Differential via hole design architecture, printed circuit board and design method

Abstract

The invention discloses a differential via hole design architecture, a printed circuit board and a design method, and the differential via hole design architecture can effectively optimize the space utilization rate in the PCB design by introducing a milling groove to separate via holes; specifically, one via hole is divided into at least two parts by the milling groove, so that the first signal line and the second signal line of the differential line can be arranged among different signal layers through different parts of the first via hole, the requirement on the wiring space is reduced, and the design allows the wiring space to be reduced on the premise of keeping the signal integrity. The number of the needed differential via holes is effectively reduced, the problem of space congestion caused by increase of the number of the high-speed signal pins is further relieved, the signal performance is guaranteed, meanwhile, the layout is optimized, and the design complexity and cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of circuit board design, and in particular to a design architecture of a differential via, a printed circuit board and a design method. Background Art

[0002] With the rapid development of electronic information technology and the continuous improvement of signal transmission rate, the requirements for signal performance and quality are becoming increasingly stringent, and the margin of link design is gradually shrinking. In this context, designers need to consider and optimize various issues in PCB (Printed Circuit Board) design more carefully during the research and development process to achieve optimal performance while reducing costs, shortening design cycles and improving production efficiency.

[0003] In current PCB and signal integrity design, differential vias usually use a pair of high-speed signal holes, supplemented by GND (Ground) return holes. However, as the number of high-speed signal pins of chips and connectors continues to increase, the layout of signal layer-changing vias in the fan-out area becomes more and more dense, and the required layout and wiring space also increases. In addition, as the signal rate increases, the optimization requirements for high-speed signal layer-changing vias become more detailed, and the number of GND return holes increases from one pair to two or even three pairs, which further exacerbates the space occupation problem and is not conducive to the high-density PCB design.

[0004] Therefore, how to optimize the layout of differential vias and GND return holes while ensuring performance has become an important challenge in current PCB design. Summary of the invention

[0005] The purpose of the present invention is to provide a design architecture, printed circuit board and design method of differential vias, which reduce the demand for wiring space. This design allows the number of required differential vias to be effectively reduced while maintaining signal integrity, thereby alleviating the space crowding problem caused by the increase in the number of high-speed signal pins, while ensuring signal performance, optimizing the layout and reducing the complexity and cost of the design.

[0006] In order to solve the above technical problems, the present invention provides a design architecture of a differential via, which is applied to a printed circuit board, wherein the printed circuit board includes a plurality of signal layers, and the design architecture of the differential via includes:

[0007] a first via hole, passing through a first signal layer and a second signal layer of the printed circuit board;

[0008] at least one milling groove, each of the milling grooves runs through the first signal layer and the second signal layer, and all of the milling grooves are used to divide the first via hole into at least two parts;

[0009] The first signal line of the differential line is inserted through the first part of the first via hole on the first signal layer and extends through the first part of the first via hole on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via hole on the first signal layer and extends through the second part of the first via hole on the second signal layer.

[0010] Among them, the number of the milling grooves is 1, the milling groove is arranged radially along the first via hole, and is connected to the parallel structure, used to divide the first via hole into two parts, and the parallel structure includes a first signal line and a second signal line parallel to each other in the differential line.

[0011] Wherein, the difference between the length of the milling groove along the extension direction of the differential line and the preset length is greater than the first length and less than the second length;

[0012] The preset length is a larger value of a first diameter of a pad outside the first via hole on the first signal layer and a second diameter of a pad outside the first via hole on the second signal layer.

[0013] Wherein, the width of the preset milling groove along the extension direction perpendicular to the differential line is greater than the line distance of the differential line;

[0014] The line pitch is a larger value of a first distance between the first signal line and the second signal line on the first signal layer and a second distance between the first signal line and the second signal line on the second signal layer.

[0015] Wherein, the width of the preset milling groove along the extension direction perpendicular to the differential line is smaller than the diameter of the inner side of the first via hole.

[0016] Wherein, the number of the milling grooves is greater than 2, and all the milling grooves are used to divide the first via hole into at least three parts;

[0017] The first signal line of the differential line is inserted through the first part of the first via on the first signal layer and extends out through the first part of the first via on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via on the first signal layer and extends out through the second part of the first via on the second signal layer. The other part of the first via serves as a signal return hole.

[0018] Wherein, the first signal line of the differential line is inserted from a first part of a first via hole on the first signal layer along a first direction, and extends from a first part of a first via hole on the second signal layer along a second direction;

[0019] The second signal line of the differential line is inserted from the second part of the first via hole of the first signal layer along the first direction, and extends from the second part of the first via hole on the second signal layer along the second direction;

[0020] The first direction is opposite to the second direction.

[0021] Wherein, the number of the milling grooves is 2;

[0022] The first milling groove is arranged radially along the first via hole and forms a preset angle with the parallel structure. One end of the second milling groove is connected to the midpoint of the first milling groove, and the second milling groove is connected to the parallel structure. The parallel structure includes a first signal line and a second signal line that are parallel to each other in the differential line.

[0023] Wherein, the length of the first milling groove along the extending direction perpendicular to the differential line is greater than the first length and less than the second length, and the difference between the length and the preset length is greater than the first length and less than the second length;

[0024] The preset length is a larger value between a first diameter of the pad outside the first via hole on the first signal layer and a second diameter of the pad outside the first via hole on the second signal layer;

[0025] The width of the first milling groove along the extension direction of the differential line is greater than the line distance of the differential line;

[0026] The line pitch is a larger value of a first distance between the first signal line and the second signal line on the first signal layer and a second distance between the first signal line and the second signal line on the second signal layer.

[0027] Wherein, the length of the second milling groove along the extension direction of the differential line is not less than the third distance between the midpoint of the first milling groove and the pad outside the first via hole;

[0028] The width of the second milling groove along the extending direction perpendicular to the differential line is equal to the width of the first milling groove.

[0029] In order to solve the above technical problem, the present invention provides a printed circuit board, including the above-mentioned differential via design architecture.

[0030] In order to solve the above technical problems, the present invention provides a design method of a differential via, which is applied to the design architecture of the differential via described above. The design method of the differential via includes:

[0031] Get the target design size;

[0032] Controlling a first drill needle to drill a first via hole on the printed circuit board according to the target design size, wherein the first via hole penetrates a first signal layer and a second signal layer of the printed circuit board;

[0033] Plating copper inside the first via hole to cover the hole wall of the first via hole to form a conductive layer;

[0034] Etching the pad outside the first via and the differential line according to the target design size, wherein the width of the pad is equal to the line spacing of the differential line, and the line spacing of the differential line is the distance between the first signal line and the second signal line parallel to each other in the differential line;

[0035] Drilling at least one milling groove on the printed circuit board according to the target design size; all the milling grooves are used to divide the first via hole into at least two parts;

[0036] Filling the first via hole and all the milling grooves with resin respectively;

[0037] The first signal line of the differential line is inserted through the first part of the first via hole on the first signal layer and extends through the first part of the first via hole on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via hole on the first signal layer and extends through the second part of the first via hole on the second signal layer.

[0038] The present invention provides a design architecture of a differential via, a printed circuit board and a design method. The differential via design architecture can effectively optimize the space utilization in PCB design by introducing a milling groove to separate the vias. Specifically, the milling groove divides a via into two parts, so that a first signal line and a second signal line of a differential line can be laid out between different signal layers through different parts of the first via, thereby reducing the demand for wiring space. This design allows the number of required differential vias to be effectively reduced while maintaining signal integrity, thereby alleviating the space crowding problem caused by the increase in the number of high-speed signal pins, optimizing the layout while ensuring signal performance, and reducing the complexity and cost of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in 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 paying creative work.

[0040] Figure 1 A schematic diagram of a preliminary design of a differential via design architecture provided by the present invention;

[0041] Figure 2 A schematic diagram of a first differential via design architecture provided by the present invention on a first signal layer;

[0042] Figure 3 A schematic diagram of a first differential via design architecture provided by the present invention on a second signal layer;

[0043] Figure 4 A schematic diagram of a pad design of a first differential via design architecture provided by the present invention;

[0044] Figure 5 A three-dimensional schematic diagram of a first differential via design architecture provided by the present invention;

[0045] Figure 6 A schematic diagram of a second differential via design architecture provided by the present invention on a first signal layer;

[0046] Figure 7 A schematic diagram of a second differential via design architecture provided by the present invention on a second signal layer;

[0047] Figure 8 A schematic diagram of a pad design of a second differential via design architecture provided by the present invention;

[0048] Fig. 9 A three-dimensional schematic diagram of a second differential via design architecture provided by the present invention;

[0049] Fig.10 The present invention provides a flow chart of a method for designing a differential via. DETAILED DESCRIPTION

[0050] The core of the present invention is to provide a design architecture, printed circuit board and design method of differential vias, which reduce the demand for wiring space. This design allows the number of required differential vias to be effectively reduced while maintaining signal integrity, thereby alleviating the space crowding problem caused by the increase in the number of high-speed signal pins. While ensuring signal performance, the layout is optimized and the design complexity and cost are reduced.

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution 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 described embodiments are 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 creative work are within the scope of protection of the present invention.

[0052] First, as Figure 1, Figure 2 As shown, the present invention provides a design architecture of a differential via, which is applied to a printed circuit board. The printed circuit board includes multiple signal layers. The design architecture of the differential via includes:

[0053] A first via 11 passes through a first signal layer and a second signal layer of the printed circuit board;

[0054] At least one milling groove 11, each milling groove 11 runs through the first signal layer and the second signal layer, and all the milling grooves 11 are used to divide the first via hole 11 into at least two parts;

[0055] The first signal line 13 of the differential line is inserted through the first part of the first via 11 on the first signal layer and extends through the first part of the first via 11 on the second signal layer. The second signal line 14 of the differential line is inserted through the second part of the first via 11 on the first signal layer and extends through the second part of the first via 11 on the second signal layer.

[0056] The differential via design architecture of this embodiment significantly optimizes the space utilization and signal transmission efficiency of the printed circuit board (PCB) by introducing the configuration of the milling groove 11. First, the first via 11 in the design architecture runs through multiple signal layers, providing a basic signal transmission channel. On this basis, the introduction of at least one milling groove 11 enables the first via 11 to be divided into at least two parts. This design concept allows the first signal line 13 and the second signal line 14 of the differential line to be arranged through different parts in the same via by effectively isolating the signal path, which not only reduces the demand for wiring space, but also optimizes the overall layout.

[0057] Specifically, the presence of the milling groove 11 enables the signal line to be flexibly transmitted between different signal layers without having to rely on additional vias, thereby reducing the complexity of the overall design. By dividing a via into two parts, this design ensures signal integrity while effectively reducing the number of differential vias required. Especially when the number of high-speed signal pins increases, this design can effectively alleviate the wiring congestion problem caused by insufficient space, thereby improving the high-density design capability of the PCB.

[0058] In addition, this architecture significantly reduces the cost of design and production while ensuring signal performance. This optimized layout design method provides a more flexible and efficient solution for modern high-frequency applications, which not only improves the stability of signal transmission, but also provides strong support for the efficient production of PCBs. Therefore, this differential via design architecture brings new ideas and practical guidance to the design and manufacture of printed circuit boards.

[0059] As an optional embodiment, the number of milling grooves 12 is 1, the milling groove 12 is radially arranged along the first via 11, and is connected to the parallel structure, used to divide the first via 11 into two parts, and the parallel structure includes a first signal line 13 and a second signal line 14 parallel to each other in the differential line.

[0060] In this optional embodiment, a milling groove 12 is introduced in the design, and its main function is to divide the first via 11 into two parts, further optimizing the signal transmission path and the space utilization of the PCB. The milling groove 12 is arranged along the radial direction of the first via 11 and is connected to the parallel structure, which includes a first signal line 13 and a second signal line 14 parallel to each other in the differential line. Through this design, the milling groove 12 provides an effective signal channel, so that the two signal lines can be arranged in different paths in the same via, thereby achieving more flexible signal transmission.

[0061] Specifically, the milling groove 12 allows the first signal line 13 and the second signal line 14 of the differential line to be transmitted through different parts of the first via 11, which can significantly reduce the need for additional vias. This design not only reduces the complexity of wiring, but also effectively improves the integrity of the signal and reduces the interference caused by the intersection of signal paths.

[0062] At the same time, the milling groove 12 is connected to the parallel structure to ensure the mutual isolation of the signal lines and further enhance the anti-interference ability of the circuit.

[0063] The main advantage of this structure is that the traditional design usually requires multiple vias for each pair of differential signals, which significantly increases the demand for wiring space. However, this design effectively reduces the demand for wiring space by achieving the crossing of two differential lines in one via, alleviating the space crowding problem caused by the increase in the number of high-speed signal pins.

[0064] It should be noted that, using this method, one via can transmit two signals of a differential signal. In this case, a GND via is provided on both sides of the first via 11 as a ground return via (eg, Figure 1 as shown).

[0065] This design can maintain good signal quality during high-speed signal transmission. At the same time, in a high-density PCB layout, a single milling groove 12 is used to achieve signal diversion, which effectively saves wiring space, optimizes the design process, and reduces production costs.

[0066] As an optional embodiment, the difference between the length of the milling groove 12 along the extension direction of the differential line and the preset length is greater than the first length and less than the second length;

[0067] The preset length is a larger value of a first diameter of a pad outside the first via hole 11 on the first signal layer and a second diameter of a pad outside the first via hole 11 on the second signal layer.

[0068] In this optional embodiment, the difference between the length of the milling groove 12 and the preset length in the extension direction is controlled within a specific range to ensure that it can effectively separate the first via 11 into two parts. Specifically, the length of the milling groove 12 is greater than the first length and less than the second length, which can ensure that sufficient space is provided between the pad and the signal line, while not over-extending to affect the integrity of the signal.

[0069] The preset length is defined as the larger value of the diameter of the outer pad of the first via 11 on the first signal layer and the second signal layer, and this selection ensures that the length of the milling groove 12 can be properly matched with the pad. Through this design, the milling groove 12 can provide effective isolation in the signal transmission channel, avoid interference between signal lines, and maintain good electrical connection.

[0070] This design principle not only improves the signal transmission quality, but also ensures the compactness and efficiency of the PCB layout. By properly controlling the relationship between the length of the milling groove 12 and the pad size, the function of the milling groove 12 can be fully utilized, so that the first via 11 can be reliably divided into two parts, thereby providing flexibility for the routing of differential lines, optimizing the design process, and reducing potential signal integrity issues.

[0071] As an optional embodiment, the width of the preset milling groove 12 along the extending direction perpendicular to the differential line is greater than the line distance of the differential line;

[0072] The line pitch is a larger value of a first distance between the first signal line 13 and the second signal line 14 on the first signal layer and a second distance between the first signal line 13 and the second signal line 14 on the second signal layer.

[0073] In this optional embodiment, the width of the preset milling groove 12 is designed to be greater than the line spacing of the differential line. This design concept is intended to enhance the performance and signal integrity of PCB signal transmission. The line spacing refers to the distance between the first signal line 13 and the second signal line 14 that are parallel to each other on the first signal layer and the second signal layer. This distance is crucial to ensure the effective transmission of the differential signal. By setting the width of the milling groove 12 to be greater than the line spacing, the milling groove 12 can provide additional space to ensure the independence of the signal line during the wiring process and avoid interference between signals.

[0074] This design allows the milling groove 12 to play a better role in separating the signal transmission path, so that the two signal lines of the differential line can be arranged in a more ideal way in the same via, while reducing the possibility of signal cross interference. In addition, the larger width of the milling groove 12 can also improve heat management and current carrying capacity, ensuring that the stability of the signal is not affected under high-frequency transmission.

[0075] As an optional embodiment, the width of the preset milling groove 12 along the extending direction perpendicular to the differential line is smaller than the diameter of the inner side of the first via hole 11 .

[0076] In this optional embodiment, the width of the preset milling groove 12 is designed to be smaller than the inner diameter of the first via hole 11. The core of this design principle is to ensure that the existence of the milling groove 12 does not affect the integrity of the first via hole 11. By controlling the width of the milling groove 12, the first via hole 11 can be effectively avoided from being cut, thereby maintaining the effectiveness and reliability of the signal transmission channel.

[0077] Specifically, if the width of the milling groove 12 exceeds the inner diameter of the first via hole 11, the structure of the via hole may be damaged, thereby affecting the signal transmission path, and even causing problems such as short circuit or signal loss. By ensuring that the width of the milling groove 12 is smaller than the inner diameter of the via hole, the design can effectively provide the necessary separation space while avoiding physical damage to the via hole, ensuring that the signal line can be safely and effectively transmitted between different layers.

[0078] In one specific embodiment, currently Figure 1 In the scheme, the diameter of the differential signal via is 10mil, and the center spacing between the differential signal vias is 40mil. There is at least one pair of GND signal return holes next to it, and the diameter of the signal return hole is also 10mil, and the spacing between the GND hole and the differential signal via is 40mil. Moreover, the number of GND signal return holes increases from 1 pair to 2 pairs, or even 3 pairs, and the space occupied is getting larger and larger. Using the scheme of milling a milling groove 12 in this application, only 3 equally spaced signal holes need to be drilled on the PCB board, and the center spacing S between two adjacent signal vias is 40mil. The middle one is a differential signal hole (that is, the first via 11) to transmit DP and DN differential signals, and the two signal holes on both sides transmit GND signals (that is, GND signal return holes). The original diameter size C of the signal hole is 10mil, and then copper with a thickness of 1mil is electroplated on the inner wall of the hole. After electroplating, the completed diameter size D of the signal hole is 8mil, that is, D=C-2mil. Compared with the existing 4 vias to complete a signal layer change, the layout and wiring space occupied is reduced by 25% (such as Figure 1 as shown).

[0079] Specifically, in terms of design dimensions, in a specific embodiment, reference may be made to Figure X , the pad diameter of the first via 11 is P, and the pad ring width is PW, that is, P=D+2PW. In order to maintain the continuity of the signal impedance at the first via 11 as much as possible, the pad ring width PW of the surface layer of the first via 11 is consistent with the width W of the two signal lines DPin and DNin in the differential line, and the pad ring width of the inner layer of the first via 11 is consistent with the line width of the signal lines DPout and DNout. The schematic diagram of the transmission signal of the first signal layer is as follows Figure 2 The schematic diagram of the transmission signal of the second signal layer is as follows Figure 3 The pad design is as follows Figure 4 shown.

[0080] The milling groove 12 is a long groove with a length of N and a width of M, which disconnects the DP and DN signals. In order to ensure that the signal is completely disconnected without short circuit and to avoid the influence of processing errors, the length N of the milling groove 12 needs to be slightly larger than the diameter P of the pad. The diameter of the pad is the larger value of the surface layer (first signal layer) and the inner layer (second signal layer) pad, that is, the minimum value of N is Nmin=P+4mil. In order to reduce the mutual interference between differential signals, the width M of the milling groove 12 needs to be larger than the distance between the two differential lines. The distance between the differential lines is the larger value of the distance between the surface layer (first signal layer) differential lines DPin and DNin and the distance between the inner layer (second signal layer) differential lines DPout and DNout, such as Figure 5 shown.

[0081] Since the number of vias required for a signal layer change is reduced, more differential signal layer change vias can be arranged in the same wiring space, thereby saving wiring space and increasing wiring density. At the same time, since the spacing between the two differential signals DP and DN at the vias is reduced, the coupling of high-speed differential signals at the vias can be enhanced, which is beneficial to improving the integrity of high-speed signals.

[0082] like Figure 6 , Figure 7 As shown, as an optional embodiment, the number of the milling grooves is greater than 2, and all the milling grooves are used to divide the first via hole 11 into at least three parts;

[0083] The first signal line 13 of the differential line is inserted through the first part of the first via 11 on the first signal layer and extends through the first part of the first via 11 on the second signal layer. The second signal line 14 of the differential line is inserted through the second part of the first via 11 on the first signal layer and extends through the second part of the first via 11 on the second signal layer. The other part of the first via 11 serves as a signal return hole.

[0084] In this optional embodiment, the first via 11 is divided into at least three parts by providing a plurality of milling grooves, and this design realizes effective management of signal return. In this structure, the first signal line 13 and the second signal line 14 are inserted and extended through different parts of the first via 11, allowing signals to be smoothly transmitted between different signal layers. At the same time, the remaining part of the first via 11 is used as a signal return hole, so that there is no need to design a separate GND via.

[0085] The key to this design is to increase the number of milling slots so that the signal return can be effectively processed within the same via, thereby simplifying the overall design complexity of the PCB. Since signal return usually requires a low-impedance path, this method can ensure the efficiency of the return path while reducing the number of vias on the PCB, avoiding additional space occupation and potential signal integrity issues.

[0086] In addition, the design is very advantageous in high-density PCB layout, and it can more flexibly adapt to complex signal transmission requirements without sacrificing signal performance. This embodiment effectively optimizes PCB design, improves space utilization, reduces design and manufacturing costs, and maintains good signal quality and reliability in a high-speed signal transmission environment.

[0087] As an optional embodiment, the first signal line 13 of the differential line is inserted from a first part of the first via hole 11 on the first signal layer along a first direction, and extends from a first part of the first via hole 11 on the second signal layer along a second direction;

[0088] The second signal line 14 of the differential line is inserted from the second part of the first via hole 11 of the first signal layer along the first direction and extends from the second part of the first via hole 11 on the second signal layer along the second direction;

[0089] The first direction is opposite to the second direction.

[0090] In this optional embodiment, the first signal line 13 of the differential line is inserted from the first part of the first via hole 11 on the first signal layer along the first direction, and extends from the first part of the first via hole 11 on the second signal layer along the second direction. This design ensures that the transmission path of the signal line can effectively match the layout of the circuit board and improves the integrity of the signal.

[0091] The second signal line 14 of the differential line is inserted from the second part of the first via 11 along the first direction, and extends from the second part of the first via 11 of the second signal layer along the second direction. This arrangement of signal lines ensures that the two differential signal lines are parallel to each other in the same plane, thereby reducing potential signal crosstalk and interference. It is worth noting that the first direction is opposite to the second direction. For example, the first direction is from -x to +x, and the second direction is from +x to -x. In some embodiments, the projection of the signal line on the first signal layer coincides with the projection of the signal line on the second signal layer (e.g., Figure 6 DPin and DNin in Figure 7 This layout not only improves the signal transmission efficiency, but also optimizes the space utilization of the PCB. By making the projections of the signal lines overlap, the designer can effectively reduce the area requirement of the PCB, and can use the solution of dividing the first via 11 into at least three parts in this embodiment to achieve higher density signal transmission in the same space.

[0092] As an optional embodiment, the number of milled grooves is 2;

[0093] The first milling groove 21 is radially arranged along the first via 11 and forms a preset angle with the parallel structure, one end of the second milling groove 22 is connected to the midpoint of the first milling groove 21, and the second milling groove 22 is connected to the parallel structure, and the parallel structure includes a first signal line 13 and a second signal line 14 parallel to each other in the differential line. As an optional embodiment, the preset angle is 90 degrees.

[0094] In this optional embodiment, the design principle of dividing the first via 11 into three parts by setting two milling grooves is mainly based on the efficiency of signal transmission and the optimization of structure. First, the first milling groove 21 is arranged along the radial direction of the first via 11 and is at a preset angle with the parallel structure. This configuration not only provides a more flexible layout space for the signal line, but also enhances the path selection of the signal through the connection with the parallel structure, making the signal transmission smoother. One end of the second milling groove 22 is connected to the midpoint of the first milling groove 21 and is connected to the parallel structure. This design ensures the isolation of the signal lines, reduces possible crosstalk, and effectively manages the signal transmission path in the same space.

[0095] By combining the two milling slot designs, the first via 11 can be divided into three parts: the first part and the second part are used for differential signal transmission, and the third part serves as a signal return hole. This division not only improves signal integrity, but also optimizes PCB design efficiency.

[0096] In this way, each part of the first via 11 has its specific function, ensuring the stability and reliability of the differential signal during transmission. In addition, the configuration of the milling groove can effectively manage space in a high-density signal environment, making the entire PCB design more compact while ensuring that the signal quality is not affected. This design method combines structural rationality with signal performance optimization to meet the needs of modern high-frequency applications.

[0097] As an optional embodiment, the length of the first milling groove 21 along the extension direction perpendicular to the differential line is greater than the first length and less than the second length.

[0098] The preset length is a larger value of a first diameter of a pad outside the first via hole 11 on the first signal layer and a second diameter of a pad outside the first via hole 11 on the second signal layer;

[0099] The width of the first milling groove 21 along the extension direction of the differential line is greater than the line distance of the differential line;

[0100] The line pitch is a larger value of a first distance between the first signal line 13 and the second signal line 14 on the first signal layer and a second distance between the first signal line 13 and the second signal line 14 on the second signal layer.

[0101] As an optional embodiment, the length of the second milling groove 22 along the extension direction of the differential line is not less than the third distance between the midpoint of the first milling groove 21 and the pad outside the first via hole 11;

[0102] The width of the second milling groove 22 along the extending direction perpendicular to the differential line is equal to the width of the first milling groove 21 .

[0103] The first milling groove 21 is Figure 8 Groove A in: With the center of the drill hole and the pad as the center, the length of groove A is L and the width is F. To ensure that the signal is completely disconnected and avoid short circuits, the length L of groove A needs to be slightly larger than the diameter P of the pad. The diameter of the pad takes the larger value of the surface layer and the inner layer pad, so the minimum value of L is Lmin = P + 4mil. In addition, the width F of groove A must be larger than the distance between the two differential lines, which is the larger value of the first distance between the differential lines DPin and DNin on the first signal layer and the second distance between the differential lines DPout and DNout on the second signal layer.

[0104] The second milling groove 22 is Figure 8Groove B in the milling process: It is perpendicular to milling groove A, with a length of H and a width of K, and the size of K is equal to F. The design of groove B needs to ensure that the pad of the via is milled off, so the minimum value of its length H needs to be slightly larger than the ring width PW of the pad, that is, Hmin = PW + 4mil, and the additional 4mil is used to avoid processing errors. At the same time, the maximum value of H cannot mill off the pad on the GND signal side, so Hmax = PW + D + 4mil.

[0105] In a specific embodiment, when the input and output of the first signal line 13 and the second signal line 14 in the differential line are in the same direction, the number of layer-changing vias can be further reduced, and only one via is required to complete a high-speed signal layer change. The design schematic diagram of the signal input and output in the same direction is as follows Figure 6 and Figure 7 The process of drilling holes, etching of pads and circuits is consistent with the first scheme.

[0106] After etching, since the DP, DN, and GND signals are short-circuited together, they need to be separated by the milling process. Two long grooves A and B need to be milled, as shown in the following diagram Figure 8 As shown. The first milling groove 21A is centered on the center of the drill hole and the pad, with a length of L and a width of F. In order to ensure that the signal is completely disconnected and not short-circuited, and to avoid the influence of processing errors, the length L of groove A needs to be slightly larger than the diameter P of the pad. The diameter of the pad takes the larger value of the surface and inner pads, that is, the minimum value of L is Lmin=P+4mil. The width F of groove A needs to be larger than the distance between the two differential lines. The distance between the differential lines takes the larger value of the distance between the surface differential lines DPin and DNin and the distance between the inner differential lines DPout and DNout. The second milling groove 22B is perpendicular to the first milling groove 21A, with a length of H and a width of K, and the size of K is equal to F. Groove B needs to ensure that the pad of the via is milled off, so the minimum value of its length H needs to be slightly larger than the ring width of the pad, that is, Hmin=PW+4mil. The added 4mil is to avoid the influence of processing errors. The maximum value of length H cannot mill off the pad on the GND signal side, so Hmax=PW+D+4mil. The schematic diagram of this solution is as follows Fig. 9 shown.

[0107] By adding a milling process, one signal via can transmit two or three signals, greatly reducing the layout and wiring space required for differential signal layer-changing vias. By reducing the distance between the DP and DN signals at the vias, the coupling of differential signals at the layer-changing vias is enhanced. Finally, the via unit is completely filled with resin to reduce the loss and crosstalk of high-speed signals at the vias, optimize the electrical performance of the PCB, and improve the signal transmission quality. The layout and wiring space occupied by high-speed signal layer-changing vias can be greatly reduced, especially in places such as chips and high-speed connectors where there are a large number of high-speed signals that need to change layers. In addition, by reducing the center spacing of differential vias, the signal impedance at the vias can be effectively reduced, which is beneficial to maintaining the impedance continuity of the entire link, especially for the design of multi-layer boards and long vias.

[0108] In a second aspect, the present invention provides a printed circuit board, including the above-mentioned differential via design architecture.

[0109] For other introductions to the printed circuit board, please refer to the above embodiments, and this application will not go into details here.

[0110] In a third aspect, the present invention provides a design method for a differential via, which is applied to the above-mentioned design architecture of a differential via. The design method for a differential via includes:

[0111] S11: Obtain target design size;

[0112] S12: controlling a first drill needle to drill a first via hole on the printed circuit board according to a target design size, wherein the first via hole penetrates a first signal layer and a second signal layer of the printed circuit board;

[0113] S13: copper plating inside the first via hole to cover the hole wall of the first via hole to form a conductive layer;

[0114] S14: etching the pad outside the first via hole and the differential line according to the target design size, wherein the width of the pad is equal to the line spacing of the differential line, and the line spacing of the differential line is the distance between the first signal line and the second signal line parallel to each other in the differential line;

[0115] S15: drilling at least one milling groove on the printed circuit board according to the target design size; all the milling grooves are used to divide the first via hole into at least two parts;

[0116] S16: Filling the first via hole and all the milling grooves with resin respectively;

[0117] The first signal line 13 of the differential line is inserted through the first part of the first via 11 on the first signal layer and extends through the first part of the first via 11 on the second signal layer. The second signal line 14 of the differential line is inserted through the second part of the first via 11 on the first signal layer and extends through the second part of the first via 11 on the second signal layer.

[0118] In this differential via design method, it is intended to achieve efficient and reliable signal transmission while optimizing the space utilization and complexity of PCB design. First, step S11 provides the necessary parameter basis for subsequent drilling and wiring by obtaining the target design size. Then, in S12, the first drill needle is controlled according to these sizes to accurately drill the first via 11 on the printed circuit board to ensure that the via can penetrate the first signal layer and the second signal layer to form a basic channel for signal transmission. Subsequently, in S13, copper is plated inside the first via 11 to form a conductive layer. This process can provide good electrical connection and ensure smooth transmission of signals between layers. Next, S14 etches the pads and differential lines outside the first via 11 according to the target design size. The pad width is equal to the line spacing of the differential line. This design helps to maintain uniform impedance characteristics during connection and signal transmission, and reduce signal reflection and interference. In S15, the designer drills at least one milling groove on the printed circuit board to divide the first via 11 into at least two parts. The introduction of the milling groove enhances the separation of signals and optimizes the signal return path. Finally, step S16 involves filling the first via hole 11 and all the milling grooves with resin, which not only improves the mechanical strength of the structure, but also enhances the insulation performance, thereby further ensuring the reliability and stability of signal transmission.

[0119] As an optional embodiment, the method further includes: testing the design architecture of the first via hole to determine whether the design architecture of the first via hole satisfies a preset test result;

[0120] If the preset test result is met, the design architecture of the first via is determined to be the final design architecture of the first via. Specifically, the design architecture of the first via is tested to determine whether the design architecture of the first via meets the preset test result, including: determining whether the first part of the first via used to transmit the first signal line and the second part of the electroplated copper used to transmit the second signal line in the first via are damaged; performing an open circuit test on the first signal line of the first signal layer and the first signal line of the second signal layer, and performing an open circuit test on the second signal line of the first signal layer and the second signal line of the second signal layer, respectively, to determine whether there is an electrical connection between the signal line of the first signal layer and the corresponding signal line of the second signal layer; performing a short circuit test on the first signal line and the second signal line of the first signal layer and the first signal line and the second signal line of the second signal layer, respectively, to determine whether there is an electrical connection between the two signal lines of the first signal layer and the two signal lines of the second signal layer; if the electroplated copper used to transmit the first part of the first signal line and the second part of the second signal line is not damaged, there is an electrical connection between the signal line of the first signal layer and the corresponding signal line of the second signal layer, and there is no electrical connection between the two signal lines of the first signal layer and the two signal lines of the second signal layer, then it is determined that the design architecture of the first via meets the preset test result.

[0121] Check for electroplated copper damage: The purpose is to ensure that the copper layer of the electroplated through-hole is not mechanically or chemically damaged during the production process and maintains its good conductive properties. If the electroplated copper layer is damaged, it may cause unstable signal transmission or poor electrical connection.

[0122] Perform open circuit test on signal lines: test the first signal line of the first signal layer and the first signal line of the second signal layer, and the second signal line of the first signal layer and the second signal line of the second signal layer respectively. The purpose of these tests is to verify whether there is a correct electrical connection between the signal lines between the vias, that is, to ensure that the signal between the first signal layer and the second signal layer can be transmitted normally through the first via without being cut off. In other words, the open circuit test is to confirm whether the signal line is connected normally. If there is an electrical connection between the signal lines, it means that the first via has correctly completed the signal transmission path.

[0123] Perform a short circuit test on the signal lines: Test the first signal line and the second signal line of the first signal layer, and the first signal line and the second signal line of the second signal layer respectively. The purpose of this step is to ensure that there is no unnecessary electrical short circuit in the first via design, that is, to confirm that there is no unexpected electrical connection between the signal lines. In other words, the short circuit test is used to verify whether there is an unexpected electrical connection between the signal lines. If the test results show that there is a short circuit connection between the signal lines, it may mean that the design is defective and needs to be adjusted.

[0124] By checking whether the electroplated copper is damaged and performing an open circuit test, it can be ensured that the electroplated through-hole will not have signal transmission problems in actual use; the short circuit test can confirm whether the first via design effectively avoids unwanted signal interference, thereby ensuring the purity and electrical performance of the signal; the design conditions that meet all preset test results indicate that the design architecture of the differential via can operate stably in actual applications, thereby meeting the design requirements and ensuring the performance and reliability of the circuit board.

[0125] Overall, this design method not only ensures signal integrity and electrical performance through fine control of each step, but also effectively improves the space utilization efficiency of PCB design, reduces production complexity and cost, and provides a solid foundation for the realization of high-density, high-performance electronic devices. For other introductions to the design method of differential vias, please refer to the above embodiments, and this application will not go into details here.

[0126] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0127] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A design architecture of a differential via, characterized in that: Applied to a printed circuit board, the printed circuit board includes a plurality of signal layers, and the design architecture of the differential via includes: a first via hole, passing through a first signal layer and a second signal layer of the printed circuit board; at least one milling groove, each of the milling grooves runs through the first signal layer and the second signal layer, and all of the milling grooves are used to divide the first via hole into at least two parts; The first signal line of the differential line is inserted through the first part of the first via hole on the first signal layer and extends through the first part of the first via hole on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via hole on the first signal layer and extends through the second part of the first via hole on the second signal layer.

2. The differential via design architecture as claimed in claim 1, characterized in that: The number of the milling grooves is 1, the milling grooves are arranged radially along the first via hole, and are connected to the parallel structure for dividing the first via hole into two parts, and the parallel structure includes a first signal line and a second signal line parallel to each other in the differential line.

3. The differential via design architecture as claimed in claim 1, characterized in that: The difference between the length of the milling groove along the extension direction of the differential line and the preset length is greater than the first length and less than the second length; The preset length is a larger value of a first diameter of a pad outside the first via hole on the first signal layer and a second diameter of a pad outside the first via hole on the second signal layer.

4. The differential via design architecture as claimed in claim 1, wherein: The width of the preset milling groove along the extending direction perpendicular to the differential line is greater than the line distance of the differential line; The line pitch is a larger value of a first distance between the first signal line and the second signal line on the first signal layer and a second distance between the first signal line and the second signal line on the second signal layer.

5. The differential via design architecture as claimed in claim 4, characterized in that: The width of the preset milling groove along the extending direction perpendicular to the differential line is smaller than the inner diameter of the first via hole.

6. The differential via design architecture according to any one of claims 1 to 5, characterized in that: The number of the milling grooves is greater than 2, and all the milling grooves are used to divide the first via hole into at least three parts; The first signal line of the differential line is inserted through the first part of the first via on the first signal layer and extends out through the first part of the first via on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via on the first signal layer and extends out through the second part of the first via on the second signal layer. The other part of the first via serves as a signal return hole.

7. The differential via design architecture as claimed in claim 6, characterized in that: The first signal line of the differential line is inserted from a first part of a first via hole on the first signal layer along a first direction, and extends from a first part of the first via hole on the second signal layer along a second direction; The second signal line of the differential line is inserted from the second part of the first via hole of the first signal layer along the first direction, and extends from the second part of the first via hole on the second signal layer along the second direction; The first direction is opposite to the second direction.

8. The differential via design architecture as claimed in claim 7, characterized in that: The number of the milling grooves is 2; The first milling groove is arranged radially along the first via hole and forms a preset angle with the parallel structure. One end of the second milling groove is connected to the midpoint of the first milling groove, and the second milling groove is connected to the parallel structure. The parallel structure includes a first signal line and a second signal line that are parallel to each other in the differential line.

9. The differential via design architecture as claimed in claim 8, characterized in that: The length of the first milling groove along the extending direction perpendicular to the differential line is greater than the first length and less than the second length. The preset length is a larger value between a first diameter of the pad outside the first via hole on the first signal layer and a second diameter of the pad outside the first via hole on the second signal layer; The width of the first milling groove along the extension direction of the differential line is greater than the line distance of the differential line; The line pitch is a larger value of a first distance between the first signal line and the second signal line on the first signal layer and a second distance between the first signal line and the second signal line on the second signal layer.

10. The differential via design architecture as claimed in claim 8, characterized in that: The length of the second milling groove along the extension direction of the differential line is not less than the third distance between the midpoint of the first milling groove and the pad outside the first via hole; The width of the second milling groove along the extending direction perpendicular to the differential line is equal to the width of the first milling groove.

11. A printed circuit board, characterized in that: A design architecture comprising a differential via as described in any one of claims 1-10.

12. A method for designing a differential via, characterized in that: Applied to the design architecture of the differential via according to any one of claims 1 to 10, the design method of the differential via comprises: Get the target design size; Controlling a first drill needle to drill a first via hole on the printed circuit board according to the target design size, wherein the first via hole penetrates a first signal layer and a second signal layer of the printed circuit board; Plating copper inside the first via hole to cover the hole wall of the first via hole to form a conductive layer; Etching the pad outside the first via and the differential line according to the target design size, wherein the width of the pad is equal to the line spacing of the differential line, and the line spacing of the differential line is the distance between the first signal line and the second signal line parallel to each other in the differential line; Drilling at least one milling groove on the printed circuit board according to the target design size; all the milling grooves are used to divide the first via hole into at least two parts; Filling the first via hole and all the milling grooves with resin respectively; The first signal line of the differential line is inserted through the first part of the first via hole on the first signal layer and extends through the first part of the first via hole on the second signal layer. The second signal line of the differential line is inserted through the second part of the first via hole on the first signal layer and extends through the second part of the first via hole on the second signal layer.

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