Method for manufacturing a printed circuit board and printed circuit board

Abstract

The application discloses a printed circuit board preparation method and a printed circuit board. The printed circuit board is provided with a multi-sectioned gold finger. The preparation method comprises the following steps: a groove is formed at a preset position of a semi-cured sheet corresponding to a sectional gap of the gold finger, and a washable ink is filled into the groove; the semi-cured sheet filled with the washable ink is compressed with a core plate to form a multi-layer board, and the washable ink is embedded in the interior of the multi-layer board; a conductive circuit corresponding to the gold finger and a surface copper layer are formed on the multi-layer board, and the board is gold-plated; the washable ink, the copper layer and the gold layer attached to the surface of the ink are removed, a sectional gap is formed between adjacent sections of the gold finger, and the multi-sectioned gold finger is prepared. The conductive circuit corresponding to the gold finger and the surface copper layer are formed on the multi-layer board, and the board is gold-plated, then the washable ink, the copper layer and the gold layer attached to the surface of the ink are removed, and thus the multi-sectioned gold finger is prepared.

Description

Technical Field

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

[0002] With the current trend of electronic products moving towards higher data transmission rates, the gold finger, as a key interconnect structure for high-speed signals, is facing unprecedented challenges in its manufacturing process. As signal frequencies increase, the multi-segment design of the gold finger becomes a necessary means to achieve impedance matching and signal integrity, but this also significantly increases the difficulty of the etching process.

[0003] First, the micro-etching at the segment locations must be completed within extremely narrow spacing. Any minute process fluctuations can lead to localized thinning of the metal layer, resulting in collapse under subsequent thermal cycling or mechanical stress, thus compromising the continuity and reliability of the circuit. Second, as the number of segments increases, the number of fine leads remaining after etching rises sharply. Removing these leads requires not only higher precision but also avoids secondary damage to adjacent metal structures. Traditional chemical stripping or plasma cleaning is often insufficient for complete removal and can easily leave residues at the roots of the leads, leading to increased local resistance or micro-short circuits. Furthermore, high-speed signals place extremely stringent requirements on the surface roughness and morphology of the gold fingers. Any surface unevenness caused by uneven etching will introduce additional scattering and reflection during high-frequency transmission, thereby weakening signal integrity.

[0004] The challenges of manufacturing multi-segment gold fingers are increasing, and with the development of the PCIe protocol, the demand for multi-segment gold fingers is also rising. How to produce high-quality multi-segment gold fingers has become a problem that major manufacturers need to solve. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for manufacturing printed circuit boards that can obtain multi-segmented gold fingers without gold plating edge collapse defects, enabling the product to meet the requirements of high-frequency and high-speed products.

[0006] The present invention further proposes a printed circuit board.

[0007] According to a first aspect of the present invention, a method for manufacturing a printed circuit board is provided on the printed circuit board, wherein the printed circuit board is provided with segmented gold fingers. The manufacturing method includes the following steps: forming a groove at a preset position corresponding to the segment gap of the gold fingers on a prepreg, and filling the groove with washable ink; pressing the prepreg filled with the washable ink with a core board to form a multilayer board, wherein the washable ink is embedded inside the multilayer board; fabricating conductive lines and surface copper layers corresponding to the gold fingers on the multilayer board, and gold plating the board; removing the washable ink and the copper and gold layers attached to the ink surface, forming a separation gap between the segments of adjacent gold fingers, thereby manufacturing the segmented gold fingers.

[0008] According to the method for manufacturing a printed circuit board according to an embodiment of the present invention, conductive lines and surface copper layers corresponding to gold fingers are fabricated on a multilayer board, and the board is gold-plated. Then, by removing washable ink and copper and gold layers adhering to the ink surface, a separation gap can be formed between the segments of adjacent gold fingers, thereby producing multi-segmented gold fingers. This results in multi-segmented gold fingers without gold-plated edge collapse defects, enabling the product to meet the requirements of high-frequency and high-speed products.

[0009] According to some embodiments of the present invention, the step of fabricating the conductive lines corresponding to the gold fingers on the multilayer board includes: drilling the multilayer board after lamination to form through holes corresponding to the gold fingers; and performing copper plating on the through holes.

[0010] According to some embodiments of the present invention, after the step of performing copper plating on the via, the method further includes the following steps: performing resin plugging on the metallized via to fill the via with resin; and performing copper plating on the plugged board to form a continuous copper coating layer on the outer surface of the board.

[0011] According to some embodiments of the present invention, after the step of forming a continuous copper coating layer on the outer surface of the board, a first etching process is further included: attaching a first photosensitive dry film to the outer surface of the board, and after exposure and development, etching the copper coating layer on the surface of the board to remove the copper coating layer above the washable ink area and expose the surface of the washable ink.

[0012] According to some embodiments of the present invention, after the first etching process, a thin copper layer formation process is further included: performing copper plating on the exposed washable ink surface, and then removing the first photosensitive dry film on the board surface; performing flash plating on the board to form a thin copper layer on the washable ink surface, wherein the thin copper layer is electrically connected to the surrounding covering copper layer.

[0013] According to some embodiments of the present invention, after the step of forming a thin copper layer, a second etching step is further included: a second photosensitive dry film is attached to the surface of the board, and after exposure and development, the covering copper layer on the surface of the board is etched, retaining only the covering copper layer in the area corresponding to the gold fingers and the area corresponding to the washable ink.

[0014] According to some embodiments of the present invention, the step of creating a groove at a preset position corresponding to the segmented gap of the gold finger on the prepreg includes: forming a groove on the prepreg using a grooving process.

[0015] According to some embodiments of the present invention, the step of removing the washable ink and the metal layer attached to the ink surface further includes: washing the plate to dissolve and remove the washable ink, while removing the copper layer and gold layer attached to the surface of the washable ink along with the washable ink.

[0016] According to some embodiments of the present invention, after the multi-segmented gold fingers are formed, a solder resist processing step is further included: a solder resist layer is formed in the non-soldering area of ​​the board to obtain the printed circuit board.

[0017] According to a second aspect of the present invention, a printed circuit board is provided on its surface with segmented gold fingers, the segmented gold fingers being prepared by the aforementioned preparation method.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a cross-sectional view of step one of the methods for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of step two of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of step three of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of step four of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 5 This is a cross-sectional view of step five of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 6 This is a cross-sectional view of step six of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 7 This is a cross-sectional view of step seven of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 8 This is a cross-sectional view of step eight of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 9 This is a cross-sectional view of step nine of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 10 This is a cross-sectional view of step ten of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 11 This is a top view of step ten of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 12 This is a cross-sectional view of step eleven of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 13 This is a cross-sectional view of step twelfth in the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 14 This is a top view of step twelfth in the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 15 This is a cross-sectional view of step thirteen of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 16 This is a top view of step thirteen of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 17 This is a cross-sectional view of step fourteen of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 18 This is a top view of step fourteen of the method for manufacturing a printed circuit board according to an embodiment of the present invention; Figure 19 This is a cross-sectional view of step fifteen of the method for manufacturing a printed circuit board according to an embodiment of the present invention.

[0020] Figure label: 100. Printed circuit boards; 11. Prepreg; 12. Washable ink; 13. Core board; 14. Metal layer; 15. Through hole; 16. Copper cover layer; 17. Resin; 18. Thin copper layer; 20. Copper layer; 21. Gold layer; 22. Solder mask. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0022] The following is for reference. Figures 1-19The invention describes a method for manufacturing a printed circuit board 100 according to an embodiment of the invention, and also provides a printed circuit board 100.

[0023] Reference Figures 1-19 As shown, the method for manufacturing a printed circuit board 100 according to an embodiment of the present invention includes a printed circuit board 100 having segmented gold fingers.

[0024] The preparation method includes the following steps: Reference Figure 1 and Figure 2 As shown, grooves are formed at preset positions on the prepreg 11 corresponding to the segmented gaps of the gold fingers, and washable ink 12 is filled into the grooves. The washable ink 12 serves as a sacrificial filler material. Reference Figure 3 and Figure 4 As shown, a prepreg filled with washable ink 12 is laminated with a core board 13 and a metal layer 14 to form a multilayer board, with the washable ink 12 embedded inside the multilayer board. Specifically, after the prepreg filled with washable ink 12 is laminated with the core board 13 and the metal layer 14 according to the designed stacking structure, a multilayer board is formed by lamination process, so that the washable ink 12 is completely embedded in the corresponding position inside the multilayer board.

[0025] Conductive circuits and a surface copper layer 20 corresponding to the gold fingers are fabricated on a multilayer board, and the board is then gold-plated. The conductive circuits and surface copper layer 20 corresponding to the gold fingers are fabricated on the multilayer board, and the entire board is gold-plated so that both the gold finger area and the area above the ink are covered with a gold layer 21.

[0026] The washable ink 12 and the copper layer 20 and gold layer 21 adhering to the ink surface are removed, forming a separation gap between the segments of adjacent gold fingers, thus producing a multi-segmented gold finger. The washable ink 12 inside is removed by the washing process, and at the same time, the copper layer 20 and gold layer 21 adhering to the ink surface are detached along with the ink, forming a regular separation gap between the segments of adjacent gold fingers, and finally producing a high-quality multi-segmented gold finger structure without edge collapse and without residual leads.

[0027] Therefore, conductive lines and surface copper layers 20 corresponding to the gold fingers are fabricated on the multilayer board, and the board is gold-plated. Then, by removing the washable ink 12 and the copper layer 20 and gold layer 21 attached to the ink surface, a separation gap can be formed between the segments of adjacent gold fingers, thereby producing multi-segmented gold fingers. This results in multi-segmented gold fingers without gold-plated edge collapse defects, enabling the product to meet the requirements of high-frequency and high-speed products.

[0028] The steps for fabricating the conductive lines corresponding to the gold fingers on a multilayer board include: Reference Figure 5As shown, the laminated multilayer board is drilled to form vias 15 corresponding to the gold fingers. When fabricating conductive lines corresponding to the gold fingers on the multilayer board, high-precision drilling is first performed on the laminated multilayer board according to the interlayer interconnection design of the gold fingers. The vias 15 are formed at the pad positions corresponding to the gold fingers, and the hole position deviation is strictly controlled to match the circuit layout of the gold fingers. Reference Figure 6 As shown, the via 15 is subjected to copper plating. First, a conductive copper seed layer is deposited on the insulating hole wall surface through a chemical copper plating process. Then, the copper layer 20 on the hole wall is thickened through an electroplating process, so that the hole wall of the via 15 is completely metallized, realizing reliable electrical conduction between different layers of the multilayer board, completing the hole-forming of the gold finger conductive path, and ensuring the continuity of high-speed signal transmission between layers.

[0029] After the copper plating process is performed on the via 15, the following steps are also included: Reference Figure 7 As shown, the metallized via 15 is filled with resin 17 to completely fill the interior of the via 15. Specifically, after copper plating, the metallized via 15 is filled with resin 17. An insulating resin 17 suitable for PCB manufacturing is selected, and the resin 17 is injected under pressure into the via 15 using a filling device, completely filling the cavity. A curing process then ensures the resin 17 bonds tightly to the hole wall, eliminating cavities and preventing defects such as hole depressions and residual chemicals in subsequent electroplating and surface treatment processes, effectively ensuring the flatness of the board surface.

[0030] Reference Figure 8 As shown, after the via plugging is performed, copper plating is applied to the board to form a continuous copper layer 16 on the outer surface of the board. That is, after the via plugging is completed, the entire board is subjected to copper plating and electroplating to form a continuous and uniform copper layer 16 on the outer surface of the board and the surface of the via plugging resin 17. This provides a complete and continuous copper layer 20 substrate for subsequent circuit pattern etching and gold finger structure fabrication, while ensuring the consistency of the thickness of the copper layer 20 on the entire board, providing a stable conductive foundation for the subsequent gold plating process.

[0031] Reference Figure 9 and Figure 10 As shown, after the step of forming a continuous copper overlay layer 16 on the outer surface of the board, a first etching process is also included: a first photosensitive dry film is attached to the outer surface of the board, and after exposure and development, the copper overlay layer 16 on the surface of the board is etched to remove the copper overlay layer 16 above the area of ​​the washable ink 12, exposing the surface of the washable ink 12. The purpose of the first etching process is to expose the top surface of the washable ink 12 embedded in the board.

[0032] The specific steps are as follows: a first photosensitive dry film is flatly attached to the outer surface of the board. The first photosensitive dry film is an anti-etching photosensitive dry film. After precise alignment with the film, it is exposed to cause the dry film in the non-ink area to polymerize and solidify. Then, the dry film in the area corresponding to the washable ink 12 is removed by the developing process to expose the underlying copper covering layer 16. Subsequently, the board is etched using an acidic etching solution to completely remove the copper layer 16 covering the area directly above the washable ink 12, precisely exposing the top surface of the washable ink 12 buried underneath. During the etching process, the etching parameters and time are strictly controlled to avoid excessive side etching that could affect the processing accuracy of the surrounding circuits. At the same time, it ensures that the surface of the washable ink 12 is fully exposed without any residual copper layer 20 obstructing it, thus preparing for the subsequent fabrication of a thin copper layer 18 on the surface of the washable ink 12.

[0033] Reference Figure 11 As shown, after the first etching process, a thin copper layer 18 formation process is also included: copper plating is performed on the exposed washable ink 12 surface, and then the first photosensitive dry film on the board surface is removed; the board is flash plated to form a thin copper layer 18 on the washable ink 12 surface, and the thin copper layer 18 is electrically connected to the surrounding cover copper layer 16. The thin copper layer 18 is used to construct a conductive layer on the insulating washable ink 12 surface, and the thin copper layer 18 is tightly connected to the surrounding cover copper layer 16, maintaining complete electrical conductivity. This ensures that during subsequent gold plating of the entire board, the area corresponding to the washable ink 12 can also normally deposit the gold layer 21, guaranteeing consistent gold plating potential in each segment and gap area of ​​the gold fingers, and avoiding defects such as uneven gold plating thickness and incomplete plating.

[0034] The specific working steps are as follows: First, chemical copper plating is performed on the exposed washable ink 12 surface and the entire board to deposit an extremely thin chemical copper seed layer on the ink surface, so that the originally insulating ink surface has conductivity. Then, the first photosensitive dry film attached to the surface of the board is completely removed by a special film removal solution. The copper layer 20 attached to the dry film is also removed along with the dry film, leaving only the copper layer 20 on the ink surface and the surrounding circuit area. The entire board is then subjected to flash plating, a rapid thin copper plating process. By precisely controlling the current density and processing time of the plating, a thin copper layer 18 of uniform thickness is formed on the chemical copper layer 20 on the surface of the washable ink 12.

[0035] Reference Figure 12As shown, after the step of forming the thin copper layer 18, a second etching step is included: a second photosensitive dry film is attached to the surface of the board, and after exposure and development, the cover copper layer 16 on the surface of the board is etched, retaining only the cover copper layer 16 corresponding to the gold fingers and the washable ink 12. Specifically, the second photosensitive dry film is flatly attached to the surface of the board, and high-precision film is used for alignment and exposure. The dry film corresponding to the gold fingers and the washable ink 12 is retained and cured, while the dry film in the remaining non-circuit areas is completely removed after development. Subsequently, the cover copper layer 16 on the surface of the board is etched using an etching solution to remove all non-retained areas of the cover copper layer 16, leaving only the cover copper layer 16 corresponding to the gold fingers and the washable ink 12, forming a complete gold finger pattern outline.

[0036] The copper layer 20 above the washable ink 12 serves as a temporary conductive structure between the segments of the gold finger, ensuring the overall conductivity of the subsequent gold plating process and ensuring that each segment and gap area of ​​the gold finger can be uniformly gold-plated, thus avoiding the problem of poor gold plating in individual segments.

[0037] The step of creating grooves at preset positions corresponding to the segmented gaps of the gold fingers on the prepreg 11 includes: forming grooves on the prepreg 11 using a grooving process. The grooving process utilizes a punching die precisely matched to the groove design dimensions to punch and cut at the preset positions on the prepreg 11, forming the groove structure in one step. The grooving process offers high dimensional accuracy and avoids mechanical damage to other areas of the prepreg 11 during processing, ensuring the bonding strength and reliability of the prepreg 11 during subsequent pressing.

[0038] The depth of the groove is consistent with the thickness of the prepreg 11, ensuring that after the washable ink 12 is filled, the ink can completely correspond to the segmented gap position of the gold fingers during the pressing process, providing a basis for the subsequent formation of regular separation gaps.

[0039] Reference Figure 17 and Figure 18 As shown, the steps for removing the washable ink 12 and the metal layer 14 adhering to the ink surface further include: washing the board to dissolve and remove the washable ink 12, while simultaneously removing the copper layer 20 and gold layer 21 adhering to the surface of the washable ink 12 along with the washable ink 12. When removing the washable ink 12 and the metal layer 14 adhering to the ink surface, a weakly alkaline washing solution is used to treat the board. The washing solution can be fully contacted with the washable ink 12 by immersion or spraying. The weakly alkaline solution can specifically react with the washable ink 12, gradually dissolving and peeling off the ink. Furthermore, the weakly alkaline solution will not damage the gold layer 21 and the underlying copper layer structure of the gold fingers, thus ensuring the integrity of the gold finger plating.

[0040] As the washable ink 12 gradually dissolves, the thin copper layer 18 and gold layer 21 adhering to the ink surface lose their supporting base and detach from the board along with the ink, thus forming a separation gap between adjacent gold finger segments with a depth consistent with the ink thickness. Furthermore, since the separation gap is formed by pre-embedding ink and then removing it, rather than by surface micro-etching, the sidewalls of the gap are steep and flat, avoiding the problem of gold layer 21 edge collapse caused by etching side etching, and also preventing the residue of fine leads that cannot be completely removed by traditional etching processes. At the same time, the end face of the gold finger is flat and smooth with extremely low surface roughness, which can effectively ensure impedance continuity during high-frequency signal transmission, avoid signal scattering and reflection, and significantly improve the integrity of high-speed signals.

[0041] Reference Figure 19 As shown, after the multi-segmented gold fingers are formed, a solder mask processing step is also included: a solder mask layer 22 is formed in the non-soldering area of ​​the board to obtain the printed circuit board 100. After high-temperature curing, the solder mask layer 22 has good insulation and environmental protection properties. It can not only insulate and protect the internal circuits of the board to avoid short circuit faults between adjacent circuits, but also improve the oxidation resistance, corrosion resistance and wear resistance of the board, extend the service life of the printed circuit board 100, and finally obtain a complete finished printed circuit board 100.

[0042] The solder mask layer 22 is manufactured as follows: First, the board is thoroughly cleaned to remove residual stripping solution, impurities, and copper oxide layer from the board surface, ensuring the cleanliness of the board surface; then, solder mask ink is applied to the board surface by screen printing or attachment; through the exposure and development pattern transfer process, the soldering contact area of ​​the gold fingers and other exposed pads and test points are exposed, while the remaining non-soldering and non-contact circuit areas are completely covered by the solder mask layer 22. According to a second aspect embodiment of the present invention, the printed circuit board 100 has segmented gold fingers on its surface, which are fabricated using a specific method. The gold fingers of the printed circuit board 100 have vertically flat sidewalls between the segments, free from gold layer collapse, edge burrs, residual leads, and other processing defects. The gold fingers exhibit high surface flatness, low roughness, and good impedance continuity, meeting the signal transmission requirements of high-speed communication products such as 224G and adapting to application scenarios of high-speed protocols such as PCIE. Furthermore, the gold fingers of the printed circuit board 100 have high processing precision, resulting in good yield and consistency in mass production. This effectively improves the signal integrity and operational reliability of high-speed, high-frequency electronic products, making it suitable for high-end communication equipment, servers, high-speed storage devices, and other electronic product fields with stringent gold finger performance requirements.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0045] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for manufacturing a printed circuit board, wherein the printed circuit board is provided with segmented gold fingers, characterized in that, Includes the following steps: A groove is made at a preset position corresponding to the segmented gap of the gold finger on the prepreg, and washable ink is filled into the groove; A prepreg filled with the washable ink is pressed together with a core board to form a multilayer board, wherein the washable ink is embedded inside the multilayer board; Conductive lines and surface copper layers corresponding to the gold fingers are fabricated on the multilayer board, and the board is then gold-plated. The washable ink and the copper and gold layers adhering to the ink surface are removed, and a separation gap is formed between the segments of the adjacent gold fingers to produce the multi-segmented gold fingers.

2. The method for preparing a printed circuit board according to claim 1, characterized in that, The step of fabricating the conductive lines corresponding to the gold fingers on the multilayer board includes: The laminated multilayer board is drilled to form through holes corresponding to the gold fingers; The via is subjected to copper plating.

3. The method for preparing a printed circuit board according to claim 2, characterized in that, After the step of performing copper plating on the via, the method further includes the following steps: The metallized via is then filled with resin to ensure that the resin completely fills the via. After the vias are plugged, the board is subjected to copper plating to form a continuous copper coating on the outer surface of the board.

4. The method for preparing a printed circuit board according to claim 3, characterized in that, Following the step of forming a continuous copper coating on the outer surface of the board, a first etching process is also included: A first photosensitive dry film is attached to the outer surface of the board. After exposure and development, the copper coating on the surface of the board is etched to remove the copper coating above the washable ink area, exposing the surface of the washable ink.

5. The method for preparing a printed circuit board according to claim 4, characterized in that, The process described includes a thin copper layer formation step following the first etching step: The exposed washable ink surface is subjected to copper plating treatment, and then the first photosensitive dry film on the surface of the board is removed. The board is flash plated to form a thin copper layer on the washable ink surface, and the thin copper layer is electrically connected to the surrounding covering copper layer.

6. The method for manufacturing a printed circuit board according to claim 5, characterized in that, Following the thin copper layer formation process, a second etching process is also included: A second photosensitive dry film is attached to the surface of the board. After exposure and development, the copper coating on the surface of the board is etched, leaving only the copper coating in the area corresponding to the gold fingers and the area corresponding to the washable ink.

7. The method for preparing a printed circuit board according to claim 1, characterized in that, The step of creating grooves at predetermined positions corresponding to the segmented gaps of the gold fingers on the prepreg includes: A groove is formed on the prepreg using a grooving process.

8. The method for preparing a printed circuit board according to claim 1, characterized in that, The step of removing the washable ink and the metal layer adhering to the ink surface further includes: The plate is washed to dissolve and remove the washable ink, and at the same time, the copper and gold layers attached to the surface of the washable ink are removed along with the washable ink.

9. The method for manufacturing a printed circuit board according to claim 1, characterized in that, After producing multi-segmented gold fingers, the process also includes a solder mask processing step: A solder resist layer is fabricated in the non-soldering area of ​​the board to obtain the printed circuit board.

10. A printed circuit board, characterized in that, The printed circuit board surface is provided with segmented gold fingers, which are prepared by the preparation method of any one of claims 1-9.

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