Method for manufacturing printed circuit board and printed circuit board

Abstract

The application relates to the technical field of printed circuit board manufacturing, and discloses a printed circuit board manufacturing method and a printed circuit board. The printed circuit board manufacturing method comprises the following steps: providing a substrate, the substrate comprising a base material and a conductive layer which are arranged in a laminated mode, the substrate being provided with a blind hole, the blind hole penetrating through the conductive layer and at least part of the base material; electroplating the substrate by using a first current density to obtain a first conductive material, the first conductive material covering the inner hole wall of the blind hole, and the first conductive material covering at least part of the conductive layer; and electroplating the substrate by using a second current density to obtain a second conductive material, the second current density being smaller than the first current density, the second conductive material covering the first conductive material, and the first conductive material and the second conductive material jointly filling the blind hole. The printed circuit board manufacturing method provided by the application is used to solve the problem that the traditional method is difficult to meet the requirements of filling the conductive material in the blind hole and the flatness of the hole.

Description

Technical Field

[0001] This application relates to the field of printed circuit board manufacturing technology, and in particular to a method for manufacturing a printed circuit board and a printed circuit board. Background Technology

[0002] In high-frequency, high-speed printed circuit board (FPC) interconnect applications such as 5G communication, millimeter-wave antennas, and flexible electronics, FPCs are increasingly adopting low-loss materials such as polytetrafluoroethylene (PTFE) and modified polyimide (MPI). These high-frequency substrates possess low dielectric constants, low losses, and good signal transmission performance; however, they exhibit low surface adhesion and poor hole wall wettability. After blind via processing, resin debris, dust, and air bubbles easily remain, posing challenges to subsequent conductivity and electroplating filling.

[0003] Traditional hole-filling methods cannot simultaneously meet the requirements of filling the blind hole with conductive material and making the hole opening flat. If the blind hole depression is too large, it is easy to cause stress concentration cracking or reliability reduction during subsequent processes such as lamination, welding or bending. Summary of the Invention

[0004] This application provides a method for manufacturing a printed circuit board, which solves the problem that traditional methods struggle to simultaneously meet the requirements of filling blind vias with conductive material and ensuring the via openings are flat.

[0005] In a first aspect, embodiments of this application provide a method for manufacturing a printed circuit board, comprising: A substrate is provided, the substrate comprising a substrate and a conductive layer stacked thereon, the substrate having a blind via penetrating the conductive layer and at least a portion of the substrate; The substrate is electroplated using a first current density to obtain a first conductive material, the first conductive material covering the inner wall of the blind hole, and the first conductive material covering at least a portion of the conductive layer; The substrate is electroplated using a second current density to obtain a second conductive material. The second current density is less than the first current density. The second conductive material covers the first conductive material, and the first conductive material and the second conductive material together fill the blind via.

[0006] In some embodiments, prior to electroplating the substrate with a first current density, the method for manufacturing the printed circuit board further includes: The substrate is sent into the shadow line. The shadow line first sprays a hole-forming solution onto the upper and lower sides of the substrate and into the blind hole to adjust the charge on the inner wall of the blind hole. Then, the shadow line sprays a shadow solution onto the upper and lower sides of the substrate and into the blind hole to attach the first graphite carbon to the inner wall of the blind hole. The substrate is flipped over and then sent back into the shadow line. The shadow line sprays a hole-forming solution onto the upper and lower sides of the substrate and into the blind hole to adjust the charge on the inner wall of the blind hole. Then, the shadow line sprays a second graphite carbon onto the inner wall of the blind hole. The substrate is electroplated using a first current density through the first graphite carbon and the second graphite carbon.

[0007] In some embodiments, the conductive layer is provided on both opposite sides of the substrate, and the blind via is provided on both opposite sides of the substrate, the blind via penetrating the corresponding conductive layer and at least a portion of the substrate.

[0008] In some embodiments, prior to electroplating the substrate with a first current density, the method for manufacturing the printed circuit board further includes: The substrate is immersed in an acidic solution for pickling and then subjected to electronic vibration treatment.

[0009] In some embodiments, the electronic vibration is set to pause for 3-5 seconds every 5-7 seconds of operation, with an amplitude of 1-2 cm.

[0010] In some embodiments, the substrate has a bending region, the conductive layer includes a retention portion and an etched portion, the etched portion corresponding to the bending region; after electroplating the substrate with a second current density, the method for manufacturing the printed circuit board further includes: etching away the first conductive material corresponding to the etched portion and the second conductive material corresponding to the etched portion.

[0011] In some embodiments, before the etching removes the first conductive material corresponding to the etched portion and the second conductive material corresponding to the etched portion, the method for manufacturing the printed circuit board further includes: An etch-resistant film is disposed on the substrate, the etch-resistant film covering the second conductive material corresponding to the retained portion and the second conductive material corresponding to the blind via, the etch-resistant film being provided with an opening window exposing the second conductive material corresponding to the etched portion; When the etching removes the first conductive material and the second conductive material corresponding to the etched portion, a slope is formed at the connection between the first conductive material and the second conductive material corresponding to the retained portion and the edge of the etched portion.

[0012] In some embodiments, the first current density is 1.8 ASD-2.0 ASD, and the electroplating time corresponding to the first current density is 5 min-15 min; the second current density is 1.2 ASD-1.4 ASD, and the electroplating time corresponding to the second current density is 60 min-80 min.

[0013] In some embodiments, electroplating the substrate with a first current density includes: placing the substrate in an electroplating tank for vertical continuous electroplating, wherein nozzles are provided on both sides of the electroplating tank, the nozzles are used to spray electroplating solution onto the substrate, and the spray flow rate of the nozzles is 1.5L / min-3.0L / min. And / or, the electroplating of the substrate using a second current density includes: The substrate is placed in an electroplating tank for vertical continuous electroplating. A first nozzle and a second nozzle are provided on both sides of the electroplating tank. The first nozzle and the second nozzle are arranged along the moving direction of the substrate. Both the first nozzle and the second nozzle are used to spray electroplating solution onto the substrate. The spray flow rate of the first nozzle is 2.3L / min-2.7L / min, and the spray flow rate of the second nozzle is 1.3L / min-1.7L / min.

[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 printed circuit board manufacturing method provided in this application has the following advantages: Since the substrate includes a substrate and a conductive layer stacked together, and the substrate is provided with blind holes that penetrate the conductive layer and at least part of the substrate, and the substrate is first electroplated with a first current density, a first conductive material covering the inner wall of the blind hole can be quickly obtained, and the first conductive material covers at least part of the conductive layer, avoiding the first conductive material covering the conductive layer being too thick. Then, the substrate is electroplated with a second current density to obtain a second conductive material. The second current density is less than the first current density, and the second conductive material covers the first conductive material, so the protrusion at the opening of the blind hole due to overplating can be suppressed, and the second conductive material can be added to the recessed area inside the blind hole more quickly. Thus, the blind hole can be filled by the first conductive material and the second conductive material together, and the opening of the blind hole is relatively flat.

[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 This is a flowchart of a method for manufacturing a printed circuit board in one embodiment of this application; Figure 2 This is a schematic diagram of the substrate structure in one embodiment of this application; Figure 3 It uses the first current density pair Figure 2 A schematic diagram of the substrate being electroplated; Figure 4 It uses the second current density pair Figure 3 A schematic diagram of the substrate being electroplated; Figure 5 Is Figure 4 A schematic diagram showing an anti-etching film disposed on a substrate; Figure 6 It is etching removal Figure 4 A schematic diagram of the first conductive material and the second conductive material corresponding to the etched portion on the substrate shown; Figure 7 It is to remove Figure 6 A schematic diagram of the etch-resistant film on the substrate shown.

[0019] The markings in the diagram mean: 10. Substrate; 101. Blind via; 11. Substrate; 12. Conductive layer; 121. Retained area; 122. Etched area; 20. First conductive material; 30. Second conductive material; 40. Anti-etching film; 41. Open a window. 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 high-frequency, high-speed printed circuit board (FPC) interconnect applications such as 5G communication, millimeter-wave antennas, and flexible electronics, FPCs are increasingly adopting low-loss materials such as polytetrafluoroethylene (PTFE) and modified polyimide (MPI). These high-frequency substrates possess low dielectric constants, low losses, and good signal transmission performance; however, they exhibit low surface adhesion and poor hole wall wettability. After blind via processing, resin debris, dust, and air bubbles easily remain, posing challenges to subsequent conductivity and electroplating filling.

[0025] For micro-deep blind vias with a large depth-to-diameter ratio (greater than or equal to 1), such as those with a diameter of approximately 150 μm, a depth of approximately 150 μm, and a depth-to-diameter ratio close to 1:1, existing processes typically face two types of problems: First, to obtain a continuous copper layer on the bottom and sidewalls of the blind via, electroplating requires a large current density and a long plating time, which can easily lead to overplating at the via opening, excessively thick copper on the surface, and voids inside the blind via; Second, to meet the dynamic bending resistance requirements of the bending zone, the copper on the surface needs to be thinned to a relatively thin range, but overall mechanical brushing and thinning can easily result in problems such as rough copper on the surface, residual copper, uncontrolled linewidth, and excessively large blind via depressions.

[0026] Traditional one-time high-current via filling methods cannot simultaneously meet the requirements of filling the blind via with conductive material and the smoothness of the via opening. If the blind via depression is too large, it can easily cause stress concentration cracking or reliability reduction during subsequent processes such as lamination, welding or bending.

[0027] In view of this, this application provides a method for manufacturing a printed circuit board to solve the problem that traditional methods are difficult to simultaneously meet the requirements of filling blind vias with conductive material and ensuring the smoothness of the via opening.

[0028] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.

[0029] Please refer to Figures 1 to 4 In a first aspect, embodiments of this application provide a method for manufacturing a printed circuit board, comprising: S100: A substrate 10 is provided. The substrate 10 includes a substrate 11 and a conductive layer 12 stacked together. The substrate 10 is provided with a blind via 101, which penetrates the conductive layer 12 and at least a portion of the substrate 11.

[0030] The substrate 11 includes resin, glass fiber, and may also include low-loss materials such as polytetrafluoroethylene (PTFE) and modified polyimide (MPI). The conductive layer 12 can be made of copper, silver, or aluminum, and one or more blind vias 101 can be provided. The substrate 10 may also have through holes, and the substrate 10 is drilled to form deep blind vias 101 and through holes.

[0031] S200: Electroplating is performed on substrate 10 using a first current density to obtain a first conductive material 20. The first conductive material 20 covers the inner wall of blind hole 101 and covers at least part of conductive layer 12.

[0032] When electroplating the substrate 10 using the first current density, a first conductive material 20 can be quickly deposited on the bottom and sidewalls of the blind hole 101. The first conductive material 20 can be copper.

[0033] S300: Electroplating is performed on substrate 10 using a second current density to obtain a second conductive material 30. The second current density is less than the first current density. The second conductive material 30 covers the first conductive material 20. The first conductive material 20 and the second conductive material 30 together fill the blind hole 101.

[0034] When electroplating the substrate 10 using the first current density, the second current density is lower than the first current density. Therefore, it can suppress the protrusion of the blind hole 101 at the opening due to overplating, and can accelerate the replenishment of the second conductive material 30 in the recessed area of ​​the blind hole 101, making the opening of the blind hole 101 more flat. The second conductive material 30 can be copper.

[0035] As can be seen from the above, the method for manufacturing a printed circuit board provided in this application embodiment includes a substrate 10 comprising a substrate 11 and a conductive layer 12 stacked together. The substrate 10 is provided with a blind hole 101, which penetrates the conductive layer 12 and at least part of the substrate 11. The substrate 10 is first electroplated with a first current density, thus quickly obtaining a first conductive material 20 covering the inner wall of the blind hole 101. The first conductive material 20 covers at least part of the conductive layer 12, avoiding excessive thickness of the first conductive material 20 covering the conductive layer 12. Then, the substrate 10 is electroplated with a second current density to obtain a second conductive material 30. The second current density is less than the first current density, and the second conductive material 30 covers the first conductive material 20. Therefore, it can suppress the protrusion at the opening of the blind hole 101 due to overplating, and can accelerate the replenishment of the second conductive material 30 in the recessed area of ​​the blind hole 101. Thus, the blind hole 101 can be filled by the first conductive material 20 and the second conductive material 30 together, making the opening of the blind hole 101 relatively flat.

[0036] It is understood that the printed circuit board provided in the embodiments of this application may be a flexible printed circuit board.

[0037] Please refer to Figures 1 to 4 In some embodiments, before electroplating the substrate 10 with a first current density, the method for manufacturing the printed circuit board further includes: First, the substrate 10 is sent into the shadow line. The shadow line sprays a hole-forming solution onto the upper and lower sides of the substrate 10 and into the blind hole 101 to adjust the charge on the inner wall of the blind hole 101. Then, the shadow line sprays a first graphite carbon onto the inner wall of the blind hole 101.

[0038] Next, the substrate 10 is flipped and sent into the shadow line again. The shadow line first sprays a hole-forming agent on the upper and lower sides of the substrate 10 and inside the blind hole 101 to adjust the charge on the inner wall of the blind hole 101. Then, the shadow line sprays a second graphite carbon on the upper and lower sides of the substrate 10 and inside the blind hole 101 to attach the second graphite carbon to the inner wall of the blind hole 101.

[0039] The substrate 10 is electroplated using a first current density through a first graphite carbon and a second graphite carbon.

[0040] By adopting the above scheme, the hole-forming solution and the shadow solution inside the blind hole 101 can be fully exchanged, ensuring that the charge on the inner wall of the blind hole 101 can be better adjusted, so that the inner wall of the blind hole 101 is completely covered by the deposition of the first graphite carbon and the second graphite carbon, providing a conductive foundation for the hole wall for subsequent electroplating and ensuring the effect of electroplating.

[0041] It is understood that the carbon powder adhesion ability in the blind holes 101 and through holes of the substrate 10 with high frequency substrate 11 is relatively weak. In the printed circuit board manufacturing method provided in this application embodiment, by flipping the substrate 10, the chemical solution in the hole is sprayed alternately from the top and bottom to act on the blind hole 101, so that the hole is fully coated with carbon, and the inner wall of the blind hole 101 is completely covered by the deposition of the first graphite carbon and the second graphite carbon.

[0042] In this process, the charge on the inner wall of blind hole 101 is adjusted by the whole hole solution, and ultrasonic vibration is used to reduce the surface tension inside the hole and remove the residue on the hole wall.

[0043] After carbonization using the black shadow method, the hole walls should not have localized gaps, agglomerated particles, or carbon buildup at the hole openings. Residual carbon, contaminants, and carbon deposits inside the holes are removed through fixing, micro-etching, and water washing. Specifically, black shadow solution is sprayed onto both the top and bottom sides of the substrate 10, followed by fixing, and then micro-etching to remove surface carbon powder and contaminants. The linear velocity of the black shadow lines is approximately 1.3 m / min; the linear velocity of the micro-etched lines is approximately 2.5 m / min, and the water washing spray pressure after fixing is 0.4 kg / cm²-1.2 kg / cm².

[0044] It should be noted that before the substrate 10 is sent into the shadow line, the substrate 10 can be subjected to pre-treatment such as plasma bombardment (nitrogen, oxygen, carbon tetrafluoride) and chemical cleaning to remove adhesive (hydrogen peroxide, sulfuric acid) to remove drilling smudges, residual adhesive and organic matter from the hole walls of the blind holes 101, roughen the hole walls and enhance hydrophilicity, and form a negative charge so that the toner can be better adsorbed during the shadow line process.

[0045] Optionally, conductive layers 12 are provided on both opposite sides of the substrate 11, and blind vias 101 are provided on both opposite sides of the substrate 10. The blind vias 101 penetrate the corresponding conductive layers 12 and at least a portion of the substrate 11.

[0046] This configuration ensures that the inner walls of the blind holes 101 on both sides of the substrate 11 are completely covered by the deposition of the first graphite carbon and the second graphite carbon, thus guaranteeing the effect of subsequent electroplating of the substrate 10.

[0047] Please refer to Figures 1 to 4 In some embodiments, before electroplating the substrate 10 with a first current density, the method for manufacturing the printed circuit board further includes: The substrate 10 is immersed in an acidic solution for pickling and then subjected to electronic vibration treatment.

[0048] By adopting the above solution, the gas inside the blind hole 101 can be dislodged, and the acidic solution can occupy the space inside the hole. This facilitates the full exchange of the electroplating solution inside the hole when the substrate 10 is electroplated with the first current density in the subsequent process, thus avoiding gas blockage and ensuring the electroplating effect.

[0049] It should be noted that after the second graphite carbon is attached to the inner wall of the blind hole 101, the substrate 10 undergoes degreasing (cleaning), hot water washing, micro-etching, water washing and acid washing in sequence.

[0050] Optionally, the electronic vibration is set to pause for 3-5 seconds every 5-7 seconds of operation, with an amplitude of 1-2 cm.

[0051] This configuration allows the air inside the blind hole 101 to be vibrated out more completely.

[0052] It should be noted that the acidic solution is placed in the circulation tank, and the circulation rate of the solution in the circulation tank is 10 turns / H-12 turns / H.

[0053] Please refer to Figures 1 to 7 In some embodiments, the substrate 10 has a bending region, and the conductive layer 12 includes a retention portion 121 and an etched portion 122, the etched portion 122 corresponding to the bending region; after electroplating the substrate 10 with a second current density, the method for manufacturing the printed circuit board further includes: etching to remove the first conductive material 20 corresponding to the etched portion 122 and the second conductive material 30 corresponding to the etched portion 122.

[0054] By adopting the above solution, better flexural reliability can be provided for the bending area.

[0055] It should be noted that the conductive layer 12 is originally on the substrate 11, and its flexibility is not affected. For example, after etching away the first conductive material 20 and the second conductive material 30 corresponding to the etched portion 122, the remaining etched portion 122 is a copper layer on the surface of the substrate 11. It is rolled copper, which has better flexibility than the copper-plated layer and has a longer bending performance life.

[0056] The first conductive material 20 and the second conductive material 30 corresponding to the etched part 122 can be removed by acid etching to thin the bending area. The etching parameters required for the thinning thickness can be tested in advance.

[0057] Optionally, before etching away the first conductive material 20 corresponding to the etched portion 122 and the second conductive material 30 corresponding to the etched portion 122, the method for manufacturing the printed circuit board further includes: An etch resist film 40 is provided on the substrate 10. The etch resist film 40 covers the second conductive material 30 corresponding to the retention portion 121 and the second conductive material 30 corresponding to the blind via 101. The etch resist film 40 is provided with an opening window 41, which exposes the second conductive material 30 corresponding to the etched portion 122.

[0058] The resist film 40 can be a dry film or a wet film. For example, the resist film 40 can be deposited on the substrate 10 by vacuum lamination of a dry film and exposure and development. The portion corresponding to the non-bending area that is not exposed is protected by the resist film 40, so that the bending area obtains a thinner, more uniform, and controllable etched portion 122.

[0059] When etching away the first conductive material 20 and the second conductive material 30 corresponding to the etched portion 122, a slope is formed at the connection between the first conductive material 20 and the second conductive material 30 corresponding to the retained portion 121 and the edge of the etched portion 122.

[0060] It is understandable that after etching away the first conductive material 20 and the second conductive material 30 corresponding to the etched part 122, the anti-etching film 40 is removed.

[0061] This configuration removes the first conductive material 20 and the second conductive material 30 corresponding to the etched portion 122, providing better bending resistance and reliability for the bending area. It also allows the connection between the first conductive material 20 and the second conductive material 30 corresponding to the retained portion 121 and the edge of the etched portion 122 to form a slope. During subsequent circuit fabrication of the circuit layer formed by the retained portion 121, the first conductive material 20 and the second conductive material 30 corresponding to the retained portion 121, the dry film can be compacted on the slope to prevent the dry film from being not compacted during circuit fabrication, thus reducing the probability of open circuits caused by broken wires and improving the circuit yield. This balances circuit reliability and dynamic bending performance.

[0062] It is understandable that the slope formed between the retention portion 121, the first conductive material 20 corresponding to the retention portion 121, and the second conductive material 30 corresponding to the retention portion 121 and the etching portion 122 will inevitably form a vertical step.

[0063] It should be noted that the printed circuit board manufacturing method provided in this application embodiment can form a uniformly bonded conductive material in the blind hole 101 of the substrate 10 having a high-frequency substrate 11 and a small-diameter deep blind hole 101, reducing the risk of voids, bubbles, hole bulges and residual copper; at the same time, the depression at the hole opening of the blind hole 101 is controlled to within about 10μm, and the thickness of the circuit layer formed by the reserved portion 121, the first conductive material 20 corresponding to the reserved portion 121 and the second conductive material 30 corresponding to the reserved portion 121 is stabilized within the optimal half-etch adaptation range of 40μm-50μm, providing better bending resistance reliability for the bending area.

[0064] Please refer to Figures 1 to 4 In some embodiments, the first current density is 1.8 ASD-2.0 ASD, and the electroplating time corresponding to the first current density is 5 min-15 min; the second current density is 1.2 ASD-1.4 ASD, and the electroplating time corresponding to the second current density is 60 min-80 min.

[0065] By adopting the above scheme, the protrusion at the opening of the blind hole 101 due to overplating can be suppressed, and the electroplating rate of the second conductive material 30 inside the blind hole 101 can be greater than the electroplating rate of the second conductive material 30 outside the blind hole 101, thereby accelerating the replenishment of the second conductive material 30 in the recessed area inside the blind hole 101. As a result, the blind hole 101 can be filled by the first conductive material 20 and the second conductive material 30 together, and the opening of the blind hole 101 is relatively flat.

[0066] Optionally, electroplating the substrate 10 using a first current density includes: placing the substrate 10 in an electroplating tank to perform vertical continuous plating (VCP) on the substrate 10. The electroplating tank is provided with nozzles on both sides, and the nozzles are used to spray electroplating solution onto the substrate 10. The spray flow rate of the nozzles is 1.5L / min-3.0L / min.

[0067] This configuration allows the electroplating solution inside the blind hole 101 to be exchanged in a timely manner, quickly obtaining the first conductive material 20 covering the inner wall of the blind hole 101, so that the bottom of the blind hole 101 achieves a certain amount of filling effect.

[0068] And / or, electroplating the substrate 10 using a second current density, including: The substrate 10 is placed in an electroplating tank for vertical continuous electroplating. A first nozzle and a second nozzle are provided on both sides of the electroplating tank. The first nozzle and the second nozzle are arranged along the moving direction of the substrate 10. Both the first nozzle and the second nozzle are used to spray electroplating solution onto the substrate 10. The spray flow rate of the first nozzle is 2.3L / min-2.7L / min, and the spray flow rate of the second nozzle is 1.3L / min-1.7L / min.

[0069] With this configuration, electroplating solution can be sprayed onto the substrate 10 through the first nozzle at the front end, so that the electroplating solution in the blind hole 101 can be replaced in time. In the rear end, since a certain amount of second conductive material 30 has been filled into the blind hole 101, the spray flow rate can be reduced through the second nozzle, so that the opening of the blind hole 101 is relatively flat and the depression is controlled within 10μm.

[0070] In the printed circuit board manufacturing method provided in this application embodiment, the substrate 10 undergoes two full-board electroplating processes, resulting in a smooth surface without steps, which facilitates the application of dry film.

[0071] Secondly, embodiments of this application provide a printed circuit board, which is manufactured by the printed circuit board manufacturing method of the first aspect.

[0072] The printed circuit board provided in this application embodiment includes a substrate 10 comprising a substrate 11 and a conductive layer 12 stacked together. The substrate 10 is provided with a blind via 101, which penetrates the conductive layer 12 and at least part of the substrate 11. The substrate 10 is first electroplated with a first current density, thus quickly obtaining a first conductive material 20 covering the inner wall of the blind via 101. The first conductive material 20 covers at least part of the conductive layer 12, preventing the thickness of the first conductive material 20 covering the conductive layer 12 from being too thick. Then, the substrate 10 is electroplated with a second current density to obtain a second conductive material 30. The second current density is less than the first current density, and the second conductive material 30 covers the first conductive material 20. Therefore, it can suppress the protrusion at the opening of the blind via 101 due to overplating, and can accelerate the replenishment of the second conductive material 30 in the recessed area of ​​the blind via 101. Thus, the blind via 101 can be filled by the first conductive material 20 and the second conductive material 30 together, making the opening of the blind via 101 relatively flat.

[0073] 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 comprising a substrate and a conductive layer stacked thereon, the substrate having a blind via penetrating the conductive layer and at least a portion of the substrate; The substrate is electroplated using a first current density to obtain a first conductive material, the first conductive material covering the inner wall of the blind hole, and the first conductive material covering at least a portion of the conductive layer; The substrate is electroplated using a second current density to obtain a second conductive material. The second current density is less than the first current density. The second conductive material covers the first conductive material, and the first conductive material and the second conductive material together fill the blind via.

2. The method for manufacturing a printed circuit board according to claim 1, characterized in that, Before electroplating the substrate using a first current density, the method for manufacturing the printed circuit board further includes: The substrate is sent into the shadow line. The shadow line first sprays a hole-forming solution onto the upper and lower sides of the substrate and into the blind hole to adjust the charge on the inner wall of the blind hole. Then, the shadow line sprays a shadow solution onto the upper and lower sides of the substrate and into the blind hole to attach the first graphite carbon to the inner wall of the blind hole. The substrate is flipped over and then sent back into the shadow line. The shadow line sprays a hole-forming solution onto the upper and lower sides of the substrate and into the blind hole to adjust the charge on the inner wall of the blind hole. Then, the shadow line sprays a second graphite carbon onto the inner wall of the blind hole. The substrate is electroplated using a first current density through the first graphite carbon and the second graphite carbon.

3. The method for manufacturing a printed circuit board according to claim 2, characterized in that, The conductive layer is provided on both opposite sides of the substrate, and the blind via is provided on both opposite sides of the substrate, the blind via penetrating the corresponding conductive layer and at least a portion of the substrate.

4. The method for manufacturing a printed circuit board according to claim 1, characterized in that, Before electroplating the substrate using a first current density, the method for manufacturing the printed circuit board further includes: The substrate is immersed in an acidic solution for pickling and then subjected to electronic vibration treatment.

5. The method for manufacturing a printed circuit board according to claim 4, characterized in that, The electronic vibration is set to pause for 3-5 seconds every 5-7 seconds of operation, with an amplitude of 1-2 cm.

6. The method for manufacturing a printed circuit board according to claim 1, characterized in that, The substrate has a bending region, and the conductive layer includes a retention portion and an etched portion, wherein the etched portion corresponds to the bending region. After electroplating the substrate with a second current density, the method for manufacturing the printed circuit board further includes: etching away the first conductive material corresponding to the etched portion and the second conductive material corresponding to the etched portion.

7. The method for manufacturing a printed circuit board according to claim 6, characterized in that, Before the etching process removes the first conductive material corresponding to the etched portion and the second conductive material corresponding to the etched portion, the method for manufacturing the printed circuit board further includes: An etch-resistant film is disposed on the substrate, the etch-resistant film covering the second conductive material corresponding to the retained portion and the second conductive material corresponding to the blind via, the etch-resistant film being provided with an opening window exposing the second conductive material corresponding to the etched portion; When the etching removes the first conductive material and the second conductive material corresponding to the etched portion, a slope is formed at the connection between the first conductive material and the second conductive material corresponding to the retained portion and the edge of the etched portion.

8. The method for manufacturing a printed circuit board according to any one of claims 1 to 7, characterized in that, The first current density is 1.8 ASD-2.0 ASD, and the electroplating time corresponding to the first current density is 5 min-15 min; the second current density is 1.2 ASD-1.4 ASD, and the electroplating time corresponding to the second current density is 60 min-80 min.

9. The method for manufacturing a printed circuit board according to claim 7, characterized in that, The method of electroplating the substrate with a first current density includes: placing the substrate in an electroplating tank for vertical continuous electroplating, wherein nozzles are provided on both sides of the electroplating tank, the nozzles are used to spray electroplating solution onto the substrate, and the spray flow rate of the nozzles is 1.5L / min-3.0L / min. And / or, the electroplating of the substrate using a second current density includes: The substrate is placed in an electroplating tank for vertical continuous electroplating. A first nozzle and a second nozzle are provided on both sides of the electroplating tank. The first nozzle and the second nozzle are arranged along the moving direction of the substrate. Both the first nozzle and the second nozzle are used to spray electroplating solution onto the substrate. The spray flow rate of the first nozzle is 2.3L / min-2.7L / min, and the spray flow rate of the second nozzle is 1.3L / min-1.7L / min.

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.

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