Printed circuit board and manufacturing method thereof
By setting recesses and conductive materials on the substrate of the printed circuit board, and combining through-hole and back-drilling processing technologies, the problem of residual piles caused by dielectric layer thickness tolerance and drilling depth control tolerance was solved, achieving a zero residual pile effect and improving signal transmission quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN KINWONG ELECTRONICS
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-01
AI Technical Summary
In existing technologies, factors such as the thickness tolerance of the dielectric layer on the printed circuit board and the depth control tolerance of the drilling rig make it impossible to accurately remove residual piles, thus affecting the quality of high-speed signal transmission.
A recess is provided on the substrate of the printed circuit board, and conductive material penetrates the target metal layer. Through holes and back drill holes are processed on the lamination plate. The conductive material provides processing allowance to ensure the complete removal of residual stubs and realize the connection between the target metal layer and the signal line layer.
It achieves a zero-residual-pile effect, improves the quality of high-speed signal transmission, and ensures a stable connection between the target metal layer and the signal line layer.
Smart Images
Figure CN121968476A_ABST
Abstract
Description
Printed Circuit Boards and Their Manufacturing Methods Technical Field
[0001] This application relates to the field of printed circuit board technology, and in particular to a printed circuit board and a method for manufacturing the same. Background Technology
[0002] In the process of manufacturing printed circuit boards (PCBs), in order to improve the transmission quality of high-speed signals, after copper plating and electroplating of the holes, it is often necessary to remove the excess copper on one side of the target copper layer, which is called a stub. Currently, back drilling is commonly used to remove stubs.
[0003] In related technologies, the thickness tolerance of the dielectric layer of the printed circuit board and the depth control tolerance of the drilling rig are limited, making it impossible to remove residual piles with high precision. Summary of the Invention
[0004] This application provides a printed circuit board and a method for manufacturing the same, which can more accurately remove residual stubs and improve signal transmission quality.
[0005] In a first aspect, embodiments of this application provide a method for manufacturing a printed circuit board, comprising: providing a substrate, the substrate including a dielectric layer and a target metal layer stacked thereon, a recessed portion disposed on the substrate, the recessed portion penetrating the target metal layer, the dielectric layer defining a bottom wall of the recessed portion, the diameter of the recessed portion being D1, a conductive material disposed inside the recessed portion, the conductive material being connected to and electrically connected to the target metal layer; sequentially disposing a first connection layer and a first sub-board on the side of the target metal layer opposite to the dielectric layer, and sequentially disposing a second connection layer and a second sub-board on the side of the dielectric layer opposite to the target metal layer, the second sub-board being provided with a signal line layer; and sequentially disposing of the first sub-board, the first connection layer, the substrate, the second connection layer, and the first sub-board... Two sub-boards are laminated to obtain a laminated plate. A through hole is machined on the laminated plate, the through hole penetrating the first sub-board, the first connecting layer, the conductive material, the second connecting layer, and the signal line layer. The through hole is coaxially arranged with the recessed portion, and the diameter of the through hole is D2, which is less than D1. A conductive portion is provided on the inner wall of the through hole, and the conductive material and the signal line layer are electrically connected through the conductive portion. A back-drilled hole is machined on the laminated plate from the side of the first sub-board away from the first connecting layer. The back-drilled hole extends to the conductive material and is coaxially arranged with the recessed portion. The back-drilled hole is connected to the remaining through hole, and the diameter of the back-drilled hole is D3, which is greater than or equal to D2 and less than D1.
[0006] In some embodiments, the recess is an annular blind groove, the outer diameter of the annular blind groove is D1, the inner diameter of the annular blind groove is D0, and D2 is greater than D0.
[0007] In some embodiments, the recess is a blind hole.
[0008] In some embodiments, prior to providing the substrate, the method for manufacturing the printed circuit board further includes: providing a processing board, the processing board including an insulating layer and a base metal layer stacked together; processing the recessed portion on the processing board, the recessed portion penetrating the base metal layer, the base metal layer forming the target metal layer, the insulating layer defining the bottom wall of the recessed portion, the insulating layer forming the dielectric layer; and disposing the conductive material inside the recessed portion to obtain the substrate.
[0009] In some embodiments, after the conductive material is disposed inside the recess, the target metal layer is fabricated to form a target pad, such that a portion of the target metal layer forms a target pad, and the conductive material is connected to the target pad and electrically conductive.
[0010] In some embodiments, when the target metal layer is fabricated, a portion of the target metal layer forms an inner target; when a through hole is machined on the lamination plate, the inner target is used as a reference; when a back-drilled hole is machined on the lamination plate from the side of the first sub-board away from the first connecting layer, the inner target is used as a reference.
[0011] In some embodiments, when the recess is machined on the processing plate, an alignment target is made on the processing plate; when the circuit is fabricated on the target metal layer, the alignment target is used as a reference.
[0012] In some embodiments, when the conductive material is disposed inside the recess, a portion of the conductive material covers the surface of the target metal layer away from the dielectric layer.
[0013] In some embodiments, the step of setting the conductive material inside the recess includes: setting the conductive material inside the recess by deposition or electroplating; or, setting a conductive slurry inside the recess and baking and curing the conductive slurry to form the conductive material.
[0014] Secondly, embodiments of this application provide a printed circuit board, which is manufactured by the printed circuit board manufacturing method described in the first aspect.
[0015] The method for manufacturing a printed circuit board provided in this application has the following advantages: The substrate includes a dielectric layer and a target metal layer stacked together. A recessed portion is provided on the substrate, penetrating the target metal layer. The dielectric layer defines the bottom wall of the recessed portion. The diameter of the recessed portion is D1. A conductive material is disposed inside the recessed portion, and the conductive material is connected to and electrically conductive with the target metal layer. First, a first connection layer and a first sub-board are sequentially disposed on the side of the target metal layer opposite to the dielectric layer. Then, a second connection layer and a second sub-board are sequentially disposed on the side of the dielectric layer opposite to the target metal layer. The second sub-board has a signal line layer. Finally, the first sub-board, the first connection layer, the substrate, the second connection layer, and the second sub-board are laminated to obtain a laminated board. Next, through holes are machined on the laminating plate. The through holes penetrate the first sub-board, the first connecting layer, the conductive material, the second connecting layer, and the signal line layer. The through holes are coaxially arranged with the recessed portion. The diameter of the through holes is D2, which is smaller than D1. Then, conductive parts are set on the inner wall of the through holes. The conductive material and the signal line layer are electrically connected through the conductive parts. Therefore, when back-drilling holes are machined on the laminating plate from the side of the first sub-board away from the first connecting layer, the machining "allowance" provided by the conductive material for the back-drilling holes can ensure that the conductive parts (i.e., residual piles) located on the side of the target metal layer away from the signal line layer are completely removed, and the connection between the target metal layer and the signal line layer through the conductive material is ensured, which can achieve the effect of zero residual piles and improve the quality of high-speed signal transmission.
[0016] The advantages of the printed circuit board provided in this application compared to the prior art can be seen in the description of the advantages of the manufacturing method of the printed circuit board provided in this application compared to the prior art, which will not be repeated here. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 is a flowchart of a printed circuit board manufacturing method in one embodiment of this application; Figure 2 is a structural schematic diagram of a processing board in one embodiment of this application; Figure 3 is a schematic diagram of a recessed portion processed on the processing board shown in Figure 2; Figure 4 is a top view of the processing board shown in Figure 3; Figure 5 is a structural schematic diagram of a substrate obtained by setting conductive material inside the recessed portion of the processing board shown in Figure 3; Figure 6 is a structural schematic diagram of a press-fitted board obtained by pressing the substrate, first sub-board, first connecting layer, substrate, second connecting layer and second sub-board shown in Figure 5; Figure 7 is a schematic diagram of a through hole processed on the press-fitted board shown in Figure 6; Figure 8 is a schematic diagram of a conductive portion provided on the inner wall of the through hole of the press-fitted board shown in Figure 7; Figure 9 is a schematic diagram of a back-drilled hole processed on the press-fitted board from the side of the first sub-board of the press-fitted board away from the first connecting layer shown in Figure 8.
[0019] The markings in the diagram represent the following: 100, lamination plate; 101, processing plate; 1011, insulating layer; 1012, base metal layer; 1013, base circuit layer; 10, substrate; 11, dielectric layer; 12, target metal layer; 13, connection circuit layer; 14, recess; 15, conductive material; 20, first connection layer; 30, first sub-board; 40, second connection layer; 50, second sub-board; 51, signal circuit layer; 60, through hole; 70, conductive part; 80, back drill hole. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0023] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.
[0024] In the process of manufacturing printed circuit boards, in order to improve the transmission quality of high-speed signals, after copper plating and electroplating of the holes, it is often necessary to remove the excess copper on one side of the target copper layer, which is called a stub. Currently, back drilling is commonly used to remove stubs.
[0025] In related technologies, the thickness tolerance of the dielectric layer of the printed circuit board and the depth control tolerance of the drilling rig are limited, making it impossible to remove residual piles with high precision.
[0026] In view of this, this application provides a printed circuit board and a method for manufacturing the same. The substrate includes a dielectric layer and a target metal layer stacked together. A recess is provided on the substrate, penetrating the target metal layer. The dielectric layer defines the bottom wall of the recess. The diameter of the recess is D1. A conductive material is disposed inside the recess, and the conductive material is connected to and electrically conductive with the target metal layer. First, a first interconnect layer and a first sub-board are sequentially disposed on the side of the target metal layer opposite to the dielectric layer. Then, a second interconnect layer and a second sub-board are sequentially disposed on the side of the dielectric layer opposite to the target metal layer. The second sub-board has a signal line layer. Then, the first sub-board, the first interconnect layer, the substrate, the second interconnect layer, and the second sub-board are laminated to obtain a laminated board. A through hole is machined on the laminating plate, penetrating the first sub-board, the first connecting layer, the conductive material, the second connecting layer, and the signal line layer. The through hole is coaxially arranged with the recessed part, and the diameter of the through hole is D2, which is smaller than D1. A conductive part is then provided on the inner wall of the through hole. The conductive material and the signal line layer are electrically connected through the conductive part. Therefore, when a back-drilled hole is machined on the laminating plate from the side of the first sub-board away from the first connecting layer, the machining "allowance" provided by the conductive material for the back-drilled hole can ensure that the conductive part (i.e., the residual stake) located on the side of the target metal layer away from the signal line layer is completely removed, and the connection between the target metal layer and the signal line layer through the conductive material is ensured, achieving the effect of zero residual stake and improving the quality of high-speed signal transmission.
[0027] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.
[0028] Please refer to Figures 1 to 5. In a first aspect, embodiments of this application provide a method for manufacturing a printed circuit board, including: S100: providing a substrate 10, the substrate 10 including a dielectric layer 11 and a target metal layer 12 stacked together, a recess 14 provided on the substrate 10, the recess 14 penetrating the target metal layer 12, the dielectric layer 11 defining the bottom wall of the recess 14, the diameter of the recess 14 being D1, a conductive material 15 disposed inside the recess 14, the conductive material 15 being connected to and electrically conductive with the target metal layer 12.
[0029] The dielectric layer 11 may include resin and glass fiber, etc., and the target metal layer 12 may be made of copper, silver, or aluminum, etc. For example, the substrate 10 may be a copper-clad laminate, etc. The recess 14 may be a blind trench or a blind via, etc. The conductive material 15 may be made of copper, silver, or aluminum, etc.
[0030] It should be noted that the target metal layer 12 is the circuit layer that needs to be connected later.
[0031] S200: Please refer to Figure 6. On the side of the target metal layer 12 away from the dielectric layer 11, a first connection layer 20 and a first sub-board 30 are sequentially provided. On the side of the dielectric layer 11 away from the target metal layer 12, a second connection layer 40 and a second sub-board 50 are sequentially provided. The second sub-board 50 is provided with a signal line layer 51.
[0032] The first connecting layer 20 and the second connecting layer 40 can both be prepregs, etc. The first sub-board 30 and the second sub-board 50 can both be copper foil, double-layer boards, or multi-layer boards, etc. The signal line layer 51 can be made of copper, silver, or aluminum, etc. The first sub-board 30, the first connecting layer 20, the substrate 10, the second connecting layer 40, and the second sub-board 50 can be fused and / or riveted together.
[0033] S300: Press the first sub-board 30, the first connecting layer 20, the substrate 10, the second connecting layer 40, and the second sub-board 50 together to obtain a press-fit plate 100.
[0034] The first sub-board 30, the first connecting layer 20, the substrate 10, the second connecting layer 40, and the second sub-board 50 can be pressed together using a press.
[0035] S400: Please refer to Figure 7 as well. A through hole 60 is machined on the press plate 100. The through hole 60 passes through the first sub-plate 30, the first connecting layer 20, the conductive material 15, the second connecting layer 40 and the signal line layer 51. The through hole 60 is coaxially arranged with the recessed part 14. The diameter of the through hole 60 is D2, and D2 is less than D1.
[0036] Among them, a PCB CNC drilling machine can be used to process through holes 60 on the laminating plate 100, and after processing through holes 60, the glue can be removed.
[0037] S500: Please refer to Figure 8 as well. A conductive part 70 is provided on the inner wall of the through hole 60. The conductive material 15 and the signal line layer 51 are electrically connected through the conductive part 70.
[0038] The conductive part 70 can be provided on the inner wall of the through hole 60 by means of copper plating or electroplating. The material of the conductive part 70 can be copper or the like.
[0039] It is understood that the first sub-board 30 may include an outer circuit layer, a through-hole 60 penetrating the outer circuit layer, and a conductive part 70 connected to and electrically conductive with the outer circuit layer.
[0040] S600: Please refer to Figure 9 as well. A back drill hole 80 is machined on the pressing plate 100 from the side of the first sub-plate 30 away from the first connecting layer 20. The back drill hole 80 extends to the conductive material 15 and is coaxially arranged with the recess 14. The back drill hole 80 is connected to the remaining through hole 60. The diameter of the back drill hole 80 is D3, which is greater than or equal to D2 and less than D1.
[0041] In this process, a PCB CNC drilling machine can be used to process a back drill hole 80 on the laminating plate 100 to remove the conductive part 70 located on the side of the target metal layer 12 away from the signal line layer 51, and at the same time remove the through hole 60 on the side of the target metal layer 12 away from the signal line layer 51. The back drill hole 80 is connected to the remaining through hole 60.
[0042] Due to the presence of conductive material 15, machining allowance is provided when back-drilled holes 80 are machined on the lamination plate 100. The depth of the recess 14 serves as the machining tolerance when back-drilled holes 80 are machined, ensuring that the conductive part 70 (i.e., residual stake) located on the side of the target metal layer 12 away from the signal line layer 51 is completely removed, achieving the effect of zero residual stake. While obtaining a printed circuit board with zero residual stake, it is ensured that the target metal layer 12 is connected to the signal line layer 51 through the remaining conductive material 15, without affecting the conductivity between the target metal layer 12 and the signal line layer 51.
[0043] It is understandable that after the back drill hole 80 is processed on the laminating plate 100 from the side of the first sub-board 30 away from the first connecting layer 20, subsequent processes such as outer layer pattern transfer, solder mask, testing, surface treatment, and appearance inspection can be carried out according to conventional processes to obtain the finished printed circuit board.
[0044] The printed circuit board manufacturing method provided in this application embodiment includes a substrate 10 comprising a dielectric layer 11 and a target metal layer 12 stacked together. A recess 14 is provided on the substrate 10, penetrating the target metal layer 12. The dielectric layer 11 defines the bottom wall of the recess 14. The diameter of the recess 14 is D1. A conductive material 15 is disposed inside the recess 14, and the conductive material 15 is connected to and electrically conductive with the target metal layer 12. First, a first connection layer 20 and a first sub-board 30 are sequentially disposed on the side of the target metal layer 12 facing away from the dielectric layer 11. Then, a second connection layer 40 and a second sub-board 50 are sequentially disposed on the side of the dielectric layer 11 facing away from the target metal layer 12. The second sub-board 50 has a signal line layer 51. Next, the first sub-board 30, the first connection layer 20, the substrate 10, the second connection layer 40, and the second sub-board 50 are laminated to obtain a laminated board 100. A through hole 60 is machined on the press plate 100. The through hole 60 penetrates the first sub-plate 30, the first connecting layer 20, the conductive material 15, the second connecting layer 40, and the signal line layer 51. The through hole 60 is coaxially arranged with the recessed portion 14. The diameter of the through hole 60 is D2, which is smaller than D1. A conductive portion 70 is then provided on the inner wall of the through hole 60. The conductive material 15 and the signal line layer 51 are electrically connected through the conductive portion 70. Therefore, when a back drill hole 80 is machined on the press plate 100 from the side of the first sub-plate 30 away from the first connecting layer 20, the machining "allowance" provided by the conductive material 15 for the back drill hole 80 can ensure that the conductive portion 70 (i.e., the residual stake) located on the side of the target metal layer 12 away from the signal line layer 51 is completely removed. It also ensures that the target metal layer 12 is connected to the signal line layer 51 through the conductive material 15, achieving the effect of zero residual stake and improving the quality of high-speed signal transmission.
[0045] Please refer to Figures 3 to 5. As an implementable method, the recess 14 is an annular blind groove with an outer diameter of D1 and an inner diameter of D0. D2 is greater than D0.
[0046] This configuration allows for a smaller space to be filled when the conductive material 15 is placed in the recess 14, ensuring that the conductive material 15 can completely fill the recess 14 without causing recesses or voids, and without affecting the connection between the target metal layer 12 and the signal line layer 51 through the conductive material 15.
[0047] In other embodiments, the recess 14 is a blind hole.
[0048] With this configuration, when a back-drilled hole 80 is machined on the laminating plate 100 from the side of the first sub-board 30 away from the first connecting layer 20, the conductive material 15 can provide machining "allowance" for the back-drilled hole 80, ensuring that the target metal layer 12 is connected to the signal line layer 51 through the conductive material 15.
[0049] Please refer to Figures 2 to 5. In some embodiments, before providing the substrate 10, the method for manufacturing the printed circuit board further includes: first, providing a processing board 101, which includes an insulating layer 1011 and a base metal layer 1012 stacked together.
[0050] The processing board 101 can be a copper-clad laminate or a multilayer board, etc.
[0051] Next, a recess 14 is machined on the processing plate 101. The recess 14 penetrates the base metal layer 1012. The base metal layer 1012 forms the target metal layer 12. The insulating layer 1011 defines the bottom wall of the recess 14. The insulating layer 1011 forms the dielectric layer 11.
[0052] The recess 14 can be formed by mechanical drilling and milling or laser ablation. For example, the recess 14 can be formed on the processing plate 101 by CFM (Conformal Film Modification) laser engraving or LDD (Laser Direct Drilling) laser engraving.
[0053] In this embodiment, laser drilling is used to process the recess 14. Due to the characteristics of laser processing, the longitudinal section of the recess 14 is usually triangular or trapezoidal (wide opening and narrow bottom), and its depth is smaller than the thickness of the processing plate 101. If other processing methods are used to process the recess 14, the longitudinal section of the recess 14 can also be rectangular or square, without limitation.
[0054] Next, a conductive material 15 is disposed inside the recess 14 to obtain a substrate 10.
[0055] Conductive material 15 can be provided inside the recess 14 by means of copper plating or electroplating. The conductive material 15 is made of copper.
[0056] By adopting the above method, the substrate 10 can be manufactured relatively easily.
[0057] As an implementable method, a conductive material 15 is disposed inside the recess 14, including: disposing the conductive material 15 inside the recess 14 by deposition or hole-filling electroplating.
[0058] This arrangement allows for the convenient placement of conductive material 15 inside the recess 14, and enables the conductive material 15 to completely fill the recess 14.
[0059] As an implementable method, a conductive paste is disposed inside the recess 14 and the conductive paste is baked and cured, so that the conductive paste forms a conductive material 15.
[0060] This arrangement allows for the convenient placement of conductive material 15 inside the recess 14, and enables the conductive material 15 to completely fill the recess 14.
[0061] It should be noted that conductive paste can be printed inside the recess 14, and the conductive paste can be copper paste.
[0062] Optionally, when a conductive material 15 is disposed inside the recess 14, a portion of the conductive material 15 covers the surface of the target metal layer 12 away from the dielectric layer 11.
[0063] This configuration ensures that the thickness of the target metal layer 12 corresponding to the back drill hole 80 meets the usage requirements.
[0064] Optionally, after the conductive material 15 is placed inside the recess 14, the target metal layer 12 is fabricated to form a target pad, so that a portion of the target metal layer 12 forms a target pad, and the conductive material 15 is connected to the target pad and electrically conductive.
[0065] With this setup, circuitry can be fabricated on the target metal layer 12 to obtain the target pads and inner layer circuitry.
[0066] It is understood that the circuitry of the target metal layer 12 can be fabricated through lamination, exposure, development, and etching. When conductive material 15 is placed inside the recess 14, part of the conductive material 15 covers the surface of the target pad facing away from the dielectric layer 11. The size of the recess 14 is smaller than the size of the target pad. The processing board 101 may also include a base circuit layer 1013. When the circuitry of the target metal layer 12 is fabricated, the circuitry of the base circuit layer 1013 is also fabricated simultaneously, and the base circuit layer 1013 forms the connecting circuit layer 13.
[0067] As an implementable method, when fabricating the circuit of the target metal layer 12, a portion of the target metal layer 12 is made into an inner target; when a through hole 60 is machined on the lamination plate 100, the inner target is used as a reference; when a back drill hole 80 is machined on the lamination plate 100 from the side of the first sub-board 30 away from the first connecting layer 20, the inner target is used as a reference.
[0068] This configuration ensures the alignment accuracy of the target pad, through-hole 60, and back drill hole 80.
[0069] It should be noted that using the inner target as a reference can be done by directly using the inner target as a reference, or by first performing X-ray drilling on the inner target to obtain an X-ray target, and then using the X-ray target as a reference. That is, when machining the through hole 60 on the press plate 100 and when machining the back drill hole 80 on the press plate 100 from the side of the first sub-plate 30 away from the first connecting layer 20, the X-ray target is used as a reference.
[0070] Optionally, when the recess 14 is machined on the processing plate 101, an alignment target is made on the processing plate 101; when the circuit is fabricated on the target metal layer 12, the alignment target is used as a reference.
[0071] This configuration ensures the alignment accuracy between the recessed portion 14 and the target pad.
[0072] It should be noted that when the recess 14 is processed on the processing board 101 by laser process, a laser marking target is also made as a positioning target. When the circuit is made on the target metal layer 12, the laser marking target is used as a reference.
[0073] Secondly, embodiments of this application provide a printed circuit board, which is manufactured by the printed circuit board manufacturing method of the first aspect.
[0074] The printed circuit board provided in this application embodiment includes a substrate 10 comprising a dielectric layer 11 and a target metal layer 12 stacked together. A recess 14 is provided on the substrate 10, penetrating the target metal layer 12. The dielectric layer 11 defines the bottom wall of the recess 14. The diameter of the recess 14 is D1. A conductive material 15 is disposed inside the recess 14, and the conductive material 15 is connected to and electrically conductive with the target metal layer 12. First, a first connection layer 20 and a first sub-board 30 are sequentially disposed on the side of the target metal layer 12 facing away from the dielectric layer 11. Then, a second connection layer 40 and a second sub-board 50 are sequentially disposed on the side of the dielectric layer 11 facing away from the target metal layer 12. The second sub-board 50 has a signal line layer 51. The first sub-board 30, the first connection layer 20, the substrate 10, the second connection layer 40, and the second sub-board 50 are then laminated to obtain a laminated board 100. Next, further lamination is performed... A through hole 60 is machined on the laminate 100. The through hole 60 penetrates the first sub-plate 30, the first connecting layer 20, the conductive material 15, the second connecting layer 40, and the signal line layer 51. The through hole 60 is coaxially arranged with the recess 14. The diameter of the through hole 60 is D2, which is smaller than D1. A conductive part 70 is then provided on the inner wall of the through hole 60. The conductive material 15 and the signal line layer 51 are electrically connected through the conductive part 70. Therefore, when a back drill hole 80 is machined on the laminate 100 from the side of the first sub-plate 30 away from the first connecting layer 20, the machining "allowance" provided by the conductive material 15 for the back drill hole 80 can ensure that the conductive part 70 (i.e., the residual pile) located on the side of the target metal layer 12 away from the signal line layer 51 is completely removed. It also ensures that the target metal layer 12 is connected to the signal line layer 51 through the conductive material 15, achieving the effect of zero residual pile and improving the quality of high-speed signal transmission.
[0075] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for manufacturing a printed circuit board, characterized in that, include: A substrate is provided, the substrate including a dielectric layer and a target metal layer stacked thereon, a recess is provided on the substrate, the recess penetrates the target metal layer, the dielectric layer defines the bottom wall of the recess, the diameter of the recess is D1, a conductive material is disposed inside the recess, the conductive material is connected to the target metal layer and is electrically conductive; A first connection layer and a first sub-board are sequentially disposed on the side of the target metal layer opposite to the dielectric layer, and a second connection layer and a second sub-board are sequentially disposed on the side of the dielectric layer opposite to the target metal layer. The second sub-board is provided with a signal line layer. The first sub-board, the first connection layer, the substrate, the second connection layer, and the second sub-board are laminated to obtain a laminated plate. A through hole is processed on the laminated plate, the through hole penetrating the first sub-board, the first connection layer, the conductive material, the second connection layer, and the signal line layer. The through hole is coaxially arranged with the recessed portion, and the diameter of the through hole is D2, which is smaller than D1. A conductive portion is provided on the inner wall of the through hole, and the conductive material is electrically connected to the signal line layer through the conductive portion. A back-drilled hole is machined on the lamination plate from the side of the first sub-board away from the first connecting layer. The back-drilled hole extends to the conductive material and is coaxially arranged with the recessed portion. The back-drilled hole is connected to the remaining through hole. The diameter of the back-drilled hole is D3, which is greater than or equal to D2 and smaller than D1.
2. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The recessed portion is an annular blind groove, the outer diameter of the annular blind groove is D1, the inner diameter of the annular blind groove is D0, and D2 is greater than D0.
3. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The recessed portion is a blind hole.
4. The method for manufacturing a printed circuit board according to any one of claims 1 to 3, characterized in that, Before providing the substrate, the method for manufacturing the printed circuit board further includes: providing a processing board, the processing board including an insulating layer and a base metal layer stacked together; processing the recessed portion on the processing board, the recessed portion penetrating the base metal layer, the base metal layer forming the target metal layer, the insulating layer defining the bottom wall of the recessed portion, the insulating layer forming the dielectric layer; and disposing the conductive material inside the recessed portion to obtain the substrate.
5. The method for manufacturing a printed circuit board according to claim 4, characterized in that, After the conductive material is placed inside the recess, the target metal layer is fabricated to form a target pad, and the conductive material is connected to the target pad and electrically conductive.
6. The method for manufacturing a printed circuit board according to claim 5, characterized in that, When fabricating the circuit of the target metal layer, a portion of the target metal layer forms an inner target; when machining through holes on the laminating plate, the inner target is used as a reference; when machining back drill holes on the laminating plate from the side of the first sub-board away from the first connecting layer, the inner target is used as a reference.
7. The method for manufacturing a printed circuit board according to claim 5, characterized in that, When the recessed portion is machined on the processing plate, an alignment target is made on the processing plate; when the circuit is fabricated on the target metal layer, the alignment target is used as a reference.
8. The method for manufacturing a printed circuit board according to claim 4, characterized in that, When the conductive material is disposed inside the recess, a portion of the conductive material covers the surface of the target metal layer that is away from the dielectric layer.
9. The method for manufacturing a printed circuit board according to claim 4, characterized in that, The provision of the conductive material inside the recess includes: providing the conductive material inside the recess by deposition or electroplating; or, providing a conductive slurry inside the recess and baking and curing the conductive slurry to form the conductive material.
10. A printed circuit board, characterized in that, The printed circuit board is manufactured by the printed circuit board manufacturing method as described in any one of claims 1 to 9.