Via hole structure for multi-signal transmission and printed circuit board

Abstract

The utility model discloses a multi-signal transmission via hole structure and a printed circuit board, relates to the field of circuit design, and is used for solving the problems of large spacing of multi-signal layer-changing via holes and low utilization rate of single-hole signal transmission. According to the via hole structure of the scheme, a plurality of hole structures are arranged in a bonding pad of a single via hole to form a plurality of isolated signal channels, and any two adjacent signal via holes are tangent to each other and the bonding pad is designed to isolate the signal channels. The occupied space of the signal layer changing via hole is obviously reduced, the signal bearing capacity of a single via hole is greatly improved, the signal integrity is guaranteed, the signal transmission utilization rate of the single via hole is improved, the high-density design of the single-end signal via hole and the differential signal via hole is achieved, and the via hole structure of the scheme is easy to achieve, flexible, diverse, easy to machine and low in cost. Therefore, on the premise that the production design difficulty is not increased, the distance between the signal layer-changing via holes is reduced, and the signal transmission utilization rate of a single via hole is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit design, and particularly relates to a via structure for multi-signal transmission and a printed circuit board. BACKGROUND

[0002] With the development of electronic information technology and the improvement of signal transmission rate, the requirements for signal performance and quality are also increasing, especially the wide application of high-speed signal transmission technology, which significantly increases the design difficulty and implementation cost of printed circuit board wiring. In the design of printed circuit board, the printed circuit board is usually designed as multiple layers, and the layer change transmission of signals is realized through vias, and the design and optimization of the vias directly affect the transmission quality of signals and the wiring density of the printed circuit board.

[0003] With the increase of the number of chip and connector signal pins and the continuous improvement of signal rate, the signal layer change vias in the fan-out area are more and more dense. The traditional via design has certain limitations for both single-ended signals and differential signals, and cannot meet the design requirements of modern printed circuit boards. CONTENT OF THE INVENTION

[0004] The present application provides a via structure for multi-signal transmission and a printed circuit board to at least solve the problems of large multi-signal layer change via spacing and low utilization rate of single-hole signal transmission in the related art.

[0005] The present application provides a via structure for multi-signal transmission, comprising: a via unit, the via unit comprising at least one first via and a conductive layer covering the inner wall of each first via, a second via being formed by the area of the first via other than the conductive layer surrounded by the inner wall of the conductive layer, the second via having a first end face on one side in the extension direction, and the plane where the first end face is located being a first plane;

[0006] At least one pad corresponding to the first via and located on the first plane, the projection of the pad on the first plane surrounding the first end face, the pad having at least one split hole penetrating through the pad, the split hole being located at the edge of the first end face, and the pad comprising a plurality of interval regions, any two adjacent interval regions being spaced apart by the split hole.

[0007] The present application also provides a printed circuit board, comprising: the via structure for multi-signal transmission as described above.

[0008] Through the application, since multiple independent segmentation holes are designed in the pads of a single via, independent transmission of multiple different signals through one hole is realized, the spacing between signal layer-changing vias is greatly reduced, for the signal transmitted through multiple vias, since any two adjacent vias are tangent to each other, the tangent part is open circuit, while the pads corresponding to the adjacent vias are connected, and then the pads corresponding to the two adjacent vias are segmented by the multiple independent segmentation holes on the pads to realize the open circuit between any two adjacent vias, thereby realizing independent transmission of signals. Through the arrangement of the segmentation holes, the spacing between the vias is reduced without increasing the production design difficulty, and the signal transmission utilization rate of a single via is improved. Therefore, the technical problems of large spacing between multiple signal layer-changing vias and low signal transmission utilization rate of a single via can be solved, and the technical effects of greatly reducing the layout and wiring space occupied by signal layer-changing vias, improving the density of printed circuit board signal fan-out, enhancing signal integrity, reducing signal impedance at the via, and enhancing the coupling of differential signals are achieved. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0010] Figure 1 A single-ended signal layer-changing transmission scheme in the prior art;

[0011] Figure 2 A differential signal layer-changing transmission scheme in the prior art;

[0012] Figure 3 A first via in a multi-signal transmission via structure provided by an embodiment of the present application;

[0013] Figure 4 A single-via multi-signal transmission via structure provided by an embodiment of the present application;

[0014] Figure 5 A multi-via multi-signal transmission via structure provided by an embodiment of the present application;

[0015] Figure 6 A not-equal-size via structure provided by an embodiment of the present application;

[0016] Figure 7 Another not-equal-size via structure provided by an embodiment of the present application;

[0017] Figure 8A minimum segmentation hole arrangement schematic diagram provided for the embodiment of the present application;

[0018] Figure 9 A segmentation hole arrangement schematic diagram provided for the embodiment of the present application;

[0019] Figure 10 A multi-signal transmission via hole arrangement structure schematic diagram provided for the embodiment of the present application;

[0020] Figure 11 Another multi-signal transmission via hole arrangement structure schematic diagram provided for the embodiment of the present application;

[0021] Figure 12 Another minimum segmentation hole arrangement schematic diagram provided for the embodiment of the present application;

[0022] Figure 13 A maximum segmentation hole arrangement schematic diagram provided for the embodiment of the present application;

[0023] Figure 14 Still another multi-signal transmission via hole arrangement structure schematic diagram provided for the embodiment of the present application.

[0024] Among them, the above-mentioned drawings include the following reference signs:

[0025] 10, via hole unit; 11, first via hole; 12, conductive layer; 13, second via hole; 20, pad; 21, segmentation hole; 131, first target via hole; 132, second target via hole; 200, pad unit; 30, insulating part; 40, DP and DN high-speed signal exchange layer via hole; 50, GND signal backflow hole; 60, via hole. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] It should be noted that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. The terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. The terms "parallel", "perpendicular", "equal" include the described case and the approximate case similar to the described case, and the approximate case is within the acceptable deviation range, which is determined by the ordinary skilled person in the art considering the measurement being discussed and the error related to the measurement of the specific quantity (i.e. the limitation of the measurement system). For example, "parallel" includes absolute parallel and approximate parallel, and the acceptable deviation range of approximate parallel can be, for example, within 5°; "perpendicular" includes absolute perpendicular and approximate perpendicular, and the acceptable deviation range of approximate perpendicular can also be, for example, within 5°. "Equal" includes absolute equality and approximate equality, and the acceptable deviation range of approximate equality can be, for example, that the difference between the two equalities is less than or equal to 5% of either. For the ordinary skilled person in the art, the specific meaning of the above terms in the present application can be understood in specific cases.

[0028] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below in conjunction with the drawings and specific embodiments.

[0029] As shown in Figure 1 and Figure 2 , the Figure 1 is a schematic diagram of a single-ended signal layer change scheme in the prior art, Figure 2 is a schematic diagram of a differential signal layer change scheme in the prior art. In the prior art, single-ended signals are generally concentrated together for layer change, and the center distance of the via 60 is more than 18 mil. The design of differential via is generally a pair of DP and DN high-speed signal layer change via 40, with a pair of GND signal reflow hole 50 beside it, and the center distance between the differential vias is 40 mil. However, this occupies a larger area of the printed circuit board, and the number of vias that can be set on the printed circuit board is limited.

[0030] To solve the above technical problems, in one aspect, embodiments of the present application provide a via structure for multi-signal transmission, as shown in Figure 3 , Figure 4 and Figure 5 , Figure 3 is a first via schematic diagram of a via structure for multi-signal transmission provided by the present application, Figure 4 is a schematic diagram of a via structure for single-hole multi-signal transmission provided by the present application, Figure 5 is a schematic diagram of a via structure for multi-hole multi-signal transmission provided by the present application, which comprises:

[0031] a via unit 10, comprising at least one first via 11 and a conductive layer 12 covering the inner wall of each first via 11, a second via 13 being surrounded by the inner wall of the conductive layer 12, the first end face of the second via 13 having a first end face, and the plane where the first end face is located being a first plane;

[0032] at least one pad 20 corresponding to the first via 11 one by one and located on the first plane, the projection of the pad 20 on the first plane surrounding the first end face, the pad 20 having at least one split hole 21 passing through, the split hole 21 being located at the edge of the first end face, the pad 20 comprising a plurality of interval regions, any two adjacent interval regions being spaced apart by the split hole 21, the second via 13 being in communication with the insulating material and / or tangentially communicating with any adjacent second via 13 through the split hole 21.

[0033] The first via 11 serves as the basic structure of signal layer change, and effectively constructs the conductive path for signal transmission by covering the conductive layer 12 on the inner wall. The arrangement of the conductive layer 12 ensures the conductive performance of the via;

[0034] The second via 13 is located in the inner wall of the conductive layer 12 of the first via 11, and has interval regions by tangentially communicating with adjacent second vias 13 or communicating with insulating material, forming a plurality of independent signal channels. This design allows multiple signals to be separated and transmitted in the same via, reduces the center distance between signal layer change vias, and provides the possibility for high-density wiring. At the same time, the tangential communication design of the second via 13 helps to enhance the coupling of differential signals, and enhances the signal integrity;

[0035] In this embodiment, the pads 20 serve as connection points for signal vias to external circuits. The pads 20 are divided into multiple spaced regions by providing through-dividing holes 21 in the pads 20. This design ensures signal connection while effectively isolating different signal paths, reducing signal interference and crosstalk, and enhancing signal integrity. The through-dividing holes 21 are located at the edge of the first end face, meaning that each spaced region closely surrounds a second via 13. This structure further reduces the spacing between signal second vias 13, improves signal fan-out density, and ensures isolation between second vias 13 through the communication of the through-dividing holes 21 and insulating material, thereby reducing signal impedance at the vias, enhancing the coupling of differential signals at the layer-changing vias, and optimizing signal transmission quality.

[0036] The spacing between adjacent spaced regions is determined by the through-dividing holes 21, which ensures the independence of each second via 13 while maintaining their close coupling. By precisely controlling the position and size of the through-dividing holes 21, effective isolation between the spaced regions can be achieved, reducing signal crosstalk and interference. Additionally, due to the compact layout of the spaced regions, the center-to-center spacing of the second vias 13 is further reduced.

[0037] This embodiment also creates multiple independent signal paths through the second vias 13 surrounded by the conductive layer 12, meaning that one via can transmit multiple signals simultaneously. Compared to the traditional design of a single via carrying only one signal, this structure significantly improves the signal carrying capacity of a single via, reduces the number of vias required for signal layer changes in a printed circuit board, saves valuable wiring space, and improves signal fan-out density.

[0038] As an optional embodiment, as shown in Figure 4 and Figure 5 , the second via 13 is filled with an insulating portion 30 covering the inner wall of the conductive layer 12. This design forms an insulating portion 30 inside the via to enhance the electrical isolation performance of the via structure and prevent signal crosstalk and loss. The insulating portion 30 filler can be selected from resin, and the present application does not make specific limitations.

[0039] The conductive layer 12 covers the inner wall of the first via 11, constructing the basic conductive path of the via unit 10. The presence of the conductive layer 12 ensures the continuous transmission of signals, but at the same time may introduce signal coupling and crosstalk, especially in high-density wiring scenarios. Therefore, the design of the conductive layer 12 needs to find a balance between conductivity and signal isolation. The insulating part 30 is arranged in the inner wall of the conductive layer 12 and directly fills the inside of the second via 13, which is the key to optimizing the signal path inside the via unit 10. The presence of the insulating part 30 ensures electrical isolation between the second vias 13, avoiding signal short circuit or crosstalk inside the via unit 10, enhancing signal integrity and reducing signal impedance at the via. When dealing with differential signals, the precise arrangement and filling of the insulating part 30 can control the center distance between differential vias, thereby optimizing the coupling degree of differential signals. This optimization helps to maintain the impedance continuity of the signal link, improves the transmission stability of differential signals, reduces the loss of signals at the via, and further enhances the coupling and integrity of differential signals.

[0040] As an optional embodiment, the number of second vias 13 is 1, and the single second via 13 is divided into multiple independent signal channels by designing multiple split holes 21 in the pad 20 of the single second via 13, realizing the concentrated layer change transmission of multiple signals. At the same time, by controlling the number and position of the split holes 21, the impedance continuity and signal integrity of signal transmission are optimized, the signal transmission efficiency and signal quality of a single via are improved, and the number of signals that need to be transmitted by layer change can be effectively increased. Figure 4 As an optional embodiment, the number of second vias 13 is 1, and the single second via 13 is divided into multiple independent signal channels by designing multiple split holes 21 in the pad 20 of the single second via 13, realizing the concentrated layer change transmission of multiple signals. At the same time, by controlling the number and position of the split holes 21, the impedance continuity and signal integrity of signal transmission are optimized, the signal transmission efficiency and signal quality of a single via are improved, and the number of signals that need to be transmitted by layer change can be effectively increased.

[0041] As an optional embodiment, the number of second vias 13 is 1, and the single second via 13 is divided into multiple independent signal channels by designing multiple split holes 21 in the pad 20 of the single second via 13, realizing the concentrated layer change transmission of multiple signals. At the same time, by controlling the number and position of the split holes 21, the impedance continuity and signal integrity of signal transmission are optimized, the signal transmission efficiency and signal quality of a single via are improved, and the number of signals that need to be transmitted by layer change can be effectively increased. Figure 4As shown, a single second via 13 is divided into four parts, a first via 11 with a diameter F of 10 mils, and the inner wall of the first via 11 is covered with a conductive layer 12 of copper with a thickness of 1 mil. The aperture size d of the second via 13 is 8 mils, i.e. d = F - 2 mils. The diameter P of the pad 20 is mils, i.e. P = d + 8 mils. On the circumference of the second via 13, four small through-holes S1, S2, S3, S4, i.e. division holes 21, are drilled, and the four small through-holes are equal in size, which equally divides the pad 20 into four parts, and each part can transmit one signal. Among them, the centers of the projections of S1 and S3 on the first plane are on a straight line, and the centers of the projections of S2 and S4 on the first plane are on a straight line. The diameter of the circular hole is at least the ring width of the pad 20, i.e. 4 mils. Compared with the existing design scheme in which each through-hole transmits one signal, the space occupied by the signal exchange hole is greatly reduced, and the exchange utilization rate of a single via is greatly improved. In the figure, only an example is given, and the single via can be divided into other reasonable numbers, and in particular, the pad 20 can also be unequally divided. The person skilled in the art should select according to the specific situation, and the present application does not make specific limitations.

[0042] In the present embodiment, the introduction of the division hole 21 is the key to realizing one-hole multi-signal transmission. The arrangement of at least two division holes 21 can divide a single via into multiple independent signal transmission paths, and each path transmits different signals or signal types. Not only does it ensure the independence of the signals and reduce the coupling and crosstalk between the signals, but it also allows more signals to be transmitted in a limited space. At the same time, the layout of the division hole 21 optimizes the electrical characteristics of the signal path, such as capacitance and inductance, thereby reducing the reflection and loss of the signal at the exchange via, enhancing the signal integrity, optimizing the signal impedance matching, and further reducing the signal impedance at the via.

[0043] Among them, as an optional embodiment, as Figure 5As shown, the via unit 10 includes a plurality of second vias 13, the number of second vias 13 in the via unit 10 is m, the number of segmentation holes 21 is n, n = 2(m-1). In this design, the via acts as a carrier for signal layer change, and the number n directly determines the number of signals that a single via unit 10 can carry. Traditional via design usually transmits only one signal per via, while the present application integrates multiple vias (m) in one via unit 10, realizing the ability to transmit multiple signals in the same physical space, greatly improving the density of signal fanout, reducing the number of vias required for signal layer change and the overall layout space, making the design of printed circuit board more compact and efficient. The relationship between the number n of segmentation holes 21 and the number m of vias is n = 2(m-1), which is set to create sufficient isolation between the m vias to ensure independent transmission of signals. The key to this design is that each segmentation hole 21 is located at the first end surface edge of the adjacent second via 13, and by setting the segmentation hole 21, the adjacent second vias 13 are precisely separated, avoiding signal crosstalk and interference, enhancing signal integrity, and reducing signal impedance at the via.

[0044] As an optional embodiment, as shown in Figure 6 As shown, the via unit 10 includes a plurality of second vias 13, a conductive layer 12, and a first via 11, wherein the aperture of at least two second vias 13 is different. This design aims to improve the flexibility and signal quality of signal transmission, and different aperture second vias 13 are used for different types of signals (such as power signals, low-speed signals), especially for power signal holes, to optimize signal transmission performance and reduce signal interference. Increasing the aperture can ensure the flow of signals at the second via 13 and reduce signal loss.

[0045] As an optional embodiment, as shown in Figure 6 As shown, any two adjacent second vias 13 in the via unit 10 are a first target via 131 and a second target via 132, the aperture of the first target via 131 is smaller than the aperture of the second target via 132, and the projection of the pad 20 on the first plane is circular, and the radius of the pad 20 corresponding to the first target via 131 is equal to the aperture of the segmentation hole 21.

[0046] Through the above structural design, the aperture of the first target via hole 131 is smaller than that of the second target via hole 132, which takes into account the transmission requirements of different signals. The first target via hole 131 with a smaller aperture is more suitable for transmitting low-speed or low-current signals, while the second target via hole 132 with a larger aperture is suitable for transmitting high-speed or power signals. The circular projection design of the pad 20 on the first plane provides stable signal connection and good electrical performance. The radius of the pad 20 corresponding to the first target via hole 131 is equal to the aperture of the segmentation hole 21, which means that the segmentation hole 21 is located exactly at the edge of the pad 20. This size matching can prevent unnecessary crosstalk between the pad 20 and the via hole, ensuring signal path isolation while reducing via hole spacing, enhancing signal integrity, especially for differential signals that require high signal integrity. By controlling the via hole spacing and aperture, signal loss and crosstalk can be reduced, and signal quality can be improved.

[0047] The embodiment also provides a via hole structure, as shown in Figure 7 , Figure 7 A schematic diagram of the second via hole 13 with unequal size in a multi-signal transmission via hole structure provided by the present application. The via hole unit 10 is composed of the first via hole 11, the conductive layer 12 and the second via hole 13, the number of segmentation holes 21 n = m-1, m is the number of second via holes 13 in the via hole unit 10, any two adjacent second via holes 13 in the via hole unit 10 are the first target via hole 131 and the second target via hole 132, the aperture of the first target via hole 131 is smaller than that of the second target via hole 132, and the projection of the pad 20 on the first plane is circular, the minimum aperture of the segmentation hole 21 R' (as shown in Figure 7 ), R' is the radius of the pad 20 corresponding to the first target via hole 131.

[0048] As an optional embodiment, as shown in Figure 8 and Figure 9 , Figure 8 A schematic diagram of the case where the segmentation hole 21 takes the minimum value in a multi-signal transmission via hole structure provided by the present application, Figure 9 A schematic diagram of the case where the segmentation hole 21 takes the maximum value in a multi-signal transmission via hole structure provided by the present application, the via hole unit 10 includes a plurality of second via holes 13, the projection of the pad 20 on the first plane is circular, and the minimum value D min =R-d / 2 and the maximum value D max =R of the aperture of the segmentation hole 21. In this design, the aperture of the segmentation hole 21 is controlled within the range of D min =R-d / 2 to D max =R, which takes into account the balance between signal isolation and coupling. The minimum aperture D min= R-d / 2, which ensures that the split hole 21 separates the two adjacent second vias 13 corresponding to the pads 20, thereby achieving good signal isolation and reducing signal crosstalk. When the maximum aperture D max = R, the split hole 21 is tangent, which is beneficial in scenarios that require enhanced signal coupling, such as differential signal transmission, by minimizing the center-to-center spacing between the second vias 13 to enhance the coupling of differential signals. The circular design of the pad 20 also simplifies the manufacturing process, reduces manufacturing errors introduced by irregular pad 20 shapes, and further improves signal transmission quality.

[0049] Exemplarily, as shown in Figure 8 and Figure 9 , a schematic diagram of a differential via provided by the present application is given, the diameter F of the first via 11 is 10 mil, and the inner wall of the first via 11 covers a conductive layer 12 with a thickness of 1 mil. The aperture d of the second via 13 is 8 mil, i.e. d = F-2 mil. The aperture size D of the split hole 21, and the diameter P of the pad 20 are 16 mil, i.e. P = D+8 mil, and the center-to-center spacing of the projection of the two adjacent second vias 13 on the first plane is 8 mil, which is significantly reduced compared to the existing differential signal 40 mil via center-to-center spacing. Since the two second vias 13 are in a tangent relationship, the signals are short-circuited, and at the position where the two signal holes are tangent, two split holes 21 are drilled to separate the second vias 13 connected together. The minimum aperture of the split hole 21 is the ring width of the pad 20, i.e. 4 mil, as shown in Figure 8 , and the maximum aperture is the radius R of the pad 20, i.e. 8 mil, as shown in Figure 9 .

[0050] As an optional embodiment, as shown in Figure 10 , the via unit 10 is composed of a row of second vias 13, a first via 11 and a conductive layer, and the pads 20 corresponding to the row of second vias 13 are connected to each other to form a pad unit 200, wherein the pad unit 200 is as shown in Figure 11As shown, the number of interval regions in the pad unit 200 is greater than or equal to the number of segmentation holes 21, and the second via 13 is in communication with any adjacent second via 13 through the plurality of segmentation holes 21. This design forms a via string by designing a row of tangentally communicated vias, and uses the segmentation hole 21 to isolate the vias in the via string as independent signal channels, realizing efficient transmission of multi-signal concentrated layer change. The pad unit 200 includes at least as many interval regions as the number of segmentation holes 21, and there is enough space around each segmentation hole 21 to ensure signal isolation, and the second via 13 is in tangent communication with the adjacent second via 13. This design makes the vias physically closely connected, but electrically isolated through the segmentation hole 21. The tangent communication design maximizes the center distance between the vias, improves the density of signal fan-out, and at the same time, due to the close layout between the vias, the signal impedance at the via can be reduced, the electrical performance of the via unit 10 is improved, the signal transmission link is optimized, the printed circuit board space is fully utilized, and the density of signal layout is improved. In this embodiment, the number of segmentation holes 21 is n, n = 2(m-1), m is the number of second vias 13 in the via unit 10, and the structure of the conductive layer 12 is the same as that of other embodiments of the present application. This embodiment will not be described again.

[0051] This embodiment also provides another via structure, as shown in Figure 12 As shown, unlike the above-mentioned via structure of this embodiment, the number of segmentation holes 21 is N, N = m, m is the number of second vias 13 in the via unit 10, and the via unit 10 is composed of the first via 11, the conductive layer 12 and the second via 13. One segmentation hole 21 is arranged between every two adjacent vias in the pad 20. In addition to the technical effects brought by the above-mentioned arrangement of n segmentation holes 21, compared with the arrangement of n segmentation holes 21, it is easier to realize and the required cost is lower.

[0052] Among them, as an optional embodiment, the via is a differential via for transmitting differential signals.

[0053] A differential via is a pair of vias that are used to transmit differential signals, i.e., a pair of complementary signals (DP and DN). A differential via is typically composed of two closely located vias that transmit the positive and negative phases of a pair of differential signals to achieve vertical signal layer transition. By closely locating two vias, a differential via significantly reduces the physical space required for signal layer transition. Compared to traditional single-ended signal vias, differential vias have a smaller center-to-center spacing. The compact layout of differential vias reduces the capacitance and inductance of the signal path, which helps to lower the signal impedance at the via, reducing signal reflection and loss at the via, ensuring stable signal transmission, and improving the performance margin of the link. By reducing the distance between the DP and DN signal lines, differential vias enhance the coupling of differential signals, which is crucial for maintaining impedance continuity of the signal link. Enhanced coupling of differential signals means that the phase difference between signals can be more stably maintained, improving the signal's resistance to interference, especially in multi-layer printed circuit boards and long via designs.

[0054] As some optional embodiments, as shown in Figure 13 and Figure 14 , Figure 13 is a schematic diagram of the case where the split hole 21 takes the minimum value provided by the present embodiment, Figure 14 is a schematic diagram of the case where the split hole 21 takes the maximum value provided by the present embodiment. The via unit 10 includes a plurality of second vias 13, first vias 11, conductive layers 12, and the number of split holes 21 is equal to the number of second vias 13. The projection of the pad 20 on the first plane is circular, and the aperture D of the split hole 21 ranges from where R is the radius of the pad 20 and r is the radius of the second via 13. In this design, multiple second vias 13 are used, allowing multiple signals to be transmitted simultaneously within a single via unit 10, reducing the space occupied by the via unit 10, and optimizing the compactness and efficiency of the board design. The number N of split holes 21 is equal to the number M of second vias 13, which means that each second via 13 has a corresponding split hole 21. This one-to-one relationship ensures the independence of signal transmission for each second via 13, reduces signal crosstalk and mutual influence, and enhances signal integrity.

[0055] In the above optional embodiments, the aperture D of the split hole 21 ranges from where R is the radius of the pad 20 and r is the radius of the second via 13. The lower limit of the aperture D ensures that the opening of the split hole 21 is sufficient to split the pad 20, effectively isolating the signals, reducing signal coupling and crosstalk, and enhancing signal integrity. The upper limit of the aperture D Therefore, the split hole 21 does not remove the whole pad 20, avoids the damage of the structure of the pad 20, and ensures the sufficient area of the pad 20 to maintain the electrical characteristics at the via and reduce the signal impedance at the via.

[0056] Overall, the design improves the structure of the signal layer-changing via unit and achieves the following technical effects:

[0057] 1. The layout and wiring space occupied by the signal layer-changing via is greatly reduced, especially for the ball grid array (BGA) chip and high-speed connector with a large number of signal layers, which is conducive to the high-density design of the printed circuit board, effectively reduces the signal impedance at the via by reducing the center distance of the differential via, and is conducive to enhancing the coupling of the differential signal, maintaining the signal integrity of the whole link, especially suitable for the design of multi-layer boards and long vias in server printed circuit board design.

[0058] 2. The signal loss and crosstalk inside the via can be reduced by filling the insulating part, and the transmission quality of the signal can be improved. The split hole structure can realize the design of one hole with multiple lines at a short distance, which is simple to process and manufacture, low in process cost, short in processing period, and has strong flexibility and replicability.

[0059] On the other hand, the application also provides a printed circuit board comprising the multi-signal transmission via structure as described above.

[0060] The scheme of the application can be applied not only to all server board designs, but also to other board cards with signal layer-changing requirements. In addition, it can be applied not only to through-hole boards, but also to high-density interconnect (HDI) boards with blind holes and buried holes to realize signal layer changing. For the design description of other board cards, please refer to the above embodiments, which will not be described here.

[0061] The multi-signal transmission via structure provided by the application is described in detail above. The principles and implementation modes of the application are described by applying specific examples in this paper, and the above description of the embodiments is only used to help understand the method and core idea of the application. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and modifications can be made to the application without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A via structure for multi-signal transmission, comprising: a via unit comprising at least one first via and a conductive layer covering the inner wall of each of the first vias, wherein the area of the first via other than the conductive layer constitutes a second via, and the second via has a first end surface on one side in the extending direction; and at least one pad corresponding to each of the first vias and located on a first plane, wherein the projection of the pad on the first plane surrounds the first end surface, the pad has at least one split hole passing therethrough, the split hole is located at the edge of the first end surface, and the pad comprises a plurality of interval regions, wherein any two adjacent interval regions are spaced apart by the split hole, and the first plane is the plane on which the first end surface is located, and in the case of multiple second vias, any two adjacent second vias are tangent and connected. 2.The via structure for multi-signal transmission according to claim 1, wherein the via unit comprises a plurality of second vias, and the aperture of at least two second vias is different. 3.The via structure for multi-signal transmission according to claim 2, wherein any two adjacent second vias in the via unit are a first target via and a second target via, the aperture of the first target via is smaller than that of the second target via, and the projection of the pad on the first plane is circular, the radius of the pad corresponding to the first target via is equal to the aperture of the split hole. 4.The via structure for multi-signal transmission according to claim 1, wherein R is the radius of the pad, and d is the aperture of the via. 5.The via structure for multi-signal transmission according to any one of claims 1 to 4, wherein the via unit comprises a plurality of second vias, the number of second vias in the via unit is m, and the number of split holes is n, wherein n=2(m-1). 6.The via structure for multi-signal transmission according to any one of claims 1 to 4, wherein the via unit is composed of a row of second vias, the pads corresponding to the row of second vias are connected to each other to form a pad unit, the number of interval regions in the pad unit is greater than or equal to the number of split holes, and the second vias are connected to any adjacent second vias through a plurality of split holes. 7.The via structure for multi-signal transmission according to any one of claims 1 to 4, further comprising: an insulating part filled in the second via and covering the inner wall of the conductive layer. 8.The via structure for multi-signal transmission according to any one of claims 1 to 4, wherein the via is a differential via for transmitting a differential signal. 9.The via structure for multi-signal transmission according to claim 1, wherein the number of second vias is 1, the number of split holes is greater than or equal to 2, and the projection area of a plurality of interval regions on the first plane is equal. The via unit includes a plurality of the second vias, a projection of the pad on the first plane is circular, and an aperture of the segmentation hole has a minimum value D min , D min = R - d / 2, where, 10.A device comprising the via structure for multi-signal transmission according to any one of claims 1 to 10. ​ ​ ​ ​ 7. The multi-signal transmission via structure of any one of claims 1 to 4, wherein, ​ ​ ​ ​ ​ ​ ​ The via unit comprises a plurality of the second vias, the number of the segmentation holes is equal to the number of the second vias, the projection of the pad on the first plane is circular, the aperture D of the segmentation hole ranges from 0.5R to 1.5R wherein a radius of the pad is R and a radius of the via is r.

11. A printed circuit board, characterized by ​

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