A method for manufacturing a six-layer rigid-flexible board

Abstract

The present invention relates to a method for manufacturing a six-layer rigid-flexible board, comprising: providing a double-sided flexible board and two double-sided copper-clad boards; making a circuit layer on both sides of the double-sided flexible board, and providing a covering film layer; making a circuit layer on the inner copper foil of the double-sided copper-clad board, and etching away the surface copper of the pre-opening area on the copper foil; laser cutting the inner dielectric layer of the double-sided copper-clad board from the inner side, and retaining the connection points, and the cutting depth is the thickness of the inner dielectric layer of the board; respectively providing an inter-board dielectric layer between the double-sided flexible board and the two double-sided copper-clad boards and performing substrate compounding, and providing a window in the inter-board dielectric layer corresponding to the pre-opening area; making a circuit layer on the copper foil on the outer side of the double-sided copper-clad board, and etching away the copper foil of the laser cutting seam, and opening the cover along the laser cutting seam in a gong shape to remove the waste material in the pre-opening area, and completing the uncovering. The method of the present invention can effectively reduce the product thickness, improve the flatness of the hard board area, and meet customer needs.

Description

Technical Field

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

[0002] Conventional six-layer rigid-flex PCBs are produced using laser depth-controlled cutting on both sides. Laser depth-controlled cutting requires high-quality equipment and carries certain risks, potentially damaging inner-layer circuitry. Currently, customers are demanding higher standards for product thickness and flatness. Six-layer PCBs feature both flexible areas with solder pad openings in the flexible PCB area and rigid areas, saving internal space, reducing product size, and improving performance.

[0003] like Figure 8 The figure shows the hierarchical structure of a six-layer rigid-flex PCB. The traditional six-layer rigid-flex PCB manufacturing method begins with the inner circuit layers L3 and L4. A protective film C3 is applied to circuit L3, and a protective film C4 is applied to circuit L4. Then, a dielectric layer PP23, double-sided copper-clad laminate layers L1 and L2 are applied sequentially to protective film C3. A dielectric layer PP45, and double-sided copper-clad laminate layers L5 and L6 are applied sequentially to protective film C4. This method of producing a six-layer rigid-flex PCB presents challenges during laser depth-controlled cutting of the outer layers. If the laser depth-controlled cutting is too shallow, the cover is difficult to remove and abnormal tearing of the FR4 in the rigid board area can occur. If the laser depth-controlled cutting is too deep, there is a risk of damaging the inner circuit layers and production stability is low. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides a method for manufacturing a six-layer rigid-flex PCB, which overcomes technical prejudices, can effectively reduce product thickness, improve the flatness of the rigid board area, and meet customer needs.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for manufacturing a six-layer rigid-flex PCB, comprising:

[0007] S1, set a double-sided soft board as the inner soft board and set two double-sided copper clad boards as the outer hard boards;

[0008] S2, manufacturing circuit layers on both sides of the double-sided flexible circuit board, and providing cover film layers on both sides of the circuit layers of the double-sided flexible circuit board;

[0009] S3, forming a circuit layer on the copper foil on the inner side of the double-sided copper clad laminate, and etching away the surface copper in the pre-opened area of ​​the copper foil to expose the inner dielectric layer of the double-sided copper clad laminate, where the inner side refers to the side facing the double-sided flexible printed circuit board;

[0010] S4, laser cutting the dielectric layer of the double-sided copper clad laminate along the edge of the pre-opened area from the inner side of the double-sided copper clad laminate, and retaining the connection points. The cutting depth is equal to the thickness of the dielectric layer of the double-sided copper clad laminate.

[0011] S5, providing an inter-board dielectric layer between the double-sided flexible board and the two outer circuit boards and performing base material lamination, wherein the inter-board dielectric layer has a window corresponding to the pre-opened cover area;

[0012] S6, making a circuit layer on the copper foil on the outer side of the double-sided copper clad laminate, etching away the copper foil at the laser cutting seam, and opening the cover in a gong shape along the laser cutting seam to remove waste material in the pre-opening area.

[0013] On the basis of the above technical solution, the present invention can also be improved as follows.

[0014] Preferably, the middle dielectric layer of the double-sided flexible board is 20um PI, and the circuit layers on both sides of the double-sided flexible board are made of 1 / 3oz Cu.

[0015] Preferably, the middle dielectric layer of the double-sided copper clad laminate is 2mil FR4, and the copper foil layers on both sides of the double-sided copper clad laminate are made of 1 / 3oz Cu.

[0016] Preferably, step S2 further includes: opening a window in an area corresponding to the pad on the cover film layer, so that the circuit in the windowed area of ​​the pad is exposed.

[0017] Preferably, step S2 further includes: after the covering film layer of the double-sided flexible board is set, measuring the expansion and contraction data of the double-sided flexible board, and calculating the drilling parameters of the two double-sided copper clad boards and the processing parameters of the inter-board dielectric layer based on the expansion and contraction data.

[0018] Preferably, in step S5, the material and thickness parameters of the inter-board dielectric layer are set according to the processing parameters of the inter-board dielectric layer, and the circuit layers on both sides of the double-sided flexible board are respectively laminated with the two double-sided copper clad laminates.

[0019] Preferably, in step S4, the laser cutting direction is from the circuit side of the double-sided copper clad laminate toward the copper foil side, the cutting depth is to completely cut through the dielectric layer inside the double-sided copper clad laminate and retain the single-sided copper foil, and at least one connection point is retained in the cutting route.

[0020] Preferably, the laser cutting width is less than 0.15 mm.

[0021] Preferably, in step S5, the edge of the cutting area of ​​the inter-board dielectric layer extends 0.2 mm toward the center of the pre-opening area.

[0022] Preferably, step S6 further includes drilling holes in the double-sided copper clad laminate and / or the double-sided flexible laminate according to the drilling parameters.

[0023] The beneficial effects of the present invention are as follows: the method of the present invention uses two double-sided copper-clad laminates and a double-sided flexible laminate in a laminated manner, and sets the double-sided flexible laminate between the two double-sided copper-clad laminates. First, the circuits on both sides of the double-sided flexible laminate are made as inner circuits, and protective films are applied to them respectively; then, the inner circuits of the two double-sided copper-clad laminates are made respectively, and PP material is used as the inter-board dielectric layer between the flexible laminate and the hard laminate to fill the inner single-sided circuit of the double-sided copper-clad laminate. The inner dielectric layer FR4 of the two double-sided copper-clad laminates is laser-controlled deep-cut along the inner single-sided circuit toward the outer copper foil layer. Finally, the outer circuit layer of the two double-sided copper-clad laminates is made, the copper foil in the pre-opening area is etched away, and then the cover and gong shape are performed along the exposed laser cutting seam. This method can reduce the difficulty of production, effectively reduce the thickness of the product, improve the flatness of the hard board area, and meet customer needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for manufacturing a six-layer rigid-flex PCB according to the present invention;

[0025] Figure 2 Schematic diagram of the double-sided flexible board structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the double-sided flexible board after laminating the cover film layer in the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of the inner side circuit of the double-sided copper clad laminate after the process in the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the double-sided copper clad laminate after laser reverse cutting on the inner side of the laminate in the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the rigid-flex board substrate after composite construction in the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of the outer circuit of the double-sided copper clad laminate after the process in the present invention;

[0031] Figure 8 This is a schematic diagram of the finished product structure of the rigid-flex board after the cover is removed in the present invention.

[0032] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0033] L1~L6, circuit layer, PI, inner dielectric layer of double-sided flexible board, PP23 / PP45, inter-board dielectric layer, FR4, inner dielectric layer of double-sided copper clad board, C3 / C4, cover film layer. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] like Figure 1 FIG. 1 is a flow chart of a method for manufacturing a six-layer rigid-flex PCB provided in this embodiment. Figure 8 Figure 3 is a schematic diagram of the finished structure of a rigid-flex PCB manufactured using the method of this embodiment. L1 to L6 are circuit layers, PI is the intra-board dielectric layer of the double-sided flexible PCB, PP23 and PP45 are the inter-board dielectric layers between the double-sided flexible PCB and the two double-sided copper-clad laminates, C3 and C4 are the cover film layers attached to the circuit layers on both sides of the double-sided flexible PCB, and the two FR4s are the intra-board dielectric layers of the two double-sided copper-clad laminates.

[0036] like Figure 1 As shown, the present embodiment provides a method for manufacturing a six-layer rigid-flex PCB, including:

[0037] S1, set a double-sided soft board as the inner soft board and set two double-sided copper clad boards as the outer hard boards.

[0038] like Figure 8 As shown in the finished product structure diagram, after the rigid-flex board is completed, the double-sided flexible board is located in the middle layer, and the two double-sided copper clad boards are located on the outside of the circuit layers on both sides of the double-sided flexible board.

[0039] S2, such as Figures 2-3 As shown, circuit layers L3 / L4 are respectively made on both sides of the double-sided flexible circuit board, and covering film layers C3 / C4 are respectively provided on the circuit layers L3 / L4 on both sides of the double-sided flexible circuit board;

[0040] The cover film layer C3 / C4 serves as a protective layer on the circuit layers L3 / L4 on both sides of the double-sided flexible board, covering the circuits on the circuit layers L3 / L4 to prevent the circuits on the flexible board from being corroded by the chemicals in the subsequent circuit process of the rigid board.

[0041] S3, such as Figure 4 As shown, circuit layers L2 / L5 are respectively made on the copper foil on the inner side of the two double-sided copper clad laminates, and the surface copper of the pre-opened area on the copper foil is etched away to expose the dielectric layer FR4 inside the double-sided copper clad laminate. The inner side refers to the side of the double-sided copper clad laminate facing the double-sided flexible board, for example Figure 8 Line layer L2 / L5;

[0042] Circuit layers L2 / L5 are first created on the inner copper foil of the double-sided copper-clad laminate to prepare for the subsequent substrate lamination process. Etching away the copper foil in the pre-opened areas of circuit layers L2 / L5 prepares for subsequent laser depth-controlled cutting. Laser cutting machines are known for their ease in cutting FR4 but difficulty in cutting copper foil. Therefore, etching away the copper foil on the surface of the FR4 prior to cutting increases the accuracy of laser depth-controlled cutting, facilitating the cutting process and achieving optimal results.

[0043] S4, such as Figure 5 As shown, the dielectric layer FR4 inside the double-sided copper clad laminate is laser cut from the edge of the pre-opened area along the inner circuit layer L2 / L5 of the two double-sided copper clad laminates, and 3-5 connection points (for example, 5mm long connection positions) are retained on the cutting route. The connection positions are in the waste area of ​​the product (which can be removed through subsequent gong-shaped processes), and the cutting depth is the thickness of the dielectric layer FR4 inside the double-sided copper clad laminate.

[0044] In this step, the inner dielectric layer FR4 of the double-sided copper-clad laminate is first cut in reverse, retaining the single-sided copper foil on the outer layer of the double-sided copper-clad laminate. This operation facilitates the subsequent wiring process of the outer layer circuit boards L1 / L6 and reduces the difficulty of gong-forming the cover opening area. During gong-forming, the gong machine only needs to cut each connection point to remove the waste material in the cover opening area.

[0045] S5, such as Figure 6 As shown, inter-board dielectric layers PP23 / PP45 are respectively arranged between the double-sided flexible board and the two outer circuit boards (i.e., double-sided copper-clad boards) and substrate composite is performed, and the inter-board dielectric layer PP23 / PP45 is provided with windows corresponding to the pre-opening area.

[0046] Specifically, the outer copper foil of the lower double-sided copper-clad laminate (corresponding to the subsequent circuit layer L6) is first positioned downward. An inter-board dielectric layer PP45 is placed between the circuit layer L5 of this double-sided copper-clad laminate and the cover film layer C4 of the double-sided flexible printed circuit board. The openings in the inter-board dielectric layer PP45 are aligned with the pre-opened areas on the circuit layer L4 of the double-sided flexible printed circuit board. The cover film layer C4 of the double-sided flexible printed circuit board, the inter-board dielectric layer PP45, and the circuit layer L5 of the double-sided copper-clad laminate are then laminated to form a single component. Similarly, the double-sided flexible printed circuit board is laminated to another double-sided copper-clad laminate. An inter-board dielectric layer PP23 is placed between the cover film layer C3 of the double-sided flexible printed circuit board and the circuit layer L2 of another double-sided copper-clad laminate. The openings in the inter-board dielectric layer PP23 are aligned with the pre-opened areas on the circuit layer L3 of the double-sided flexible printed circuit board. The double-sided flexible PCB's cover film layer C3, inter-board dielectric layer PP23, and circuit layer L2 of the double-sided copper-clad laminate are then laminated together to form a single, integrated structure. It's worth noting that because the inter-board dielectric layers PP23 and PP45 are made of semi-cured polypropylene, which exhibits a certain degree of fluidity, during the lamination process, the inter-board dielectric layer PP23 fills the circuit layer L2 of the double-sided copper-clad laminate, while the inter-board dielectric layer PP45 fills the circuit layer L5 of the double-sided copper-clad laminate. Simultaneously, the inter-board dielectric layers PP23 and PP45 adhere to the laser-cut gaps in the inner dielectric layer FR4 of the double-sided copper-clad laminate. This prevents the etching process for the outer circuit layers L1 / L6 from causing corrosion damage to the inner circuit layers L2 / L3 / L4 / L5. Furthermore, the slightly weaker strength of PP material compared to FR4 does not affect the subsequent gong-shaped process.

[0047] S6, such as Figure 7 As shown, the circuit layer L1 / L6 is made on the copper foil on the outer side of the double-sided copper clad laminate, and the copper foil of the laser cutting seam is etched away. The cover is opened along the laser cutting seam to remove the waste material in the pre-opening area. The structure of the soft-rigid combination board after the cover is opened is as shown Figure 8 shown.

[0048] This step, after the substrate lamination process, involves the outermost circuit processing of the rigid-flex board. During this process, the copper foil corresponding to the laser-cut seams on the circuit layers L1 / L6 is etched away, exposing the connection points of the laser-cut seams and the PP adhesive filled during the substrate lamination process. A gong machine is used to gong the connection points and the PP adhesive filling the laser-cut seams, removing the waste material from the pre-opening area and completing the opening process. Finally, the entire process is completed by printing ink, gold plating, text, and the gong shape as required.

[0049] The method of this embodiment uses two double-sided copper-clad laminates and a double-sided flexible laminate in a stacked manner, with the double-sided flexible laminate placed between the two double-sided copper-clad laminates. First, the two-sided circuits L3 / L4 of the double-sided flexible laminate are made as inner circuits, and the protective film C3 / C4 is attached. Then, the inner circuits L2 / L5 of the two double-sided copper-clad laminates are made separately. PP material is used as the inter-board dielectric layer between the flexible and rigid laminates to fill the single-sided circuits L2 / L5 of the double-sided copper-clad laminates. The inner dielectric layer FR4 of the two double-sided copper-clad laminates is laser-deep-cut along the circuit layer L2 / L5. Finally, the outer circuits L1 / L6 of the two double-sided copper-clad laminates are made, the copper foil in the pre-opened area is etched away, and then the cover and gong shape are performed along the exposed laser-cut seam. This method can reduce production difficulty, effectively reduce product thickness, improve the flatness of the rigid board area, and meet customer needs.

[0050] Based on the above technical solution, this embodiment can also be improved as follows.

[0051] In this embodiment, the intermediate dielectric layer (PI) of the double-sided flexible board utilizes 20 μm thick PI (Polyimide), a new high-temperature-resistant thermosetting engineering plastic with excellent electrical insulation, wear resistance, high-temperature radiation resistance, and physical and mechanical properties. Both circuit layers (L3 / L4) on both sides of the double-sided flexible board are constructed from 1 / 3 oz Cu, significantly reducing the overall thickness of the rigid-flex board while meeting the required electrical performance.

[0052] In this embodiment, the intermediate dielectric layer FR4 of the double-sided copper clad laminate is 2mil FR4, and the copper foil layers on both sides of the double-sided copper clad laminate are made of 1 / 3oz Cu. The intermediate dielectric layer FR4 of the double-sided copper clad laminate is made of FR4, a glass fiber epoxy resin composite material with advantages such as stable electrical insulation performance, good flatness, a smooth surface, no pits, and standard thickness tolerance. It is suitable for use in products requiring high-performance electronic insulation. The copper foil layers on both sides of the double-sided copper clad laminate are made of 1 / 3oz Cu. While meeting the electrical performance requirements of the circuit board, it can significantly reduce the overall thickness of the flexible and rigid combination board, meeting customer requirements.

[0053] In this embodiment, step S2 further includes: opening windows in areas corresponding to the pads on the cover film layer C3 / C4 on the double-sided flexible circuit board, so that the circuits in the windowed areas of the pads are exposed.

[0054] like Figure 3 As shown in the figure, some rigid-flex boards have pads on the cover area of ​​the flexible board for electrical connection with peripherals. Figure 3As shown, when applying cover film layer C3 to the circuit layer L3 of a double-sided flexible circuit board, the window openings on cover film layer C3 corresponding to the pads must be aligned with the pads, so that the pads are exposed after the film is applied. At the same time, cover film layer C3 must cover the remaining circuits on circuit layer L3 to prevent damage from subsequent processing and thus extend the product's service life.

[0055] In this embodiment, step S2 further includes: after the cover film layers C3 / C4 of the double-sided flexible circuit board are set, measuring the expansion and contraction data of the double-sided flexible circuit board, and calculating the drilling parameters of the two double-sided copper-clad laminates and the processing parameters of the inter-board dielectric layer PP23 / PP45 based on the expansion and contraction data. After the cover film layers C3 / C4 are filled with the circuit layers L3 / L4 of the double-sided flexible circuit board, the expansion and contraction rates of different double-sided flexible circuit boards vary due to differences in the circuit layers. The different expansion and contraction data will affect the overall thickness of the finished rigid-flex circuit board, thereby affecting the parameters of subsequent processes, such as the drilling depth of the circuit board. For example, to achieve the predetermined thickness of the rigid-flex circuit board, the expansion and contraction data of the cover film layers C3 / C4 is also required to determine the thickness of the inter-board dielectric layer PP23 / PP45 to be used.

[0056] In this embodiment, based on the expansion and contraction data obtained in step S2, in step S5, the material and thickness parameters of the inter-board dielectric layer PP23 / PP45 are set according to the processing parameters of the inter-board dielectric layer PP23 / PP45, and the circuit layers L3 / L4 on both sides of the double-sided flexible board and the covering film layers C3 / C4 thereof are respectively composited with the two double-sided copper clad laminates for substrates.

[0057] In this embodiment, in step S4, the laser cutting direction is from the circuit side of the double-sided copper clad laminate to the copper foil side, that is, in one double-sided copper clad laminate, laser-controlled depth cutting is performed from its circuit layer L2 to its circuit layer L1, and in another double-sided copper clad laminate, laser-controlled depth cutting is performed from its circuit layer L5 to its circuit layer L6; the cutting depth is to completely cut through the inner dielectric layer FR4 of the double-sided copper clad laminate and retain the single-sided copper foil (corresponding to the circuit layer L1 / L6), and at least one connection point is retained in the cutting route to prevent the inner dielectric layer FR4 of the pre-opening area from falling off when the circuit process of the outermost circuit layer L1 / L6 is performed, causing the solution to enter the inner circuit layer and corrode the circuit layer L2 / L5 and the solder pads on the flexible circuit board.

[0058] To achieve optimal laser cutting results and facilitate the subsequent gong-shaped process, the laser cutting width is set to less than 0.15mm. At this cutting width, the PP adhesive in the PP23 / PP45 inter-board dielectric layer effectively fills and adheres to the laser-cut gaps during the substrate lamination process. The copper-free waste area of ​​the double-sided copper-clad laminate covers the pre-opened area of ​​the FPC, protecting it and preventing liquid chemicals from entering the circuit board during the subsequent outer layer process.

[0059] Because the flexible board area has solder pad windows, if not properly protected, the adhesive can seep into the board through the laser-cut gaps and corrode the internal circuitry. Therefore, in this embodiment, in step S5, to ensure sufficient PP adhesive to fill and seal the laser-cut gaps during the substrate lamination process, the edges of the cut area of ​​the inter-board dielectric layer PP23 / PP45 are extended 0.2mm toward the center of the pre-opened area. This measure will result in a 0.2mm expansion of the rigid board area's edges in the product's appearance. Because the rigid board area has an adhesive overflow requirement of less than 0.5mm, this 0.2mm expansion is a lamination requirement.

[0060] In this embodiment, based on the expansion and contraction data and drilling parameters obtained in step S2, step S6 further includes drilling holes in the double-sided copper-clad laminate and / or double-sided flexible printed circuit board according to the drilling parameters. The drilling process is completed after the substrate is laminated. After the drilling process is completed, copper plating and etching of the outer layer circuits are sequentially performed to complete the circuit processing of the outermost circuit layer L1 / L6. Finally, ink printing, gold plating, text, and gong shape are performed as required to complete the entire rigid-flex board manufacturing process.

[0061] The method of this embodiment utilizes two double-sided copper-clad laminates and a double-sided flexible laminate, with the flexible laminate positioned between the two double-sided copper-clad laminates. First, the double-sided circuits L3 / L4 of the flexible laminate are fabricated as inner circuits, and protective films C3 / C4 are applied to them. Next, the inner circuits L2 / L5 of the two double-sided copper-clad laminates are fabricated. PP material PP23 / PP45 is used as the inter-board dielectric layer between the flexible and rigid laminates to fill the single-sided circuits L2 / L5 of the double-sided copper-clad laminates. Laser-controlled depth-reverse cutting is performed on the inner dielectric layers FR4 of the two double-sided copper-clad laminates along the circuit layers L2 / L5. Finally, the outer circuits L1 / L6 of the two double-sided copper-clad laminates are fabricated. The copper foil in the pre-opened area is etched away, and the cover and gong are then removed along the exposed laser-cut seams. This method reduces production complexity, effectively reduces product thickness, and improves the flatness of the rigid laminate area, meeting customer needs. Since there are pad windows in the FPC area of ​​the pre-opened cover, if the protection is not good, the liquid will seep into the circuit during the circuit process of the outermost circuit board L1 / L6 and corrode the circuit. Therefore, during the substrate compounding process, PP material is used to fill the laser cutting seam to prevent the liquid from entering the FPC area, thus effectively protecting the pads.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a six-layer rigid-flex board, characterized in that: include: S1, set a double-sided soft board as the inner soft board and set two double-sided copper-clad boards as the outer hard boards; S2, manufacturing circuit layers on both sides of the double-sided flexible board respectively, and providing covering film layers on the circuit layers on both sides of the double-sided flexible board respectively; S3, making a circuit layer on the copper foil on the inner side of the double-sided copper clad laminate, and etching away the surface copper of the pre-opened area on the copper foil to expose the inner dielectric layer of the double-sided copper clad laminate, wherein the inner side refers to the side facing the double-sided flexible board; S4, laser cutting the dielectric layer inside the double-sided copper clad laminate along the edge of the pre-opened cover area from the inner side of the double-sided copper clad laminate, and retaining the connection points, and the cutting depth is the thickness of the dielectric layer inside the double-sided copper clad laminate; S5, respectively setting an inter-board dielectric layer between the double-sided flexible board and the two outer circuit boards and performing substrate lamination, wherein the inter-board dielectric layer is provided with a window corresponding to the pre-opened cover area; during the substrate lamination process, the inter-board dielectric layer will fill the circuit layer of the double-sided copper clad board, and the inter-board dielectric layer will fill and adhere to the laser cutting gap of the inner dielectric layer of the double-sided copper clad board; S6, making a circuit layer on the copper foil on the outer side of the double-sided copper clad laminate, etching away the copper foil of the laser cut seam, and opening the cover in a gong shape along the laser cut seam to remove waste in the pre-opening area.

2. According to claim 1, a method for manufacturing a six-layer rigid-flexible board is characterized in that: The middle dielectric layer of the double-sided soft board is 20um PI, and the circuit layers on both sides of the double-sided soft board are made of 1 / 3oz Cu.

3. A method for manufacturing a six-layer rigid-flex PCB according to claim 1 or 2, characterized in that: The middle dielectric layer of the double-sided copper clad laminate is 2mil FR4, and the copper foil layers on both sides of the double-sided copper clad laminate are made of 1 / 3oz Cu.

4. According to claim 1, a method for manufacturing a six-layer rigid-flexible board is characterized in that: Step S2 also includes: opening a window in the area corresponding to the pad on the cover film layer, so that the circuit in the window area of ​​the pad is exposed.

5. According to the method for manufacturing a six-layer rigid-flex PCB as claimed in claim 1, it is characterized in that: Step S2 also includes: after the cover film layer of the double-sided flexible board is set, measuring the expansion and contraction data of the double-sided flexible board, and calculating the drilling parameters of the two double-sided copper clad boards and the processing parameters of the inter-board dielectric layer according to the expansion and contraction data.

6. The method for manufacturing a six-layer rigid-flex PCB according to claim 5, characterized in that: In step S5, the material and thickness parameters of the inter-board dielectric layer are set according to the processing parameters of the inter-board dielectric layer, and the circuit layers on both sides of the double-sided flexible board are respectively laminated with the two double-sided copper-clad laminates.

7. The method for manufacturing a six-layer rigid-flex PCB according to claim 1, characterized in that: In step S4, the laser cutting direction is from the circuit side of the double-sided copper clad laminate to the copper foil side, the cutting depth is to completely cut through the inner dielectric layer of the double-sided copper clad laminate and retain the single-sided copper foil, and at least one connection point is retained in the cutting route.

8. A method for manufacturing a six-layer rigid-flex PCB according to claim 7, characterized in that: Laser cutting width <0.15mm.

9. The method for manufacturing a six-layer rigid-flex PCB according to claim 1, characterized in that: In step S5, the edge of the cutting area of ​​the inter-board dielectric layer extends 0.2 mm toward the center of the pre-covering area.

10. A method for manufacturing a six-layer rigid-flex PCB according to claim 5, characterized in that: Step S6 also includes drilling holes in the double-sided copper clad laminate and / or the double-sided flexible laminate according to the drilling parameters.

Images