Manufacturing method of thick copper large-current high-flexibility hollowed-out circuit rigid-flex printed circuit board

Abstract

The present invention discloses a manufacturing method for a rigid-flex printed circuit board with thick copper, large current-carrying capacity, and high flexibility and hollowed-out circuits. A rigid core board with a copper layer and a prepreg on its surfaces is manufactured. A flexible copper clad laminate is taken to manufacture a first circuit pattern, and then a first opening window is made corresponding to the flexible area to form a flexible board. A single-sided flexible copper clad laminate is taken, a second circuit pattern is made corresponding to the first opening window, and it is cut corresponding to the flexible area, and then it is laminated with the flexible board to form a flexible core board. The rigid core board and the flexible core board are stacked and laminated, and then the cover is removed for processing, and then the second circuit pattern is laser milled to form a rigid-flex printed circuit board. A low-flow prepreg is arranged between layers to reduce the risk of insufficient resin filling or uneven board surface. The second circuit pattern is made using a single-sided flexible copper clad laminate, and the second circuit pattern and the first circuit pattern are designed with a dislocation to play a role in adjusting the resin flow, forming an effective encapsulation of the first circuit pattern. The laser milling forms a hollowed-out circuit, thereby improving the bending performance of the flexible area.

Description

Technical Field

[0001] The present invention relates to the field of printed circuit board manufacturing, particularly to the field of flexible circuit board manufacturing, and more particularly to a manufacturing method for a rigid-flex printed circuit board with thick copper, large current-carrying capacity, high flexibility, and hollowed-out circuits. Background Art

[0002] With the development of the fields of intelligent connected vehicles, charging piles, and low-altitude aircraft, higher requirements are put forward for the circuit boards applied thereto. Not only do they need to have flexible assembly characteristics, but they also need to be able to carry large currents or instantaneous large currents. For this reason, a rigid-flex printed circuit board with thick copper is designed. Among them, the thick copper circuit ensures high current-carrying capacity and excellent heat dissipation performance, while the rigid-flex design combines the support stability of the rigid board and the flexible assembly advantages of the flexible board.

[0003] Generally, this type of rigid-flex printed circuit board with thick copper is produced by traditional manufacturing methods, including steps such as manufacturing a rigid core board and a flexible core board, stacking and pressing, etc. Subsequently, the processing of the surface circuit and the solder mask layer is completed, and finally, the rigid-flex printed circuit board is formed.

[0004] However, the traditional processing method has the following disadvantages:

[0005] (1) To ensure sufficient glue filling between the thick copper layers and good interlayer bonding force, large pressure and high-temperature and long-time pressing parameters are required, but this often leads to unevenness on the surface of the board, affecting the interlayer thickness accuracy and the quality of the surface circuit; if the pressing parameters are reduced, problems such as insufficient glue filling and a decrease in interlayer bonding force may occur, and there is a risk of delamination or even board explosion;

[0006] (2) For the flexible area, if large pressing parameters are used to fill the circuit gaps, the surface unevenness will increase; if a thicker cover film is used to avoid the above problems, the bending ability of the flexible area will be reduced, and it is easy to cause "dead folds" or rebounds during assembly or use, thereby affecting the electrical signal transmission quality and the overall reliability of the circuit board.

[0007] Therefore, to solve the above-mentioned problems, a manufacturing method for a rigid-flex printed circuit board with thick copper, large current-carrying capacity, high flexibility, and hollowed-out circuits is needed. Summary of the Invention

[0008] The present invention aims to solve the comprehensive problems that the existing rigid-flex printed circuit boards cannot simultaneously meet the requirements of thick copper and large current-carrying capacity and high flexibility, and proposes a manufacturing method for a rigid-flex printed circuit board with thick copper, large current-carrying capacity, high flexibility, and hollowed-out circuits. The rigid-flex printed circuit board includes a rigid area and a flexible area. The manufacturing method includes the following steps:

[0009] S10: Fabricate a rigid core board with a copper layer on one side and a prepreg on the other side through pre-process machining;

[0010] S20: Take a flexible copper clad laminate, fabricate a first circuit pattern, and then make a first opening in the insulating dielectric layer of the flexible copper clad laminate corresponding to the flexible region, and the flexible copper clad laminate forms a flexible board;

[0011] S30: Take a single-sided flexible copper clad laminate, fabricate a second circuit pattern corresponding to the first opening, and cut it corresponding to the flexible region to form a pattern cover film, and then align and press the pattern cover film with the flexible board to form a flexible core board;

[0012] The first circuit pattern and the second circuit pattern are offset from each other;

[0013] S40: Stack and press the rigid core board and the flexible core board to form a pressed board;

[0014] S50: Perform a lid-lifting process on the flexible region of the pressed board to expose the flexible core board, and then perform laser milling on the corresponding second circuit pattern and form it to form the rigid-flex board.

[0015] Further, forming the rigid core board further includes making blind slots in the edge of the prepreg corresponding to the flexible region.

[0016] Further, forming the rigid core board is: Take a copper foil, a low-flow prepreg, and a single-sided copper clad laminate, stack and press them in sequence, and then etch the surface copper layer of the single-sided copper clad laminate to form the rigid core board.

[0017] Further, the surface copper layer is a thin copper foil with a thickness of 5 μm to 10 μm.

[0018] Further, the insulating dielectric layer of the single-sided copper clad laminate is a high-flow prepreg.

[0019] Further, the first opening is divided into a plurality of first sub-openings by a plurality of the first circuit patterns.

[0020] Further, fabricating the second circuit pattern is to fabricate a plurality of second sub-circuit patterns corresponding to each of the first sub-openings.

[0021] Further, the unilateral side of the second sub-circuit pattern is smaller than the corresponding first sub-opening.

[0022] Further, the area of the laser milling corresponds to the second circuit pattern and is tangent to the edge of the flexible region.

[0023] Further, the length of the region of the pattern cover film facing the rigid region and corresponding to the second circuit pattern is less than or equal to the flexible region.

[0024] The technical solution of the present invention first processes the rigid core board separately, sets low-flow epoxy prepreg between layers, and further uses a single-sided copper clad laminate containing high-flow epoxy prepreg. By combining the high adhesion performance of the high-flow epoxy prepreg with the filling performance of the low-flow epoxy prepreg, it ensures that the voids between thick copper lines can be effectively filled under high temperature and high pressure conditions, reducing the risk of insufficient glue filling or uneven board surface, and solving the problems of insufficient glue filling and decreased interlayer bonding force in the prior art. By using a single-sided flexible copper clad laminate to replace the cover film to make the pattern, and setting the misalignment design between the second circuit pattern and the first circuit pattern, it plays an adjustment role in the flow of the colloid, forms an effective wrapping of the first circuit pattern, and improves the bending performance of the flexible area, solving the problems that using a relatively thick cover film in the prior art will reduce the bending ability of the flexible area and easily cause problems such as "dead fold" or rebound during assembly or use. On the other hand, after the first circuit pattern is wrapped, it can effectively prevent the side of the copper surface of the hollowed-out circuit from being exposed, thereby preventing problems such as oxidation and aging of the circuit copper surface during application. Finally, the second circuit pattern used as an auxiliary lamination is removed by laser cutting technology to form the hollowed-out first circuit pattern in the flexible area, reducing the constraint of the material layer in the plane direction, thereby improving the bending performance of the flexible area. The front and back processes cooperate with each other to form an effective technical correlation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0026] Figure 1 It is a schematic process flow diagram of an embodiment of the present invention;

[0027] Figure 2 It is a plan view of the rigid core board of an embodiment of the present invention;

[0028] Figure 3 is Figure 2 A-A cross-sectional view of;

[0029] Figure 4 It is a plan view of the flexible board of an embodiment of the present invention;

[0030] Figure 5 is Figure 4 B-B cross-sectional view of;

[0031] Figure 6 It is a cross-sectional view of the stacked structure of an embodiment of the present invention;

[0032] Figure 7 Schematic plan view of the flexible core board according to an embodiment of the present invention;

[0033] Figure 8 is Figure 7 Schematic cross-sectional view taken along line C-C of;

[0034] Figure 9 Schematic cross-sectional view of the laminated board according to an embodiment of the present invention;

[0035] Figure 10 Schematic cross-sectional view of the cover board to be peeled off according to an embodiment of the present invention;

[0036] Figure 11 Schematic plan view of the milled board according to an embodiment of the present invention;

[0037] Figure 12 is Figure 11 Schematic cross-sectional view taken along line D-D of;

[0038] Figure 13 Schematic plan view of the rigid-flex printed circuit board according to an embodiment of the present invention.

[0039] Explanation of the reference numerals in the drawings: 10 - rigid core board; 1010 - blind via; 20 - flexible board; 2010 - first circuit pattern; 2020 - first opening; 2030 - insulating dielectric layer of the flexible copper clad laminate; 30 - stacked structure; 3010 - pattern cover film; 3010a - second circuit pattern; 3010b - adhesive layer of the single-sided flexible copper clad laminate; 3010c - PI layer of the single-sided flexible copper clad laminate; 40 - flexible core board; 50 - laminated board; 60 - cover board to be peeled off; 70 - milled board; 80 - rigid-flex printed circuit board.

[0040] The realization of the object, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed embodiments

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0043] In addition, in the present invention, descriptions such as "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0044] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] Please refer to Figure 1 , Figure 1 which is a schematic process flow diagram of an embodiment of the present invention.

[0046] The manufacturing process of the embodiment of the present invention includes the implementation of each step process in Figure 1 , and the following will further explain each step process in Figure 1 step by step.

[0047] The rigid-flexible printed circuit board of the embodiment of the present invention includes a rigid region and a flexible region.

[0048] Please refer to Figure 2 and Figure 3 , Figure 2 which is a plan view of the rigid core board of an embodiment of the present invention; Figure 3 is Figure 2 a schematic cross-sectional view taken along line A-A of

[0049] Step S10:

[0050] A rigid core board 10 with a copper layer on one side and a prepreg on the other side is formed through pre-process machining.

[0051] One side of the rigid core board 10 is a copper layer to provide an electrical connection path, and the other side is a prepreg that can flow and fill voids when heated and pressurized, providing a processing basis for forming a strong bonding layer in the subsequent pressing process.

[0052] As an alternative embodiment, the formation of the rigid core board 10 is as follows: taking a copper foil, a low-flow prepreg, and a single-sided copper clad laminate, stacking and pressing them in sequence, and then etching the surface copper layer of the single-sided copper clad laminate to form the rigid core board 10.

[0053] First, the rigid core board 10 is processed separately, and a low-flow epoxy prepreg is arranged between layers for interlayer bonding to ensure that the voids between thick copper circuits can be effectively filled under high temperature and high pressure conditions, reducing the risk of insufficient glue filling or uneven board surface. Moreover, copper foils and a single-sided copper clad laminate form upper and lower copper layers, and then the rigid core board 10 is formed through subsequent pressing processes, providing a pressing basis for using larger pressing parameters.

[0054] During this pressing process, the low-flow epoxy prepreg can ensure the tight bonding between board layers while avoiding the problem of resin overflow caused by excessive glue volume.

[0055] It should be noted that the single-sided copper clad laminate is arranged to participate in the pressing to form a corresponding effect of upper and lower surface materials with the copper foil. Moreover, the copper foil can improve the fluidity and filling property of the colloid inside the board body during the pressing process, enhance the glue filling effect of the circuit gaps and the interlayer bonding force. And since the lower surface copper foil does not need to be retained subsequently, the surface copper layer of the single-sided copper clad laminate is set as a thin copper foil, which is convenient for more precise control subsequently, reduces the workload of etching off the excess copper layer in the follow-up process, and improves the production efficiency.

[0056] Optionally, the thickness of the thin copper foil is 5 μm to 10 μm.

[0057] Furthermore, the insulating dielectric layer of the single-sided copper clad laminate is a high-flow epoxy prepreg.

[0058] It can improve the fluidity and filling property of the colloid during the pressing process, and provide better adhesion conditions when pressing with the flexible board 20 subsequently (etching off the thin copper foil to expose the high-flow epoxy prepreg), ensuring a good bonding force between the rigid core board 10 and the flexible board 20.

[0059] In this embodiment, forming the rigid core board 10 further includes making blind grooves 1010 at the edges of the epoxy prepreg corresponding to the flexible areas.

[0060] It is convenient for the subsequent lid-lifting processing, that is, removing the rigid board layer on the flexible area to expose the underlying flexible layer, ensuring that no unnecessary damage is caused to the flexible area during the manufacturing process, and at the same time ensuring the structural integrity and functional performance of the final product.

[0061] Optionally, mechanical milling or laser milling is used to make the blind grooves 1010, and preferably laser blind grooves 1010 are used.

[0062] Optionally, the depth of the blind grooves 1010 is 0.05 mm to 0.5 mm, and the width is 0.05 mm to 0.2 mm.

[0063] Please refer to Figure 4 and Figure 5 , Figure 4 which is a schematic plan view of the flexible board according to the embodiment of the present invention;Figure 5 for Figure 4 Schematic diagram of BB cross section.

[0064] Step S20:

[0065] A flexible copper clad laminate is taken to make a first circuit pattern 2010, and then a first window 2020 is made on the insulating dielectric layer 2030 of the flexible copper clad laminate corresponding to the flexible area, so that the flexible copper clad laminate forms a flexible board 20.

[0066] The first opening 2020 is formed in that a covering film needs to be attached to the flexible area in the subsequent process to form a hollow circuit structure in which the flexible area is covered by the covering film. Therefore, the covering film is laser cut. When the covering film is attached to the formed hollow circuit, the middle insulating layer is removed, and the colloid can directly "wrap" the first circuit pattern 2010, forming a "colloid-to-colloid" adhesion mode, thereby enhancing the bonding force between the colloid and the first circuit pattern 2010 and improving the overall stability of the flexible board 20.

[0067] Furthermore, the first circuit pattern 2010 is hollowed out to reduce the depth of subsequent laser cutting, thereby reducing laser energy, avoiding deformation of the flexible zone due to excessive ablation, and reducing the amount of carbon powder generated by subsequent laser cutting, preventing problems such as short circuits and pollution caused by carbon powder.

[0068] This method reduces the constraints of the material layer in the plane direction of the flexible area, so that the flexible area has better bending performance and ensures good electrical connectivity and mechanical strength.

[0069] In this embodiment, the first window 2020 is divided into a plurality of first sub-windows by a plurality of first circuit patterns 2010, and a plurality of second sub-circuit patterns are produced corresponding to each first sub-window.

[0070] Furthermore, a single side of the second sub-circuit pattern is smaller than the corresponding first sub-window.

[0071] On the one hand, it provides an allowable error distance for the laser cutting of the second circuit pattern 3010a in the subsequent process to avoid slight deviations during laser milling, which may affect the functionality of the circuit or cause short circuits. On the other hand, the first circuit pattern 2010 divides the single first window 2020 into multiple first sub-windows, which cooperate with the laser milling in the subsequent process to form an independent hollow first circuit pattern 2010 wrapped by a covering film in the flexible area, thereby reducing the material coverage of the flexible area on the plane, thereby improving the flexural performance of the flexible area.

[0072] Optionally, a single side of the second sub-circuit pattern is 20 μm to 70 μm smaller than the corresponding first sub-window.

[0073] See also Figure 6 , Figure 7And Figure 8 , Figure 6 is a schematic cross-sectional view of the stacked structure according to an embodiment of the present invention; Figure 7 is a schematic plan view of the flexible core board according to an embodiment of the present invention; Figure 8 is Figure 7 the C-C cross-sectional view of

[0074] Step S30:

[0075] Take a single-sided flexible copper clad laminate, fabricate a second circuit pattern 3010a corresponding to the first opening 2020, and cut it corresponding to the flexible area to form a pattern cover film 3010. Then align the pattern cover film 3010 with the flexible board 20 to form a stacked structure 30, and then press it to integrally form a flexible core board 40; the first circuit pattern 2010 and the second circuit pattern 3010a are mutually offset.

[0076] By using a single-sided flexible copper clad laminate (including the adhesive layer 3010b of the single-sided flexible copper clad laminate and the PI layer 3010c of the single-sided flexible copper clad laminate) to fabricate the second circuit pattern 3010a to form a pattern cover film 3010 to replace the ordinary cover film. During the pressing process, since the area corresponding to the position of the second circuit pattern 3010a has been hollowed out, the adhesive layer 3010b of the single-sided flexible copper clad laminate can bypass the second circuit pattern 3010a and flow into the hollowed positions that need to be filled, thereby forming an effective encapsulation of the first circuit pattern 2010, improving the stability and reliability of the overall structure. That is, the second circuit pattern 3010a forms a "copper-to-copper" setting by using the second circuit pattern 3010a above the stacked structure 30 and the second circuit pattern 3010a below the stacked structure 30, enhancing the evenness of the force during pressing.

[0077] And during the pressing process, the second circuit pattern 3010a can play a role in fixing the first circuit pattern 2010, preventing it from being displaced, skewed or deformed, ensuring the precise layout and electrical performance of the first circuit pattern 2010. In view of the fact that this part of the second circuit pattern 3010a needs to be removed by means such as laser cutting ultimately, the "copper-to-copper" setting is only an auxiliary means during the processing process and will not have a negative impact on the finished board body.

[0078] Furthermore, the length of the area of the pattern cover film 3010 facing the rigid area and corresponding to the second circuit pattern 3010a is less than or equal to the flexible area.

[0079] Considering the functional requirements of different regions, for the part of the first circuit pattern 2010, the cover film needs to extend into the rigid board region to ensure the connection strength; while for the region of the first opening 2020 (i.e., the part to be made into a hollowed-out part later), if the cover film also extends into the rigid board region, it may affect the bonding force between the rigid boards. Therefore, shortening the length of the cover film 3010 of this part of the pattern helps to improve the bonding effect between the rigid boards, thereby enhancing the mechanical strength and stability of the entire circuit board.

[0080] Optionally, the size less than is from 50 μm to 1.5 mm.

[0081] Please refer to Figure 9 , Figure 9 which is a schematic cross-sectional view of the laminated board of the embodiment of the present invention.

[0082] Step S40:

[0083] Stack and laminate the rigid core board 10 and the flexible core board 40 to form a laminated board 50.

[0084] Please refer to Figure 10 , Figure 11 , Figure 12 and Figure 13 , Figure 10 which is a schematic cross-sectional view of the cover board removed of the embodiment of the present invention; Figure 11 which is a schematic plan view of the milled board of the embodiment of the present invention; Figure 12 is Figure 11 the D-D cross-sectional view of; Figure 13 which is a schematic plan view of the rigid-flexible printed circuit board of the embodiment of the present invention.

[0085] Step S50:

[0086] Perform a cover-removing process on the flexible region of the laminated board 50 to form a cover-removed board 60, exposing the flexible core board 40, then perform laser milling corresponding to the second circuit pattern 3010a to form a milled board 70, and then perform shaping to form a rigid-flexible printed circuit board 80.

[0087] In this embodiment, the region of laser milling corresponds to the second circuit pattern 3010a and is tangent to the edge of the flexible region.

[0088] That is, mill off the second circuit pattern 3010a as an auxiliary circuit, and the long side facing the rigid region is the long side of laser milling, and the long side coincides with the rigid-flexible junction line, forming a hollow structure of a plurality of first sub-circuits connecting adjacent rigid regions.

[0089] It is worth noting that the width of the laser milling is greater than the width of the second circuit pattern 3010a. On the one hand, the previous process performed pre-reduction processing when making the second circuit pattern 3010a, so there is a certain gap between the second circuit pattern 3010a and the first circuit pattern 2010, reserving enough space for laser cutting. On the other hand, due to the lamination process, the second circuit pattern 3010a will produce certain offset and deformation errors. Therefore, widening the width of the laser milling can ensure that the laser cutting cuts the covering film and the glue layer, and ensures that the cutting of the second circuit pattern 3010a can fall completely within the cutting range.

[0090] Preferably, the width of the laser milling is greater than the width of the second circuit pattern 3010a, preferably greater than 20 μm to 50 μm. Further, the width of the laser milling is smaller than the width of the first sub-window.

[0091] That is, the milling line in the width direction of the laser milling is located between the first sub-window and the corresponding second circuit pattern 3010a, ensuring that the edges of the second circuit pattern 3010a "wrapped" by the glue layer 3010b of the single-sided flexible copper clad laminate and the PI layer 3010c of the single-sided flexible copper clad laminate will not be cracked by the laser milling.

[0092] During the lamination process of the multilayer board, the influence of factors such as temperature and pressure may cause offset or deformation between the layers. If the error is not properly compensated, it may lead to inaccurate laser cutting, which in turn affects the function and reliability of the circuit. Therefore, by adding an additional width of 20μm to 50μm, these errors can be absorbed to a certain extent, ensuring that even if these changes occur, the second circuit pattern 3010a can still fall accurately within the laser cutting range to ensure the cutting quality.

[0093] Although laser cutting has high precision, there is a certain error range in actual operation. Reserving additional gaps can provide a buffer space for these possible errors and achieve precise cutting effects. In addition to cutting the second circuit pattern 3010a, it is also necessary to remove the covering film and glue layer on the corresponding area. Therefore, appropriate gaps help the laser penetrate these material layers more thoroughly to ensure the formation of a clear and complete hollow structure.

[0094] It is worth noting that the present invention is aimed at processing the case where the line gap in the flexible area is relatively large (preferably the gap is above 100μm). For the case where the line gap in the flexible area is relatively dense, the pressing and shrinkage may affect the actual accuracy and the laser cutting accuracy may be insufficient.

[0095] In this embodiment, regarding the dimensional correlation of the hollowed-out area, taking the first sub-opening window as the reference, where the single side of the second sub-circuit pattern is smaller than the corresponding first sub-opening window. The area of the pattern covering film 3010 facing the rigid area and corresponding to the second circuit pattern 3010a has a length less than or equal to that of the flexible area, and the laser milling area corresponds to the second circuit pattern 3010a and is tangent to the edge of the flexible area. Further, the width of the laser milling is smaller than the width of the first sub-opening window; an overall dimensional correlation of the processing process at the position of the first sub-opening window is formed to ensure that the second circuit pattern 3010a is effectively "wrapped" after processing.

[0096] In this embodiment, by combining the high adhesion performance of the high-flow epoxy prepreg and the filling performance of the low-flow epoxy prepreg, on the one hand, it ensures that the voids between thick copper circuits can be effectively filled under high-temperature and high-pressure conditions, reducing the risk of insufficient glue filling or uneven board surface; more importantly, a good bonding layer is formed in the previous process, providing more effective conformal ability for the subsequent process of laminating and filling the glue for the "wrapping" of the hollowed-out circuits. Then, a single-sided flexible copper clad laminate is used to replace the covering film to fabricate the second circuit pattern 3010a that undertakes the auxiliary lamination function. The second circuit pattern 3010a is set through a misalignment design with the first circuit pattern 2010, which plays a role in adjusting the flow of the colloid, forming an effective wrapping of the first circuit pattern 2010, improving the bending performance of the flexible area. Further, after the first circuit pattern 2010 is effectively wrapped, it can effectively prevent the side exposure of the copper surface of the hollowed-out circuit, preventing risks such as oxidation and aging of the circuit copper surface during application. An overall relationship of the lamination effect before and after is formed, and the lamination in the previous process affects the smooth glue filling effect of the hollowed-out circuit in the subsequent process.

[0097] It should be noted that since the design and processing process of the flexible circuit board are relatively precise, the structure in the actual processing process and the dimensions such as the thickness between layers and the line width are all at the micron level. If the drawings are made according to the enlarged scale of the actual structure, the problem of unclear illustration will occur. Therefore, in order to more clearly and intuitively represent the implementation process of the manufacturing method of this embodiment, the drawings of this embodiment are all schematic diagrams of enlarged technical features, which do not represent the dimensions of the actual structure, nor are they enlarged diagrams of the actual structure in proportion.

[0098] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a thick copper, high current carrying, high flexibility hollow circuit rigid-flexible board, the rigid-flexible board comprising a rigid area and a flexible area, characterized in that: The production method comprises the following steps: S10: After the previous process, a rigid core board is formed with a copper layer on one side and a prepreg on the other side; S20: Take a flexible copper-clad laminate, make a first circuit pattern, and then make a first window on the insulating dielectric layer of the flexible copper-clad laminate corresponding to the flexible area, so that the flexible copper-clad laminate forms a flexible board; S30: taking a single-sided flexible copper-clad laminate, making a second circuit pattern corresponding to the first opening, cutting it corresponding to the flexible area to form a pattern covering film, and then aligning and pressing the pattern covering film with the flexible board to form a flexible core board; The first circuit pattern and the second circuit pattern are offset from each other; S40: stacking and pressing the rigid core board and the flexible core board to form a pressed board; S50: performing a cover-lifting process on the flexible area of ​​the laminated board to expose the flexible core board, and then performing laser milling and molding corresponding to the second circuit pattern to form the rigid-flexible board.

2. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 1, characterized in that: The forming of the rigid core board also includes making a blind groove on the edge of the prepreg corresponding to the flexible area.

3. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 1, characterized in that: The rigid core board is formed by taking copper foil, low-flow adhesive prepreg and single-sided copper clad laminate, stacking and pressing them in sequence, and then etching the surface copper layer of the single-sided copper clad laminate to form the rigid core board.

4. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 3, characterized in that: The surface copper layer is a thin copper foil with a thickness of 5 μm to 10 μm.

5. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 4, characterized in that: The insulating dielectric layer of the single-sided copper clad laminate is a high-flow adhesive prepreg.

6. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 1, characterized in that: The first window is divided into a plurality of first sub-windows by a plurality of the first line patterns.

7. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 6, characterized in that: The step of making the second circuit pattern is to make a plurality of second sub-circuit patterns corresponding to each of the first sub-windows.

8. The method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board according to claim 7, characterized in that: The second sub-circuit pattern is smaller than the corresponding first sub-window on one side.

9. A method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board as claimed in claim 1 or 8, characterized in that: The laser milling area corresponds to the second circuit pattern and is tangent to the edge of the flexible area.

10. A method for manufacturing a thick copper, large current-carrying, high-flexibility hollow circuit rigid-flexible board as claimed in claim 1 or 8, characterized in that: The pattern covering film faces the rigid area and corresponds to the area of ​​the second circuit pattern, and has a length that is less than or equal to the flexible area.

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