Circuit board and manufacturing method thereof

Abstract

A circuit board includes a multilayer structure and a transparent insulating layer. The multilayer structure includes a conductive circuit layer, an ion storage layer, an electrolyte layer, an electrochromic layer, and a transparent flexible conductive polymer layer. The conductive circuit layer has a first arc-shaped surface; the ion storage layer covers and adheres to the first arc-shaped surface and has a second arc-shaped surface; the electrolyte layer covers and adheres to the second arc-shaped surface and has a third arc-shaped surface; the electrochromic layer covers and adheres to the third arc-shaped surface and has a fourth arc-shaped surface; the transparent flexible conductive polymer layer covers and adheres to the fourth arc-shaped surface and has a fifth arc-shaped surface; and the transparent insulating layer covers and adheres to the fifth arc-shaped surface to encapsulate the multilayer structure.

Description

Technical Field

[0001] This invention relates to a conductive circuit structure, a circuit board, and a method for manufacturing the same. Prior Technology

[0002] With the increasing sophistication of electronic products, the requirements for circuit boards used in these products are becoming more and more diverse. Currently, there is a type of transparent circuit board where the insulating substrate and cover film used to support and protect the conductive circuit layers are made of transparent materials, making the internal conductive circuit layers visible due to the transparency of the substrate and cover film. Summary of the Invention

[0003] At least one embodiment of the present invention provides a circuit board that has the effect of indicating whether power is on.

[0004] At least another embodiment of the present invention provides a method for manufacturing the above-mentioned circuit board, so as to help improve the circuit board's ability to indicate whether it is powered on.

[0005] At least one other embodiment of the present invention provides a conductive circuit structure that can improve applicability.

[0006] At least another embodiment of the present invention provides a method for manufacturing the above-described conductive circuit structure, in order to help improve the applicability of the above-described conductive circuit structure.

[0007] A circuit board according to at least one embodiment of the present invention includes a multilayer structure and a transparent insulating layer. The multilayer structure includes a conductive circuit layer, an ion storage layer, an electrolyte layer, an electrochromic layer, and a transparent flexible conductive polymer layer. The conductive circuit layer has a first arcuate surface. The ion storage layer covers and adheres to the first arcuate surface and has a second arcuate surface. The electrolyte layer covers and adheres to the second arcuate surface and has a third arcuate surface. The electrochromic layer covers and adheres to the third arcuate surface and has a fourth arcuate surface. The transparent flexible conductive polymer layer covers and adheres to the fourth arcuate surface and has a fifth arcuate surface. The transparent insulating layer covers and adheres to the fifth arcuate surface to cover the multilayer structure.

[0008] In at least one embodiment of the present invention, the first arcuate surface has a first arcuate upper surface and a first arcuate lower surface connected to the first arcuate upper surface, and the ion storage layer includes a first ion storage portion and a second ion storage portion, the first ion storage portion covers and adheres to the first arcuate upper surface, and the second ion storage portion covers and adheres to the first arcuate lower surface and is connected to the first ion storage portion.

[0009] In at least one embodiment of the present invention, the second arcuate surface has a second arcuate upper surface and a second arcuate lower surface connected to the second arcuate upper surface, and the electrolyte layer includes a first electrolyte portion and a second electrolyte portion, the first electrolyte portion covers and adheres to the second arcuate upper surface, and the second electrolyte portion covers and adheres to the second arcuate lower surface and is connected to the first electrolyte portion.

[0010] In at least one embodiment of the present invention, the third arcuate surface has a third arcuate upper surface and a third arcuate lower surface connected to the third arcuate upper surface, and the electrochromic layer includes a first electrochromic portion and a second electrochromic portion. The first electrochromic portion covers and adheres to the third arcuate upper surface, and the second electrochromic portion covers and adheres to the third arcuate lower surface and is connected to the first electrochromic portion.

[0011] In at least one embodiment of the present invention, the fourth arcuate surface has a fourth arcuate upper surface and a fourth arcuate lower surface connected to the fourth arcuate upper surface, and the transparent flexible conductive polymer layer includes a first transparent flexible conductive polymer portion and a second transparent flexible conductive polymer portion. The first transparent flexible conductive polymer portion covers and adheres to the fourth arcuate upper surface, and the second transparent flexible conductive polymer portion covers and adheres to the fourth arcuate lower surface and is connected to the first transparent flexible conductive polymer portion.

[0012] In at least one embodiment of the present invention, the material of the electrochromic layer comprises polypyrrole, polyaniline, polyazine, polythiophene, polyindole, polycarbazole, or a combination thereof.

[0013] In at least one embodiment of the present invention, the material of the transparent flexible conductive polymer layer includes graphene and conductive polymer materials.

[0014] In at least one embodiment of the present invention, the material of the transparent insulating layer includes polyethylene terephthalate, polyimide, polyethylene naphthalate, or a combination thereof.

[0015] In at least one embodiment of the present invention, the linewidth of the conductive line layer is 1 mm to 5 mm.

[0016] A method for manufacturing a circuit board according to at least another embodiment of the present invention includes the following steps: (a) providing an insulating structure, the insulating structure comprising a first insulating layer, a second insulating layer located on the first insulating layer, and a third insulating layer located on the second insulating layer. (b) forming a photoresist pattern on the third insulating layer. (c) etching the insulating structure using the photoresist pattern as a mask to form holes, wherein the etching rate of the third insulating layer is different from the etching rate of the first insulating layer and the etching rate of the second insulating layer. (d) forming initial conductive lines in the holes. (e) forming a fourth insulating layer on the initial conductive lines. (f) after forming the fourth insulating layer, removing the insulating structure to expose the initial arcuate surface of the initial conductive lines. (g) sequentially spraying an initial ion storage portion, an initial electrolyte portion, an initial electrochromic portion, and an initial transparent flexible conductive polymer portion onto the initial arcuate surface of the initial conductive lines. (h) after forming the initial ion storage portion, the initial electrolyte portion, the initial electrochromic portion, and the initial transparent flexible conductive polymer portion, forming an initial transparent insulating portion on the initial transparent flexible conductive polymer portion. (i) Remove the fourth insulating layer to expose the flat surface of the initial conductive line portion, and grind down from the flat surface to remove a portion of the initial conductive line portion, a portion of the initial ion storage portion, a portion of the initial electrolyte portion, a portion of the initial electrochromic portion, a portion of the initial transparent flexible conductive polymer portion, and a portion of the initial transparent insulating portion to form a first circuit board structure. (j) Repeat steps (a) to (i) above to form a second circuit board structure. (k) Press the first circuit board structure and the second circuit board structure together.

[0017] In at least another embodiment of the present invention, the etch rate of the first insulating layer is less than the etch rate of the second insulating layer, and the etch rate of the second insulating layer is less than the etch rate of the third insulating layer.

[0018] In at least another embodiment of the present invention, the etch rate of the first insulating layer is greater than the etch rate of the second insulating layer, and the etch rate of the second insulating layer is greater than the etch rate of the third insulating layer.

[0019] A conductive circuit structure according to at least another embodiment of the present invention includes an insulating layer and a conductive circuit portion. The conductive circuit portion is disposed on the surface of the insulating layer, and the cross-sectional shape of the conductive circuit portion is semi-elliptical. The conductive circuit portion has a thickness along the normal line to the surface of the insulating layer, and the conductive circuit portion has a width in the direction perpendicular to the normal line, wherein the thickness is less than the width.

[0020] A method for fabricating a conductive circuit structure according to at least another embodiment of the present invention includes the following steps: Providing an insulating structure comprising a first insulating layer, a second insulating layer on the first insulating layer, and a third insulating layer on the second insulating layer. Forming a photoresist pattern on the third insulating layer. Wet etching the insulating structure using the photoresist pattern as a mask to form holes, wherein the etching rate of the first insulating layer is less than the etching rate of the second insulating layer, and the etching rate of the second insulating layer is less than the etching rate of the third insulating layer. Forming conductive circuit portions in the holes. Forming an insulating layer on the conductive circuit portions. After forming the insulating layer, removing the insulating structure to expose the arcuate surface of the conductive circuit portions, wherein the cross-sectional shape of the conductive circuit portions is semi-elliptical.

[0021] A conductive circuit structure according to at least another embodiment of the present invention includes an insulating layer and a conductive circuit portion. The conductive circuit portion is disposed on the surface of the insulating layer, and the cross-sectional shape of the conductive circuit portion is semi-elliptical. The conductive circuit portion has a thickness along the normal line of the surface of the insulating layer, and the conductive circuit portion has a width in the direction perpendicular to the normal line, wherein the thickness is greater than the width.

[0022] A method for fabricating a conductive circuit structure according to at least another embodiment of the present invention includes the following steps: Providing an insulating structure comprising a first insulating layer, a second insulating layer on the first insulating layer, and a third insulating layer on the second insulating layer. Forming a photoresist pattern on the third insulating layer. Wet etching the insulating structure using the photoresist pattern as a mask to form holes, wherein the etching rate of the first insulating layer is greater than that of the second insulating layer, and the etching rate of the second insulating layer is greater than that of the third insulating layer. Forming conductive circuit portions in the holes. Forming an insulating layer on the conductive circuit portions. After forming the insulating layer, removing the insulating structure to expose the arcuate surface of the conductive circuit portions, wherein the cross-sectional shape of the conductive circuit portions is semi-elliptical. Simple Explanation of the Diagram

[0023] Figure 1 is a partial cross-sectional schematic diagram of a circuit board according to at least one embodiment of the present invention. Figures 2A to 2J are partial cross-sectional views of the circuit board of Figure 1 at different process stages. Figures 3A to 3F are partial cross-sectional views of a circuit board according to at least another embodiment of the present invention at different process stages. Implementation

[0024] In the following text, to clearly present the technical features of the present invention, the dimensions (e.g., length, width, thickness, and depth) of the elements (e.g., layers, films, substrates, and regions) in the drawings will be enlarged proportionally, and the number of some elements may be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of elements in the drawings or the size and shape of the elements, but should cover the size, shape, and deviations from both caused by actual manufacturing processes and / or tolerances. For example, a flat surface shown in the drawings may have rough and / or non-linear characteristics, and an acute angle shown in the drawings may be rounded. Therefore, the elements presented in the drawings of the present invention are mainly for illustration and are not intended to accurately depict the actual shape of the elements, nor are they intended to limit the scope of the claims of the present invention.

[0025] Secondly, the terms "approximately," "approximately," or "substantially" used in this invention not only cover explicitly stated numerical values ​​and ranges, but also the permissible deviation range understandable to those skilled in the art. This deviation range can be determined by errors generated during measurement, which may arise from limitations of the measurement system or process conditions. For example, two objects (e.g., planes or traces of a substrate) are "substantially parallel" or "substantially perpendicular." "Substantially parallel" and "substantially perpendicular" respectively indicate that the parallelism and perpendicularity between the two objects can include non-parallelism and non-perpendicularity caused by permissible deviation ranges.

[0026] The spatial relative terms used in this invention, such as "below," "under," "above," and "above," are for the convenience of describing the relative relationship between one element or feature and another, as illustrated in the figures. The true meaning of these spatial relative terms includes other orientations. For example, when the illustration is rotated 180 degrees vertically, the relationship between one element and another may change from "below" or "under" to "above" or "above." Furthermore, the spatial relative descriptions used in this invention should be interpreted in the same way.

[0027] It should be understood that although the present invention may use terms such as "first," "second," and "third" to describe various elements or features, these elements or features should not be limited by these terms. These terms are primarily used to distinguish one element from another, or one feature from another. Furthermore, the term "or" as used in the present invention may, as appropriate, include any combination of one or more of the associated listed items.

[0028] Although this invention uses a series of operations or steps to illustrate the manufacturing method, the order in which these operations or steps are shown should not be construed as a limitation of the invention. For example, some operations or steps may be performed in a different order and / or simultaneously with other steps. Furthermore, each operation or step described herein may comprise several sub-steps or actions.

[0029] Furthermore, the present invention can be implemented or applied through other different specific embodiments, and the details of the present invention can also be combined, modified and changed in various embodiments based on different viewpoints and applications without departing from the concept of the present invention.

[0030] Figure 1 is a partial cross-sectional schematic diagram of a circuit board according to at least one embodiment of the present invention. Referring to Figure 1, the circuit board 10 includes a stacked structure 100 and a transparent insulating layer 200. The stacked structure 100 includes a conductive circuit layer 101, an ion storage layer 102, an electrolyte layer 103, an electrochromic layer 104, and a transparent flexible conductive polymer layer 105.

[0031] The conductive circuit layer 101 has a first arcuate surface S1. The ion storage layer 102 covers and adheres to the first arcuate surface S1 and has a second arcuate surface S2. The electrolyte layer 103 covers and adheres to the second arcuate surface S2 and has a third arcuate surface S3. The electrochromic layer 104 covers and adheres to the third arcuate surface S3 and has a fourth arcuate surface S4. The transparent flexible conductive polymer layer 105 covers and adheres to the fourth arcuate surface S4 and has a fifth arcuate surface S5. The transparent insulating layer 200 covers and adheres to the fifth arcuate surface S5 to encapsulate the laminated structure 100.

[0032] Since the electrochromic layer 104 covers the conductive circuit layer 101 and the transparent flexible conductive polymer layer 105 covers the electrochromic layer 104, the voltage between the conductive circuit layer 101 and the transparent flexible conductive polymer layer 105 can be controlled by whether the conductive circuit layer 101 is energized, thereby determining whether the electrochromic layer 104 changes color, thus enabling the circuit board 10 to have the effect of indicating whether it is energized.

[0033] Therefore, by using the electrochromic layer 104 to cover the conductive circuit layer 101, the color change of the electrochromic layer 104 can be seen when viewing the circuit board 10 from the front, indicating whether the conductive circuit layer 101 is energized. It can also be seen when viewing the circuit board 10 from the side, thus improving the applicability and aesthetics of the circuit board 10. Furthermore, since the cross-sectional shape of the stacked structure 100 includes an arc shape, and each layer in the stacked structure 100 has an arc-shaped surface, the layers in the stacked structure 100 are not affected by angles in the structure, such as right angles, which could lead to uneven thickness and poor electrical connection, thus improving yield. In addition, by providing a transparent flexible conductive polymer layer 105, the stacked structure 100 can be bent, thereby improving the bendability of the circuit board 10.

[0034] In detail, as shown in Figure 1, the first arcuate surface S1 has a first arcuate upper surface S1A and a first arcuate lower surface S1B connected to the first arcuate upper surface S1A. The ion storage layer 102 includes a first ion storage portion 102A and a second ion storage portion 102B. The first ion storage portion 102A covers and adheres to the first arcuate upper surface S1A, and the second ion storage portion 102B covers and adheres to the first arcuate lower surface S1B and is connected to the first ion storage portion 102A. In other words, the conductive line layer 101 includes a first conductive line portion 101A and a second conductive line portion 101B connected to the first conductive line portion 101A. The first conductive line portion 101A and the second conductive line portion 101B respectively have a first arcuate upper surface S1A and a first arcuate lower surface S1B. The first ion storage portion 102A and the second ion storage portion 102B respectively cover and adhere to the first arcuate upper surface S1A and the first arcuate lower surface S1B, and are connected to each other to cover and adhere to the first arcuate surface S1A.

[0035] The second arc-shaped surface S2 has a second arc-shaped upper surface S2A and a second arc-shaped lower surface S2B connected to the second arc-shaped upper surface S2A. The electrolyte layer 103 includes a first electrolyte part 103A and a second electrolyte part 103B. The first electrolyte part 103A covers and adheres to the second arc-shaped upper surface S2A, and the second electrolyte part 103B covers and adheres to the second arc-shaped lower surface S2B and is connected to the first electrolyte part 103A.

[0036] The third arc-shaped surface S3 has a third arc-shaped upper surface S3A and a third arc-shaped lower surface S3B connected to the third arc-shaped upper surface S3A. The electrochromic layer 104 includes a first electrochromic part 104A and a second electrochromic part 104B. The first electrochromic part 104A covers and adheres to the third arc-shaped upper surface S3A, and the second electrochromic part 104B covers and adheres to the third arc-shaped lower surface S3B and is connected to the first electrochromic part 104A.

[0037] The fourth arc-shaped surface S4 has a fourth arc-shaped upper surface S4A and a fourth arc-shaped lower surface S4B connected to the fourth arc-shaped upper surface S4A. The transparent flexible conductive polymer layer 105 includes a first transparent flexible conductive polymer part 105A and a second transparent flexible conductive polymer part 105B. The first transparent flexible conductive polymer part 105A covers and adheres to the fourth arc-shaped upper surface S4A, and the second transparent flexible conductive polymer part 105B covers and adheres to the fourth arc-shaped lower surface S4B and is connected to the first transparent flexible conductive polymer part 105A.

[0038] The fifth arc-shaped surface S5 has a fifth arc-shaped upper surface S5A and a fifth arc-shaped lower surface S5B connected to the fifth arc-shaped upper surface S5A. The transparent insulating layer 200 includes a first transparent insulating part 200A and a second transparent insulating part 200B. The first transparent insulating part 200A covers and adheres to the fifth arc-shaped upper surface S5A, and the second transparent insulating part 200B covers and adheres to the fifth arc-shaped lower surface S5B and is connected to the first transparent insulating part 200A.

[0039] By using the arc-shaped surface design of the conductive circuit layer 101, the thickness of the ion storage layer 102, electrolyte layer 103, electrochromic layer 104 and transparent flexible conductive polymer layer 105 sequentially disposed on the conductive circuit layer 101 can be more uniform, thereby improving the yield. In some embodiments, the cross-sectional shape of the stacked structure 100 can be olive-shaped or elliptical.

[0040] In some embodiments, the linewidth of the conductive circuit layer 101 can be from 1 mm to 5 mm, for example, 2 mm, so that the human eye can observe whether the electrochromic layer 104 changes color to determine whether the conductive circuit layer 101 is energized. The material of the conductive circuit layer 101 may include metals, such as copper. The material of the electrochromic layer 104 may include polypyrole, polyaniline, polyazulene, polythiophene, polyindole, polycarbazole, or combinations thereof. For example, polypyroleum can be selected, which has a lower oxidation potential, higher current efficiency, and longer repetition life compared to other materials. Therefore, as a material for the electrochromic layer 104, it can have higher stability and improve the reliability of the circuit board 10.

[0041] In some embodiments, the electrolyte layer 103 may be made of electrolyte materials such as lithium perchlorate or sodium perchlorate, while the ion storage layer 102 is used to store corresponding ions with opposite charges when the electrochromic layer 104 undergoes a redox reaction, thereby maintaining charge balance. The transparent flexible conductive polymer layer 105 may be made of graphene and conductive polymer materials. The transparent insulating layer 200 may be made of polyester polymer compounds. The transparent insulating layer 200 may be made of polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), or a combination thereof. By selecting the aforementioned materials, the transparency and flexibility of the circuit board 10 can be effectively improved.

[0042] Figures 2A to 2J are partial cross-sectional views of the circuit board of Figure 1 at different process stages. Referring to Figure 2A, an insulating structure IL is provided, which includes a first insulating layer IL1, a second insulating layer IL2 located on the first insulating layer IL1, and a third insulating layer IL3 located on the second insulating layer IL2, and a photoresist pattern RL is formed on the third insulating layer IL3.

[0043] Next, referring to Figure 2B, the insulating structure IL is etched using the photoresist pattern RL as a mask to form the hole H. The etching rate of the third insulating layer IL3 is different from the etching rate of the first insulating layer IL1 and the etching rate of the second insulating layer IL2. In some embodiments, the etching of the insulating structure IL can be performed by a wet etching process.

[0044] For example, as shown by the arrow in Figure 2B, the etching solution can be injected into the opening of the photoresist pattern RL for rinsing and etching. Since the etching rate of the first insulating layer IL1 is less than that of the second insulating layer IL2, and the etching rate of the second insulating layer IL2 is less than that of the third insulating layer IL3, that is, for the aforementioned etching solution, the tolerance of the first insulating layer IL1 is greater than that of the second insulating layer IL2, and the tolerance of the second insulating layer IL2 is greater than that of the third insulating layer IL3. Therefore, the third insulating layer IL3 is etched over the largest area, with obvious lateral etching, resulting in a wider opening for the hole H. The first insulating layer IL1 is etched over the smallest area, with only slight forward etching, thus obtaining a semi-elliptical hole H, which is beneficial for the subsequent formation of an arc-shaped stacked structure.

[0045] Referring to Figures 2C and 2D, an initial conductive line portion 101I is formed in the hole H. Specifically, as shown in Figure 2C, the photoresist pattern RL is first removed, and a seed layer SL is formed on the surface of the hole H. Next, as shown in Figure 2D, a conductive portion is formed on the seed layer SL to fill the hole H, and then a portion of the seed layer SL and a portion of the conductive portion are removed to form the initial conductive line portion 101I in the hole H. In some embodiments, the formation of the seed layer SL can be performed by a coating process, the formation of the conductive portion to fill the hole H can be performed by an electroplating process, and the removal of a portion of the seed layer SL and a portion of the conductive portion can be performed by a polishing process.

[0046] Referring to FIG2E, a fourth insulating layer IL4 is formed on the initial conductive line portion 101I and the insulating structure IL. In some embodiments, the formation of the fourth insulating layer IL4 may be performed by a lamination process. Next, referring to FIG2F, after the formation of the fourth insulating layer IL4, the insulating structure IL is removed to expose the initial arcuate surface CS of the initial conductive line portion 101I. As shown in FIG2F, the cross-sectional shape of the initial conductive line portion 101I is semi-elliptical, and the initial conductive line portion 101I is located on the surface of the fourth insulating layer IL4. The initial conductive line portion 101I has a thickness T1 on the normal line (i.e., the first direction D1) of the aforementioned surface of the fourth insulating layer IL4, and the initial conductive line portion 101I has a width T2 on the second direction D2 perpendicular to the normal line of the aforementioned surface of the fourth insulating layer IL4. The thickness T1 is smaller than the width T2.

[0047] It is worth noting that the initial conductive line portion 101I and the fourth insulating layer IL4 in Figure 2F can serve as a conductive line structure 20, for example, as a solder pad. That is to say, after completing the steps shown in Figure 2F, depending on the product to which it is intended, the subsequent steps in Figures 2G to 2J can be performed to form a circuit board, or other steps can be performed, or even no subsequent steps can be performed to form other products.

[0048] Referring to Figure 2G, the initial ion storage portion 102I, the initial electrolyte portion 103I, the initial electrochromic portion 104I, and the initial transparent flexible conductive polymer portion 105I are sequentially sprayed onto the initial arc-shaped surface CS of the initial conductive line portion 101I. In some embodiments, the initial ion storage portion 102I, the initial electrolyte portion 103I, and the initial electrochromic portion 104I can be formed by a spraying process and a baking process. The initial transparent flexible conductive polymer portion 105I can be formed by a spraying process and a baking process or a photocuring process. Furthermore, since the initial conductive line portion 101I has an initial arc-shaped surface CS and its junction with the fourth insulating layer IL4 is not at a right angle, the uniformity of the spraying of the aforementioned layers can be improved, and the adhesion of the aforementioned layers at the junction can be further improved by the spraying process.

[0049] Referring to Figure 2H, after forming the initial ion storage portion 102I, the initial electrolyte portion 103I, the initial electrochromic portion 104I, and the initial transparent flexible conductive polymer portion 105I, an initial transparent insulating portion 200I is formed on the initial transparent flexible conductive polymer portion 105I. In some embodiments, the initial transparent insulating portion 200I can be formed by a lamination process.

[0050] Please refer to Figures 2H and 2I. The fourth insulating layer IL4 is removed to expose the flat surface PS of the initial conductive line portion 101I. Part of the initial conductive line portion 101I, part of the initial ion storage portion 102I, part of the initial electrolyte portion 103I, part of the initial electrochromic portion 104I, part of the initial transparent flexible conductive polymer portion 105I, and part of the initial transparent insulating portion 200I are removed by grinding from the flat surface PS to form the first circuit board structure 10A. The first circuit board structure 10A includes the first conductive line portion 101A, the first ion storage portion 102A, the first electrolyte portion 103A, the first electrochromic portion 104A, the first transparent flexible conductive polymer portion 105A, and the first transparent insulating portion 200A.

[0051] Repeat Figures 2A to 2I above to form a second circuit board structure 10B. The second circuit board structure 10B includes a second conductive line portion 101B, a second ion storage portion 102B, a second electrolyte portion 103B, a second electrochromic portion 104B, a second transparent flexible conductive polymer portion 105B, and a second transparent insulating portion 200B. Next, referring to Figure 2J, the first circuit board structure 10A and the second circuit board structure 10B are pressed together to form a circuit board 10.

[0052] Figures 3A to 3F are partial cross-sectional views of a circuit board of at least another embodiment of the present invention at different process stages. Referring to Figure 3A, an insulating structure IL' is provided, which includes a first insulating layer IL1', a second insulating layer IL2' located on the first insulating layer IL1', and a third insulating layer IL3' located on the second insulating layer IL2', and a photoresist pattern RL is formed on the third insulating layer IL3'.

[0053] Next, referring to Figure 3B, the insulating structure IL' is etched using the photoresist pattern RL as a mask to form the hole H'. The etching rate of the third insulating layer IL3' is different from the etching rate of the first insulating layer IL1' and the second insulating layer IL2'. In some embodiments, the etching of the insulating structure IL' can be performed by a wet etching process.

[0054] For example, as shown by the arrow in Figure 3B, the etching solution can be injected and rinsed through the opening of the photoresist pattern RL to perform etching. Since the etching rate of the first insulating layer IL1' is greater than that of the second insulating layer IL2', and the etching rate of the second insulating layer IL2' is greater than that of the third insulating layer IL3', that is, for the aforementioned etching solution, the tolerance of the first insulating layer IL1' is less than that of the second insulating layer IL2', and the tolerance of the second insulating layer IL2' is less than that of the third insulating layer IL3'. Therefore, the third insulating layer IL3 is etched to the smallest extent, and there is very little or no lateral etching, resulting in the hole wall slope of hole H' being higher than that of hole H in Figure 2B.

[0055] Referring to Figures 3C and 3D, an initial conductive line portion 101I' is formed in the hole H'. Next, referring to Figure 3E, a fourth insulating layer IL4 is formed on the initial conductive line portion 101I' and the insulating structure IL'. The aforementioned steps and processes are similar to those in Figures 2C to 2E, so the same features will not be described again.

[0056] Referring to Figure 3F, after forming the fourth insulating layer IL4, the insulating structure IL' is removed to expose the initial arcuate surface CS' of the initial conductive line portion 101I'. Subsequent steps and processes are similar to those in Figures 2G to 2J, so the same features will not be described again.

[0057] It is worth noting that, as shown in Figure 3F, the cross-sectional shape of the initial conductive line portion 101I' is semi-elliptical, and the initial conductive line portion 101I' is located on the surface of the fourth insulating layer IL4. The initial conductive line portion 101I' has a thickness T1' on the normal line (i.e., the first direction D1) of the aforementioned surface of the fourth insulating layer IL4, and a width T2' on the second direction D2 perpendicular to the normal line of the aforementioned surface of the fourth insulating layer IL4. The thickness T1' is greater than the width T2'. In other words, the cross-sectional shape of the initial conductive line portion 101I' is a semi-elliptical shape with its major axis extending along the first direction D1 and its minor axis extending along the second direction D2, while the cross-sectional shape of the initial conductive line portion 101I in Figure 2F is also a semi-elliptical shape with its minor axis extending along the first direction D1 and its major axis extending along the second direction D2.

[0058] Furthermore, the initial conductive line portion 101I' and the fourth insulating layer IL4 in Figure 3F can serve as a conductive line structure 20', for example, as a solder pad. In other words, after completing the steps shown in Figure 3F, depending on the product to which it is intended, the subsequent steps in Figures 2G to 2J can be performed to form a circuit board, or other steps can be performed, or even no subsequent steps can be performed to form other products.

[0059] In summary, in the conductive circuit structure, circuit board and manufacturing method of the present invention in at least one embodiment, since the electrochromic layer covers the conductive circuit layer and the transparent flexible conductive polymer layer covers the electrochromic layer, the voltage between the conductive circuit layer and the transparent flexible conductive polymer layer can be controlled by whether the conductive circuit layer is energized, thereby determining whether the electrochromic layer changes color, and thus enabling the circuit board to have the effect of indicating whether it is energized.

[0060] By using an electrochromic layer to cover the conductive circuit layer, the electrochromic layer can be seen to indicate whether the conductive circuit layer is energized when the circuit board is viewed from the front, and it can also be seen when the circuit board is viewed from the side. Therefore, the electrochromic layer can be seen to indicate whether the conductive circuit layer is energized from different viewing angles, which can improve the applicability and aesthetics of the circuit board.

[0061] Furthermore, because the cross-sectional shape of the stacked structure includes arcs, the layers in the stacked structure are not affected by angles, such as right angles, which would lead to uneven thickness and poor electrical connections, thus improving yield. In addition, by adding a transparent flexible conductive polymer layer, the stacked structure can be bent, thereby improving the flexibility of the circuit board. Moreover, since the cross-sectional shape of the conductive circuit section of the conductive circuit structure is semi-elliptical, the applicability of the conductive circuit structure can be improved.

[0062] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art can make some 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.

[0063] 10: Circuit board 10A: First circuit board structure 10B: Second Circuit Board Structure 20, 20': Conductive circuit structure 100: Stacked structure 101: Conductive circuit layer 101A: First Conductive Circuit Section 101B: Second Conductive Circuit Section 101I, 101I': Initial conductive circuit section 102: Ion Storage Layer 102A: First Ion Storage Unit 102B: Second Ion Storage Unit 102I: Initial ion storage section 103: Electrolyte layer 103A: First Electrolyte Section 103B: Second Electrolyte Section 103I: Initial Electrolyte Section 104: Electrochromic layer 104A: First electrochromic section 104B: Second electrochromic part 104I: Initial electrochromic part 105: Transparent flexible conductive polymer layer 105A: First transparent flexible conductive polymer component 105B: Second transparent flexible conductive polymer part 105I: Initially transparent, flexible, conductive polymer component 200: Transparent insulating layer 200A: First transparent insulating part 200B: Second transparent insulating part 200I: Initial transparent insulating part CS, CS': Initial curved surface D1: First Direction D2: Second Direction H, H': Hole IL, IL': Insulation structure IL1, IL1': First insulating layer IL2, IL2': Second insulating layer IL3, IL3': Third insulating layer IL4: Fourth insulating layer PS: Flat surface RL: Photoresist pattern S1: First arc-shaped surface S1A: First arc-shaped upper surface S1B: First arc-shaped lower surface S2: Second arc-shaped surface S2A: Second arc-shaped upper surface S2B: Second arc-shaped lower surface S3: Third arc surface S3A: Third arc-shaped upper surface S3B: Third arc-shaped lower surface S4: Fourth arc-shaped surface S4A: Fourth arc-shaped upper surface S4B: Fourth arc-shaped lower surface S5: Fifth arc-shaped surface S5A: Fifth arc-shaped upper surface S5B: Fifth arc-shaped lower surface SL: Seed layer T1, T1': Thickness T2, T2': Width

[0064] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A circuit board, comprising: A multilayer structure includes: a conductive circuit layer having a first arcuate surface; an ion storage layer covering and adhering to the first arcuate surface and having a second arcuate surface; and an electrolyte layer covering and adhering to the second arcuate surface and having a third arcuate surface. An electrochromic layer covers and adheres to the third arcuate surface and has a fourth arcuate surface; a transparent flexible conductive polymer layer covers and adheres to the fourth arcuate surface and has a fifth arcuate surface, wherein the fourth arcuate surface has a fourth arcuate upper surface and a fourth arcuate lower surface connected to the fourth arcuate upper surface, wherein the transparent flexible conductive polymer layer includes a first transparent flexible conductive polymer portion and a second transparent flexible conductive polymer portion, wherein the first transparent flexible conductive polymer portion covers and adheres to the fourth arcuate upper surface, and the second transparent flexible conductive polymer portion covers and adheres to the fourth arcuate lower surface and is connected to the first transparent flexible conductive polymer portion; and a transparent insulating layer covers and adheres to the fifth arcuate surface to cover the stacked structure.

2. The circuit board as claimed in claim 1, wherein the first arcuate surface has a first arcuate upper surface and a first arcuate lower surface connected to the first arcuate upper surface, wherein the ion storage layer includes a first ion storage portion and a second ion storage portion, wherein the first ion storage portion covers and adheres to the first arcuate upper surface, and the second ion storage portion covers and adheres to the first arcuate lower surface and is connected to the first ion storage portion.

3. The circuit board as claimed in claim 1, wherein the second arcuate surface has a second arcuate upper surface and a second arcuate lower surface connected to the second arcuate upper surface, wherein the electrolyte layer includes a first electrolyte portion and a second electrolyte portion, wherein the first electrolyte portion covers and adheres to the second arcuate upper surface, and the second electrolyte portion covers and adheres to the second arcuate lower surface and is connected to the first electrolyte portion.

4. The circuit board as claimed in claim 1, wherein the third arcuate surface has a third arcuate upper surface and a third arcuate lower surface connected to the third arcuate upper surface, wherein the electrochromic layer includes a first electrochromic portion and a second electrochromic portion, wherein the first electrochromic portion covers and adheres to the third arcuate upper surface, and the second electrochromic portion covers and adheres to the third arcuate lower surface and is connected to the first electrochromic portion.

5. The circuit board as claimed in claim 1, wherein the material of the electrochromic layer includes polypyrrole, polyaniline, polyazine, polythiophene, polyindole, polycarbazole, or a combination thereof.

6. The circuit board as claimed in claim 1, wherein the material of the transparent flexible conductive polymer layer includes graphene and conductive polymer materials.

7. The circuit board as claimed in claim 1, wherein the material of the transparent insulating layer includes polyethylene terephthalate, polyimide, polyethylene naphthalate, or a combination thereof.

8. The circuit board as claimed in claim 1, wherein the linewidth of the conductive line layer is 1 mm to 5 mm.

9. A method for manufacturing a circuit board as claimed in claim 1, comprising the following steps: (a) providing an insulating structure, wherein the insulating structure includes a first insulating layer, a second insulating layer on the first insulating layer, and a third insulating layer on the second insulating layer; (b) forming a photoresist pattern on the third insulating layer; (c) etching the insulating structure with the photoresist pattern as a mask to form a hole, wherein the etching rate of the third insulating layer is different from the etching rate of the first insulating layer and the etching rate of the second insulating layer; (d) forming an initial conductive line portion in the hole; (e) forming a fourth insulating layer on the initial conductive line portion; (f) after forming the fourth insulating layer, removing the insulating structure to expose an initial arcuate surface of the initial conductive line portion; (g) sequentially spraying an initial ion storage portion, an initial electrolyte portion, an initial electrochromic portion, and an initial transparent flexible conductive polymer portion onto the initial arcuate surface. (h) After forming the initial ion storage portion, the initial electrolyte portion, the initial electrochromic portion, and the initial transparent flexible conductive polymer portion, an initial transparent insulating portion is formed on the initial transparent flexible conductive polymer portion; (i) The fourth insulating layer is removed to expose a flat surface of the initial conductive line portion, and a portion of the initial conductive line portion, a portion of the initial ion storage portion, a portion of the initial electrolyte portion, a portion of the initial electrochromic portion, a portion of the initial transparent flexible conductive polymer portion, and a portion of the initial transparent insulating portion are ground down from the flat surface to form a first circuit board structure; (j) Steps (a) to (i) are repeated to form a second circuit board structure; and (k) The first circuit board structure and the second circuit board structure are pressed together.

10. The manufacturing method as described in claim 9, wherein the etch rate of the first insulating layer is less than the etch rate of the second insulating layer, and the etch rate of the second insulating layer is less than the etch rate of the third insulating layer.

11. The manufacturing method as described in claim 9, wherein the etch rate of the first insulating layer is greater than the etch rate of the second insulating layer, and the etch rate of the second insulating layer is greater than the etch rate of the third insulating layer.

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