A rigid-flex board with plug-in holes and a manufacturing method thereof

Abstract

The present invention discloses a method for manufacturing a rigid-flexible board with plug-in holes, the manufacturing method comprising: providing an outer rigid board to be pressed, a plurality of inner flexible boards, and a plurality of semi-cured sheets; wherein the plurality of inner flexible boards comprise a flexible board copper layer and a flexible board polyimide layer, the flexible board copper layer undergoes a first windowing process at the plug-in hole, and the flexible board polyimide layer undergoes a second windowing process at the plug-in hole; the outer rigid board, the plurality of inner flexible boards, and the plurality of semi-cured sheet layers undergo a pressing process to obtain a pressed rigid-flexible board; the pressed rigid-flexible board undergoes a post-processing process in sequence to obtain a rigid-flexible board with plug-in holes. The present invention performs two different windowing processes on the inner flexible board, so that the semi-cured sheet layer can flow into the corresponding windowing hole, thereby reducing the performance difference of the materials, thereby effectively solving the problem of copper nodules and improving the processing quality.

Description

Technical Field

[0001] The present invention relates to the field of circuit boards, and in particular to a method for manufacturing a rigid-flexible board with an insert hole and the rigid-flexible board with an insert hole. Background Art

[0002] At present, a rigid-flexible board with multiple layers of flexible boards (or flexible boards), that is, a rigid-flexible board with multiple circuit layers (i.e., copper layers) on the flexible board layer is called a rigid-flexible board with multiple flexible board layers; wherein, the flexible board layer can also be subdivided into a copper layer and a dielectric layer, wherein the dielectric layer is generally a polyimide material layer.

[0003] In the prior art, in the process steps of manufacturing a rigid-flexible board with multiple flexible board layers, the dielectric layer finally located in the multiple flexible board layers, in addition to the polyimide material layer, also includes a pure adhesive layer (i.e., an epoxy resin layer without glass fiber) to ensure the flexural performance of the flexible board. The dielectric layer material of the flexible board layer is the material layer covering the entire board surface, that is, the corresponding rigid board area is also covered with the same pure adhesive layer material.

[0004] According to the conventional setup described above, the dielectric layer in the rigid board area of ​​a rigid-flex board with multiple flexible layers includes the epoxy-glass resin dielectric layer of the copper-clad laminate, the pure adhesive layer dielectric layer (an epoxy resin layer without glass fiber), and the polyimide dielectric layer. Therefore, the dielectric layers in the rigid board area exhibit diversity. For rigid-flex boards with multiple flexible layers that require plug-in holes in the rigid board area, due to the diversity of the inherent dielectric layer materials, during the processing from drilling to electroplating, when the drilled holes need to be desmeared after drilling, different materials have different tolerances to the desmearing process. This may result in sufficient desmearing of the pure adhesive layer but insufficient desmearing of the polyimide layer, or sufficient desmearing of the polyimide layer but insufficient desmearing of the pure adhesive layer. This can easily lead to copper nodules in the electroplating process, seriously affecting the electroplating quality.

[0005] At present, the desmearing process is generally changed from chemical desmearing to plasma desmearing. However, the improvement effect of plasma desmearing is not obvious, but it increases the processing cost.

[0006] Therefore, based on the above problems, it is necessary to provide a rigid-flex board with plug-in holes and a manufacturing method thereof to improve the problem of copper nodules in the prior art. Summary of the Invention

[0007] The main purpose of the present invention is to provide a rigid-flexible board with plug-in holes and a manufacturing method thereof, aiming to solve the problem that the existing rigid-flexible board with plug-in holes is prone to copper nodules due to the inconsistent tolerance of different materials to the desmear processing process.

[0008] To achieve the above-mentioned object, the present invention proposes a method for manufacturing a rigid-flex board with plug-in holes, the manufacturing method comprising:

[0009] providing an outer rigid plate to be pressed;

[0010] Providing a plurality of inner-layer flexible boards to be laminated, wherein the plurality of inner-layer flexible boards include a flexible board copper layer and a flexible board polyimide layer, the flexible board copper layer undergoes a first windowing process at the plug-in hole, and the flexible board polyimide layer undergoes a second windowing process at the plug-in hole;

[0011] Providing a plurality of prepregs to be laminated, wherein the plurality of prepregs undergo a third windowing process in the bending region of the rigid-flexible board to form a first prepreg layer located between the inner flexible boards and a second prepreg layer located between the inner flexible board and the outer rigid board, placing a pure adhesive layer in the windowing region of the first prepreg layer, and placing a polyimide layer with a pure adhesive layer in the windowing region of the second prepreg layer;

[0012] Performing a lamination process on the outer rigid board, the plurality of inner flexible boards, and the plurality of prepreg layers to obtain a laminated rigid-flex board;

[0013] The laminated rigid-flex board is subjected to subsequent post-processing to obtain a rigid-flex board with plug-in holes.

[0014] Furthermore, the first window opening process is an etching window opening process, and the second window opening process is a laser ablation window opening process.

[0015] Furthermore, the step of performing a first windowing process on the copper layer of the flexible board at the plug-in hole includes:

[0016] The flexible board copper layer is sequentially processed by lamination, exposure, and etching processes to obtain a window pattern of the flexible board copper layer at the plug-in hole; wherein, the window pattern of the flexible board copper layer is a first circle, and the diameter of the first circle is smaller than the diameter of the plug-in hole, wherein, assuming that the diameter of the plug-in hole is d, the diameter of the first circle is D, and 0.4mm≤dD≤4.0mm.

[0017] Furthermore, the step of performing a second windowing process on the polyimide layer of the flexible board at the plug-in hole includes:

[0018] The flexible board polyimide layer is subjected to a laser ablation process according to the window pattern, and the window pattern of the flexible board polyimide layer is obtained at the plug-in hole; wherein, the window pattern of the flexible board polyimide layer includes a laser ablation area and a reserved area, and the laser ablation area and the reserved area are alternately arranged to form a second circle, and the diameter of the second circle is greater than the diameter of the plug-in hole, wherein, assuming that the diameter of the plug-in hole is d, the diameter of the second circle is H, 1.0mm≤Hd≤4.0mm.

[0019] Furthermore, the shape of the laser ablation area is a triangle, a trapezoid or a rectangle.

[0020] Furthermore, one end of the pattern of the laser ablation area is located at the edge of the second circle, and the other end extends to the edge of the first circle.

[0021] Furthermore, the step of placing a polyimide layer with a pure adhesive layer in the window area of ​​the second prepreg layer includes:

[0022] A polyimide layer with a pure adhesive layer is placed in the window area of ​​the second prepreg layer; wherein the polyimide layer is adjacent to the outer rigid board, and the pure adhesive layer is adjacent to the inner flexible board.

[0023] Furthermore, the outer rigid board comprises a double-sided copper layer and an epoxy resin-glass fiber dielectric layer located between the double-sided copper layers, wherein the glue content of the prepreg is within a range of 10% of the glue content of the epoxy resin-glass fiber dielectric layer of the outer rigid board.

[0024] Furthermore, the pure adhesive layer is an epoxy resin layer that does not contain glass fiber.

[0025] To achieve the above-mentioned object, the present invention proposes a rigid-flex board with an insert hole, and the rigid-flex board with an insert hole is manufactured by the above-mentioned manufacturing method.

[0026] In the technical solution of the present invention, the present invention provides a method for manufacturing a rigid-flexible board with plug-in holes. By performing two different window opening treatments on the inner flexible board, the semi-cured sheet layer can flow into the corresponding window opening holes, thereby reducing the performance difference of the materials, thereby effectively solving the problem of copper nodules and improving the processing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 Schematic diagram of the process flow of a method for manufacturing a rigid-flex board with plug-in holes according to the present invention;

[0029] Figure 2 This is a structural schematic diagram of a rigid-flex board with a plug-in hole according to the present invention;

[0030] Figure 3 This is a schematic structural diagram of a rigid-flex board with plug-in holes to be pressed together according to the present invention;

[0031] Figure 4 For the present invention Figure 3 Schematic diagram of the structure of a window in the polyimide layer of the flexible board;

[0032] Figure 5 For the present invention Figure 3 Schematic diagram of the structure of another window in the polyimide layer of the flexible board;

[0033] Figure 6 This is a schematic structural diagram of a rigid-flex board with a plug-in hole after being pressed together according to the present invention;

[0034] Figure 7 The figure is a schematic structural diagram of a rigid-flex board with plug-in holes after drilling.

[0035] Description of Figure Numbers:

[0036] Label name Label name 100 Rigid-flex PCB with plug-in holes 101 Plug-in hole 110 Outer rigid plate 101A Second circle 111 Rigid board copper layer 120 Inner flexible board 112 Epoxy-fiberglass dielectric layer 121 Flexible board copper layer 130 Prepreg 122 Polyimide layer of flexible board 131 First prepreg layer A bendable area 132 Second prepreg layer B Reserved Area 133、134 Pure adhesive layer C Laser ablation area 135 Polyimide layer / /

[0037] 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

[0038] 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.

[0039] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between 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.

[0040] 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.

[0041] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] 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.

[0043] In the prior art, the typical manufacturing process for ordinary circuit boards includes: cutting; inner layer pattern processing (pre-processing micro-etching, laminating the photosensitive layer, exposure, development, etching, and stripping); layout and lamination; drilling; electroplating (copper deposition, board electroplating); outer layer pattern processing; pattern electroplating; solder mask processing; surface treatment; molding; electrical testing; FQC appearance inspection; packaging; and shipping. The rigid-flex PCB manufacturing method of this embodiment focuses on the layout and lamination process.

[0044] Please refer to Figure 1 and Figure 2 , Figure 1 Schematic diagram of the process flow of a method for manufacturing a rigid-flex board with plug-in holes according to the present invention; Figure 2 The figure is a structural schematic diagram of a rigid-flex board with plug-in holes according to the present invention.

[0045] like Figure 2 As shown, the rigid-flex board 100 with plug-in holes in this embodiment is composed of Figure 1The rigid-flex board 100 with an insert hole comprises, from the inside to the outside, a plurality of inner flexible boards 120 and a first prepreg layer 131 located between the inner flexible boards 120, two outer rigid boards 110 and a second prepreg layer 132 located between the outer rigid boards 110 and the inner flexible boards 120, a welding layer 140 located outside the two outer rigid boards 110, and an insert hole 101 that penetrates the welding layer 140, the outer rigid boards 110, and the inner flexible boards 120. The rigid-flex board 100 with an insert hole further comprises a bending region A.

[0046] Please also refer to Figures 1 to 7 The steps of the manufacturing method of a rigid-flex board with plug-in holes of the present invention specifically include:

[0047] Step S10: providing an outer rigid plate to be pressed.

[0048] like Figure 3 As shown, in this embodiment, outer rigid boards 110 are provided for lamination. These are the rigid boards on the outer sides of the rigid-flex board. The outer rigid boards to be lamination are already pre-wired. For example, the upper and lower rigid boards 110 (circuitry not shown) are shown in the figure.

[0049] Specifically, the outer rigid board 110 is a double-sided board, consisting of a double-sided copper layer 111 and an epoxy resin-glass fiber dielectric layer 112 positioned between the double-sided copper layers 111. The epoxy resin-glass fiber dielectric layer 112 has a 55% adhesive content. In other embodiments, the outer rigid board 110 can also be a single-layer rigid board or a multi-layer rigid board. This is not a limitation here, and the outer double-sided board is used as an example for description.

[0050] Step S20: providing a plurality of inner-layer flexible boards to be pressed together, wherein the plurality of inner-layer flexible boards include a flexible board copper layer and a flexible board polyimide layer, the flexible board copper layer undergoes a first windowing treatment at the plug-in hole, and the flexible board polyimide layer undergoes a second windowing treatment at the plug-in hole.

[0051] In this embodiment, three inner flexible boards 120 are provided for lamination. In other embodiments, the number of inner flexible boards 120 may be two, four, or more. This is not a limitation and is described using three inner flexible boards 120 as an example. The inner flexible boards 120 to be laminarized are already pre-wired inner flexible boards.

[0052] The inner flexible board 120 includes a flexible board copper layer 121 and a flexible board polyimide layer 122. The flexible board copper layer 121 undergoes a first windowing process at the plug-in hole 101, and the flexible board polyimide layer 122 undergoes a second windowing process at the plug-in hole 101. The first windowing process is an etching process, and the second windowing process is a laser ablation process.

[0053] Specifically, the step of performing a first windowing process on the flexible copper layer at the plug-in hole includes: sequentially performing film lamination, exposure, and etching on the flexible copper layer to obtain a window pattern on the flexible copper layer at the plug-in hole. The first windowing process can be performed simultaneously with the inner layer patterning process, specifically including pre-processing micro-etching, lamination of a photosensitive layer, exposure, development, etching, and film stripping, thereby obtaining a window pattern on the flexible copper layer. The inner layer patterning process adopts existing circuit board preparation methods and will not be further described here.

[0054] The window pattern of the flexible PCB copper layer 121 is a first circle, and the diameter of the first circle is smaller than the diameter of the plug-in hole. Assuming the diameter of the plug-in hole 101 is d, the diameter of the first circle is D, and 0.4 mm ≤ dD ≤ 4.0 mm. Specifically, the first circle is located in the middle of the plug-in hole 101, so that the radius of the window pattern of the flexible PCB copper layer 121, i.e., each single side is 0.2 mm to 2.0 mm smaller than the plug-in hole, and the entire window diameter is 0.4 mm to 4.0 mm smaller than the diameter of the plug-in hole 101. Generally, the window pattern of the flexible board copper layer 121 is generally circular, matching the plug-in hole 101. The diameter of the copper layer window pattern is generally 0.2mm-2.0mm smaller than the plug-in hole on one side. Therefore, if the plug-in hole is circular, the window pattern of the flexible board copper layer can be circular. In other embodiments, if the plug-in hole is square, the window pattern of the flexible board copper layer is square. These are not listed here. The window pattern can be 0.2mm-2.0mm smaller than the plug-in hole on one side. The window pattern of the flexible board copper layer 121 is set so that the colloid of the upper and lower prepreg layers can be fully and effectively filled into the laser ablation area C of the polyimide layer of the flexible board during the lamination process. If no window is set, the flexible board copper layer blocks the flow of the colloid of the upper prepreg layer.

[0055] Furthermore, the step of performing a second window opening treatment on the flexible board polyimide layer 122 at the plug-in hole 101 includes: performing a laser ablation process on the flexible board polyimide layer 122 according to the window opening pattern to obtain the window opening pattern of the flexible board polyimide layer 122 at the plug-in hole 101; wherein, the window opening pattern of the flexible board polyimide layer 122 includes a laser ablation area C and a reserved area B, and the laser ablation area C and the reserved area B are alternately arranged to form a second circle 101A, and the diameter of the second circle 101A is greater than the diameter of the plug-in hole 101, wherein, assuming the diameter of the plug-in hole 101 is d, the diameter of the second circle 101A is H, 1.0mm≤Hd≤4.0mm.

[0056] like Figure 4 or Figure 5 As shown, a second circular area 101A (or transition zone) is provided on the corresponding polyimide layer 122 of the flexible board. To balance the performance differences between the polyimide layer 122 and the pure adhesive layer, a portion of the polyimide layer is removed from the polyimide layer, forming a laser-ablated area C (i.e., a blank area). During subsequent lamination, the adhesive from the prepreg layer will fill this blank area C, resulting in a partially polyimide and partially prepreg material structure in the corresponding area of ​​the polyimide layer 122 of the flexible board. The laser-ablated area A is the blank area where the polyimide is etched away. The transition zone is generally circular, matching the diameter of the plug-in hole. The circular diameter of the transition zone is generally 0.5mm to 2.0mm larger than the plug-in hole diameter on one side, ensuring that it does not damage nearby circuit patterns. The laser etching "removal" process is produced by laser ablation. After laser ablation, the carbon powder generated by ablation can be removed by cleaning. The cleaning method can be chemical cleaning or plasma cleaning. After cleaning the carbon powder, it can effectively prevent the carbon powder from causing short circuit problems in the circuit.

[0057] Specifically, the shape of the laser ablation area C on the polyimide layer of the flexible board is a triangle (see Figure 4 ), trapezoidal or rectangular (see Figure 5 One end of the laser ablation region C is located at the edge of the second circle 101A, and the other end extends to the edge of the first circle. The outer contour of the second circle 101A (or transition zone), the diameter of the plug-in hole, and the diameter of the copper layer window (i.e., the first circle) are gradually reduced.

[0058] Step S30: providing a plurality of semi-cured sheets to be pressed together, wherein the plurality of semi-cured sheets are subjected to a third windowing process in the bending area of ​​the rigid-flexible board to form a first semi-cured sheet layer located between the inner flexible boards and a second semi-cured sheet layer located between the inner flexible board and the outer rigid board, a pure adhesive layer is placed in the windowing area of ​​the first semi-cured sheet layer, and a polyimide layer with a pure adhesive layer is placed in the windowing area of ​​the second semi-cured sheet layer.

[0059] In this embodiment, the multiple prepregs 130 provided for lamination are epoxy-glass fiber dielectric layers. The adhesive content of the prepregs 130 is within 10% of the adhesive content of the epoxy-glass fiber dielectric layer 112 of the outer rigid board. If the adhesive content of the epoxy-glass fiber dielectric layer 112 is 55%, the adhesive content of the prepregs 130 is 55% ± 10%. Using prepregs instead of pure adhesive layers allows for a more consistent material and performance with the epoxy-glass fiber dielectric layer within the copper-clad laminate, facilitating consistent processing. Limiting the adhesive content of the prepregs to that of the epoxy-glass fiber dielectric layer within the copper-clad laminate further enhances material uniformity and reduces processing issues that can arise from heterogeneous material properties while maintaining consistent processing parameters. Pure adhesive is still used in the flexible board area (and the junction area where the flexible board extends into the rigid board) to ensure flexibility.

[0060] Specifically, each of the semi-cured sheets 130 is subjected to a third windowing process in the bending area A of the rigid-flexible board. The third windowing process is a milling board windowing process, in which the bending area A of the rigid-flexible board is hollowed out, and the width of the hollowed-out window is greater than the width of the actual bendable area; thereby forming a first semi-cured sheet layer 131 located between the inner flexible boards and a second semi-cured sheet layer 132 located between the inner flexible board and the outer rigid board; further, a pure glue layer 133 is placed in the windowing area of ​​the first semi-cured sheet layer 131, and a polyimide layer 135 with a pure glue layer 134 is placed in the windowing area of ​​the second semi-cured sheet layer 132; wherein, the polyimide layer 135 is adjacent to the outer rigid board 110, and the pure glue layer 134 is adjacent to the inner flexible board 120; in this embodiment, the pure glue layer 133 and the pure glue layer 134 are both epoxy resin layers without glass fiber. The adhesive layer 133 becomes a part of the first prepreg layer 131 after being pressed together, and the adhesive layer 134 and the polyimide layer 135 become a part of the second prepreg layer 132 after being pressed together.

[0061] Step S40: performing a lamination process on the outer rigid board, the plurality of inner flexible boards, and the plurality of prepreg layers to obtain a laminated rigid-flex board.

[0062] like Figure 3As shown, with the outer rigid board 110 on the outside and the inner flexible board 120 on the inside, a prepreg and a pure adhesive layer 133 located at the prepreg window are placed between two inner flexible boards 120, and a prepreg and a polyimide layer 135 with a pure adhesive layer 134 located at the prepreg window are placed between the outer rigid board and the inner flexible board 120, wherein the polyimide layer 135 is close to the outer rigid board 110, and the pure adhesive layer 134 is close to the inner flexible board 120. According to the above placement rules, the two outer rigid boards 110, the three inner flexible boards 120 and the four prepreg layers to be laminated are subjected to a lamination process to obtain a laminated rigid-flexible composite board (see Figure 6 ).

[0063] Step S50: performing post-processing on the laminated rigid-flex board in sequence to obtain a rigid-flex board with plug-in holes.

[0064] The laminated rigid-flexible board is subjected to subsequent post-processing to obtain a rigid-flexible board with plug-in holes. The post-processing includes drilling (see Figure 7 The following steps are followed by conventional circuit board manufacturing methods, including debonding, electroplating, outer layer patterning, pattern electroplating, solder mask, surface treatment, and molding, which will not be described in detail here. The molding process includes a cover removal process, ultimately forming a rigid-flex board 100 having an insert hole 101.

[0065] In this embodiment, by replacing the pure adhesive layer 133 material with a semi-cured sheet 130, the performance matching degree of the dielectric layer material in the rigid area is effectively improved, and a transition zone C is set in the polyimide layer 122 corresponding to the position of the plug-in hole 101, and a window pattern is set in the area of ​​the corresponding copper layer 121, so that the colloid of the semi-cured sheet can fully flow into the transition zone C during the pressing process, so that the transition zone C forms a bonding area between the polyimide material and the semi-cured sheet material, reducing the performance difference of the materials, facilitating subsequent drilling and desmearing processing, providing good hole wall basic conditions for electroplating, and effectively preventing the occurrence of copper nodules.

[0066] To sum up, in the technical solution of the present invention, the present invention provides a method for manufacturing a rigid-flexible board with plug-in holes, which performs two different window opening treatments on the inner flexible board, so that the semi-cured sheet layer can flow into the corresponding window opening holes, thereby reducing the performance difference of the materials, thereby effectively solving the problem of copper nodules and improving the processing quality.

[0067] 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 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-flex board with a plug-in hole, characterized in that: The production method comprises: providing an outer rigid plate to be pressed; Providing a plurality of inner-layer flexible boards to be laminated, wherein the plurality of inner-layer flexible boards include a flexible board copper layer and a flexible board polyimide layer, the flexible board copper layer undergoes a first windowing process at the plug-in hole, and the flexible board polyimide layer undergoes a second windowing process at the plug-in hole; The window pattern of the copper layer of the flexible board is a first circle, the diameter of the first circle is smaller than the diameter of the plug-in hole, and the window pattern of the polyimide layer of the flexible board includes a laser ablation area and a reserved area, the laser ablation area and the reserved area are alternately arranged to form a second circle, the diameter of the second circle is larger than the diameter of the plug-in hole; Providing a plurality of prepregs to be laminated, wherein the plurality of prepregs undergo a third windowing process in the bending region of the rigid-flexible board to form a first prepreg layer located between the inner flexible boards and a second prepreg layer located between the inner flexible board and the outer rigid board, placing a pure adhesive layer in the windowing region of the first prepreg layer, and placing a polyimide layer with a pure adhesive layer in the windowing region of the second prepreg layer; Performing a lamination process on the outer rigid board, the plurality of inner flexible boards, and the plurality of prepreg layers to obtain a laminated rigid-flex board; The prepreg is an epoxy resin-glass fiber dielectric layer, and the glue content of the prepreg is within the range of 10% of the glue content of the epoxy resin-glass fiber dielectric layer of the outer rigid board; The laminated rigid-flex board is subjected to subsequent post-processing to obtain a rigid-flex board with plug-in holes.

2. The production method according to claim 1, wherein The first window opening process is an etching window opening process, and the second window opening process is a laser ablation window opening process.

3. The production method according to claim 2, wherein: The step of performing a first windowing process on the copper layer of the flexible board at the plug-in hole comprises: The flexible board copper layer is sequentially processed by lamination, exposure, and etching to obtain a window pattern of the flexible board copper layer at the plug-in hole; wherein, assuming that the diameter of the plug-in hole is d, the diameter of the first circle is D, and 0.4mm≤dD≤4.0mm.

4. The production method according to claim 2, wherein: The step of performing a second windowing process on the polyimide layer of the flexible board at the plug-in hole comprises: The flexible board polyimide layer is laser ablated according to the window pattern to obtain the window pattern of the flexible board polyimide layer at the plug-in hole; wherein, assuming the diameter of the plug-in hole is d, the diameter of the second circle is H, 1.0mm≤Hd≤4.0mm.

5. The production method according to claim 4, characterized in that: The shape of the laser ablation area is triangle, trapezoid or rectangle.

6. The production method according to claim 5, wherein: One end of the pattern of the laser ablation area is located at the edge of the second circle, and the other end extends to the edge of the first circle.

7. The production method according to claim 1, wherein: The step of placing a polyimide layer with a pure adhesive layer in the window area of ​​the second prepreg layer includes: A polyimide layer with a pure adhesive layer is placed in the window area of ​​the second prepreg layer; wherein the polyimide layer is adjacent to the outer rigid board, and the pure adhesive layer is adjacent to the inner flexible board.

8. The production method according to any one of claims 1 to 7, characterized in that: The outer rigid board comprises a double-sided copper layer and an epoxy resin-glass fiber dielectric layer located between the double-sided copper layers.

9. The production method according to claim 8, characterized in that: The pure glue layer is an epoxy resin layer that does not contain glass fiber.

10. A rigid-flex board with a plug-in hole, characterized in that: The rigid-flex board with plug-in holes is manufactured by the manufacturing method according to any one of claims 1 to 9.

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