Electroplating processing method for printed circuit board

Abstract

The present invention provides a method for electroplating a printed circuit board, comprising spraying a photosensitive material on an anode surface, performing a pre-baking process and an exposure process to obtain an exposed anode; wherein the exposure process comprises generating exposure data based on the distribution of hole-dense areas and hole-sparse areas on a production board, and exposing the photosensitive material on the pre-baking anode surface; performing a development process on the exposed anode to obtain a developed anode; the developed anode enters an electroplating tank at the same speed as the production board for electroplating; wherein the position of the photosensitive material window of the developed anode corresponds to the position of the hole-dense area of ​​the production board. The present invention can improve the problem of large surface copper variations between the hole-dense areas and the large areas without holes on the production board, and can controllably adjust the degree of shielding of the anode power lines to achieve efficient and continuous production without the need to stop the line to replace the anode baffle and waste production capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of copper electroplating of printed circuit boards, and relates to an electroplating processing method of a printed circuit board. Background Art

[0002] Electroplating is an essential step in the production and processing of printed circuit boards (PCBs). Traditionally, copper is plated on the walls of via holes by immersing the PCB vertically in a plating solution, which acts as the cathode. A titanium mesh serves as the anode. Direct current or pulse plating is applied to the vias. Gantry plating lines and vertical continuous plating (VCP) lines are two types of equipment used for this process. VCP, with its advantages of a smaller footprint, greater production continuity, and lower energy consumption, has gained widespread recognition and adoption within the industry.

[0003] The copper thickness and throwing power (TP) of PCB vias are among the fundamental criteria for evaluating qualified product processing. To prioritize meeting these basic criteria, traditional PCB manufacturers typically apply specific current densities and pulse waveforms. However, with the miniaturization and increasing multifunctionality of electronic products, the PCBs that support electronic devices are trending towards higher density and higher layer counts. Simultaneously, to achieve high-precision wiring and high-performance computing capabilities on PCBs, chip sizes are increasing. This has led to an increase in the area of ​​densely populated vias on PCBs, exacerbating the uneven distribution of vias. Under traditional electroplating methods, plating efficiency in densely populated via areas decreases significantly, resulting in significantly thinner surface copper in these areas than in areas with sparser vias. This leads to uneven surface copper thickness and board thickness, leading to serious quality issues such as incomplete resin polishing during the resin polishing process and open or short circuits during the pattern etching process. Summary of the Invention

[0004] In response to the problems existing in the prior art, the purpose of the present invention is to provide a method for electroplating a printed circuit board, which improves the problem of large surface copper differences between the hole-dense areas and the large areas without holes on the production board, and can controllably adjust the different degrees of shielding of the anode power lines to achieve efficient and continuous production without stopping the line to replace the anode baffle and other operations that waste production capacity.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] An embodiment of the present invention provides a method for electroplating a printed circuit board, the method comprising:

[0007] Spraying a photosensitive material on the surface of the anode, and subjecting it to a pre-bake process and an exposure process to obtain an exposed anode; wherein the exposure process includes generating exposure data based on the distribution of dense hole areas and sparse hole areas on the production board, and exposing the photosensitive material on the surface of the anode after the pre-bake process;

[0008] performing a development process on the exposed anode to obtain a developed anode;

[0009] The developed anode enters the electroplating tank at the same speed as the production board for electroplating treatment. The production board after electroplating treatment is washed with water to complete the electroplating process. The developed anode after electroplating treatment is stripped and air-dried for recycling; wherein, the window position of the photosensitive material of the developed anode corresponds to the position of the hole-dense area of ​​the production board.

[0010] Optionally, a first anode and a second anode are respectively provided on both sides of the production plate, and the structure of the first anode is the same as that of the second anode, the first anode is a post-development anode, and the second anode is a post-development anode.

[0011] Optionally, the first anode is arranged in a reel form on one side of the production board, and the tail end of the first anode that has been electroplated is wound in a direction away from the direction in which the production board enters the electroplating tank.

[0012] Optionally, the second anode is arranged in the form of a reel on the other side of the production board, and the tail end of the second anode that has been electroplated is wound in a direction away from the direction in which the production board enters the electroplating tank.

[0013] Optionally, the size of the development window of the anode is compensated for the exposure size according to the size of the hole-dense area of ​​the production plate.

[0014] Optionally, the exposure size compensation of the anodic development window is positive compensation or negative compensation.

[0015] Optionally, the electroplating treatment adopts a pulse electroplating method; the pulse power supply of the pulse electroplating includes a forward pulse and a reverse pulse.

[0016] Optionally, the ratio of the time of the forward pulse to the time of the reverse pulse is 200ms:10ms, and the current ratio of the forward pulse to the reverse pulse is 1:3.

[0017] Optionally, the waveform of the pulse plating includes any one of a square wave, a triangle wave and a sawtooth wave, or a combination of two or more of the above.

[0018] Optionally, the developed anode and the production plate need to be degreased before entering the electroplating tank.

[0019] Optionally, the photosensitive material comprises, in parts by mass, 100 parts of insulating polymer material, 2 to 10 parts of photosensitive additive, 10 to 50 parts of diluent, and 10 to 100 parts of conductive filler.

[0020] Optionally, the insulating polymer material includes any one of phenolic resin, polyester resin, polyurethane resin and epoxy resin, or a combination of two or more thereof.

[0021] Optionally, the photosensitive additive includes a photosensitive compound and / or a photosensitive monomer; wherein the photosensitive compound includes any one or a combination of two or more photosensitive compounds such as diazonaphthoquinone esters, imine sulfonates and oxime sulfonates, and the photosensitive monomer includes any one or a combination of two or more photosensitive monomers such as trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and 2-hydroxyethyl methacrylate.

[0022] Optionally, the conductive filler includes inorganic materials and / or organic materials; wherein the inorganic material includes any one or a combination of two or more conductive inorganic materials such as carbon black, carbon nanotubes, graphene, metals and metal oxides, and the organic material includes any one or a combination of two or more conductive organic materials such as polypyrrole, polythiophene and polyaniline.

[0023] Optionally, the material of the anode includes any one of metal materials such as copper, phosphor copper, aluminum, titanium, copper alloy, aluminum alloy and titanium alloy.

[0024] Optionally, the structure of the anode includes one or a combination of two or more structures selected from the group consisting of a sheet structure, a mesh structure, a wavy mesh structure and a mesh chain structure.

[0025] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] In the present invention, a photosensitive material is sprayed on the anode, and a window is opened to expose the anode in the area where the surface copper thickness of the corresponding production board needs to be increased. In the area where the copper thickness of the corresponding production board needs to be reduced, the photosensitive material is exposed to cover the anode to optimize the distribution of the anode electric field lines. The anode area covered with the photosensitive material will reduce the distribution of the electric field lines of the product board, while the window is opened to expose the anode area, which will increase the copper thickness in the hole-dense area such as BGA, thereby improving the problem of large difference in surface copper thickness between the hole-dense area and the large area without holes.

[0028] The photosensitive material of the present invention not only has the function of isolating the anode electric field lines, but also can adjust the content of the conductive filler and the thickness of the photosensitive material online to change its conductivity, and can controllably adjust the degree of shielding of the anode electric field lines, so as to further improve the distribution of the electric field lines on the production board and the electroplating effect.

[0029] The present invention adopts a roll-to-roll anode design, which allows continuous coating of the anode without stopping the line to replace components, thereby achieving efficient continuous production and adjusting the graphic distribution of the insulating material on the anode in real time according to the product design. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0031] Figure 1 Schematic diagram of the opening distribution of the cathode production plate provided by the prior art solution;

[0032] Figure 2 A schematic flow chart of a method for electroplating a printed circuit board according to an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of a developed pattern of an anode after development provided by an embodiment of the present invention;

[0034] Figure 4 Schematic diagram and technical principle diagram of a roll-to-roll design according to an embodiment of the present invention, wherein the developed anode and the production plate enter the plating tank at the same speed for electroplating treatment;

[0035] Figure 5 A technical schematic diagram of a roll-to-roll design in which a developed anode and a production plate are electroplated simultaneously in an electroplating tank according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0039] As described in the background technology, existing electroplating methods are ineffective in improving the large surface copper thickness variations between the hole-dense areas and the large areas without holes on cathode production boards, and it is difficult to ensure efficient and continuous production of PCBs. Currently, in order to reduce the processing difficulty of the pattern etching process, PCBs with uneven surface copper thickness need to undergo copper reduction rework using processes such as selective resin plugging or dry film capping to reduce the surface copper thickness in the sparsely holed areas, so that the range of copper thickness of the entire board is reduced to within the processable range of pattern etching. However, this has a significant negative impact on factory capacity and production efficiency.

[0040] Existing patent CN101260550A proposes controlling the PCB plating thickness by properly opening holes in the anode baffle. This principle also allows for selective opening of holes in densely populated areas, with the anode baffle shielding sparsely populated areas. This optimizes the distribution of electric lines and improves the surface copper extremes caused by hole distribution. However, this method is only applicable to gantry-type electroplating lines to ensure that the anode baffle opening position remains unchanged relative to the densely populated areas of the production board. Furthermore, the anode baffle with these holes can only be improved for that specific product. Switching between processing products requires additional processing of the anode baffle and line stoppage for installation, making uninterrupted continuous production impossible and impacting production capacity.

[0041] Furthermore, the hole distribution of the conventional production plate is as follows Figure 1As shown, taking the production board with a size of 24.20inch*28.20inch, a thickness of 4.5mm, an aspect ratio of 22.5:1, and an outer layer minimum line width and line spacing of 101.6μm and 101.6μm respectively as an example, the hole-dense area of ​​the production board is mainly concentrated in positions Ⅰ to Ⅷ, and the sizes of the hole-dense areas Ⅰ to Ⅷ are 2.18inch*1.33inch, 2.18inch*1.33inch, 2.18inch*1.33inch, 2.18inch*1.33inch, 0.62inch*3.66inch, 0.62inch*3.66inch, and 3.20inch*17.06inch respectively, while the large area of ​​hole-sparse area is positions ① to ⑥. During the electroplating process of the production board and anode, the anode is not coated with photosensitive material, and the production board is processed by traditional electroplating method. The current density is 1.7ASD, the electroplating time is 160min, and the pulse parameters include the ratio of the forward pulse time to the reverse pulse time is 200ms:10ms, the current ratio of the forward pulse and the reverse pulse is 1:3, and the waveform of the pulse plating can be any one of the square wave, triangle wave and sawtooth wave, or a combination of two or more.

[0042] After completing the electroplating process, the surface copper thickness of positions ① to ⑥ and positions Ⅰ to Ⅷ were measured. The surface copper thickness of positions ① to ⑥ were 24.11μm, 25.35μm, 26.31μm, 25.79μm, 28.71μm, and 27.99μm, respectively. The surface copper thickness of positions Ⅰ to Ⅷ were 63.46μm, 58.11μm, 62.56μm, 61.76μm, 59.71μm, 61.17μm, 57.34μm, and 63.76μm, respectively. The extreme difference in surface copper thickness between the hole-dense area and the large area of ​​hole-sparse area reached 39.35μm, which seriously exceeded the processing process capability of the outer layer graphic etching. It was necessary to rework the dry film to cover the holes and reduce the copper, which increased the processing time of the production board.

[0043] In response to the above problems, an embodiment of the present invention provides an electroplating processing method for printed circuit boards, which can improve the problem of large surface copper differences between densely holed areas and large areas without holes on the production board, and can controllably adjust the different degrees of shielding of the anode power lines to achieve efficient and continuous production.

[0044] Figure 2 This is a schematic flow chart of a method for electroplating a printed circuit board provided by an embodiment of the present invention. Figure 2 , the electroplating processing method specifically includes the following steps:

[0045] S110: spraying a photosensitive material on the surface of the anode, spraying the photosensitive material on both sides of the anode, so that the photosensitive material covers the surface of the anode.

[0046] The photosensitive material, calculated by weight, consists of 100 parts insulating polymer material, 2-10 parts photosensitive additive, 10-50 parts diluent, and 10-100 parts conductive filler. The conductive filler content and spray thickness can be adjusted online to alter its conductivity, achieving varying degrees of shielding for the anode power lines, improving their distribution on the production board and the plating effect.

[0047] S120: The anode after spraying the photosensitive material is subjected to a pre-baking process and an exposure process to obtain an exposed anode.

[0048] Among them, the pre-bake treatment is carried out in the pre-bake tank, and the photosensitive material on the anode surface is pre-cured by heating; the exposure treatment is carried out in the exposure tank, and the exposure data is generated according to the distribution of dense hole areas and sparse hole areas on the production board, and the photosensitive material on the anode surface after the pre-bake treatment is exposed using an exposure lamp.

[0049] S130: Developing the exposed anode to obtain a developed anode.

[0050] Figure 3 is a schematic diagram of the development pattern of the anode after development provided by an embodiment of the present invention, see Figure 3 The dark part is the part left after exposure, and the white part is the development position on the anode corresponding to the window position of the production plate. The development process is carried out in the development tank, and the corresponding pattern can be developed on the anode, that is, the exposed photosensitive material is retained on the anode surface after the development process, and the unexposed photosensitive material is completely washed away from the anode surface after the development process.

[0051] The purpose of the anodic development window treatment is to improve current distribution, ensure uniform plating, and avoid thinning the electroplated copper thickness due to dense hole spacing. The size of the anodic development window is compensated for exposure size based on the size of the dense hole area in the production board. Exposure size compensation for the anodic development window can be positive or negative. The anodic window size can be increased by 0.2 inches based on the size of the dense hole area in the production board. Within this increase range, the copper thickness in the dense hole area can be increased while avoiding a significant difference in thickness from the surrounding copper, which would be detrimental to subsequent pattern etching processes.

[0052] S140: After development, the anode enters the electroplating tank at the same speed as the production board for electroplating treatment, and the window position of the photosensitive material of the anode after development corresponds to the position of the hole-dense area of ​​the production board.

[0053] Figure 4 and Figure 5 This is a schematic diagram and technical principle diagram of the roll-to-roll design provided by the embodiment of the present invention, in which the developed anode and the production board enter the plating tank at the same speed for electroplating. Figure 4, in which, the window production can be vertically clamped by electroplating clamps and sequentially enter the degreasing tank, electroplating tank and water washing tank. At the same time, the anode after development should enter the degreasing tank, electroplating tank and water washing tank at the same time and speed as the production board; see Figure 5 The developed anode and the production board are placed in the electroplating tank, and the current is provided to the production board through the rectifier. When the production board and the developed anode enter the electroplating tank, the electric lines at the anode position covered by the photosensitive material are shielded to varying degrees, resulting in the electroplating effect at the corresponding position on the production board also being weakened to varying degrees, thereby reducing the coating thickness in the area. At the anode position not covered by the photosensitive material, the electric lines are more concentrated, which also increases the coating thickness in the corresponding area on the production board.

[0054] It should be noted that the rectifier (rectifier power supply) in the present invention is a key device for providing stable and controllable current for the cathode production plate and the anode. It can convert alternating current (AC) into direct current (DC) to provide a constant current or voltage for the electroplating tank; it supports precise control of current density (such as 1.7 ASD), voltage, and waveform (pulse / DC) to achieve overcurrent, overvoltage, and short-circuit protection to prevent electrode damage or coating defects; specifically, it can be a silicon-controlled rectifier, a high-frequency switching power supply, a pulse rectifier, and a transistor linear power supply, with the pulse rectifier being the preferred choice.

[0055] S150: After the electroplating treatment, the production board is washed with water to complete the electroplating process.

[0056] Among them, water washing treatment is a key step to ensure the quality of the coating and prevent pollution and corrosion. Multi-stage countercurrent water washing can be used, including the first-stage water washing, rough washing, to remove most of the plating solution; the second-stage water washing, fine cleaning, using deionized water, resistivity ≥15MΩ·cm; the third-stage water washing, spraying or ultrasonic assistance, to completely remove the residue in the hole; neutralization water washing can also be used. For example, if the plating solution is acidic (such as copper sulfate plating solution), it needs to be neutralized with a weak alkaline solution (pH=8~9) and then washed with water; finally, drying can be done, using hot air drying at a temperature of 60~80℃ to avoid oxidation of the coating caused by high temperature; or vacuum drying, which is suitable for high-precision boards to prevent water vapor residue in the holes.

[0057] S160: After the electroplating treatment, the developed anode is stripped and air-dried for recycling, and the process of step S110 is continued.

[0058] Among them, the first developed anode and the second developed anode can be respectively set on both sides of the production plate, and the structure of the first developed anode and the structure of the second developed anode are the same. The first developed anode is set in the form of a reel on one side of the production plate, and the winding direction of the tail end of the first developed anode after electroplating is away from the direction of the production plate entering the electroplating tank. The second developed anode is set in the form of a reel on the other side of the production plate, and the winding direction of the tail end of the second developed anode after electroplating is away from the direction of the production plate entering the electroplating tank. That is, the first developed anode and the second developed anode form a roll-to-roll anode structure design on both sides of the production plate, and both can be turned around by the reel design to enter the film stripping tank and the air-drying tank. After the photosensitive material on the anode is stripped and air-dried, it can be reused and the process of step S110 is cyclically performed.

[0059] Specifically, based on the above embodiment, the electroplating method of the printed circuit board includes:

[0060] Taking the production board size of 24.20inch*28.20inch, the thickness of the production board is 4.5mm, the thickness-to-diameter ratio is 22.5:1, the minimum line width and line spacing of the outer layer are 101.6μm and 101.6μm respectively, the hole-dense areas are mainly concentrated in positions Ⅰ to Ⅷ, and the sizes of the hole-dense areas Ⅰ to Ⅷ are 2.18inch*1.33inch, 2.18inch*1.33inch, 2.18inch*1.33inch, 2.18inch*1.33inch, 0.62inch*3.66inch, 0.62inch*3.66inch, and 3.20inch*17.06inch respectively, and the cathode production board structure with a large area of ​​sparse holes at positions ① to ⑥ is taken as an example, which is consistent with the existing production board structure and size parameters.

[0061] It is important that the anode is coated with a photosensitive material, which includes, by mass, 100 parts of insulating polymer material, 3 parts of photosensitive additive, 15 parts of diluent, and 90 parts of conductive filler. That is, the photosensitive material is considered a non-insulating material. During the electroplating process, the anode is coated with a photosensitive material, and the pattern left by exposure and development is as follows: Figure 3 As shown, the dark part is the part left by the exposure of the anode surface, and the white part is the window position of the anode surface corresponding to the production plate. The window size is 0.2 inches larger in the circumference than the size of the hole-dense area.

[0062] During the electroplating process, the electroplating treatment adopts the pulse electroplating method. The pulse power supply of the pulse electroplating includes a forward pulse and a reverse pulse. The ratio of the forward pulse time to the reverse pulse time is 200ms:10ms, the current ratio of the forward pulse to the reverse pulse is 1:3, and the current density of the electroplating treatment is 1.7A / dm 2The electroplating time of the electroplating treatment is 160 minutes, and the waveform of the pulse electroplating can be any one of square wave, triangle wave and sawtooth wave, or a combination of two or more.

[0063] After the electroplating process was completed, the surface copper thicknesses of positions ① to ⑥ and positions Ⅰ to Ⅷ were measured. The surface copper thicknesses of positions ① to ⑥ were 37.45μm, 34.77μm, 38.39μm, 36.63μm, 32.95μm, and 35.46μm, respectively. The surface copper thicknesses of positions Ⅰ to Ⅷ were 27.64μm, 24.62μm, 25.61μm, 28.12μm, 26.43μm, 23.71μm, 27.71μm, and 24.99μm, respectively. The range of the surface copper thickness between the hole-dense area and the large area of ​​non-porous area was reduced to 13.40μm, and the large-area occlusion caused the surface copper thickness in the middle position of the blocked area to be significantly thinner than the surface copper at the edge position, with a range of about 8μm. Although the anode is covered and blocked by a large area of ​​photosensitive material, the photosensitive material has certain conductive properties, so the electric lines in the blocked position are not completely shielded, but are weakened to a certain extent, further optimizing the distribution of the electric lines on the production board and improving the uniformity of the copper thickness on the board surface. The copper thickness of this surface is within the processing capacity range of the outer layer pattern etching.

[0064] In contrast, still based on the structure of the cathode production board mentioned above, in the electroplating process of printed circuit boards, the anode is coated with a photosensitive material. Importantly, the photosensitive material includes, by mass, 100 parts of insulating polymer material, 3 parts of photosensitive additive, 15 parts of diluent, and 0 parts of conductive filler, that is, the photosensitive material is regarded as an insulating material. During the electroplating process, the anode is coated with the photosensitive material, and the pattern left by exposure and development is as follows: Figure 3 As shown, the dark part is the part left by the exposure of the anode surface, and the white part is the window position of the anode surface corresponding to the production plate. The window size is 0.2 inches larger in the circumference than the size of the hole-dense area.

[0065] During the electroplating process, the electroplating treatment adopts the pulse electroplating method. The pulse power supply of the pulse electroplating includes a forward pulse and a reverse pulse. The ratio of the forward pulse time to the reverse pulse time is 200ms:10ms, the current ratio of the forward pulse to the reverse pulse is 1:3, and the current density of the electroplating treatment is 1.7A / dm 2 The electroplating time of the electroplating treatment is 160 minutes, and the waveform of the pulse electroplating can be any one of square wave, triangle wave and sawtooth wave, or a combination of two or more.

[0066] After the electroplating process was completed, the surface copper thicknesses of positions ① to ⑥ and positions Ⅰ to Ⅷ were measured. The surface copper thicknesses of positions ① to ⑥ were 52.22μm, 49.13μm, 51.77μm, 51.16μm, 48.65μm, and 51.79μm, respectively. The surface copper thicknesses of positions Ⅰ to Ⅷ were 20.16μm, 19.75μm, 23.79μm, 22.14μm, 22.79μm, 20.55μm, 22.89μm, and 20.15μm, respectively. The extreme difference in surface copper thickness between the pore-dense area and the large area of ​​pore-free area reached 32.47μm. Although the range is reduced compared to when the anode is not coated with photosensitive material, the surface copper thickness in the large-area sparse hole area is excessively thinned due to the large-area shielding and obstruction of the photosensitive material. In addition, the large-area obstruction causes the surface copper thickness in the middle of the blocked area to be significantly thinner than the surface copper at the edge, with a range of about 10μm. Moreover, the range of the surface copper thickness is still beyond the processing capability of the outer layer pattern etching, and rework is required to increase the processing time of the production board.

[0067] In summary, the electroplating processing method of the printed circuit board of the present invention improves the problem of large surface copper differences between the hole-dense areas and the large areas without holes on the production board, and can controllably adjust the different degrees of shielding of the anode power lines to achieve efficient and continuous production without stopping the line to replace the anode baffle and other operations that waste production capacity.

[0068] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for electroplating a printed circuit board, characterized in that: The electroplating method comprises: Spraying a photosensitive material on the surface of the anode, and subjecting it to a pre-bake process and an exposure process to obtain an exposed anode; wherein the exposure process includes generating exposure data based on the distribution of dense hole areas and sparse hole areas on the production board, and exposing the photosensitive material on the surface of the anode after the pre-bake process; performing a development process on the exposed anode to obtain a developed anode; The developed anode and the production board enter the electroplating tank at the same speed for electroplating treatment. The production board after electroplating is washed with water to complete the electroplating process. The developed anode after electroplating is stripped and air-dried for recycling. The position of the window of the photosensitive material of the developed anode corresponds to the position of the hole-dense area of ​​the production board. The photosensitive material is calculated in parts by mass, and the photosensitive material includes 100 parts of insulating polymer material, 2 to 10 parts of photosensitive additive, 10 to 50 parts of diluent and 10 to 100 parts of conductive filler; The insulating polymer material includes any one or a combination of two or more of phenolic resin, polyester resin, polyurethane resin and epoxy resin; The photosensitive additive includes a photosensitive compound and / or a photosensitive monomer; The photosensitive compound includes any one or a combination of two or more of naphthoquinone diazide esters, imine sulfonates and oxime sulfonates, and the photosensitive monomer includes any one or a combination of two or more of trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and 2-hydroxyethyl methacrylate; The conductive filler comprises inorganic material and / or organic material; The inorganic material includes any one or a combination of two or more of carbon black, carbon nanotubes, graphene, metals and metal oxides, and the organic material includes any one or a combination of two or more of polypyrrole, polythiophene and polyaniline.

2. The electroplating method for a printed circuit board according to claim 1, wherein: A first anode and a second anode are respectively provided on both sides of the production plate, and the structure of the first anode is the same as that of the second anode. The first anode is a post-development anode, and the second anode is a post-development anode.

3. The electroplating method for a printed circuit board according to claim 2, wherein: The first anode is arranged in a reel form on one side of the production plate, and the tail end of the first anode that has been electroplated is wound in a direction away from the direction in which the production plate enters the electroplating tank; The second anode is arranged in the form of a reel at the other side of the production board, and the winding direction of the tail end of the second anode after electroplating is away from the direction in which the production board enters the electroplating tank.

4. The electroplating method for a printed circuit board according to claim 1, wherein: The size of the development window of the anode is compensated for the exposure size according to the size of the hole-dense area of ​​the production plate.

5. The electroplating method for a printed circuit board according to claim 4, wherein: The exposure size compensation of the anode development window is positive compensation or negative compensation.

6. The electroplating method for a printed circuit board according to claim 1, wherein: The electroplating treatment adopts pulse electroplating; The pulse power supply of the pulse plating includes a forward pulse and a reverse pulse; The ratio of the time of the forward pulse to the time of the reverse pulse is 200ms:10ms, and the current ratio of the forward pulse to the reverse pulse is 1:

3. The waveform of the pulse plating includes any one of square wave, triangle wave and sawtooth wave or a combination of two or more of them.

7. The electroplating method for a printed circuit board according to claim 1, wherein: The developed anode and the production plate need to be degreased before entering the electroplating tank.

8. The electroplating method for a printed circuit board according to claim 1, wherein: The material of the anode includes any one of copper, aluminum, titanium, copper alloy, aluminum alloy and titanium alloy; The structure of the anode includes a sheet structure and / or a mesh structure.

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