Tear-resistant double-sided flexible circuit board and method of manufacturing the same

Abstract

The application discloses a kind of anti-tearing double-sided flexible circuit board and its manufacturing method, including providing double-sided board substrate;The preset circuit area and anti-tearing pattern area on the two surfaces of double-sided board substrate are exposed, and the double-sided board to be etched is formed;Wherein, the anti-tearing pattern area on the two surfaces is located on the waste area outside corresponding circuit area;The double-sided board to be etched is etched, and corresponding circuit layer and anti-tearing pattern are formed on the two surfaces of the double-sided board to be etched respectively;Based on the circuit layer and anti-tearing pattern on the two surfaces, the double-sided board to be etched after etching is processed, and the target double-sided flexible circuit board is formed.The application utilizes anti-tearing pattern, can effectively avoid the vertical height difference between exposed PI layer and outer copper layer after etching, reduce the tearing risk caused by exposed PI layer in the conventional process flow of flexible board manufacturing field, and then improve product yield, improve production efficiency, reduce production loss.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board manufacturing technology, specifically to a tear-resistant double-sided flexible circuit board and its manufacturing method. Background Technology

[0002] When using flexible printed circuit boards (FPCs) to manufacture electronic devices, as electronic devices become increasingly smaller and thinner, the thickness requirements for the flexible circuit boards inside the devices are also becoming thinner. At the same time, because thinner boards (i.e., thinner flexible circuit boards) are easier to bend and perform a series of processing operations, the manufacturing of flexible circuit boards is also adapting to thinner board production to adapt to the development of the times and customer needs. Among them, the 12μm polyimide substrate layer (PI layer) is widely used.

[0003] Double-sided flexible printed circuit boards (PCBs) are a mainstream structure for thin boards. They consist of a polyimide (PI) layer and two copper layers, with the two copper layers located on opposite surfaces of the PI layer. Figure 1a As shown, because it has two copper layers (the first copper layer 11 and the second copper layer 13, respectively) and the two copper layers are located on the upper and lower surfaces of the PI layer 12, the double-sided flexible circuit board is also called a double-layer board or double-sided board. When using a 12μm PI layer to make a thin double-sided board, the stack-up structure of the double-sided board is a 12μm first copper layer, a 12μm PI layer, and a 12μm second copper layer. After the etching process, and after the circuit forming on both surfaces, the copper layers on both surfaces are etched away in the area near the outer edge of the circuit area, resulting in only a single PI layer being exposed. Furthermore, there is a vertical height difference between the exposed PI layer and the unetched copper layer in the waste area (this vertical height difference exists on both the upper and lower surfaces). Figure 1b As shown, this area with vertical height differences is easily damaged by subsequent manufacturing processes such as spraying, roller extrusion, and winding / unwinding. The PI layer is prone to bending and tearing, which in turn affects the nearby circuitry, leading to low production efficiency and significant production losses. The larger the exposed area of ​​the PI layer, the greater the risk of damage. In actual production, it largely depends on careful operator handling and appropriately reducing process parameters, but it is still impossible to completely avoid a high proportion of PI tearing defects.

[0004] Therefore, in the existing technology for fabricating double-sided panels that meet the requirements of thin boards based on a 12μm polyimide substrate layer, tearing is prone to occur in the area where there is a height difference between the exposed PI layer and the outer copper layer after etching, resulting in a high risk of tearing. Summary of the Invention

[0005] In view of this, the present invention provides a tear-resistant double-sided flexible circuit board and its manufacturing method, in order to solve the problem that tearing is prone to occur in the area where there is a height difference between the exposed PI layer and the outer copper layer after etching of the double-sided board, which leads to low production efficiency and serious production losses.

[0006] This invention provides a method for manufacturing a tear-resistant double-sided flexible circuit board, comprising:

[0007] Provides dual-sided panel substrates;

[0008] The pre-defined circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate are exposed to form a double-sided board to be etched; wherein the anti-tear pattern areas on both surfaces are located on the waste areas outside the corresponding circuit areas.

[0009] The double-sided board to be etched is etched to form corresponding circuit layers and tear-resistant patterns on the two surfaces of the double-sided board to be etched.

[0010] Based on the circuit layers and the tear-resistant pattern on both surfaces, the etched double-sided board is processed to form the target double-sided flexible circuit board.

[0011] Optionally, on both surfaces of the etched double-sided panel, the anti-tear pattern is a wavy edge formed by multiple equally spaced semi-circular copper layers.

[0012] All the semicircular copper layers on each of the wavy edges are located on the same horizontal line, and all the semicircular copper layers on two of the wavy edges are parallel and staggered.

[0013] Optionally, the distance between each of the two wavy edges and the outline of the circuit layer on the corresponding surface is greater than or equal to 6 mm.

[0014] Optionally, on each of the wavy edges, the radius of each of the semi-circular copper layers ranges from 0.15 to 0.25 mm.

[0015] Optionally, on each of the wavy edges, the radius of each of the semi-circular copper layers is 0.2 mm.

[0016] Optionally, on each of the wavy edges, the spacing between each two adjacent semi-circular copper layers ranges from 0.3 to 0.5 mm.

[0017] Optionally, on each of the wavy edges, the spacing between every two adjacent semicircular copper layers is 0.4 mm.

[0018] Optionally, before exposing the preset circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate, the method further includes:

[0019] According to the preset flexible board circuit design, the corresponding circuit area and the anti-tear pattern area are respectively set on the two surfaces of the double-sided board substrate.

[0020] Optionally, before exposing the preset circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate, the method further includes:

[0021] A front and back marking alignment hole and multiple exposure alignment holes are laser-drilled on the double-sided substrate.

[0022] Optionally, exposing the pre-defined circuit areas and tear-resistant pattern areas on the two surfaces of the double-sided substrate includes:

[0023] Using the alignment holes marked on the front and back sides, the two surfaces of the double-sided substrate are marked on the front and back sides;

[0024] Using all the aforementioned exposure alignment holes, the circuit area and the anti-tear pattern area on the two surfaces of the double-sided substrate after being marked on the front and back are respectively positioned.

[0025] The circuit area and the anti-tear pattern area on the two surfaces of the positioned double-sided substrate are exposed.

[0026] Optionally, after processing the etched double-sided board based on the circuit layers and the tear-resistant pattern on both surfaces, the process further includes:

[0027] The processed double-sided board to be etched is punched according to the flexible board shape formed by the circuit layers on the two surfaces.

[0028] Optionally, the number of the dual-panel substrates may be one or more.

[0029] In addition, the present invention also provides a tear-resistant double-sided flexible circuit board, which is manufactured using the aforementioned manufacturing method.

[0030] The beneficial effects of this invention are as follows: During the exposure of the circuit areas preset on the two surfaces of the provided double-sided board substrate, the exposure of the anti-tear pattern areas preset on the two surfaces is performed simultaneously. This allows the anti-tear pattern areas to be exposed simultaneously on both surfaces of the double-sided board substrate as the circuit areas are exposed, facilitating subsequent etching of the anti-tear pattern without the need for a separate exposure process, thus improving production efficiency. The anti-tear pattern areas are located on the waste areas outside the corresponding circuit areas, making full use of the waste material of the double-sided board substrate to achieve the etching of the anti-tear pattern. The anti-tear pattern obtained by etching the waste area effectively avoids the vertical height difference between the exposed PI layer and the outer copper layer after etching, thereby reducing the risk of tearing and saving material costs. After exposure is completed, the etching of the double-sided board to be etched simultaneously forms a circuit layer that enables the normal function of the flexible board product and an anti-tear pattern that reduces the risk of tearing. Based on this circuit layer, subsequent manufacturing can be carried out according to conventional processes in the flexible board manufacturing field. Based on the anti-tear pattern, the tearing risk caused by spraying, roller extrusion, and unwinding operations in subsequent conventional processes can be effectively reduced.

[0031] The tear-resistant double-sided flexible circuit board and its manufacturing method of the present invention simultaneously expose the tear-resistant pattern area and etch the tear-resistant pattern during the exposure of the circuit area and the etching of the circuit layer. By using the tear-resistant pattern, the vertical height difference formed between the exposed PI layer and the outer copper layer after etching can be effectively avoided, reducing the tearing risk of the exposed PI layer caused by conventional processes such as spraying, roller extrusion, and unwinding in the flexible circuit board manufacturing field, thereby improving product yield, increasing production efficiency, and reducing production losses. Attached Figure Description

[0032] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0033] Figure 1a A cross-sectional view of the double-sided panel is shown.

[0034] Figure 1b This is a cross-sectional view showing the vertical height difference between the exposed PI layer after etching and the unetched copper layer in the waste area in the conventional technique.

[0035] Figure 2 A flowchart illustrating a method for manufacturing a tear-resistant double-sided flexible circuit board according to Embodiment 1 of the present invention is shown.

[0036] Figure 3 This is a top view of the layout of the pre-set circuit area and anti-tear pattern area on the double-sided substrate in Embodiment 1 of the present invention;

[0037] Figure 4 The flowchart illustrating the formation of the double-sided panel to be etched in Embodiment 1 of the present invention is shown;

[0038] Figure 5a This is a top view of the structure of the first wavy edge formed on the upper surface of the double-sided panel to be etched after etching in Embodiment 1 of the present invention.

[0039] Figure 5b The diagram shows a top view of the second wavy edge formed on the lower surface of the double-sided panel to be etched after etching in Embodiment 1 of the present invention.

[0040] Figure 5c The diagram shows a top view of the two wavy edges formed after etching of the double-sided panel in Embodiment 1 of the present invention.

[0041] Figure 6 A top view structural diagram showing the spacing relationship between the first wavy edge and the outline of the circuit layer on the corresponding surface in Embodiment 1 of the present invention is shown.

[0042] Figure 7 The image shows a top view of the two wavy edges etched in Embodiment 1 of the present invention.

[0043] Figure 8 The diagram shows a top view of the two serrated edges formed after etching of the double-sided panel in Embodiment 1 of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Double-sided board, 11. First copper layer, 12. PI layer, 13. Second copper layer, 111. First wavy edge, 112. First serrated edge, 131. Second wavy edge, 132. Second serrated edge, 100. Circuit area, 101. Circuit layer, 200. Scrap area, 201. Tear-resistant pattern area. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] A method for manufacturing a tear-resistant double-sided flexible circuit board, such as... Figure 2 As shown, it includes the following steps:

[0049] S1 provides a double-sided panel substrate.

[0050] Specifically, the double-sided panel substrate of this embodiment has the same structure as the double-sided panel 1 in conventional technology, such as... Figure 1a As shown, the double-sided copper-clad substrate is specifically composed of a first copper layer 11, a PI layer 12, and a second copper layer 13, with the first copper layer 11 and the second copper layer 13 located on both sides of the PI layer 12.

[0051] like Figure 2 As shown, in step S2, the pre-set circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate are exposed to form a double-sided panel to be etched; wherein, the anti-tear pattern areas on both surfaces are located on the waste areas outside the corresponding circuit areas.

[0052] Preferably, before S2, the method further includes:

[0053] According to the preset flexible board circuit design, the corresponding circuit area and the anti-tear pattern area are respectively set on the two surfaces of the double-sided board substrate.

[0054] The preset flexible circuit board design is a design requirement set by the user for the target double-sided flexible circuit board, including the required circuit layer positions, circuit layer sizes, and circuit layout. Based on this preset flexible circuit board design, the area where the circuit layer is located, i.e., the circuit area, can be set on the double-sided substrate. At the same time, since the anti-tear pattern is used to prevent the PI layer exposed after the circuit area is etched, the area where the anti-tear pattern is located, i.e., the anti-tear pattern area, can be further set according to the circuit area. Through the preset circuit area and the anti-tear pattern area, the production efficiency of subsequent exposure and etching processes can be improved.

[0055] A top view diagram of the pre-set circuit area and tear-resistant graphic area on the double-sided substrate in this embodiment is shown below. Figure 3 As shown, 100 refers to the circuit area, 200 refers to the waste area, and 201 refers to the anti-tear graphic area on the waste area.

[0056] Preferably, before S2, the method further includes:

[0057] A front and back marking alignment hole and multiple exposure alignment holes are laser-drilled on the double-sided substrate.

[0058] The front and back marking alignment holes are used to mark the front and back sides of the upper and lower surfaces of the double-sided substrate during exposure to prevent the front and back sides of the double-sided substrate from being placed incorrectly, which would cause manufacturing errors in subsequent processes. The exposure alignment holes are used to position the circuit area and anti-tear pattern area on the upper and lower surfaces of the double-sided substrate during exposure to prevent exposure deviation in the circuit area and anti-tear pattern area.

[0059] The number of exposure alignment holes can be set and adjusted according to actual conditions. For example, four exposure alignment holes can be evenly arranged on the waste area outside the circuit area of ​​the double-sided board substrate. The aperture of the exposure alignment holes and the aperture of the front and back marking alignment holes can also be set and adjusted according to actual conditions. For example, the aperture of the exposure alignment holes can be set to 2mm, and the aperture of the front and back marking alignment holes can be set to 3mm.

[0060] Preferably, such as Figure 4 As shown, S2 includes:

[0061] S21: Using the front and back marking alignment holes, mark the front and back sides of the two surfaces of the double-sided substrate.

[0062] S22: Using all the exposure alignment holes, the circuit area and the anti-tear pattern area on the two surfaces of the double-sided substrate after being marked on the front and back sides are respectively positioned.

[0063] S23: Expose the circuit area and the anti-tear pattern area on the two surfaces of the positioned double-sided substrate.

[0064] By using the above-mentioned front and back marking and positioning steps, the circuit area and anti-tear pattern area on both surfaces of the double-sided board substrate can be accurately exposed. This ensures the normal fabrication of the target double-sided flexible circuit board and guarantees its functionality. On the other hand, it ensures that the anti-tear pattern obtained by subsequent etching in the anti-tear pattern area can effectively reduce the risk of tearing and guarantee its anti-tear performance.

[0065] like Figure 2 As shown, in step S3, the double-sided board to be etched is etched to form the corresponding circuit area and the anti-tear pattern on the two surfaces of the double-sided board to be etched.

[0066] The etching is performed on the circuit area and tear-resistant pattern area on the double-sided board to be etched after exposure in S2, ensuring the functionality of the circuit layer and the tear-resistant performance of the tear-resistant pattern. The specific etching operation method is existing technology in this field and can be performed using conventional DES process flow (including development, etching, stripping, washing, drying, etc.). Specific details will not be elaborated here.

[0067] Preferably, on both surfaces of the double-sided panel to be etched after etching, the anti-tear pattern is a wavy edge formed by multiple equally spaced semi-circular copper layers.

[0068] All the semicircular copper layers on each of the wavy edges are located on the same horizontal line, and all the semicircular copper layers on two of the wavy edges are parallel and staggered.

[0069] The tear-resistant pattern designed above allows for the formation of an irregular, staggered, wavy edge structure between the PI layer and the outer copper layer after etching. This irregular edge effectively avoids the vertical height difference between the exposed PI layer and the outer copper layer, making the structure less susceptible to external impacts from subsequent processes such as spraying, roller pressing, and winding / unwinding. The structure has strong compressive strength and is not easily bent or torn, greatly reducing the risk of tearing.

[0070] The two surfaces of the double-sided board to be etched are the upper surface and the lower surface. The exposed structure on the upper surface is the first copper layer 11. The wavy edge formed by etching the anti-tear pattern area of ​​the first copper layer in the waste area is called the first wavy edge 111. The top view of the structure of the first wavy edge 111 formed on the upper surface is shown in the figure. Figure 5a As shown; the exposed structure on its lower surface is the second copper layer 13. The wavy edge formed by etching in the anti-tear pattern area of ​​the waste area is called the second wavy edge 131. The top view of the structure of the second wavy edge 131 formed on the lower surface is shown in the figure. Figure 5b As shown; both the first wavy edge 111 and the second wavy edge 131 have several equally spaced semi-circular copper layers, and all the semi-circular copper layers on each wavy edge are located on the same horizontal line. Looking down from the top surface of the entire double-sided panel to be etched, the top view of the two wavy edges is shown below. Figure 5c As shown, all the semi-circular copper layers on the two wavy edges are arranged in an alternating pattern, without overlap or gaps.

[0071] Preferably, the distance between the two wavy edges and the outline of the circuit layer on the corresponding surface is greater than or equal to 6 mm.

[0072] By limiting the aforementioned spacing range, a wavy edge can be designed between the exposed PI layer and the outer copper layer, where the risk of tearing is higher, while no wavy edge is designed between the exposed PI layer and the outer copper layer, where the risk of tearing is lower. Since the spacing between the exposed PI layer and the outer copper layer is usually less than 6mm inside the circuit layer, the designed wavy edges can all be located outside the outline of the circuit layer, while there are no wavy edges inside the outline of the circuit layer. This not only reduces the tearing risk of the exposed PI layer but also avoids the impact of the wavy edges on the internal circuitry of the circuit layer.

[0073] Specifically, in this embodiment, the distance between the wavy edge and the outline of the corresponding circuit layer on the surface is 6mm, such as... Figure 6 As shown. Figure 6 Middle 101 is a part of the line layer formed in line area 100. Figure 6Only the spacing between the first wavy edge 111 formed on the first copper layer and the outline of the corresponding circuit layer on the surface is shown. The spacing between the second wavy edge 131 formed on the second copper layer and the outline of the corresponding circuit layer on the surface is similar and will not be shown here.

[0074] Preferably, on each of the wavy edges, the radius of each of the semi-circular copper layers ranges from 0.15 to 0.25 mm.

[0075] The wavy edge formed by multiple semi-circular copper layers within the aforementioned radius has strong compressive strength and can effectively buffer the external force impact brought about by operations such as spraying, roller extrusion, and winding and unwinding in the flexible board manufacturing process, thereby slowing down or stopping the tearing action and thus better demonstrating the tear resistance performance.

[0076] Specifically, in this embodiment, the radius of the semi-circular copper layer on both wavy edges is 0.2 mm, such as... Figures 5a-5c and Figure 6 As shown.

[0077] Preferably, on each of the wavy edges, the interval between each two adjacent semi-circular copper layers is 0.3 to 0.5 mm.

[0078] By adjusting the spacing between the two adjacent semi-circular copper layers, all the semi-circular copper layers on the two wavy edges formed by the upper and lower surfaces can be arranged in an alternating manner without overlap or gaps, further improving the pressure resistance and tear resistance of the entire double-sided panel.

[0079] Specifically, in this embodiment, the wavy edges on both surfaces are spaced 0.4 mm apart between every two adjacent semi-circular copper layers. Figures 5a-5c and Figure 6 As shown.

[0080] A top view of the two wavy edges etched in this embodiment is shown below. Figure 7 As shown. Figure 7 In the image, the black area represents the exposed PI layer, while the light gray area represents the waste area. It can be seen that all the semi-circular copper layers on the two wavy edges are arranged in an alternating pattern without overlap or gaps.

[0081] Of course, in other alternative embodiments, the tear-resistant pattern can also be formed by multiple equidistant copper layers of other shapes, such as a serrated edge formed by multiple equidistant triangular copper layers; all the triangular copper layers on each serrated edge are located on the same horizontal line, and all the triangular copper layers on two serrated edges are staggered, such as... Figure 8 As shown. In Figure 8In the diagram, 112 represents the first serrated edge formed by etching the anti-tear pattern area of ​​the first copper layer 11 located in the waste area, and 132 represents the second serrated edge formed by etching the anti-tear pattern area of ​​the second copper layer 13 located in the waste area. This is similar to the case where the anti-tear pattern is a wavy edge. The side length range of all triangular copper layers on the first and second serrated edges (e.g., 0.4 mm) and the interval range between each pair of adjacent triangular copper layers (e.g., 0.4 mm) can be adaptively adjusted according to the case of the semi-circular copper layers on the first and second wavy edges. The spacing between the serrated edge and the outline of the circuit layer is also greater than or equal to 6 mm (e.g., 6 mm). Specific details will not be elaborated here.

[0082] like Figure 2 As shown, in step S4, based on the circuit layers and the anti-tear pattern on the two surfaces, the etched double-sided board to be etched is processed to form the target double-sided flexible circuit board.

[0083] After etching forms the circuit layer and the anti-tear pattern, based on the anti-tear pattern, during the conventional process of processing the etched double-sided board in the field of flexible circuit board manufacturing, the anti-tear properties of the anti-tear pattern can be utilized to form a target double-sided flexible circuit board with less tearing, effectively improving product yield, increasing production efficiency, and reducing production losses.

[0084] Specifically, the processing of the etched double-sided board adopts conventional post-processing procedures in the field of flexible board manufacturing, including automatic optical inspection of circuits (AOI), chemical cleaning, solder resist ink application, protective film application, fast pressing, and gold finger fabrication. These conventional processes are existing technologies in the field, and specific details will not be elaborated here.

[0085] Preferably, in step S4, after processing the etched double-sided panel, the process further includes:

[0086] The processed double-sided board to be etched is punched according to the flexible board shape formed by the circuit layers on the two surfaces.

[0087] The double-sided board to be etched is punched according to the shape of the flexible board, which can discard the anti-tear pattern along with the waste area after punching, forming a single flexible board product, without affecting the effective circuit area on the flexible board product.

[0088] Specifically, the number of the dual-panel substrates is one or more.

[0089] In actual flexible circuit board (Flexible Printed Circuit) manufacturing, roll-to-roll Flexible Circuit Boards (PCBs) are typically provided. Therefore, at least one double-sided substrate can be provided, each of which is a single PCB within the roll-to-roll PCB. Using one or more double-sided substrates, single or multiple target double-sided PCBs can be mass-produced based on the roll-to-roll PCB, depending on actual needs. When there is only one double-sided substrate, a single target double-sided PCB can be directly manufactured. When there are multiple double-sided substrates, a punching process can be combined to separate multiple target double-sided PCBs, thereby producing multiple target double-sided PCBs.

[0090] This embodiment uses a traditional method without etching the wavy edges to fabricate a batch of double-sided flexible circuit boards. A batch of target double-sided flexible circuit boards is then fabricated using the method described above. A comparison is made between the two methods, with tearing occurring at each stage from material preparation as shown in the table below. Statistical analysis shows that the tearing risk of the double-sided flexible circuit boards fabricated using the traditional method without etching the wavy edges is 9.71%, while the tearing risk of the double-sided flexible circuit boards fabricated in this embodiment is 0.87%, resulting in a yield improvement of 8.84%. This yield improvement translates to a gain of 620,000 RMB per year.

[0091] The table compares the tearing situation in each process of fabricating the target double-sided flexible circuit board using the method described in this embodiment with that of fabricating a double-sided flexible circuit board using a traditional method without etched wavy edges.

[0092]

[0093]

[0094] In this embodiment, the fabrication method described above simultaneously exposes the pre-set anti-tear pattern areas on both surfaces of the provided double-sided substrate during the exposure of the pre-set circuit areas on both surfaces. This allows the anti-tear pattern areas to be exposed simultaneously on both surfaces of the double-sided substrate as the circuit areas are exposed, facilitating subsequent etching of the anti-tear pattern without requiring a separate exposure process, thus improving production efficiency. The anti-tear pattern areas are located on the waste areas outside the corresponding circuit areas, allowing for full utilization of the waste material from the double-sided substrate for etching the anti-tear pattern. The anti-tear pattern obtained by etching from this waste area effectively avoids the vertical height difference between the exposed PI layer and the outer copper layer after etching, thereby reducing the risk of tearing and saving material costs. After exposure, etching the double-sided substrate simultaneously forms a circuit layer that enables the normal function of the flexible circuit board product and an anti-tear pattern that reduces the risk of tearing. Based on this circuit layer, subsequent fabrication can be carried out according to conventional processes in the flexible circuit board manufacturing field. Based on the anti-tear pattern, the tearing risk caused by subsequent conventional processes such as spraying, roller pressing, and unwinding / rewinding can be effectively reduced.

[0095] The method for manufacturing a tear-resistant double-sided flexible circuit board in this embodiment simultaneously exposes the tear-resistant pattern area and etches the tear-resistant pattern during the exposure of the circuit area and the etching of the circuit layer. By utilizing this tear-resistant pattern, the vertical height difference formed between the exposed PI layer and the outer copper layer after etching can be effectively avoided. This reduces the tearing risk to the exposed PI layer caused by conventional processes in the flexible circuit board manufacturing field, such as spraying, roller extrusion, and unwinding, thereby improving product yield, increasing production efficiency, and reducing production losses.

[0096] Example 2

[0097] A tear-resistant double-sided flexible circuit board is manufactured using the method described in Example 1.

[0098] The target double-sided flexible circuit board manufactured in this embodiment utilizes the tear-resistant pattern formed during the etching process to effectively avoid the vertical height difference between the exposed PI layer and the outer copper layer after etching. This reduces the tearing risk to the exposed PI layer caused by conventional processes in the flexible circuit board manufacturing field, such as spraying, roller extrusion, and unwinding. As a result, the product yield is high and the production loss is small.

[0099] The manufacturing method described in this embodiment is the same as that in Embodiment 1. For details not covered in this embodiment, please refer to Embodiment 1 and... Figures 1a to 8 The specific details will not be elaborated here.

[0100] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for manufacturing a tear-resistant double-sided flexible circuit board, characterized in that, include: Provides dual-sided panel substrates; The pre-defined circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate are exposed to form a double-sided board to be etched; wherein the anti-tear pattern areas on both surfaces are located on the waste areas outside the corresponding circuit areas. The double-sided board to be etched is etched to form corresponding circuit layers and tear-resistant patterns on the two surfaces of the double-sided board to be etched. Based on the circuit layers and the tear-resistant pattern on the two surfaces, the etched double-sided board to be etched is processed to form the target double-sided flexible circuit board. On both surfaces of the double-sided panel to be etched after etching, the anti-tear pattern is a wavy edge formed by multiple equally spaced semi-circular copper layers. All the semicircular copper layers on each of the wavy edges are located on the same horizontal line, and all the semicircular copper layers on two of the wavy edges are parallel and staggered.

2. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 1, characterized in that, The distance between each of the two wavy edges and the outline of the circuit layer on the corresponding surface is greater than or equal to 6 mm.

3. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 1, characterized in that, On each of the wavy edges, the radius of each of the semi-circular copper layers ranges from 0.15 to 0.25 mm.

4. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 3, characterized in that, On each of the wavy edges, the radius of each of the semi-circular copper layers is 0.2 mm.

5. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 1, characterized in that, On each of the wavy edges, the spacing between each pair of adjacent semi-circular copper layers ranges from 0.3 to 0.5 mm.

6. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 5, characterized in that, On each of the wavy edges, the spacing between each two adjacent semi-circular copper layers is 0.4 mm.

7. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 1, characterized in that, Before exposing the preset circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate, the process further includes: According to the preset flexible board circuit design, the corresponding circuit area and the anti-tear pattern area are respectively set on the two surfaces of the double-sided board substrate.

8. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 1, characterized in that, Before exposing the preset circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate, the process further includes: A front and back marking alignment hole and multiple exposure alignment holes are laser-drilled on the double-sided substrate.

9. The method for manufacturing a tear-resistant double-sided flexible circuit board according to claim 8, characterized in that, The exposure of the preset circuit areas and anti-tear pattern areas on the two surfaces of the double-sided substrate includes: Using the alignment holes marked on the front and back sides, the two surfaces of the double-sided substrate are marked on the front and back sides; Using all the aforementioned exposure alignment holes, the circuit area and the anti-tear pattern area on the two surfaces of the double-sided substrate after being marked on the front and back are respectively positioned. The circuit area and the anti-tear pattern area on the two surfaces of the positioned double-sided substrate are exposed.

10. The method for manufacturing a tear-resistant double-sided flexible circuit board according to any one of claims 1 to 9, wherein after processing the etched double-sided board based on the circuit layers and the tear-resistant pattern on both surfaces, the method further includes: The processed double-sided board to be etched is punched according to the flexible board shape formed by the circuit layers on the two surfaces.

11. The method for manufacturing a tear-resistant double-sided flexible circuit board according to any one of claims 1 to 9, characterized in that, The number of dual-panel substrates is one or more.

12. A tear-resistant double-sided flexible circuit board, characterized in that, It is manufactured using the manufacturing method described in any one of claims 1 to 11.

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