Circuit board and preparation method thereof, circuit board assembly and electronic device

Abstract

The invention relates to the technical field of printed circuit boards, and discloses a circuit board and a preparation method thereof, a circuit board assembly and an electronic device. The circuit board comprises a plurality of first substrates and a plurality of second substrates which are arranged in an overlapping manner; the second substrate comprises a first area and a second area which are adjacently arranged in the first direction, and the orthographic projection of the first substrate on the second substrate is located in the first area of the second substrate; the second substrate is provided with a first surface and a second surface which extend along a first direction and are opposite to each other; a groove is formed between two adjacent second substrates and the first substrate; the bonding pad golden finger layer extends on the first surface and / or the second surface along the first direction, and the orthographic projection of the bonding pad golden finger layer on the second substrate is located in the second area; the bonding pad golden finger layer is at least located on the side wall of the groove. According to the circuit board, through the structural design of the multiple layers of bonding pad golden fingers, the number of bonding pad transmission layers can be increased, and therefore the signal transmission capacity of the circuit board can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of printed circuit boards, and in particular to circuit boards and methods for preparing the same, circuit board assemblies, and electronic devices. Background Art

[0002] Gold fingers are gold-plated conductive contacts located on the edge of a printed circuit board (PCB). They are named for their golden appearance and finger-like arrangement. Their core function is to ensure stable signal transmission through low contact resistance, so they must possess excellent electrical conductivity. Furthermore, they must exhibit excellent oxidation and corrosion resistance to reduce wear during frequent plugging and unplugging.

[0003] Currently, the application of gold fingers has expanded beyond traditional computer hardware to multiple high-tech industries. In computers and consumer electronics, components such as memory modules, graphics cards, and motherboards are connected to the motherboard via gold fingers, enabling high-speed signal and data transmission. In communications equipment, 5G base stations and routers rely on gold fingers to ensure stable transmission of high-frequency signals. In the industrial and medical fields, industrial control systems and medical equipment use gold fingers to maintain reliable signal transmission in harsh environments. In emerging fields such as smart homes, autonomous driving, and aerospace, gold fingers can support complex signal interactions and modular designs.

[0004] With the increasing adoption of technologies like 5G and the Internet of Things, gold finger technology must adapt to higher frequencies and faster data rates. Simultaneously, gold finger reliability must be optimized to address impedance matching issues under high-frequency signals and enhance resistance to physical damage. With the continued expansion of gold finger applications and ongoing innovation in manufacturing processes, gold finger technology will achieve further breakthroughs in high performance, environmental friendliness, and intelligence, driving the development of more efficient and reliable electronic products. Therefore, further improvements to circuit boards with gold finger technology are urgently needed.

[0005] It should be noted that the above statements are only used to provide background technical information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0006] In view of the technical problems existing in the background technology, the first aspect of the present application provides a circuit board, including: multiple first substrates and multiple second substrates, the multiple first substrates and the multiple second substrates are arranged overlappingly; the second substrate includes a first area and a second area adjacent to each other in a first direction, and the orthographic projection of the first substrate on the second substrate is located in the first area of ​​the second substrate; the second substrate is provided with a first surface and a second surface relative to each other extending along the first direction; a groove, the groove is formed between two adjacent second substrates and the first substrate; a pad gold finger layer, the pad gold finger layer is extended along the first direction on the first surface and / or the second surface, and the orthographic projection of the pad gold finger layer on the second substrate is located in the second area; the pad gold finger layer is located at least on the side wall of the groove.

[0007] Therefore, the circuit board of the present application can increase the number of pad transmission layers through the structural design of the multi-layer pad gold finger, thereby improving the signal transmission capability of the circuit board. At the same time, the size of the circuit board can be reduced without reducing the signal density of the circuit board, so that the circuit board can improve its functional integration within a limited space, thereby improving the integration of the circuit board. The circuit board of the present application meets the signal transmission requirements of high-speed, high-frequency, and high-density electronic devices, providing strong support for the high performance and miniaturization development of electronic devices.

[0008] In some embodiments, the pad gold finger layer includes a plurality of gold fingers spaced apart along a second direction intersecting the first direction; the gold fingers on the first surface are spaced uniformly; and / or the gold fingers on the second surface are spaced uniformly. This allows for the formation of more signal transmission paths within a limited space, thereby optimizing space utilization on the circuit board.

[0009] In some embodiments, the gold fingers on the first surface and the gold fingers on the second surface of the second substrate are arranged in a symmetrical plane. This allows for more balanced stress on the circuit board during use, reduces deformation or damage to the circuit board due to stress concentration, and improves the mechanical stability and reliability of the circuit board.

[0010] In some embodiments, the spacing between the gold fingers on the first surface is different from the spacing between the gold fingers on the second surface. Thus, the circuit board of the present application can adapt to various types of signal transmission requirements, providing greater flexibility in circuit board design, and can be personalized according to specific circuit requirements and board space requirements, meeting the design requirements of complex electronic systems.

[0011] In some embodiments, the gold fingers on the first surface of the second substrate are arranged opposite to the gold fingers on the second surface of the adjacent second substrate. This can enhance the connection reliability between the circuit board and other boards, reduce poor contact caused by plugging and unplugging, and thus improve the stability and reliability of the entire electronic system.

[0012] In some embodiments, the length of the groove along the first direction is greater than or equal to the length of the pad gold finger layer; and / or, the length of the groove along the second direction is greater than or equal to the length of the pad gold finger layer. Thus, when the circuit board is assembled, other boards that are connected to the circuit board can fully contact the pad gold finger layer, thereby forming a good electrical connection and improving the reliability of the electrical connection. Alternatively, when the circuit board is assembled, the circuit board can be more accurately aligned with other boards during insertion and removal. Furthermore, during the circuit board manufacturing process, it facilitates precise groove milling with a milling cutter or laser.

[0013] In some embodiments, the thickness of the second substrate along the thickness direction of the circuit board is greater than or equal to 0.5 mm. This can improve the mechanical strength of the circuit board, reduce the risk of deformation or damage to the circuit board during insertion and removal, and thus improve the service life and reliability of the circuit board.

[0014] In some embodiments, the second substrate has a bevel depth of 1 mm to 1.5 mm and a bevel angle of 15° to 25°. This facilitates insertion and removal of the circuit board from other boards, reduces resistance and wear during insertion and removal, and improves connection convenience and reliability.

[0015] In some embodiments, the distance between adjacent pad gold finger layers within the same groove along the thickness direction of the circuit board is greater than or equal to 0.5 mm. Thus, by controlling the distance between adjacent pad gold finger layers, milling or laser milling of the circuit board during processing is facilitated, as well as assembling the circuit board with other boards.

[0016] In some embodiments, the pad gold finger layer is symmetrically distributed along the thickness of the circuit board, with the center plane of the circuit board as the symmetry plane. This balances the stress distribution along the thickness of the circuit board, reducing the risk of bending or twisting during processing and use. Furthermore, it effectively reduces lamination layer offset during processing and manufacturing, thereby improving overall manufacturing yield.

[0017] The second aspect of the present application provides a method for manufacturing the circuit board of the first aspect of the present application, comprising: alternating the first substrate and the second substrate to form the grooves, thereby obtaining the circuit board; wherein the pad gold finger layer is located on at least one side of the second substrate along the thickness direction of the circuit board. Therefore, compared with traditional stepped gold finger board designs or upgrading the factory's manufacturing process level, the method of the present application does not require additional manufacturing processes or equipment investment, and can achieve higher performance and integration of the circuit board under existing manufacturing process conditions, thereby effectively reducing the manufacturing cost of the circuit board.

[0018] In some embodiments, the steps after forming the groove include: placing a gasket in the groove and pressing the first and second substrates together. This can improve the flatness and stability of the first and second substrates during the pressing process, reduce deformation or damage caused by uneven pressure, and thus improve product yield.

[0019] In some embodiments, the steps prior to alternating the first and second substrates include: laminating the first and second substrates; and slotting the first substrate to form the grooves. This can improve the bonding strength between the first and second substrates, and the precise formation of the grooves through slotting can improve the overall quality and reliability of the circuit board.

[0020] In some embodiments, the slotting process includes mechanical milling or laser milling. Both methods can achieve precise slotting. Mechanical milling is suitable for large-scale production and is relatively low-cost; laser milling offers greater precision and flexibility, making it suitable for complex shapes and high-precision applications.

[0021] A third aspect of the present application provides a circuit board assembly, comprising the circuit board of the first aspect of the present application, or a circuit board prepared by the method of the second aspect of the present application. Thus, this assembly design can fully utilize the high-density signal transmission capabilities and miniaturized design advantages of the circuit board to ensure efficient integration and reliable connection of electronic systems.

[0022] In some embodiments, a connector is further included, wherein the connector includes a protruding post, which is located in the groove and electrically connected to the pad gold finger layer. This can form a stable electrical connection and mechanical fixation between the circuit board and other boards or components, thereby improving the assembly security and signal transmission performance of the circuit board assembly.

[0023] In some embodiments, the number of the protruding posts is the same as the number of the grooves. Thus, the number of the protruding posts is the same as the number of the grooves, so that each groove has a corresponding protruding post for connection, thereby further forming a stable electrical connection and mechanical fixation between the circuit board and other boards or components.

[0024] In some embodiments, the thickness of the protruding pillar is the same as the distance between adjacent pad gold finger layers located in the same groove. This can further secure the connector in the groove and reduce the problem of loose connection caused by thickness mismatch between the two.

[0025] In some embodiments, the protruding column includes a main body and pad layers located on both sides of the main body, wherein the pad layers are in contact with the pad gold finger layer. This can further enhance the electrical connection and mechanical strength between the connector and the circuit board, and improve the reliability and stability of the connection.

[0026] A fourth aspect of the present application provides an electronic device comprising the circuit board of the first aspect of the present application, or a circuit board prepared by the method of the second aspect of the present application, or a circuit board assembly of the third aspect of the present application. Thus, the electronic device possesses all the advantages of the circuit board of the present application, and no further details are given. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 This is a front view of a circuit board in one embodiment of the present application.

[0028] Figure 2 This is a side view of a circuit board in one embodiment of the present application.

[0029] Figure 3 This is a side view of a circuit board during processing in one embodiment of the present application.

[0030] Figure 4 This is a side view of a circuit board assembly in one embodiment of the present application.

[0031] Description of reference numerals: 1. First substrate; 11. First dielectric layer; 12. First conductive layer; 2. Second substrate; 21. Second dielectric layer; 22. Second conductive layer; 23. First region; 24. Second region; 3. Pad gold finger layer; 31. Gold finger; 4. Groove; 5. Gasket; 6. Connector; 61. Protruding column; 611. Pad layer. DETAILED DESCRIPTION

[0032] The present application will be further described below in conjunction with specific embodiments. It should be understood that these specific embodiments are only used to illustrate the present application and are not used to limit the scope of the present application.

[0033] Below, the circuit board and its preparation method, circuit board assembly, and electronic device embodiments of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0034] " scope " disclosed in the present application is limited in the form of lower limit and / or upper limit, and given range is limited by selecting a lower limit and / or an upper limit, and selected lower limit and / or upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form the scope of not clearly recording with any upper limit combination, and any lower limit can form the scope of not clearly recording with other lower limit combination, and any upper limit can form the scope of not clearly recording with any other upper limit combination. In addition, each independently disclosed point or single numerical value itself can be used as lower limit or upper limit and any other point or single numerical value combination or with other lower limit or upper limit combination to form the scope of not clearly recording. For example, if the scope of 60~120 and 80~110 is listed for specific parameters, it is understood that the scope of 60~110 and 80~120 is also expected. In addition, if the minimum range values ​​are 1 and 2, and if the maximum range values ​​are 3, 4, and 5, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise indicated, the numerical range "a-b" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for these numerical combinations. In addition, when a parameter is stated as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0036] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0037] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0038] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0039] Unless otherwise specified, the term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0040] In this application, the terms "plurality" and "multiple" refer to two or more.

[0041] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the accompanying drawings are intended to cover non-exclusive inclusions. Unless otherwise specified, the terms used in this application have the commonly understood meanings commonly understood by those skilled in the art. Unless otherwise specified, the numerical values ​​of the various parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the examples of this application).

[0042] As electronic devices develop towards high speed, high frequency and high density, the number of signal transmissions between circuit boards needs to continue to increase. One way to increase the number of signal transmissions is to increase the number of circuit boards with gold fingers 31. However, the thickness of conventional circuit boards with gold fingers 31 is limited to 1.57 mm. Under the current circuit board manufacturing process conditions, a 1.57 mm thick circuit board can be designed with a maximum of 14 layers. If there are more than 14 layers, it is necessary to improve the factory's manufacturing process level or adopt a stepped gold finger board design, but both manufacturing methods will increase the manufacturing cost of the circuit board; at the same time, in server system design, a 14-layer circuit board is difficult to meet the development needs of miniaturization of server boards.

[0043] To simultaneously meet the needs of miniaturization and high density in electronic devices, another method for increasing the number of signal transmissions is to increase the number of gold fingers 31. However, the conventional gold finger 31 pin size is 0.6mm x 3mm. If the width of the gold finger 31 pin is reduced to less than 0.6mm, the gold finger board may experience poor contact during insertion and removal, or even risk a short circuit. Therefore, it is difficult to reduce the gold finger 31 pin width to 0.6mm, which limits the number of signal transmissions on the circuit board and makes it difficult to increase the circuit board's integration level.

[0044] Based on this, the first aspect of the present application provides a circuit board, Figure 1 and Figure 2 The circuit board includes: a plurality of first substrates 1 and a plurality of second substrates 2, wherein the plurality of first substrates 1 and the plurality of second substrates 2 are overlapped; the second substrate 2 includes a first area 23 and a second area 24 adjacently arranged in a first direction, and the orthographic projection of the first substrate 1 on the second substrate 2 is located within the first area 23 of the second substrate 2; the second substrate 2 is provided with a first surface and a second surface opposite to each other extending along the first direction; a groove 4, wherein the groove 4 is formed between two adjacent second substrates 2 and the first substrate 1; a pad gold finger layer 3, wherein the pad gold finger layer 3 is extended on the first surface and / or the second surface along the first direction, and the orthographic projection of the pad gold finger layer 3 on the second substrate 2 is located within the second area 24; the pad gold finger layer 3 is located at least on the side wall of the groove 4.

[0045] Therefore, the circuit board of the present application can increase the number of pad transmission layers through the structural design of the multi-layer pad gold finger, thereby improving the signal transmission capability of the circuit board. At the same time, the size of the circuit board can be reduced without reducing the signal density of the circuit board, so that the circuit board can improve its functional integration within a limited space, thereby improving the integration of the circuit board. The circuit board of the present application meets the signal transmission requirements of high-speed, high-frequency, and high-density electronic devices, providing strong support for the high performance and miniaturization development of electronic devices.

[0046] The structure of the circuit board is further described below.

[0047] In some embodiments, the number of layers of the pad gold finger layer 3 in the circuit board is greater than 2. The present application can determine the number of layers of the pad gold finger layer 3 based on the signal integration and signal connection quantity of the required circuit board. As an example, Figure 1 and Figure 2 As shown, the circuit board can include six layers of pad gold finger layers 3: pad gold finger layer 3a, pad gold finger layer 3b, pad gold finger layer 3c, pad gold finger layer 3d, pad gold finger layer 3e, and pad gold finger layer 3f. Pad gold finger layers 3a-3f are all located within the second region 24 of the second substrate 2, meaning that the pad gold finger layers 3 are all located at one end of the circuit board. This facilitates connection of the circuit board to other boards or devices.

[0048] In some embodiments, the pad gold finger layer 3 includes a plurality of gold fingers 31 spaced apart along a second direction intersecting the first direction; the gold fingers 31 on the first surface are spaced uniformly; and / or the gold fingers 31 on the second surface are spaced uniformly. This allows for the formation of more signal transmission paths within a limited space, optimizing space utilization on the circuit board.

[0049] In some embodiments, as Figure 1 and Figure 2 As shown, the length of the gold finger 31 along the second direction is 0.6 mm-1 mm; the length of the gold finger 31 along the first direction is 1.5 mm-4.5 mm.

[0050] As an example, the length of the gold finger 31 along the second direction can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, etc., or a range consisting of any two of the above values.

[0051] As an example, the length of the gold finger 31 along the first direction can be 1.5mm, 1.7mm, 1.9mm, 2.1mm, 2.3mm, 2.5mm, 2.7mm, 2.9mm, 3.1mm, 3.3mm, 3.5mm, 3.7mm, 3.9mm, 4.1mm, 4.3mm, 4.5mm, etc., or a range consisting of any two of the above values.

[0052] As an example, the gold finger 31 includes one or more of copper and its alloys, aluminum and its alloys, thereby achieving stable signal transmission.

[0053] In some embodiments, the second direction may be perpendicular or substantially perpendicular to the first direction, wherein substantially perpendicular means that the angle between the second direction and the first direction may be 80°-100°, optionally 85°-95°, and further optionally 88°-92°.

[0054] In some embodiments, the spacing between the gold fingers 31 on the first surface is 0.35 mm to 0.45 mm. As an example, the spacing between the gold fingers 31 on the first surface can be 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.40 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, etc., or a range consisting of any two of the above values. This can further optimize the space utilization of the circuit board.

[0055] In some embodiments, the spacing between the gold fingers 31 on the second surface is 0.35 mm to 0.45 mm. For example, the spacing between the gold fingers 31 on the second surface can be 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.40 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, or a range consisting of any two of the aforementioned values. This further optimizes the space utilization of the circuit board.

[0056] In some embodiments, the gold fingers 31 on the first surface and the gold fingers 31 on the second surface of the second substrate 2 are arranged in a symmetrical plane. This allows for more balanced stress on the circuit board during use, reduces deformation or damage to the circuit board due to stress concentration, and improves the mechanical stability and reliability of the circuit board. It should be understood that the central plane of the second substrate 2 serves as the plane of symmetry.

[0057] In some embodiments, the spacing between the gold fingers 31 on the first surface is not equal to the spacing between the gold fingers 31 on the second surface. As a result, the circuit board of the present application can adapt to various types of signal transmission requirements, providing greater flexibility in circuit board design, and can be personalized according to specific circuit requirements and board space, meeting the design requirements of complex electronic systems.

[0058] In some embodiments, the gold fingers 31 on the first surface of the second substrate 2 are arranged opposite to the gold fingers 31 on the second surface of the adjacent second substrate 2. This can enhance the connection reliability between the circuit board and other boards, reduce the problem of poor contact caused by plugging and unplugging, and thus improve the stability and reliability of the entire electronic system.

[0059] In some embodiments, the pad gold finger layer 3 is symmetrically distributed along the thickness of the circuit board, with the center plane of the circuit board as the symmetry plane. This balances the stress distribution along the thickness of the circuit board, reducing the risk of bending or twisting during processing and use. It also effectively reduces lamination layer offset during processing and manufacturing, thereby improving overall manufacturing yield.

[0060] In some embodiments, the bevel depth of the second substrate 2 is 1 mm to 1.5 mm, and the bevel angle of the second substrate 2 is 15° to 25°. This facilitates insertion and removal of the circuit board from other boards, reduces resistance and wear during insertion and removal, and improves the convenience and reliability of the connection.

[0061] As an example, the bevel depth of the second substrate 2 may be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc., or a range consisting of any two of the above values.

[0062] As an example, the bevel angle of the second substrate 2 can be 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, etc., or a range consisting of any two of the above values.

[0063] In some embodiments, the thickness of the second substrate 2 along the thickness direction of the circuit board is greater than or equal to 0.5 mm. This can improve the mechanical strength of the circuit board, reduce the risk of deformation or damage to the circuit board during the plugging and unplugging process, and thus improve the service life and reliability of the circuit board.

[0064] As an example, the thickness of the second substrate 2 can be 0.50mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.60mm, 0.61mm, 0.62mm, 0.63mm, 0.64mm, 0.65mm, etc., or a range consisting of any two of the above values.

[0065] In some embodiments, the first substrate 1 and / or the second substrate 2 includes a dielectric layer. The dielectric layer not only has good insulation properties, but also can provide support for the overall structure of the circuit board to improve the flatness and rigidity of the circuit board. Figure 2 and Figure 3 As shown, the first substrate 1 is a first dielectric layer 11, and the second substrate 2 is a second dielectric layer 21. It is understood that the material of the first dielectric layer 11 can be the same as the material of the second dielectric layer 21, or the material of the first dielectric layer 11 can be different from the material of the second dielectric layer 21. Specifically, Figure 2 and Figure 3 As shown, the first dielectric layer 11 and the second dielectric layer 21 are made of the same material.

[0066] In other embodiments, the first substrate 1 and / or the second substrate 2 include a conductive layer and a dielectric layer spaced apart. The conductive layer may be a metallic copper layer. Thus, the conductive layer can serve as an isolation layer, effectively shielding signals from adjacent pad layers and reducing crosstalk and interference between different signal layers, thereby improving the stability and accuracy of signal transmission.

[0067] In some embodiments, the first substrate 1 includes a first conductive layer 12 and a first dielectric layer 11 that are spaced apart. Figure 3 As shown, the orthographic projection of the first conductive layer 12 on the first dielectric layer 11 is located within the first dielectric layer 11, and the remaining positions of the first conductive layer 12 on the same plane of the circuit board can be filled with the material of the first dielectric layer 11, thereby forming a first substrate 1. The first dielectric layer 11 can isolate adjacent first conductive layers 12 to reduce the short circuit problem caused by direct contact between two adjacent first conductive layers 12, thereby improving the accuracy and stability of signal transmission on the circuit board.

[0068] In some embodiments, the second substrate 2 includes a second conductive layer 22 and a second dielectric layer 21 that are spaced apart. Figure 3 As shown, the orthographic projection of the second conductive layer 22 on the second dielectric layer 21 is located within the second dielectric layer 21. The remaining portions of the second conductive layer 22 on the same plane of the circuit board can be filled with the material of the second dielectric layer 21, thereby forming a second substrate 2. The second dielectric layer 21 can isolate adjacent second conductive layers 22 to reduce short circuits caused by direct contact between two adjacent second conductive layers 22, thereby improving the accuracy and stability of signal transmission on the circuit board. A second conductive layer 22 can also be provided on the solder pad gold finger layer 3 on the same plane of the circuit board, but the second conductive layer 22 needs to be isolated from the solder pad gold finger layer 3. This can reduce electromagnetic coupling between different signals, reduce signal crosstalk, and improve the stability and integrity of signal transmission.

[0069] In some embodiments, the conductive layer includes one or more of copper and its alloys, aluminum and its alloys, etc. Therefore, these metals have good electrical conductivity, thereby further improving the ability to shield signals of adjacent pad layers.

[0070] In some embodiments, the dielectric layer includes one or more of resin, fiber-reinforced resin, and ceramic. Therefore, these dielectric layer materials are non-conductive and have good rigidity, providing support for the overall structure of the circuit board.

[0071] In some embodiments, the conductive layer includes a signal layer, which is electrically connected to the pad gold finger layer 3 located on the same plane. Thus, the signal layer can be directly wired to the pad gold finger layer 3 without the need for layer switching vias. This can reduce the number of vias in the circuit board, thereby increasing signal wiring space or reducing the overall size of the circuit board, thereby reducing the production cost of the circuit board.

[0072] In some embodiments, along the first direction, the length of the groove 4 is greater than or equal to the length of the pad gold finger layer 3. Thus, when the circuit board is assembled, other boards connected to the circuit board can fully contact the pad gold finger layer 3, thereby forming a good electrical connection and improving the reliability of the electrical connection.

[0073] In some embodiments, the length of the groove 4 along the second direction is greater than the length of the pad gold finger layer 3. This allows for more precise alignment of the circuit board with other boards during assembly. Furthermore, during the circuit board manufacturing process, it facilitates precise milling of the grooves with a milling cutter or laser.

[0074] In some embodiments, the distance between adjacent pad gold finger layers 3 within the same groove 4 is greater than or equal to 0.5 mm. Thus, by controlling the distance between adjacent pad gold finger layers 3, it is easier to use a milling cutter or laser to mill grooves during circuit board processing, and it is also easier to assemble the circuit board with other boards.

[0075] As an example, the distance between adjacent pad gold finger layers 3 located in the same groove 4 can be 0.50mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.60mm, 0.61mm, 0.62mm, 0.63mm, 0.64mm, 0.65mm, etc., or a range consisting of any two of the above values.

[0076] For the circuit board of the present application, the number of layers of the pad gold finger can be adjusted according to the density required by the signal and electronic device on the circuit board. For example, if the signal density required by the electronic device is low, one groove 4 can be used, and the circuit board can include 4 layers of pad gold finger layers 3; if the signal density required by the electronic device is high, two grooves 4 can be used, and the circuit board can include 6 layers of pad gold finger layers 3. If the electronic device requires a higher signal density, the number of grooves 4 can be further increased. The circuit board of the present application can be flexibly designed to meet the actual configuration requirements of high-density circuit boards, so as to promote the development of large-scale high-computing power servers in the future.

[0077] For the circuit board of the present application, the distance between adjacent pad gold finger layers 3 located in the same groove 4 can be adjusted according to the actual circuit board card thickness, the number of circuit board stacks, and the number of grooves 4.

[0078] For the circuit board of the present application, when the thickness of the circuit board is the conventional fixed size of 1.57 mm, one groove 4 can be used, and the circuit board can include 4 layers of solder pad gold finger layers 3; when the thickness of the circuit board is 3 mm, two grooves 4 can be used, and the circuit board can include 6 layers of solder pad gold finger layers 3, so as to improve the practical reliability of the circuit board and reduce the production and assembly costs of the entire electronic system.

[0079] The thickness of the circuit board of this application increases with the number of layers of the gold finger board (the gold finger board comprises a second substrate 2 and pad gold finger layers 3 located on both surfaces of the second substrate). If the electronic device requires a lower signal density, the number of gold finger board layers can be reduced; if the electronic device requires a higher signal density, the number of gold finger board layers can be increased. The circuit board of this application allows for flexible design to meet the actual requirements of high-density gold finger board configurations.

[0080] The second aspect of the present application provides a method for preparing the circuit board of the first aspect of the present application, comprising: alternating a first substrate 1 and a second substrate 2 to form grooves 4 to obtain a circuit board; wherein a pad gold finger layer 3 is located on at least one side of the second substrate 2 along the thickness direction of the circuit board. Thus, compared with traditional stepped gold finger board designs or factory manufacturing process upgrades, the method of the present application does not require additional manufacturing processes or equipment investment, and can achieve higher performance and integration of the circuit board under existing manufacturing process conditions, thereby effectively reducing the manufacturing cost of the circuit board.

[0081] In some embodiments, the steps after forming the groove 4 include: placing a gasket 5 in the groove 4 and pressing the first substrate 1 and the second substrate 2 together. This can improve the flatness and stability of the first substrate 1 and the second substrate 2 during the pressing process, reduce deformation or damage to the circuit board caused by uneven pressure, and thus improve the product yield.

[0082] As an example, a method for preparing a circuit board includes: first, making a single gold finger board (a single gold finger board includes the second substrate 2 of the present application and the pad gold finger layer 3 located on both surfaces of the second substrate 2, and the single gold finger board can be made using a process known in the art); then, alternately stacking multiple gold finger boards and the first substrate 1, adding gaskets 5 (such as Figure 3 As shown), a pressing process is performed; after the pressing process is completed, the gasket 5 is removed; and gold is electroplated to obtain a circuit board.

[0083] In other embodiments, the steps prior to alternating the first and second substrates 1, 2 include: laminating the first and second substrates 1, 2; slotting the first substrate 1 to form grooves 4; and electroplating the grooves with gold to produce a circuit board. This manufacturing method can improve the bonding strength between the first and second substrates 1, 2. Furthermore, the precise formation of grooves 4 through slotting improves the overall quality and reliability of the circuit board.

[0084] In some embodiments, the slotting process includes mechanical milling or laser milling. Both methods can achieve precise slotting. Mechanical milling is suitable for large-scale production and is relatively low-cost; laser milling offers greater precision and flexibility, making it suitable for complex shapes and high-precision applications.

[0085] As an example, a method for manufacturing a circuit board includes: alternately stacking a plurality of first substrates 1 and second substrates 2 and performing a lamination process; then milling the first substrates 1 using a milling cutter or laser to form grooves 4, and then electroplating them with gold to obtain a circuit board. This embodiment can improve manufacturing yield and thereby reduce manufacturing costs.

[0086] The two methods for preparing circuit boards proposed in this application are conducive to subsequent popularization and promotion, and improve the manufacturing yield of circuit boards.

[0087] During the gold finger board packaging process, conventional gold finger boards only have their top and bottom surfaces plugged into and fixed to connector 6 on another board, resulting in a weak connection. As the integration of gold finger boards increases, such as in graphics processing units (GPUs), the overall weight of the board increases. If the screws are not securely fastened when connecting the gold finger board to another board, the increased force on the heavier gold finger board during transportation of the electronic product can easily cause breakage at the gold finger connection, leading to an open circuit and affecting the product's reliability and service life.

[0088] Based on this, the third aspect of the present application provides a circuit board assembly, comprising the circuit board of the first aspect of the present application, or comprising a circuit board prepared by the method of the second aspect of the present application. Thus, this assembly design can fully utilize the high-density signal transmission capabilities and miniaturized design advantages of the circuit board to ensure efficient integration and reliable connection of electronic systems.

[0089] In some embodiments, the circuit board assembly further includes a connector 6, which includes a protruding post 61. The protruding post 61 is located in the groove 4 and electrically connected to the pad gold finger layer 3. This allows for a stable electrical connection and mechanical fixation between the circuit board and other boards or components, thereby improving the assembly security and signal transmission performance of the circuit board assembly.

[0090] In some embodiments, the number of protrusions 61 is the same as the number of grooves 4; and / or the thickness of the protrusions 61 is the same as the distance between adjacent pad gold finger layers 3 located in the same groove 4. Thus, the same number of protrusions 61 as grooves 4 ensures that each groove 4 has a corresponding protrusion 61 for connection, further ensuring a stable electrical connection and mechanical fixation between the circuit board and other boards or components. The same thickness of the protrusions 61 as the distance between adjacent pad gold finger layers 3 located in the same groove 4 further secures the connector 6 within the groove 4, reducing the problem of loose connection caused by thickness mismatch between the two.

[0091] In some embodiments, as Figure 4 As shown, the protruding column 61 includes a main body and pad layers 611 located on both sides of the main body. The pad layers 611 contact the pad gold finger layer 3. This further enhances the electrical connection and mechanical strength between the connector 6 and the circuit board, improving the reliability and stability of the connection. As an example, the material of the pad layer 611 can be the same as that of the conductive layer.

[0092] In this application, the connector 6 corresponding to the circuit board parameters can be designed based on the thickness of the entire circuit board, the number of pad gold finger layers 3, and the distance between adjacent pad gold finger layers 3 located in the same groove 4. The number of layers of the pad layer 611 of the connector 6 is consistent with the number of layers of the pad gold finger layer 3, and the number of protruding columns 61 is consistent with the number of grooves 4. In this way, the circuit board and the connector 6 can be accurately inserted.

[0093] The fourth aspect of the present application provides an electronic device, including the circuit board of the first aspect of the present application, or the circuit board prepared by the method of the second aspect of the present application, or the circuit board assembly of the third aspect of the present application.

[0094] In some embodiments, the electronic device can be any of a high-computing-power server, a high-performance central processing unit (CPU), a high-performance graphics processing unit (GPU), a high-performance data processing unit (DPU), a fiber-to-the-room (FTTR) device, a set-top box, a router, an optical modem, a passive optical network (PON) device, a base station device, a converged gateway, and a 5G customer premises equipment (5G CPE). Specifically, the circuit board of the present application is suitable for high-speed, high-frequency, high-density, and highly integrated electronic devices, for example, electronic devices that have higher requirements for signal transmission and connection density as high-performance CPU chips, GPU chips, or DPU chips are developed.

[0095] In this application, real-time adjustment and optimization can be made based on the overall configuration of the electronic device and the space of the entire machine. If the space is limited and it is necessary to reduce the length of the circuit board (the second direction is recorded as the length direction of the circuit board), the stacking and thickness of the gold finger board can be increased, thereby increasing the number of pad layers, which can greatly reduce the length of the gold finger and facilitate assembly with other boards to enhance the stability of the high-frequency and high-speed signal circuit board and transmission. This design method has been widely used in the future as the configuration of CPU or GPU has developed. It has greatly reduced the scale of board assembly and increased the density of the board, which is conducive to promoting the development of electronic devices, especially high-computing power servers, towards high density and miniaturization.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A circuit board, characterized in that: include: A plurality of first substrates and a plurality of second substrates, wherein the plurality of first substrates and the plurality of second substrates are arranged overlappingly; The second substrate includes a first region and a second region adjacently arranged in a first direction, and an orthographic projection of the first substrate on the second substrate is located in the first region of the second substrate; the second substrate is provided with a first surface and a second surface opposite to each other extending along the first direction; A groove, wherein the groove is formed between two adjacent second substrates and the first substrate; A pad gold finger layer, wherein the pad gold finger layer is extended along the first direction on the first surface and / or the second surface, and the orthographic projection of the pad gold finger layer on the second substrate is located in the second area; the pad gold finger layer is at least located on the side wall of the groove.

2. The circuit board according to claim 1, characterized in that: The pad gold finger layer includes a plurality of gold fingers arranged at intervals along a second direction, and the second direction intersects with the first direction; The spacings between the gold fingers on the first surface are the same; and / or the spacings between the gold fingers on the second surface are the same.

3. The circuit board according to claim 2, characterized in that: The gold fingers on the first surface and the gold fingers on the second surface of the second substrate are arranged in a plane-symmetrical manner.

4. The circuit board according to claim 2, characterized in that: The spacing between the gold fingers on the first surface is not equal to the spacing between the gold fingers on the second surface.

5. The circuit board according to claim 2, characterized in that: The gold fingers on the first surface of the second substrate are arranged opposite to the gold fingers on the second surface of the adjacent second substrate.

6. The circuit board according to claim 2, characterized in that: Along the first direction, the length of the groove is greater than or equal to the length of the pad gold finger layer; and / or, Along the second direction, the length of the groove is greater than or equal to the length of the pad gold finger layer.

7. The circuit board according to claim 1, characterized in that: Along the thickness direction of the circuit board, the thickness of the second substrate is greater than or equal to 0.5 mm.

8. The circuit board according to claim 7, characterized in that: The bevel depth of the second substrate is 1 mm-1.5 mm, and the bevel angle of the second substrate is 15°-25°.

9. The circuit board according to claim 1, characterized in that: Along the thickness direction of the circuit board, the distance between adjacent pad gold finger layers located in the same groove is greater than or equal to 0.5 mm.

10. The circuit board according to claim 1, characterized in that: Taking the central plane of the circuit board as the symmetry plane, the pad gold finger layer is symmetrically distributed along the thickness direction of the circuit board.

11. A method for preparing a circuit board according to any one of claims 1 to 10, characterized in that: include: The first substrate and the second substrate are arranged alternately to form the grooves, so as to obtain the circuit board; wherein the pad gold finger layer is located on at least one side of the second substrate along the thickness direction of the circuit board.

12. The method according to claim 11, characterized in that The steps after forming the groove include: arranging a gasket in the groove, and pressing the first substrate and the second substrate.

13. The method according to claim 12, characterized in that The steps before alternately arranging the first substrate and the second substrate include: pressing the first substrate and the second substrate; and groove the first substrate to form the groove.

14. The method according to claim 13, characterized in that The grooving process includes mechanical grooving process or laser grooving process.

15. A circuit board assembly, characterized in that: A circuit board comprising any one of claims 1 to 10, or a circuit board prepared by the method according to any one of claims 11 to 14.

16. The circuit board assembly according to claim 15, characterized in that: A connector is also included. The connector includes a protruding column. The protruding column is located in the groove and is electrically connected to the pad gold finger layer.

17. The circuit board assembly according to claim 16, wherein: The number of the protruding columns is the same as the number of the grooves; and / or the thickness of the protruding columns is the same as the distance between adjacent pad gold finger layers located in the same groove.

18. The circuit board assembly according to claim 17, wherein: The protruding column includes a main body and pad layers located on both sides of the main body, and the pad layers are in contact with the pad gold finger layers.

19. An electronic device, characterized in that: A circuit board comprising any one of claims 1 to 10, or a circuit board prepared by the method of any one of claims 11 to 14, or a circuit board assembly comprising any one of claims 15 to 18.

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