Method for manufacturing rigid-flexible board with surface flexible layer

Abstract

The present invention discloses a method for manufacturing a rigid-flexible board with a surface flexible layer. The method comprises the following steps: taking a double-sided flexible copper-clad board, making through holes and electroplating, and then making circuit patterns to form a graphic board; making a first window covering film with windows corresponding to the gold finger area and covering the through holes, and making a second window covering film with windows corresponding to the through holes and the invalid area, and attaching them to both sides of the graphic board respectively, and then performing electrometallurgy processing to form a flexible core board; taking a rigid copper-clad board, making windows corresponding to the flexible layered area, and then making circuit patterns to form a rigid core board; stacking and pressing the above structures to form a pressed board; drilling and electroplating the pressed board, and then performing laser ablation on the through hole area, and performing post-processing to form a rigid-flexible board; by forming a new processing flow, the defects of the traditional rigid-flexible board manufacturing method in terms of low adaptability, processing accuracy and reliability are systematically solved, and high-precision processing of highly integrated rigid-flexible boards is achieved.

Description

Technical Field

[0001] The present invention relates to the field of rigid-flexible board manufacturing, and in particular to a method for manufacturing a rigid-flexible board with a surface flexible layer. Background Art

[0002] For some radar and camera modules of intelligent connected cars or low-altitude aircraft, rigid boards are usually used as effective supports for electronic components or to provide a welding basis. Flexible boards are then used to connect the rigid boards to other functional modules, and the gold fingers of the flexible boards are used to form welding or plug-in connections.

[0003] However, the processing process of this type of module is relatively long, and it is necessary to make rigid boards and flexible boards separately and then weld them to each other, which has low reliability. Furthermore, for high-precision circuit board products that require small line widths and line gaps, small hole sizes, and high board processing accuracy, there will be situations where flexible boards are welded on the upper and lower surfaces of the rigid board, which increases the difficulty of welding and is prone to problems such as cold solder joints and wrinkles on the flexible board.

[0004] Based on the above problems, a method of directly using rigid-flexible boards to replace the above modules has emerged. That is, first make the inner layer circuit pattern, then open windows on the rigid board, place pads or fillers in the middle layer, press them together, make the surface pattern, and then remove the pads or fillers.

[0005] However, there are the following processing defects:

[0006] (1) Limited scope of application: Since the pads or fillers need to be removed later, it is necessary to ensure that at least one side is in a windowed state. Therefore, this manufacturing method is more suitable for structures with a flexible layer on the inner layer. However, it is difficult to adapt to structures with a surface flexible layer welded to the surface of a rigid board. Even structures with flexible layers on both sides make it even more difficult to effectively apply this processing method.

[0007] (2) Processing quality is difficult to guarantee: If there are independent through holes on the flexible board, the process of making surface graphics after pressing is prone to water seepage problems, which affects the processing quality of the module.

[0008] Therefore, in order to solve the above-mentioned problems, it is necessary to provide a method for manufacturing a rigid-flexible board with a surface flexible layer. Summary of the Invention

[0009] The present invention aims to solve the comprehensive problems of low adaptability and difficulty in ensuring processing quality of rigid-flexible board processing methods in the prior art, and provides a method for manufacturing a rigid-flexible board with a surface flexible layer. The rigid-flexible board is designed with a forming line, the area within the forming line is an effective area, and the remaining area is an ineffective area. The effective area includes a flexible area and a rigid area. The flexible area is designed with a gold finger pattern to form a gold finger area, and the remaining area is a flexible layered area. The manufacturing method comprises the following steps:

[0010] S10: Take a double-sided flexible copper clad board, make through holes and electroplate it, and then make a circuit pattern to form a pattern board;

[0011] S20: Taking two layers of cover films, performing windowing to form a first windowed cover film and a second windowed cover film, respectively, and attaching them to two sides of the graphic board, respectively, and then performing electrometallization processing on the gold finger pattern to form a first flexible core board;

[0012] The first window covering film has a window corresponding to the gold finger area and covers the through hole;

[0013] The second window covering film is windowed corresponding to the through hole, and is windowed corresponding to the rigid area and the ineffective area;

[0014] A second flexible core board is formed by the same manufacturing method as the first flexible core board, wherein the covering film on one side corresponding to the gold finger pattern of the second flexible core board is the third window covering film, and the covering film on the other side is the fourth window covering film;

[0015] S30: Take a rigid copper clad laminate, open a window corresponding to the flexible layered area, and then make a circuit pattern to form a rigid core board;

[0016] S40: stacking the first flexible core board, the rigid core board, and the second flexible core board in sequence from top to bottom to form a stacked structure, and pressing them together to form a pressed board;

[0017] The flexible layered area of ​​the laminate forms a layered structure;

[0018] The gold finger pattern is located on the surface of the pressing plate;

[0019] S50: drilling and electroplating the rigid area of ​​the laminate, and then laser ablating the area corresponding to the through hole in the first window cover film, and then processing through a post-processing step to form a rigid-flexible composite board in which the first flexible core board and the second flexible core board are a layered structure in the flexible area.

[0020] Furthermore, forming the rigid core board includes making a first windowed semi-cured sheet and a second windowed semi-cured sheet for opening windows corresponding to the flexible layered area; forming the stacked structure includes stacking the first flexible core board, the first windowed semi-cured sheet, the rigid core board, the second windowed semi-cured sheet, and the second flexible core board in sequence from top to bottom to form a stacked structure.

[0021] Furthermore, a first reinforcing sheet and a second reinforcing sheet are respectively made corresponding to the gold finger pattern; forming the stacked structure includes stacking the first flexible core board, the first reinforcing sheet, the first windowed semi-cured sheet, the rigid core board, the second windowed semi-cured sheet, the second reinforcing sheet, and the second flexible core board in sequence from top to bottom to form a stacked structure; the first reinforcing sheet is provided with a first adhesive layer, and the first adhesive layer is attached to the surface of the first flexible core board; the second reinforcing sheet is provided with a second adhesive layer, and the second adhesive layer is attached to the surface of the second flexible core board.

[0022] Furthermore, forming the stacked structure includes forming a thermal debonding layer on a surface of the first windowed prepreg corresponding to the first reinforcing sheet, and on a surface of the second windowed prepreg corresponding to the second reinforcing sheet.

[0023] Furthermore, the colloid thickness of the thermal debonding adhesive layer is 1 μm to 10 μm, and the debonding temperature is 100° C. to 120° C.

[0024] Furthermore, the pressing is a quick pressing.

[0025] Furthermore, the drilling forms a large through hole and a small through hole, and the diameter difference between the large through hole and the small through hole is greater than or equal to 0.3 mm.

[0026] Furthermore, the first window covering film includes windows corresponding to the large through-holes and covers the small through-holes, and the second window covering film includes windows corresponding to the rigid area.

[0027] Furthermore, before the electroplating, the first window cover film covering the hole ring of the small through hole is laser ablated.

[0028] Furthermore, the thickness of the rigid-flex board is less than or equal to 1.0 mm.

[0029] The technical solution of the present invention mainly has the following beneficial effects:

[0030] (1) Processing flow: breaking the traditional method of first making a flexible board separately and then welding it to a rigid board, and the process of first filling the cavity position and pressing it and then making the surface circuit pattern, the present invention forms a process of first completely making the circuit patterns of each layer, and then making the through holes in the rigid area after pressing, eliminating the process of making the circuit pattern twice. The whole manufacturing process is more efficient, and there is coherence and correlation between each process, forming a complete high-precision surface flexible board rigid-flexible board processing.

[0031] (2) Differentiated windowing: by making the first windowing cover film and the fourth windowing cover film cover the through hole, while the second windowing cover film and the third windowing cover film correspond to the through hole opening, and after stacking and pressing, the first windowing cover film and the fourth windowing cover film form a closed structure that covers and protects the through hole on the surface, while the second windowing cover film and the third windowing cover film are located in the inner layer and will not penetrate the chemical solution, so they directly correspond to the through hole opening, which effectively avoids the problem of chemical solution seepage without affecting the final internal electrical connection, thereby ensuring the processing quality of the circuit board.

[0032] (3) Thermally debonded adhesive layer and the first adhesive layer and the second adhesive layer: The first reinforcing sheet is adhered to the surface of the first flexible core board through the first adhesive layer, and is adhered to the first windowed semi-cured sheet using the thermally debonded adhesive layer. The first adhesive layer forms a viscosity difference with the first thermally debonded adhesive, and the second adhesive layer forms a viscosity difference with the second thermally debonded adhesive. In the subsequent pressing process, the thermally debonded adhesive layer loses its viscosity during the heating stage, which ensures the effective pressing of the first reinforcing sheet and avoids the problem of the first reinforcing sheet being adhered to the first windowed semi-cured sheet and being difficult to separate, thus forming an effective delamination effect. Similarly, a viscosity difference is formed between the second reinforcing sheet, the second windowed semi-cured sheet and the second flexible core board, forming an effective coordination between the upper and lower parts, which provides a processing basis for removing the invalid area and the corresponding gold finger area in the rigid core board in the subsequent process, and forming a windowed state on one side of the flexible delamination area.

[0033] (4) In terms of overall processing technology, a technical combination of "making circuit graphics first and then pressing + differentiated window opening + thermal debonding adhesive layer pressing" is formed to form a new processing flow and form the front-end correlation of the processing flow, thereby systematically solving the defects of low adaptability, processing accuracy and reliability of traditional rigid-flex PCB manufacturing methods, and forming high-precision processing of highly integrated rigid-flex PCBs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0035] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention;

[0036] Figure 2 is a schematic cross-sectional view of a first flexible core board according to an embodiment of the present invention;

[0037] Figure 3 is a schematic cross-sectional view of a stacked structure according to an embodiment of the present invention;

[0038] Figure 4 is a schematic cross-sectional view of a pressed plate according to an embodiment of the present invention;

[0039] Figure 5 for Figure 4 Schematic diagram of the floor plan;

[0040] Figure 6 is a schematic cross-sectional view of an electroplating plate according to an embodiment of the present invention;

[0041] Figure 7 Schematic diagram of a rigid-flex board according to an embodiment of the present invention;

[0042] Figure 8 for Figure 7 Schematic diagram of the floor plan.

[0043] Explanation of the accompanying symbols: 100, forming line; 200, effective area; 300, invalid area; 210, flexible area; 220, rigid area; 2110, gold finger area; 2120, flexible layered area; 2130, through hole; 10, graphic board; 20, first flexible core board; 2010, first window covering film; 2020, second window covering film; 30, second flexible core board; 3010, third window covering film; 3020, fourth window covering film; 400, blue glue layer; 4 0, rigid core board; 5020, first reinforcement sheet; 5020A, first adhesive layer; 5030A, first thermally debonded adhesive layer; 5030B, second thermally debonded adhesive layer; 5040, first windowed prepreg; 5050, second windowed prepreg; 5060, second reinforcement sheet; 5060A, second adhesive layer; 50, stacked structure; 60, laminated board; 610, layered structure; 70, electroplated board; 7010, large through hole; 7020, small through hole; 80, rigid-flex board.

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside, etc.) are only used to explain the relative position relationship and movement status of the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0048] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] See also Figure 1 , Figure 1 Schematic diagram of the process flow of an embodiment of the present invention.

[0050] The manufacturing process of the embodiment of the present invention includes using Figure 1 The following will implement the various steps in the process Figure 1 Each step in the process is further explained step by step.

[0051] The rigid-flexible board 80 of this embodiment is designed with a forming line 100 during the processing process. The area within the forming line 100 is the effective area 200, and the remaining area is the invalid area 300. The effective area 200 includes a flexible area 210 and a rigid area 220. The flexible area 210 is designed with a gold finger pattern to form a gold finger area 2110. The remaining area is a flexible layered area 2120. The manufacturing method includes the following steps.

[0052] See also Figure 2 , Figure 2 Schematic cross-sectional view of a first flexible core board according to an embodiment of the present invention.

[0053] Step S10: Take a double-sided flexible copper clad board, make through holes 2130 and electroplate it, and then make a circuit pattern to form a pattern board 10.

[0054] First, through holes 2130 are made in the double-sided flexible copper clad laminate and electroplated to form electrical connections between the layers. Then, a circuit pattern is formed. This is equivalent to the pattern of the double-sided flexible copper clad laminate being formed. Since it has not been pressed with other core board layers at this time, etching processing can be performed more flexibly or process parameters can be adjusted in time, effectively improving the accuracy of the circuit pattern and processing efficiency.

[0055] The circuit pattern produced in this step directly participates in the lamination process of the subsequent process, providing a processing basis for the subsequent process.

[0056] See also Figure 3 , Figure 3 Schematic cross-sectional view of a stacked structure according to an embodiment of the present invention.

[0057] Step S20: Take two layers of covering film, open windows to form a first window covering film 2010 and a second window covering film 2020, and attach them to both sides of the graphic board 10 respectively, and then perform electroplating on the gold finger pattern to form a first flexible core board 20.

[0058] The first window covering film 2010 opens a window corresponding to the gold finger area 2110 and covers the through hole 2130; the second window covering film 2020 opens a window corresponding to the through hole 2130 and opens windows corresponding to the rigid area 220 and the invalid area 300; the second flexible core board 30 is manufactured according to the same manufacturing method as the first flexible core board 20.

[0059] The first window covering film 2010 has windows corresponding to the gold finger area 2110 and covers the through hole 2130 , thereby providing a processing basis for the gold finger processing and protecting the through hole 2130 .

[0060] The window position of the second window covering film 2020 corresponds to the through hole 2130 because the second window covering film 2020 is located inside the plate body after being pressed in the subsequent process, and it is impossible to use laser ablation technology to open the window. Therefore, the window must be opened first and then pressed to ensure that the through hole 2130 can be correctly connected with other layers in the final assembly to form an effective electrical connection; and after pressing, a layered structure 610 is formed, and the end of the through hole 2130 facing the outer layer is covered by the first window covering film 2010, and problems such as liquid leakage from the through hole 2130 will not occur.

[0061] Moreover, the second window covering film 2020 has windows corresponding to the rigid area 220 and the invalid area 300 at the same time, providing a window foundation for the rigid core board 40 to be pressed together with the first flexible core board 20 and the second flexible core board 30 in the subsequent process to form a stable pressed board 60 structure, thereby ensuring the mechanical strength and stability of the entire circuit board; in other words, if windows are not opened corresponding to the invalid area 300, gaps and delamination problems are likely to occur after the rigid core board 40 and the second covering film are pressed together, leading to problems such as drug seepage.

[0062] The second flexible core board 30 is manufactured according to the same manufacturing method as the first flexible core board 20, and the third window covering film 3010 of the second flexible core board 30 corresponds to the window position of the second window covering film 2020, and the fourth window covering film 3020 corresponds to the window position of the first window covering film 2010.

[0063] It is worth noting that before electro-gold processing, it is necessary to use a blue glue layer 400 to cover the other window areas except the gold fingers. After the electro-gold processing is completed, the gold fingers are covered with a blue glue layer 400 to form a protective effect and avoid scratches on the gold finger surface during subsequent pressing and other processing.

[0064] Please refer again Figure 3 .

[0065] Step S30 : Take a rigid copper clad laminate, open windows corresponding to the flexible layered area 2120 , and then make circuit patterns to form a rigid core board 40 .

[0066] The rigid core board 40 does not have windows corresponding to the gold finger area 2110 (the area corresponding to the first reinforcement sheet 5020 and the second reinforcement sheet 5060), and the two layers of reinforcement sheets are arranged on the inner layer of the press plate 60. Therefore, it is necessary to use a pressing method to press the two layers of reinforcement sheets on the surface (corresponding to the back of the gold finger area 2110). The rigid core board 40 can provide sufficient support for the area of ​​the two layers of reinforcement sheets during the pressing process to ensure that the two layers of reinforcement sheets can be effectively pressed to the designated position. Conversely, if a window is opened in the area of ​​the rigid core board 40 corresponding to the two layers of reinforcement sheets, the area will lose the support layer, thereby failing to provide effective pressure distribution, making it impossible for the two layers of reinforcement sheets to adhere correctly, which is not conducive to maintaining the mechanical strength and stability of the entire press plate 60.

[0067] Furthermore, since the rigid core board 40 is windowed corresponding to the flexible layered area 2120, in the pressed board 60 of the subsequent process, the windowed area will form a "hollow" layered structure 610 inside the board body, and the two opposite sides of the layered structure 610 are through holes 2130 and covering films, and there will be no mutual adhesion. The layered structure 610 is effectively coordinated with the forming processing of the subsequent process to remove the invalid area 300, effectively replacing the traditional processing of first padding the middle layer with a pad or filler for processing, and then removing the pad or filler. This simplifies the process flow, reduces material usage, and also reduces costs.

[0068] See also Figure 4 and Figure 5 , Figure 4 is a schematic cross-sectional view of a pressed plate according to an embodiment of the present invention; Figure 5 for Figure 4 Schematic diagram of the floor plan.

[0069] Step S40: stack the first flexible core board 20, the rigid core board 40, and the second flexible core board 30 from top to bottom to form a stacked structure 50, and press them together to form a pressed board 60; the flexible layered area 2120 of the pressed board 60 forms a layered structure 610; the gold finger pattern is located on the surface of the pressed board 60.

[0070] During the lamination process, blue glue can be used to cover the gold finger pattern to prevent problems such as damage to the gold finger pattern during lamination. After the final molding process, the blue glue is removed; the blue glue can be processed by silk screen printing or attaching blue glue.

[0071] Furthermore, forming the rigid core board 40 includes making a first windowed semi-cured sheet 5040 and a second windowed semi-cured sheet 5050 for opening windows in the corresponding flexible layered area 2120; forming the stacked structure 50 includes stacking the first flexible core board 20, the first windowed semi-cured sheet 5040, the rigid core board 40, the second windowed semi-cured sheet 5050, and the second flexible core board 30 in sequence from top to bottom to form the stacked structure 50.

[0072] Furthermore, the first reinforcement sheet 5020 and the second reinforcement sheet 5060 are respectively made corresponding to the gold finger area 2110; the formation of the stacked structure 50 includes stacking the first flexible core board 20, the first reinforcement sheet 5020, the first windowed semi-cured sheet 5040, the rigid core board 40, the second windowed semi-cured sheet 5050, the second reinforcement sheet 5060, and the second flexible core board 30 in sequence from top to bottom to form the stacked structure 50.

[0073] The first reinforcing sheet 5020 is provided with a first adhesive layer 5020A, which is attached to the surface of the first flexible core board 20 ; the second reinforcing sheet 5060 is provided with a second adhesive layer 5060A, which is attached to the surface of the second flexible core board 30 .

[0074] Furthermore, forming the stacked structure 50 includes forming a first thermal debonding layer 5030A on the surface of the first windowed prepreg 5040 corresponding to the first reinforcing sheet 5020 , and forming a second thermal debonding layer 5030B on the surface of the second windowed prepreg 5050 corresponding to the second reinforcing sheet 5060 .

[0075] This embodiment forms a stacked structure 50 in which the first flexible core board 20, the first window prepreg 5040, the first reinforcing sheet 5020, the rigid core board 40, the second reinforcing sheet 5060, the second window prepreg 5050, and the second flexible core board 30 are stacked in sequence from top to bottom. The effect of the final laminated board 60 can be referred to Figure 4 , forming an overall closed structure of the entire board surface, and the flexible layered area 2120 forms a layered structure 610 with a "hollow" center, providing a processing basis for subsequent processes.

[0076] It is worth noting that before the final lamination, the circuit patterns on the first flexible core board 20 and the second flexible core board 30 have been completed. After lamination, the circuit patterns directly become part of the surface of the lamination board 60. There is no need to produce surface circuit patterns subsequently, which eliminates the process of secondary production of circuit patterns. The entire manufacturing process is more efficient. At the same time, it also reduces material usage and process steps, thereby improving the quality of the finished product.

[0077] The first reinforcing sheet 5020 of this embodiment is adhered to the surface of the first flexible core board 20 through the first adhesive layer 5020A, and is adhered to the first windowed semi-cured sheet 5040 using the first heat-degradable adhesive layer 5030A, forming a viscosity difference between the layers. In the subsequent pressing process, the heating stage causes the first heat-degradable adhesive layer 5030A and the second heat-degradable adhesive layer 5030B to lose their viscosity, thereby ensuring the effective pressing of the first reinforcing sheet 5020 and avoiding the problem that the first reinforcing sheet 5020 is adhered to the first windowed semi-cured sheet 5040 and is difficult to separate, thereby forming an effective stratification effect. Similarly, a viscosity difference is also formed between the second reinforcing sheet 5060 and the second windowed semi-cured sheet 5050 and the second flexible core board 30, forming an effective cooperation between the upper and lower parts, providing a processing basis for removing the invalid area 300 and the part corresponding to the gold finger area 2110 in the rigid core board 40 in the subsequent process, and forming a windowed state on one side of the flexible stratification area 2120.

[0078] Furthermore, the colloid thickness of the first thermal debonding adhesive layer 5030A and the second thermal debonding adhesive layer 5030B is 1 μm to 10 μm, and the debonding temperature is 100° C. to 120° C., which facilitates the subsequent removal and cleaning of the thermal debonding adhesive layer. The debonding temperature can achieve the effect of debonding at the pressing temperature during the pressing process, without the need for separate heating for debonding.

[0079] See also Figure 6 、 Figure 7 and Figure 8 , Figure 6 is a schematic cross-sectional view of an electroplating plate according to an embodiment of the present invention; Figure 7 Schematic diagram of a rigid-flex board according to an embodiment of the present invention; Figure 8 for Figure 7 Schematic diagram of the floor plan.

[0080] Step S50: Drill and electroplate the rigid area 220 of the laminated plate 60, and then laser ablate the area corresponding to the through hole 2130 in the first window covering film 2010 to form an electroplated plate 70. After post-processing, a rigid-flexible composite board 80 is formed in which the first flexible core board 20 and the second flexible core board 30 are a layered structure 610 in the flexible area 210.

[0081] First, the rigid area 220 is drilled and electroplated, and then the areas corresponding to the through holes 2130 in the first window covering film 2010 and the fourth window covering film 3020 are ablated to form the final window. The entire processing flow uses the first window covering film 2010 and the fourth window covering film 3020 to cover the through holes 2130 to form a protective effect, effectively avoiding the injection or seepage of medicine at the position of the through holes 2130, thereby causing problems such as poor board processing.

[0082] Furthermore, a large through hole 7010 and a small through hole 7020 are formed by drilling, and the diameter difference between the large through hole 7010 and the small through hole 7020 is greater than or equal to 0.3 mm.

[0083] Furthermore, the first window covering film 2010 includes windows corresponding to the large through-hole 7010 and covers the small through-hole 7020 , and the second window covering film 2020 includes windows corresponding to the rigid area 220 .

[0084] Similarly, the fourth window covering film 3020 of the second flexible core board 30 opens windows corresponding to the large through hole 7010 and covers the small through hole 7020 , and the third window covering film 3010 opens windows corresponding to the rigid area 220 .

[0085] Furthermore, before electroplating, the first window cover film 2010 covering the hole ring of the small through hole 7020 is laser ablated.

[0086] The first window covering film 2010 is windowed in the large through hole 7010 corresponding to the rigid zone 220 in order to avoid the subsequent use of laser ablation. The area of ​​the covering film that needs to be ablated is large and the time is relatively long, thereby generating more carbon powder, which increases production cost and time; and the corresponding small through hole 7020 is not windowed because there will be processing errors in the lamination of the covering film, and the small through hole 7020 has a relatively small diameter and provides a relatively low allowable error, and the processing accuracy requirement is also relatively high, which easily leads to problems of window opening and hole misalignment, thereby affecting the subsequent post-process processing of the small through hole 7020.

[0087] Furthermore, the thickness of the rigid-flex board 80 is less than or equal to 1.0 mm.

[0088] This embodiment is suitable for completing the production of a thin rigid-flexible board 80, and can effectively avoid the occurrence of a large depression at the junction of the flexible area 210 and the rigid area 220 during pressing, causing the first flexible core board 20 and the second flexible core board 30 to have depressions, deformation, and other problems at the junction of the rigid area 220 and the flexible area 210.

[0089] Furthermore, the pressing is a quick pressing.

[0090] Since there is a "hollow" layered structure 610 in the middle during pressing and the board itself is relatively thin, if traditional pressing equipment is used for pressing, it is easy for the layered position to be concave, damaging the first flexible core board 20 and the second flexible core board 30, and it is easy for the first windowed semi-cured sheet 5040 and the second windowed semi-cured sheet 5050 to have excessive glue flow, resulting in risks such as adhesion of the layered area; therefore, this embodiment adopts a rapid pressing method, which has less pressure than ordinary pressing and a shorter pressing time, ensuring the structural stability of the board during the pressing process.

[0091] It is worth noting that this embodiment is particularly aimed at the rigid-flexible board 80 structure with the flexible board layer on the outer layer. For the rigid-flexible board with the flexible board layer on the inner layer, since it needs to be uncovered for processing, it is difficult to form through holes in the flexible board area after uncovering, so it is not suitable for the processing technology of this embodiment.

[0092] It is worth noting that since the design and processing process of the rigid-flexible board 80 of this embodiment is relatively precise, the structure of the actual processing process and the thickness of each layer, line width and other dimensions are all at the micron level. If the drawings are made according to the enlarged ratio of the actual structure, the drawings will be unclear. 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 that enlarge the technical features, which do not represent the size of the actual structure, nor are they enlarged drawings of the actual structure in proportion.

[0093] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a rigid-flexible board with a surface flexible layer, wherein the rigid-flexible board is designed with a forming line, the area within the forming line is an effective area, and the remaining area is an ineffective area, the effective area includes a flexible area and a rigid area, the flexible area is designed with a gold finger pattern to form a gold finger area, and the remaining area is a flexible layered area, characterized in that: The production method comprises the following steps: S10: Take a double-sided flexible copper clad board, make through holes and electroplate it, and then make a circuit pattern to form a pattern board; S20: Taking two layers of cover films, performing windowing to form a first windowed cover film and a second windowed cover film, respectively, and attaching them to two sides of the graphic board, respectively, and then performing electrometallization processing on the gold finger pattern to form a first flexible core board; The first window covering film has a window corresponding to the gold finger area and covers the through hole; The second window covering film is windowed corresponding to the through hole, and is windowed corresponding to the rigid area and the ineffective area; A second flexible core board is manufactured using the same manufacturing method as the first flexible core board; S30: Take a rigid copper clad laminate, open windows corresponding to the flexible layered area, and then make a circuit pattern to form a rigid core board; and make a first windowed prepreg and a second windowed prepreg with windows corresponding to the flexible layered area; A first reinforcing sheet and a second reinforcing sheet are respectively produced corresponding to the gold finger patterns; The first reinforcing sheet is provided with a first adhesive layer, and the first adhesive layer is attached to the surface of the first flexible core board; The second reinforcing sheet is provided with a second adhesive layer, and the second adhesive layer is attached to the surface of the second flexible core board; Forming a first thermally debonding adhesive layer and a second thermally debonding adhesive layer on a surface of the first windowed prepreg corresponding to the first reinforcing sheet, and on a surface of the second windowed prepreg corresponding to the second reinforcing sheet, respectively; S40: stacking the first flexible core board, the first reinforcing sheet, the first window prepreg, the rigid core board, the second window prepreg, the second reinforcing sheet, and the second flexible core board in sequence from top to bottom to form a stacked structure, and pressing them together to form a laminated board; In the lamination process, the heating stage causes the first heat-disbonding adhesive layer and the second heat-disbonding adhesive layer to lose their adhesiveness; The flexible layered area of ​​the laminate forms a layered structure; The gold finger pattern is located on the surface of the pressing plate; S50: drilling and electroplating the rigid area of ​​the laminate, and then laser ablating the area corresponding to the through hole in the first window cover film, and then processing through a post-processing step to form a rigid-flexible composite board in which the first flexible core board and the second flexible core board are a layered structure in the flexible area.

2. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 1, wherein: The colloid thickness of the thermal debonding adhesive layer is 1 μm to 10 μm, and the debonding temperature is 100° C. to 120° C.

3. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 1, wherein: The pressing is quick pressing.

4. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 1, wherein: The drilling forms a large through hole and a small through hole, and the diameter difference between the large through hole and the small through hole is greater than or equal to 0.3 mm.

5. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 4, wherein: The first window covering film includes windows corresponding to the large through-holes and covers the small through-holes, and the second window covering film includes windows corresponding to the rigid area.

6. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 5, wherein: Before the electroplating, the first window cover film covering the hole ring of the small through hole is laser ablated.

7. The method for manufacturing a rigid-flexible board with a surface flexible layer according to claim 1, wherein: The thickness of the rigid-flex board is less than or equal to 1.0 mm.

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