Flexible circuit board and manufacturing method thereof

Abstract

The invention provides a flexible circuit board and a manufacturing method thereof. The flexible circuit board comprises a flexible substrate, wherein the flexible substrate comprises a first part, two second parts, two third parts, two first bending parts and two second bending parts. The flexible circuit board comprises a first connection circuit layer which extends from the upper surface of the first part of the flexible substrate and penetrates through the first part to the upper surface of the second part, and a second connection circuit layer which extends from the lower surface of the second part and penetrates through the third part to the lower surface of the third part. A first circuit layer on an upper surface of the first portion; and a second circuit layer on a lower surface of the third portion. Therefore, according to the flexible circuit board provided by the invention, the bent flexible substrate is connected by utilizing the connecting circuit layer, so that a hole-free effect is achieved, and the high density of the circuit board is realized.

Description

Technical Field

[0001] The invention relates to a flexible circuit board and a manufacturing method thereof, and in particular to a bent flexible circuit board and a manufacturing method thereof. Background Art

[0002] In recent years, with the rapid development of various electronic devices, the application of flexible circuit boards has become more and more extensive, among which high-density circuit boards are the main development trend today. However, high-density circuit boards have higher requirements for aperture size, circuit width and number of layers. Compared with ordinary circuit boards, high-density circuit boards must reduce the number of through holes 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, which utilizes a connecting circuit layer to connect a bent flexible substrate to achieve a hole-free effect, thereby realizing a high-density circuit board.

[0004] Another aspect of the present invention is to provide a method for manufacturing a flexible printed 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 bending portions, and two second bending portions, wherein the second portion is above the third portion, and the first portion is above the second portion. The two first bending portions respectively connect the first portion and the two second portions, and the first portion and the second portion are located between the two first bending portions. The two second bending portions respectively connect the two second portions and the two third portions, and the two second bending portions are located between the second portions. The flexible circuit board includes a plurality of first connection circuit layers, which are arranged to extend from the upper surface of the first portion of the flexible substrate to penetrate the first portion to the upper surface of the second portion; a plurality of second connection circuit layers, which are arranged to extend from the lower surface of the second portion of the flexible substrate to penetrate the third portion to the lower surface of the third portion; a plurality of first circuit layers, which are arranged on the upper surface of the first portion of the flexible substrate; and a plurality of second circuit layers, which are arranged on the lower surface of the third portion of the flexible substrate.

[0006] According to an embodiment of the present invention, the flexible circuit board further comprises 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 bending portions.

[0007] According to an embodiment of the present invention, the flexible circuit board further comprises 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 printed circuit board further includes a plurality of fixed terminals, which are respectively disposed on the second portion of the flexible substrate close to the first bending portion and the end of 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, and the upper metal layer and the lower metal layer are respectively on the upper surface and the 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 connecting circuit layer and a second circuit layer on the lower surface of the flexible substrate, and forming a second connecting 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 connecting circuit layer into a portion of the plurality of openings; and performing a second bending operation on the flexible substrate to insert the second connecting circuit layer into the remaining plurality of openings.

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

[0012] According to an 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 performing the laser drilling operation on the flexible substrate and before performing 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 folding 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 the manufacturing method thereof of the present invention utilize bending of the flexible substrate to connect the circuit layers to achieve electrical connection between the layers, thereby achieving non-porous and high-density circuit boards, and improving the reliability and design freedom of the circuit boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present disclosure is better understood 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 the sake of clarity of discussion, the dimensions of many features may be arbitrarily scaled.

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

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

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

[0020] The following disclosure provides many different embodiments or examples to implement different features of the invention. The specific examples of components and configurations described below are intended to simplify the disclosure. These are of course only examples and are not intended to be limiting. For example, the description of a first feature formed on or above a second feature includes embodiments in which the first feature and the second feature are in direct contact, and also includes embodiments in which other features are formed between the first feature and the second feature, so that the first feature and the second feature are not in direct contact. In addition, the disclosure repeats component symbols and / or letters in various specific examples. The purpose of this repetition is to simplify and clarify the description and does not indicate a relationship between the various discussed embodiments and / or configurations.

[0021] Furthermore, spatially relative terms, such as "beneath," "below," "lower," "above," "upper," etc., are used to facilitate description of the relationship of parts or features illustrated in the drawings to other parts or features. Spatially relative terms encompass different orientations of the elements in use or operation in addition to the orientation depicted in the drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in the present disclosure may be interpreted so.

[0022] Existing multi-layer circuit boards must use vias to electrically connect the circuits of each layer, that is, after forming blind holes or through holes, copper plating or copper paste plugging is performed to form conductive holes. However, the existence of conductive holes will occupy the layout space of the circuit board, which is not conducive to the production of high-density circuit boards and is not conducive to improving the freedom of circuit boards. Furthermore, whether the conductive holes are formed by copper plating or copper paste plugging, the flexible circuit board cannot be bent, and the connection method of the conductive holes will affect the reliability of the circuit board.

[0023] Therefore, based on the above, the present invention provides a flexible circuit board and a manufacturing method thereof, which utilizes bending of a flexible substrate to connect circuit layers to achieve electrical connection between multiple layers, thereby achieving a non-porous and high-density circuit board, and improving the reliability and design freedom of the circuit board.

[0024] See also Figure 1 , Figure 1 A cross-sectional view of a flexible printed circuit board 100 according to some embodiments of the present invention is shown. The flexible printed 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 bending portions 113, and two second bending portions 117. The second portion 115 is located above the third portion 119, and the first portion 111 is located above the second portion 115.

[0025] The first bending portion 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 bending portions 113. The second bending portion 117 connects the two second portions 115 and the two third portions 119, respectively, and along the direction X, the two second bending portions 117 are located between the two second portions 115 (and / or between the two third portions 119). In some embodiments, the two second bending portions 117 are both between the two first bending portions 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 the first portion 111 of the flexible substrate 110 through the first portion 111 to the upper surface 115A of the second portion 115. In some embodiments, the first connection circuit layer 120 includes a conductive column 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 gold layer 128 disposed above the conductive column 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 a conductive column 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 gold layer 138 disposed above the conductive column 131. Therefore, the present invention does not need to use existing electrical connection methods such as vias, conductive glue and / or tin, but uses the first connection circuit layer 120 and the second connection circuit layer 130 to achieve the effect of interlayer interconnection.

[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 the 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 gold layer 148 on the metal layer 145. The second circuit layer 150 is disposed on the lower surface 119B of the 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 gold layer 158 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 the two second bending portions 117. Similarly, the third circuit layer 160 includes a metal layer and a gold layer (not shown). In some embodiments, the flexible circuit board 100 further includes an embedded electronic component 165 disposed on the third circuit layer 160. In other words, the third circuit layer 160 can be configured to electrically connect the embedded electronic component 165. In some embodiments, the embedded electronic component 165 can be a component such as a capacitor, a resistor, or an inductor. It should be understood that although Figure 1Only one embedded electronic component 165 is shown, and 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 a glue layer 170. The glue layer 170 is filled between the first portion 111 and the second portion 115 of the flexible substrate 110, between the second portion 115 and the third portion 119, and between the two second bending portions 117. The glue 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, wherein the fixed terminals 180A to 180D all include conductive pillars 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 accurately locate the bending position of the flexible substrate 110.

[0032] In some embodiments, the fixed 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 fixed 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 fixed 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 fixed 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 to achieve the effects of protection and insulation. In some embodiments, the cover film 190 is disposed on the first bending portion 113 and the second bending portion 117 of the flexible substrate 110 to cover the metal layer 113M and the metal layer 117M respectively, and covers the conductive pillars 181 of the fixed terminals 180A to 180C. In some embodiments, the cover film 190 is disposed on the upper surface 111A of the first portion 111 of the flexible substrate 110 and on the lower surface 119B of the third portion 119 to cover the metal layer 111M on the first portion 111 respectively.

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

[0035] FIG. 2A to FIG. 2H A cross-sectional view of an intermediate stage of a method for manufacturing a flexible printed circuit board 100 according to some embodiments of the present invention is shown. FIG. 2A to FIG. 2H The manufacturing process of the flexible printed circuit board 100 is described. First, refer to Figure 2A , providing a substrate 201. 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] See also Figure 2B , respectively depositing the first conductive layer 220A and the second conductive layer 220B on specific regions of the upper metal layer 210A and the lower metal layer 210B. In some embodiments, Figure 2B The structure is formed by performing 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] FIG. 2C to FIG. 2E For the order 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 (refer to Figure 1 ). First, see Figure 2C, patterning the upper metal layer 210A and the lower metal layer 210B 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., not aligned with each other. In some embodiments, the first patterned metal layer 230A includes a first circuit layer 140, and the second patterned metal layer 230B includes a second circuit layer 150.

[0038] Next, see Figure 2D , patterning the first conductive layer 220A and the second conductive layer 220B to form conductive pillars 181. In some embodiments, the remaining first conductive layer 220A or the second conductive layer 220B is separated from the conductive pillars 181 by grooves R1, and the grooves R1 expose 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 be staggered with the conductive pillars 181 on the lower surface 110B of the flexible substrate 110.

[0039] Then, see Figure 2E , the remaining first conductive layer 220A or the 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. In some embodiments, the conductive pillars 131 and the conductive pillars 121 are staggered, and the conductive pillars 131 are located between two adjacent conductive pillars 121.

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

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

[0042] Please also see Figure 2G and Figure 2H ,right Figure 2G The structure is bent twice to form Figure 2H First, the flexible substrate 110 is subjected to a first bending operation so that the conductive pillar 121 and the conductive pillar 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 can make the two first bending portions 113 of the flexible substrate 110 connect the first portion 111 and the remaining flexible substrate 110 respectively.

[0043] Then, the flexible substrate 110 is subjected to a second bending operation so that the conductive pillar 131 and the conductive pillar 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 fixed terminal 180C and the fixed terminal 180D respectively. The second bending operation enables the second bending portion 117 of the flexible substrate 110 to connect the second portion 115 and the third portion 119. In some embodiments, the opening O1 and the opening O2 into which the conductive pillar 181 is inserted both have one end covered by the covering film 190. At this point, the production of the flexible circuit board 100 has been substantially completed. Then, different electronic components (such as Figure 1 The electronic element 101 and / or the electronic element 103 shown in FIG. 1 are disposed on the first circuit layer 140 or the second circuit layer 150 to obtain Figure 1 The flexible printed circuit board 100 is shown.

[0044] In addition, Figure 3A and Figure 3B As shown, more embedded electronic components 165 can be disposed in the flexible printed circuit board. Figure 3A and Figure 3B The cross-sectional views of the flexible printed circuit board 300 and the flexible printed circuit board 400 according to some embodiments of the present invention are respectively shown. Figure 3A and Figure 3B A plurality of components, such as the first connection circuit layer and the second connection circuit layer, are omitted.

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

[0046] In some embodiments, see 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, wherein 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 layer 460B and the third circuit layer 460C are respectively disposed on the outer surface 417A of the second bending portion 417 of the flexible substrate 410, and the third circuit layer 460D and the third circuit layer 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 can be provided with three embedded electronic components, for example, the embedded electronic component 465 is electrically connected to the third circuit layer 460A, the embedded electronic component 461 is electrically connected to the third circuit layer 460B, the embedded electronic component 463 is electrically connected to the third circuit layer 460C, the embedded electronic component 467 is electrically connected to the third circuit layer 460D, and the embedded electronic component 469 is electrically connected to the third circuit layer 460E.

[0047] According to the above, the present invention provides a flexible circuit board and a manufacturing method thereof, which utilizes a flexible substrate to be bent so that the connecting circuit layer replaces the conductive through hole to realize the electrical connection between layers, and utilizes the positioning terminal for precise positioning, thereby achieving the circuit board without holes and high density, and improving the reliability of the circuit board. Furthermore, the flexible circuit board of the present invention can also centrally package a variety of electronic components, so it is beneficial to improve the degree of freedom of design.

[0048] Although the present invention has been disclosed as above with several embodiments, they are not intended to limit the present invention. Those skilled in the art may make various changes and modifications 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 definition of the attached claims.

[0049]

Explanation of symbols

[0050] 100: Flexible printed circuit board

[0051] 101: Electronic components

[0052] 103: Electronic components

[0053] 110:Soft substrate

[0054] 110A: Upper surface

[0055] 110B: Bottom surface

[0056] 111: Part 1

[0057] 111A: Upper surface

[0058] 111B: Lower surface

[0059] 111M: Metal layer

[0060] 113: first bending portion

[0061] 113M:Metal layer

[0062] 115: Part 2

[0063] 115A: Upper surface

[0064] 115B: Lower surface

[0065] 117: Second bending portion

[0066] 117M:Metal layer

[0067] 119: Part 3

[0068] 119B: Lower surface

[0069] 120: first connection circuit layer

[0070] 121: Conductive column

[0071] 125:Metal layer

[0072] 128:Gold layer

[0073] 130: Second connection circuit layer

[0074] 131: Conductive column

[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: The third circuit layer

[0084] 165: Embedded electronic components

[0085] 170: Adhesive layer

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

[0087] 181: Conductive column

[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 1

[0100] 311B: Bottom surface

[0101] 317: Second bending portion

[0102] 317A: Outer surface

[0103] 360A, 360B, 360C: The third circuit layer

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

[0105] 400: Flexible printed circuit board

[0106] 410:Soft substrate

[0107] 411: Part 1

[0108] 411B: Lower surface

[0109] 417: Second bending portion

[0110] 417A: Outer surface

[0111] 417B: Inner surface

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

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

[0114] O1, O2: Open

[0115] R1: Groove

[0116] X: direction.

Claims

1. A flexible circuit board, characterized in that: Include: A flexible substrate, comprising a first portion, two second portions, two third portions, two first bending portions and two second bending portions, wherein the second portion is above the third portion, and the first portion is above the second portion; The two first bending portions respectively connect the first portion and the two second portions, and the first portion and the second portion are located between the two first bending portions; The two second bending portions respectively connect the two second portions and the two third portions, and the two second bending portions are located between the second portions; A plurality of first connection circuit layers are arranged to extend from the upper surface of the first portion of the flexible substrate and penetrate through the first portion to the upper surface of the second portion; A plurality of second connection circuit layers are arranged to extend from the lower surface of the second portion of the flexible substrate and penetrate through the third portion to the lower surface of the third portion; A plurality of first circuit layers are disposed on the upper surface of the first portion of the flexible substrate; as well as A plurality of second circuit layers are disposed on the lower surface of the third portion of the flexible substrate.

2. The flexible printed circuit board according to claim 1, characterized in that: Also includes: a third circuit layer, disposed on the lower surface of the first portion of the flexible substrate and between the two second bending portions; and At least one embedded electronic component is disposed on the third circuit layer.

3. The flexible printed circuit board according to claim 1, characterized in that: Also includes: A 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; and A plurality of embedded electronic components are arranged on the third circuit layer.

4. The flexible printed 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.

5. The flexible printed circuit board according to claim 1, characterized in that: Also includes: A plurality of fixed terminals are respectively arranged on the second portion of the flexible substrate close to the first bending portion and the end of the second bending portion.

6. A method for manufacturing a flexible circuit board, characterized in that: Include: Providing a substrate, wherein the substrate comprises 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; 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 connecting circuit layer and a second circuit layer on the lower surface of the flexible substrate, and to form a second connecting 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 so that the first connecting circuit layer is inserted into a portion of the plurality of openings; as well as A second bending operation is performed on the flexible substrate so that the second connection circuit layer is inserted into the remaining openings.

7. The method for manufacturing a flexible printed circuit board according to claim 6, characterized in that: After performing the laser drilling operation on the flexible substrate and before performing the first bending operation, the method further comprises: The laminating cover film is on a part of the flexible substrate, a part of the upper metal layer and a part of the lower metal layer.

8. The method for manufacturing a flexible printed circuit board according to claim 6, wherein: Also includes: At least one electronic component is bonded to the first circuit layer and / or the second circuit layer.

9. The method for manufacturing a flexible printed circuit board according to claim 6, characterized in that: 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; and After performing the laser drilling operation on the flexible substrate and before performing the first bending operation, the method further comprises: At least one embedded electronic component is bonded on the third circuit layer.

10. The method for manufacturing a flexible printed circuit board according to claim 6, wherein: When performing the first bending operation and the second bending operation, it also includes: A plurality of adhesive layers are filled between the flexible substrate and the first connection circuit layer and the second connection circuit layer.

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