089] 190: Covering film

[0090] 201:Substrate

[0091] 210A: Upper metal layer

[0092] 210B: Lower metal layer

[0093] 220A: First conductive layer

[0094] 220B: Second conductive layer

[0095] 230A: First patterned metal layer

[0096] 230B: Second patterned metal layer

[0097] 300: Flexible Circuit Board

[0098] 310:Soft substrate

[0099] 311: Part One

[0100] 311B: Lower surface

[0101] 317: Second bend

[0102] 317A: Outer surface

[0103] 360A, 360B, 360C: Third circuit layer

[0104] 361, 363, 365: Embedded electronic components

[0105] 400: Flexible Circuit Board

[0106] 410:Soft substrate

[0107] 411: Part One

[0108] 411B: Lower surface

[0109] 417: Second bend

[0110] 417A: Outer surface

[0111] 417B: Inner surface

[0112] 460A, 460B, 460C, 460D, 460E: Third circuit layer

[0113] 461, 463, 465, 467, 469: Embedded electronic components

[0114] O1, O2: Openings

[0115] R1: Groove

[0116] X: Direction.

Claims

1. A flexible circuit board, characterized in that, Include: A flexible substrate includes a first portion, two second portions, two third portions, two first bending portions, and two second bending portions, wherein the second portions are above the third portions, and the first portions are above the second portions; The two first bends connect the first part to the two second parts respectively, and the first part and the second part are located between the two first bends; The two second bends connect the two second parts and the two third parts respectively, and the two second bends are located between the two second parts; Multiple first connection circuit layers are configured to extend from the upper surface of the first portion of the flexible substrate, penetrating the first portion to the upper surface of the second portion; Multiple second connection circuit layers are configured to extend from the lower surface of the second portion of the flexible substrate, penetrating the third portion to the lower surface of the third portion; Multiple first circuit layers are disposed on the upper surface of the first portion of the flexible substrate; Multiple second circuit layers are disposed on the lower surface of the third portion of the flexible substrate; A third circuit layer is disposed on the lower surface of the first portion of the flexible substrate, and between the two second bends; and At least one embedded electronic component is disposed on the third circuit layer.

2. The flexible circuit board according to claim 1, characterized in that, Also includes: At least one electronic component is disposed on the first circuit layer and / or on the second circuit layer of the flexible substrate.

3. The flexible circuit board according to claim 1, characterized in that, Also includes: Multiple fixed terminals are respectively disposed on the second part of the flexible substrate near the ends of the first bending portion and the second bending portion.

4. A method for manufacturing the flexible circuit board according to claim 1, characterized in that, Include: A substrate is provided, wherein the substrate includes a flexible substrate, an upper metal layer and a lower metal layer, and the upper metal layer and the lower metal layer are respectively on the upper surface and the lower surface of the flexible substrate; A first conductive layer and a second conductive layer are deposited on the upper metal layer and the lower metal layer, respectively; The upper metal layer, the lower metal layer, the first conductive layer and the second conductive layer are patterned to form a first connection circuit layer and a second circuit layer on the lower surface of the flexible substrate, and a second connection circuit layer and a first circuit layer on the upper surface of the flexible substrate, and a third circuit layer on the lower surface of the flexible substrate. Laser drilling is performed on the flexible substrate to form multiple openings in the flexible substrate; After the laser drilling operation is performed on the flexible substrate, at least one embedded electronic component is bonded to the third circuit layer. After attaching the at least one embedded electronic component to the third circuit layer, the flexible substrate is subjected to a first bending operation to allow the first connection circuit layer to be inserted into a portion of the plurality of openings; as well as The flexible substrate is then subjected to a second bending operation to allow the second connection circuit layer to be inserted into the remaining plurality of openings.

5. The method for manufacturing a flexible circuit board according to claim 4, characterized in that, After performing the laser drilling operation on the flexible substrate, and before performing the first bending operation, the method further includes: The cover film is bonded onto a portion of the flexible substrate, a portion of the upper metal layer, and a portion of the lower metal layer.

6. The method for manufacturing a flexible circuit board according to claim 4, characterized in that, Also includes: At least one electronic component is attached to the first circuit layer and / or the second circuit layer.

7. The method for manufacturing a flexible circuit board according to claim 4, characterized in that, The process of performing the first bending operation and the second bending operation also includes: Multiple adhesive layers are filled between the flexible substrate and the first and second connection circuit layers.

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