A method for manufacturing a large-current flexible circuit board

Abstract

The application discloses a manufacturing method of a large-current flexible circuit board, which comprises the following steps: splicing a plurality of independent large-current flexible circuit boards on a splicing board, wherein one single large-current flexible circuit board is designed to be at an acute angle relative to the board edge, and the single board adjacent to the single large-current flexible circuit board is designed to be at a negative equal angle relative to the board edge; thick copper layers are adopted; circuit patterns are made on part of the thickness to form a first half circuit pattern; a first window covering film is pressed on one side of the half circuit pattern; then, circuit patterns are made on the remaining part of the thickness of the thick copper layer to form a second half circuit pattern, thereby forming a thick copper single-sided pattern board; a second window covering film is pressed on one side of the second half circuit pattern; and the thick copper single-sided pattern board is formed by pressing, thereby forming the large-current flexible circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flexible circuit board processing, in particular to a manufacturing method of a large-current flexible circuit board. BACKGROUND

[0002] The development of intelligent networked vehicles, low-altitude aircraft and other fields has promoted the continuous improvement of flexible circuit board technology. For some electronic modules that need to carry large currents and need to be flexibly installed, large-current flexible circuit boards with thick copper lines have emerged.

[0003] The copper thickness of the large-current flexible circuit board is relatively thick, and it is generally designed in the form of a single-layer circuit. During processing, a single-sided thick copper flexible copper-clad plate is first taken, a single-sided pattern plate is formed after circuit pattern processing, and then a one-sided cover film is laminated to form a large-current flexible circuit board.

[0004] During the pattern processing of the circuit board, side etching occurs when the circuit pattern is etched. Generally, the thicker the copper thickness, the greater the side etching. Excessive side etching affects the line width and line spacing, and in severe cases, burrs, large fillets, or even line breaks can occur, resulting in reduced reliability and performance of the circuit board. For large-current flexible circuit boards, large side etching also occurs during etching, and because the insulating medium layer of the single-sided flexible copper-clad plate is relatively soft, the irregular side etching during etching is even greater.

[0005] When laminating a one-sided cover film, the thickness of the thick copper line is relatively thick, and the line gap depth is relatively large. However, the thickness of the cover film is limited, and during the lamination process, the cover film has difficulty effectively covering and filling the line gap. Currently, increasing the pressure and raising the temperature can improve the reliability of the laminated cover film, but this can easily cause the cover film to be crushed or the lines to deform.

[0006] Therefore, based on the above background and technology, there is a need to provide a manufacturing method that can effectively improve the circuit pattern etching and cover film lamination processing of a large-current flexible circuit board. SUMMARY

[0007] The present application aims to solve the problem of large side etching during processing of large-current flexible circuit boards with thick copper line designs, and the difficulty of effectively covering thick copper lines and filling line gaps during lamination of cover films. A manufacturing method for a large-current flexible circuit board is proposed, which includes the following steps:

[0008] S10: Splice a plurality of independent large-current flexible circuit boards on the splice plate, wherein one of the independent large-current flexible circuit boards is designed at an acute angle relative to the edge of the splice plate, and the adjacent independent large-current flexible circuit board is designed at a negative equal angle relative to the edge of the splice plate, forming a splice plate design.

[0009] S20: taking the thick copper layer, making circuit patterns on part of the thickness to form a first half circuit pattern, pressing a first window covering film on one side of the half circuit pattern, and then making circuit patterns on the remaining part of the thickness of the thick copper layer to form a second half circuit pattern, thereby forming a thick copper single-sided pattern board;

[0010] S30: pressing a second window covering film on one side of the second half circuit pattern, pressing, and then performing post-process processing to form the large-current-carrying flexible circuit board.

[0011] Further, the forming of the thick copper single-sided pattern board further comprises: pressing a first window covering film on one side of the half circuit pattern, then making a wet film layer on the surface of the first window covering film, attaching a first dry film layer to the surface of the wet film layer, and attaching a second dry film layer to the surface of the remaining part of the thick copper layer, then making circuit patterns on the remaining part of the thick copper layer to form a second half circuit pattern, and then removing the film to form a thick copper single-sided pattern board.

[0012] Further, the first dry film layer is attached with a first dry film protective film layer, and the second dry film layer is attached with a second dry film protective film layer; the making of circuit patterns on the remaining part of the thick copper layer comprises: exposing the first dry film layer and the second dry film layer, tearing off the second dry film protective film layer, then sequentially performing development and etching processing, then tearing off the first dry film protective film layer, and then removing the film.

[0013] Further, the forming of the large-current-carrying flexible circuit board further comprises:

[0014] S310: taking a single-sided copper-clad board, making a mesh pattern to form a mesh pattern cladding type board;

[0015] S320: taking a second window covering film, and stacking the second window covering film on one side of the second half circuit pattern to form a flexible board stacking structure;

[0016] S330: taking a plurality of release layers and a plurality of cladding films, sequentially arranging the mesh pattern cladding type board and the cladding film outward from both sides of the flexible board stacking structure, and arranging a release layer between the flexible board stacking structure and the mesh pattern cladding type board, and between the mesh pattern cladding type board and the cladding film,

[0017] then arranging a release layer on the outer surface to form a pressing stacking structure;

[0018] The mesh patterns are arranged away from the flexible board stacking structure;

[0019] S340: placing the lamination stack structure in a press for the lamination, and then performing post-process processing to form the large-current-carrying flexible circuit board.

[0020] Further, the manufacturing of the mesh pattern is that the size of the single-sided copper-clad plate is larger than the flexible plate stack structure on a single side, and the mesh pattern is manufactured on the whole copper layer of the single-sided copper-clad plate.

[0021] Optionally, the manufacturing of the mesh pattern is that the size of the single-sided copper-clad plate is larger than the flexible plate stack structure on a single side, and a plurality of mesh patterns are manufactured on the copper layer of the single-sided copper-clad plate according to the distribution of each large-current-carrying flexible circuit board in the panel design, each mesh pattern corresponds to the distribution of each large-current-carrying flexible circuit board, and the size of each mesh pattern is larger than that of each large-current-carrying flexible circuit board on a single side.

[0022] Further, the mesh pattern has a grid mesh number of 10 to 80 and a line width of 50 to 125 μm.

[0023] Further, the adhesive content of the dielectric layer of the single-sided copper-clad plate is 60% to 68%.

[0024] Further, the thickness of the thick copper layer is greater than or equal to 105 μm.

[0025] Further, the acute angle is an angle of 0.5° to 5°.

[0026] The panel design of the present application forms a certain angle between two adjacent large-current-carrying flexible circuit boards, which makes the adhesive form a certain resistance to the flow of the adhesive in the long direction during lamination, provides more flow of the adhesive in the longitudinal direction, and improves the covering, bonding, and filling capacity of the subsequent lamination of the opening window covering film. The thick copper layer is etched from different surfaces in two times, which forms a complete circuit pattern, and the wet film and dry film are combined to effectively improve the capacity of manufacturing the thick copper circuit pattern and reduce the problems of side etching or incomplete etching of the thick copper circuit. Further, the mesh pattern is formed by manufacturing a grid pattern, which is used as a covering buffer layer during lamination to effectively improve the directional covering capacity of the opening window covering film, improve the effect of filling the gap between the circuit by the adhesive layer of the covering film, and prevent the problems of lamination void, delamination, and even board explosion. The overall manufacturing method forms a design and processing process that cooperate with each other, effectively and feasibly forms an overall technical effect, improves the capacity of manufacturing the circuit pattern of the thick copper layer, and improves the capacity of the covering film and the thick copper circuit to combine with each other. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in the drawings without creative labor.

[0028] Figure 1 The overall process flow chart of the flexible circuit board of the embodiment of the present application;

[0029] Figure 2 The plane structure schematic diagram of the overall panel of the embodiment of the present application;

[0030] Figure 3 The cross-sectional structure schematic diagram of the single half circuit pattern board of the embodiment of the present application;

[0031] Figure 4 The cross-sectional structure schematic diagram of the single film pasting board of the embodiment of the present application;

[0032] Figure 5 The cross-sectional structure schematic diagram of the single complete etching circuit board of the embodiment of the present application;

[0033] Figure 6 The cross-sectional structure schematic diagram of the single thick copper single-sided pattern board of the embodiment of the present application;

[0034] Figure 7 The specific process flow chart of the flexible circuit board of the embodiment of the present application;

[0035] Figure 8 The cross-sectional structure schematic diagram of the overall press-bonding stack structure of the embodiment of the present application;

[0036] Figure 9 The plane structure schematic diagram of the overall mesh pattern overlay board of the embodiment of the present application;

[0037] Figure 10 The plane structure schematic diagram of another overall mesh pattern overlay board of the embodiment of the present application;

[0038] Figure 11 The cross-sectional structure schematic diagram of the single large-current flexible circuit board of the embodiment of the present application;

[0039] Figure 12 The physical section view of the large-current flexible circuit board formed by the embodiment of the present application.

[0040] Explanation of the drawing reference numerals:

[0041]

[0042] The objectives, functional features and advantages of the present application will be further described with reference to the embodiments in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0044] It should be noted that all the directionality indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings). If the certain posture changes, the directionality indications also change accordingly.

[0045] In addition, the descriptions such as “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first”, “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “plurality” is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0046] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0047] Please refer to Figure 1 ; Figure 1 Process flow chart of the flexible circuit board of the embodiment of the present application.

[0048] The manufacturing process of the embodiment of the present application includes the implementation of each step process in Figure 1 The following will make further step-by-step description of each step process in Figure 1

[0049] Please refer to Figure 2 ; Figure 2 Schematic plan structure diagram of the overall panel design of the embodiment of the present application.

[0050] Step S10:

[0051] ​Several independent large current carrying flexible circuit boards 110 are spliced on the panel 10, one of the independent large current carrying flexible circuit boards 110 is designed at an acute angle relative to the edge of the panel 10, and the adjacent independent large current carrying flexible circuit board 110 is designed at a negative equal angle relative to the edge of the panel 10, to form the panel 10 design.

[0052] Generally, the independent large current carrying flexible circuit board 110 is small in size, and needs to be spliced on a large-size board body for processing, that is, the panel 10 is used for processing to improve the processing efficiency; due to the existing processing requirements, the panel 10 is generally designed as a rectangle, and therefore the independent sub-boards distributed on the panel are generally arranged in parallel or perpendicular to the panel body.

[0053] In the embodiment, the copper thickness of the large current carrying flexible circuit board is thick, and the large current carrying flexible circuit board is designed as a single copper independent line layer for simple connection, and a large pressure is needed to fill the insulating medium layer with glue to fill the line gap during pressing. If the existing arrangement of the sub-boards in parallel or perpendicular to the panel body is used, the glue flow in the longitudinal direction of the line distribution is large during pressing, the glue flow in the vertical direction of the line distribution is small due to the line blockage, the glue flow in the longitudinal direction is large, and it is difficult to effectively fill the line gap, resulting in poor glue filling, pressing cavity and other problems.

[0054] Therefore, the panel 10 is designed in a manner that the adjacent two independent large current carrying flexible circuit boards 110 form a certain angle, so that the glue flow in the longitudinal direction is blocked during pressing, and more glue flow is provided in the vertical direction to achieve better filling effect.

[0055] Optionally, a compensation copper pattern (not shown in the drawing) is designed in the invalid area of the panel 10 without the large current carrying flexible circuit board, that is, a uniform distribution of copper mesh, copper wire and other patterns is designed on the copper layer at this position, which can further balance the glue flow and pressing thickness control effect during pressing, and prevent pressing slip and displacement.

[0056] In the embodiment, the acute angle is 0.5° to 5°; due to the limited area of the panel 10, the area of the panel 10 needs to be effectively utilized, and the angle design can meet the condition that the adjacent two independent large current carrying flexible circuit boards 110 form a certain angle.

[0057] Please refer to Figures 3 to 6 ; Figure 3 It is a cross-sectional structure diagram of the first half line pattern board of the embodiment of the application. Figure 4A cross-sectional structure diagram of a single film pasting board of an embodiment of the present application; Figure 5 A cross-sectional structure diagram of a single complete etching circuit board of an embodiment of the present application; Figure 6 A cross-sectional structure diagram of a single thick copper single-sided pattern board of an embodiment of the present application.

[0058] Step S20:

[0059] A first half circuit pattern 210 is formed by taking a thick copper layer, making a circuit pattern on part of the thickness, and then pressing a first window covering film 220 on one side of the half circuit pattern. A first half circuit pattern board 20A is formed, and then a second half circuit pattern 230 is formed by making a circuit pattern on the remaining part of the thickness of the thick copper layer. A complete etching circuit board 20C is formed, and a thick copper single-sided pattern board 20 is formed.

[0060] Since the thickness of the thick copper layer is thick, once etching can easily cause problems such as excessive side etching and incomplete etching. Therefore, a multi-step etching method is used. According to the thickness of the specific thick copper layer, the part of the thickness for making a circuit pattern in the first step is determined to be 1 / 2 to 1 / 3 of the overall thickness.

[0061] In the present embodiment, the formation of the thick copper single-sided pattern board further includes: pressing the first window covering film 220 on one side of the half circuit pattern (see Figure 3 ), and then making a wet film layer 240 on the surface of the first window covering film 220, attaching a first dry film layer 250 to the surface of the wet film layer 240, and attaching a second dry film layer 260 to the surface of the remaining part of the thickness of the thick copper layer (see Figure 4 ). A film pasting board 20B is formed, and then a circuit pattern is made on the remaining part of the thickness of the thick copper layer to form a second half circuit pattern 230 (see Figure 5 ). The film is then removed to form a thick copper single-sided pattern board 20 (see Figure 6 ).

[0062] The first half circuit pattern 210 and the second half circuit pattern 230 form a complete circuit pattern 270.

[0063] Due to the thickness of the thick copper, the first half circuit pattern 210 forms a certain height difference, and the cover film is a windowed cover film. After the pressing and covering is completed, there is a windowed area between the first half circuit pattern 210. If the dry film is directly attached to manufacture the subsequent circuit pattern, it is easy to form the problem of unstable film attachment, voids in the height difference and windowed area, which affects the subsequent exposure, development and other processes of the dry film. Therefore, the embodiment adopts the manufacturing method of first manufacturing a wet film layer 240 on the surface of the first windowed cover film 220, and attaching a first dry film layer 250 to the surface of the wet film layer 240. The wet film is used to fill the recessed concave of the height difference and the difference of the windowed area, and the flatness of the board surface is improved, and then the dry film layer is attached to form a good dry film attachment. It is worth noting that since one side of the first windowed cover film 220 has been pressed and covered, the first half circuit pattern 210 does not need to be manufactured again. Therefore, the manufacturing of the wet film layer 260 and the first dry film layer 250 will not be affected by the over-thickness of the photosensitive film. On the other hand, the remaining part of the thick copper layer has a relatively flat surface, so the normal process flow of attaching the second dry film layer 260 to manufacture the circuit pattern is adopted.

[0064] Since the cover film needs to expose the position of the plug circuit, soldering circuit, connection circuit and other circuit patterns, the cover film of the embodiment adopts a windowed cover film. The wet film layer can be manufactured by coating or silk printing.

[0065] In the embodiment, the surface of the first photosensitive layer 2510 of the first dry film layer 250 is attached with a first dry film protective film layer 2520, and the surface of the second photosensitive layer 2610 of the second dry film layer is attached with a second dry film protective film layer 2620. The manufacturing of the circuit pattern on the remaining part of the thick copper layer includes: exposing the first dry film layer 250 and the second dry film layer 260, tearing off the second dry film protective film layer 2620, then sequentially developing and etching, then tearing off the first dry film protective film layer 2520, and then removing the film.

[0066] Since one side of the first windowed cover film 220 has been pressed and covered, the circuit pattern does not need to be manufactured again. However, when manufacturing the circuit pattern of the remaining part of the thick copper layer on the other side, physical or chemical effects may be produced on the first dry film layer 250 during the process. Moreover, the first dry film layer 250 itself has a first dry film protective film layer 2520. Therefore, the first dry film protective film layer 2520 is retained during the process, and is torn off before the film is removed, which can effectively reduce the processing risk and effectively improve the supportability of the board during the process.

[0067] In the embodiment, the thickness of the thick copper layer is greater than or equal to 105μm. The thick copper flexible circuit board manufactured in the embodiment is a large current type, so the copper thickness needs to be relatively thick to be suitable for the technical process of the embodiment.

[0068] Please refer to Figures 7 to 12 ;Figure 7 A specific process flow chart for manufacturing the flexible circuit board of the embodiment of the present application is shown in FIG. 1. Figure 8 A cross-sectional structure schematic diagram of the lamination structure of the whole of the embodiment of the present application is shown in FIG. 2. Figure 9 A plane structure schematic diagram of the mesh patterned cover type board of the whole of the embodiment of the present application is shown in FIG. 3. Figure 10 A plane structure schematic diagram of another mesh patterned cover type board of the whole of the embodiment of the present application is shown in FIG. 4. Figure 11 A cross-sectional structure schematic diagram of the large current carrying flexible circuit board of the embodiment of the present application is shown in FIG. 5. Figure 12 A physical section view of the large current carrying flexible circuit board manufactured by the embodiment of the present application is shown in FIG. 6.

[0069] Step S30:

[0070] A second windowed cover film 280 is pressed onto one side of the second half circuit pattern 230, and then laminated, and then processed in subsequent processes to form the large current carrying flexible circuit board 40.

[0071] In the embodiment, the formation of the large current carrying flexible circuit board 40 further comprises:

[0072] S310: Take a single-sided copper clad board to manufacture a mesh pattern 3210, wherein the insulating medium layer of the single-sided copper clad board forms a cover type layer 3220 to form a mesh patterned cover type board 320.

[0073] S320: Take a second windowed cover film 280, and stack the second windowed cover film 280 on one side of the second half circuit pattern 230, i.e. Figure 8 stacked on the thick copper single-sided pattern board 20 to form a flexible board stacking structure 310.

[0074] S330: Take a plurality of release layers 330 and a plurality of cover type films 340, and sequentially arrange the mesh patterned cover type board 320 and the cover type film 340 outward from both sides of the flexible board stacking structure 310, and arrange the release layer 330 between the flexible board stacking structure 310 and the mesh patterned cover type board 320, and between the mesh patterned cover type board 320 and the cover type film 340, and then arrange the release layer 330 on the outer surface to form a lamination stacking structure 30;

[0075] The mesh patterns 3210 are arranged away from the flexible board stacking structure 310.

[0076] S340: Place the lamination stacking structure 30 in the press bed 350 of the press to perform the lamination, and then process in subsequent processes to form the large current carrying flexible circuit board 40.

[0077] Since the first half circuit pattern 210 and the second half circuit pattern 230 form the complete circuit pattern 270, the second windowed cover film 280 needs to be able to cover the second half circuit pattern 230, and also needs to be completed under the support and buffering effect of the first windowed cover film 220, that is, the process of simultaneously pressing the first windowed cover film 220 and the second windowed cover film 280 to fill and cover the complete circuit pattern.

[0078] In the embodiment, the adhesive content of the medium layer of the single-sided copper-clad plate is 60% to 68%, and the cover film 340 is arranged as the second buffering cover layer, which can effectively ensure the coverability in the pressing process.

[0079] In the embodiment, the mesh pattern 3210 is made on the entire copper layer of the single-sided copper-clad plate, which is larger than the flexible plate stack structure 310 in size, as shown in the figure, to form the first mesh pattern cover plate 320A. Figure 9

[0080] The mesh pattern 3210 can improve the ability of directional flow of the adhesive, prevent the adhesive from flowing excessively along the long direction of the complete circuit pattern 270, and make the adhesive flow more effectively in the thickness direction.

[0081] In an alternative embodiment, the mesh pattern 3210 is made on the copper layer of the single-sided copper-clad plate, which is larger than the flexible plate stack structure 310 in size, and a plurality of mesh patterns 3210 are made according to the distribution of each individual large-current flexible circuit board 110 in the design of the panel 10, each mesh pattern 3210 corresponding to the distribution of each individual large-current flexible circuit board 110, and each mesh pattern 3210 being larger than each individual large-current flexible circuit board 110 in size, as shown in the figure, to form the second mesh pattern cover plate 320B. Figure 10

[0082] The mesh pattern 3210 is designed and made to match each individual large-current flexible circuit board 110 to form accurate cover for each individual large-current flexible circuit board 110, and to make the adhesive for making the mesh pattern 3210 flow more fully and prevent the coverability from being weakened.

[0083] In the embodiment, the mesh pattern 3210 has a mesh count of 10 to 80, and the line width of the mesh pattern 3210 is 50μm to 125μm.

[0084] ​​According to actual application requirements, the mesh number is not too large, otherwise the covering type layer covering buffering capacity is greatly reduced, the same line width is not too wide.

[0085] In this embodiment, the release layer 330 plays a role in the pressing process and after the pressing is completed. The material of the release layer 330 can be PI, PTFE or TPX, etc.

[0086] In this embodiment, the pressing can be selected in the form of rapid pressing, under the conditions of the maximum pressure of 15 kg / cm2 to 25 kg / cm2, the highest temperature of 120 DEG C to 160 DEG C, and the pressing time of 15 min to 30 min; or the traditional pressing machine can be used for pressing, under the conditions of the maximum pressure of 220 PSI to 280 PSI, the highest temperature of 150 DEG C to 180 DEG C, and the pressing time of 10 min to 20 min.

[0087] The above description is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or direct / indirect application in other related technical fields under the inventive concept of the present application are included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a high current-carrying flexible circuit board, characterized in that: The manufacturing method comprises the following steps: S10: splice several independent large-current flexible circuit boards on a splicing board, wherein one single large-current flexible circuit board is designed at an acute angle relative to the board edge of the splicing board, and the single large-current flexible circuit board adjacent thereto is designed at a negative equal angle relative to the board edge of the splicing board, to form a splicing board design; S20: take a thick copper layer, make a circuit pattern on part of the thickness to form a first half circuit pattern, and press a first window covering film on one side of the half circuit pattern, and then make a circuit pattern on the remaining part of the thickness of the thick copper layer to form a second half circuit pattern, thereby forming a thick copper single-sided pattern board; S30: press a second window covering film on one side of the second half circuit pattern, perform pressing, and then perform post-process processing to form the large-current flexible circuit board.

2. The manufacturing method of the large-current flexible circuit board according to claim 1, wherein the thick copper single-sided pattern board further comprises the following steps: pressing a first window covering film on one side of the half circuit pattern, then making a wet film layer on the surface of the first window covering film, attaching a first dry film layer to the surface of the wet film layer, attaching a second dry film layer to the surface of the remaining part of the thick copper layer, then making a circuit pattern on the remaining part of the thick copper layer to form a second half circuit pattern, and then removing the film to form a thick copper single-sided pattern board.

3. The manufacturing method of the large-current flexible circuit board according to claim 2, wherein the surface of the first dry film layer is attached with a first dry film protective film layer, and the surface of the second dry film layer is attached with a second dry film protective film layer. The process of making a circuit pattern on the remaining part of the thick copper layer comprises the following steps: exposing the first dry film layer and the second dry film layer, tearing off the second dry film protective film layer, then sequentially performing developing and etching processing, then tearing off the first dry film protective film layer, and then removing the film. The large-current flexible circuit board is formed by the following steps: S310: take a single-sided copper-clad board, make a mesh pattern, and form a mesh pattern covering type board; 4. The method of claim 1, wherein the flexible circuit board is a large current carrying flexible circuit board. S320: take a second window covering film, and stack the second window covering film on one side of the second half circuit pattern to form a flexible board stacking structure; S330: take a plurality of release layers and a plurality of covering type films, and sequentially arrange the mesh pattern covering type board and the covering type film outward from both sides of the flexible board stacking structure, and arrange a release layer between the flexible board stacking structure and the mesh pattern covering type board, and between the mesh pattern covering type board and the covering type film, then arrange a release layer on the outer surface to form a pressing stacking structure; the mesh pattern is arranged away from the flexible board stacking structure; S340: place the pressing stacking structure in a pressing machine to perform pressing, and then perform post-process processing to form the large-current flexible circuit board. The mesh pattern is made by the following steps: the size of the single-sided copper-clad board is larger than that of the flexible board stacking structure on a single side, and the mesh pattern is made on the entire copper layer of the single-sided copper-clad board.

5. The method of claim 4, wherein the flexible circuit board is a large current carrying flexible circuit board. The mesh pattern is made by the following steps: the size of the single-sided copper-clad board is larger than that of the flexible board stacking structure on a single side, 6. The method of claim 4, wherein the flexible circuit board is a large current carrying flexible circuit board. ​ ​ A plurality of said mesh patterns are made on the copper layer of said single-sided copper-clad plate, each of said mesh patterns corresponding to the distribution of each of said large-current flexible circuit boards in said panel design, Each of said mesh patterns has a size larger than each of said large-current flexible circuit boards in a single side.

7. The method of claim 5 or 6, wherein the step of applying a layer of conductive material to the flexible substrate comprises applying a layer of conductive material to the flexible substrate by screen printing. The mesh pattern has a grid mesh number of 10 to 80 and a line width of 50 to 125 μm.

8. The method of claim 4, wherein the flexible circuit board is a large current carrying flexible circuit board. The single-sided copper-clad plate has a glue content of 60% to 68% in the dielectric layer.

9. The method of claim 1, wherein the flexible circuit board is a large current carrying flexible circuit board. The thick copper layer has a thickness of 105 μm or more.

10. The method of claim 1, wherein the flexible circuit board is a high current flexible circuit board. The acute angle is 0.5° to 5°.

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