Forming method of via hole group on circuit board and circuit board

Abstract

The invention belongs to the technical field of circuit board manufacturing, and particularly relates to a forming method of a via hole group in a circuit board and the circuit board. The invention discloses a forming method of a via hole group on a circuit board. The forming method comprises the following steps: acquiring a board main body; a differential base hole is drilled in the to-be-drilled area of the plate body in the thickness direction of the to-be-drilled area, and a grounding base hole is drilled in the position adjacent to the differential base hole; a circle of grounding coating is formed on the hole wall of the grounding base hole, and a circle of differential coating is formed on the hole wall of the differential base hole; removing partial material of the differential plating layer along the thickness direction of the plate main body to obtain a plurality of differential wires which are mutually spaced and extend along the thickness direction of the plate main body so as to form differential via holes; and / or removing a part of material of the grounding plating layer along the thickness direction of the plate main body to obtain a grounding wire which extends along the thickness direction of the plate main body and is close to the differential wire so as to form a grounding via hole. At least one differential pair signal layer change can be completed through one differential via hole and one grounding via hole, so that the number of via holes is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit board manufacturing, and particularly relates to a method for forming a via group on a circuit board and a circuit board. Background Art

[0002] A printed circuit board (PCB) includes a plurality of circuit layers stacked on top of each other. In order to connect different circuit layers, vias (VIA holes) are provided on the circuit board.

[0003] In the existing circuit boards, a via is an integral part and is in the shape of a barrel. It is either connected to a power supply, or connected to GND (abbreviation for the wire grounding end), or a specific signal. In the application of high-speed signal layer change, four vias are required to implement the layer change function of a differential pair. One via is connected to the first signal of the differential pair signal, another via is connected to the second signal of the differential pair signal, and the remaining two vias are connected to the ground signal and are respectively arranged close to the two vias connected to the differential pair signal.

[0004] Therefore, four vias are required to implement the layer change function of a differential pair. For circuit boards with a high application density, the number of vias is large, occupying a large space, greatly reducing the strength of the circuit board, and causing the circuit board to be easily damaged under stress and external forces. Moreover, too many vias will excessively consume the conductive copper foil on the circuit layer, resulting in a weakened current-carrying capacity of the circuit layer. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: aiming at the problem of a large number of vias in the existing circuit boards, to provide a method for forming a via group on a circuit board and a circuit board.

[0006] To solve the above technical problem, on the one hand, an embodiment of the present invention provides a method for forming a via group on a circuit board, and the forming method includes: Obtain a board body; wherein, the board body includes circuit layers and a substrate stacked on top of each other; Drill differential base holes in the area to be drilled of the board body along its thickness direction, and drill ground base holes at positions adjacent to the differential base holes; Form a ring of ground plating on the hole wall of the ground base hole, and form a ring of differential plating on the hole wall of the differential base hole; Remove part of the material of the differential plating along the thickness direction of the board body to obtain a plurality of differential traces spaced apart from each other and extending along the thickness direction of the board body, so as to form differential vias; And / or, remove part of the material of the ground plating along the thickness direction of the board body to obtain a ground trace extending along the thickness direction of the board body and close to the differential trace, so as to form a ground via.

[0007] Optionally, drilling differential base holes along the thickness direction of the area to be drilled on the board body, and drilling ground base holes at positions adjacent to the differential base holes, includes: Drilling differential base holes with a triangular cross-sectional shape along the thickness direction of the area to be drilled on the board body; Drilling a ground base hole beside one hole wall of the differential base hole.

[0008] Optionally, removing part of the material of the differential plating along the thickness direction of the board body to obtain multiple differential traces spaced apart from each other and extending along the thickness direction of the board body to form differential vias, includes: Removing the materials at both ends of the corners and the middle position of the side wall adjacent to the ground base hole on the differential plating along the thickness direction of the board body, to obtain two differential traces spaced apart on the hole wall of the differential via adjacent to the ground base hole.

[0009] Optionally, drilling a ground base hole beside one hole wall of the differential base hole, includes: Drilling a ground base hole with a triangular cross-sectional shape beside one hole wall of the differential base hole; wherein, the adjacent hole walls between the ground base hole and the differential base hole are parallel.

[0010] Optionally, removing part of the material of the ground plating along the thickness direction of the board body to obtain a ground trace extending along the thickness direction of the board body and close to the differential trace to form a ground via, includes: Removing the materials at both ends of the corners of the side wall of the ground plating close to the differential plating along the thickness direction of the board body, and a ground trace extending along the thickness direction of the board body is formed on the hole wall of the ground base hole close to the differential base hole.

[0011] Optionally, drilling differential base holes along the thickness direction of the area to be drilled on the board body, and drilling ground base holes at positions adjacent to the differential base holes, includes: Drilling a first differential base hole and a second differential base hole with a triangular cross-sectional shape along the thickness direction of the area to be drilled on the board body; Drilling the ground base hole with a triangular cross-sectional shape between the first differential base hole and the second differential base hole; wherein, the adjacent hole walls between the ground base hole and the first differential base hole are parallel, and the adjacent hole walls between the ground base hole and the second differential base hole are parallel.

[0012] Optionally, removing part of the material of the ground plating along the thickness direction of the board body to obtain a ground trace extending along the thickness direction of the board body and close to the differential trace to form a ground via, includes: Remove the materials at three corners of the grounding plating along the thickness direction of the board body to obtain three grounding traces spaced apart from each other and extending along the thickness direction of the board body; wherein, one of the grounding traces is formed on the hole wall of the grounding base hole parallel to the first differential base hole, and another grounding trace is formed on the hole wall of the grounding base hole parallel to the second differential base hole.

[0013] Optionally, removing a part of the material of the differential plating along the thickness direction of the board body to obtain a plurality of differential traces spaced apart from each other and extending along the thickness direction of the board body to form differential vias, including: Machine at least two dividing holes along the thickness direction of the board body. During the process of forming the dividing holes, remove a part of the material of the differential plating to obtain a plurality of differential traces spaced apart from each other and extending along the thickness direction of the board body.

[0014] Optionally, the dividing holes are machined by laser cutting, laser drilling or mechanical drilling.

[0015] On the other hand, the present invention provides a circuit board, including a via group and a board body. The board body includes a circuit layer and a substrate stacked, and the via group penetrates at least one of the substrates. The via group includes at least one differential via and at least one grounding via disposed adjacent to the differential via; The differential via includes a differential base hole and a plurality of differential traces disposed at intervals around the differential base hole on the hole wall of the differential base hole. The grounding via includes a grounding base hole and at least one grounding trace disposed on the hole wall of the grounding base hole; The grounding trace and the differential trace extend along the thickness direction of the board body. Each differential trace can electrically connect a differential signal on the circuit layer, and each grounding trace can electrically connect a grounding signal on the circuit layer, so that one via group can transmit at least one differential pair signal.

[0016] Optionally, the cross-sectional shape of the differential base hole is triangular.

[0017] Optionally, two spaced differential traces are disposed on the hole wall of the differential base hole adjacent to the grounding base hole. One differential trace can electrically connect the first signal of a differential pair signal, and the other differential trace can electrically connect the second signal of a differential pair signal.

[0018] Optionally, the cross-sectional shape of the grounding base hole is triangular. The adjacent hole walls between the grounding base hole and the differential base hole are parallel, and the grounding trace is disposed on the hole wall of the grounding base hole adjacent to the differential base hole.

[0019] Optionally, the via group includes two differential vias, namely a first differential via and a second differential via, and the ground via is disposed between the first differential via and the second differential via; Two spaced ground traces are provided on the hole wall of the ground base hole, namely a first ground trace and a second ground trace. The first ground trace is disposed on the side wall of the ground base hole adjacent to the first differential via, and the second ground trace is disposed on the side wall of the ground base hole adjacent to the second differential via.

[0020] Optionally, at each of the differential vias, a split hole is provided between any two adjacent differential traces, and the split hole penetrates the hole wall of the differential base hole along the thickness direction of the board body.

[0021] The method for forming a via group on a circuit board according to the present invention is to remove part of the material from a whole circle of differential plating on the hole wall of a differential base hole to obtain a plurality of spaced differential traces. Each differential trace can connect differential signals. The ground via is disposed adjacent to the differential via, and the ground via can cooperate with a plurality of differential traces in the differential via to meet the differential signal impedance requirements, so that at least one differential via and a ground via can complete the layer change operation of at least one differential pair signal. The present invention can complete the layer change of at least one differential pair signal through at least one differential via and a ground via, so as to reduce the number of vias required to complete the layer change of the differential pair signal, which is beneficial to ensuring the strength of the circuit board, reducing the possibility that the circuit board fails under the action of external force and stress due to the large number of vias, and also reducing the damage of the differential base hole to the conductive copper foil on the circuit layer, which is beneficial to ensuring the current-carrying capacity of the circuit layer. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of step S2 of the method for forming a via group on a circuit board provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of step S3 of the method for forming a via group on a circuit board provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of steps S4 and S5 of the method for forming a via group on a circuit board provided by an embodiment of the present invention; Figure 4 is Figure 3 a schematic diagram when the planar shapes of the differential base hole and the ground base hole in Figure 5 It is a schematic diagram of steps S4 and S5 of the method for forming a via group on a circuit board provided by another embodiment of the present invention.

[0023] The reference numerals in the specification are as follows: 1. Board main body; 11. Substrate; 12. Circuit layer; 2. Differential via; 21. Differential base hole; 22. Differential plating; 23. Differential trace; 24. First differential via; 25. Second differential via; 3. Ground via; 31. Ground base hole; 32. Ground plating; 33. Ground trace; 34. First ground trace; 35. Second ground trace; 4. Split hole. Detailed implementation manner

[0024] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] As Figures 1 to 3 shown, an embodiment of the present invention provides a method for forming a via group on a circuit board. The forming method includes: S1: Obtain the board main body 1; wherein, the board main body 1 includes a circuit layer 12, a substrate 11 and a ground layer stacked. S2: As Figure 1 shown, drill differential base holes 21 in the area to be drilled of the board main body 1 along its thickness direction, and drill ground base holes 31 at positions adjacent to the differential base holes 21. S3: As Figure 2 shown, form a ring of ground plating 32 on the hole wall of the ground base hole 31, and form a ring of differential plating 22 on the hole wall of the differential base hole 21. S4: As Figure 3 shown, remove part of the material of the differential plating 22 along the thickness direction of the board main body 1 to obtain a plurality of differential traces 23 that are spaced apart from each other and extend along the thickness direction of the board main body 1, so as to form differential vias 2. And / or, as Figure 3 shown, S5: Remove part of the material of the ground plating 32 along the thickness direction of the board main body 1 to obtain a ground trace 33 that extends along the thickness direction of the board main body 1 and is close to the differential trace 23, so as to form a ground via 3.

[0026] In step S3, to form the ground plating 32 on the hole wall of the ground base hole 31 and the differential plating 22 on the hole wall of the differential base hole 21, the common electroless copper plating process in the field of circuit board manufacturing technology is adopted, which will not be elaborated here.

[0027] As can be seen from step S4, for the differential vias 2 of the present invention, a part of the material of a complete circle of differential plating layer 22 on the hole wall of the differential base hole 21 is removed to obtain a plurality of differential traces 23 spaced from each other. One end of a differential trace 23 extending in the thickness direction of the board body 1 can be electrically connected to the first signal of the differential pair signal on a circuit layer 12, and the other end outputs the first signal to another circuit layer 12. One end of another differential trace 23 extending in the thickness direction of the board body 1 can be electrically connected to the second signal of the differential pair signal, and the other end outputs the second signal to another circuit layer 12, so as to realize the layer change of the differential pair signal.

[0028] The differential signal requires to meet the impedance continuity condition and has a high requirement for impedance. Therefore, a grounding via 3 is arranged near the differential via 2. First, it can provide a good signal return path for the signal carried by the differential trace 23, reduce the signal return path area, thereby reducing the influence of the signal return path on the impedance of the signal and reducing impedance discontinuity. Second, it can eliminate the electromagnetic field radiation between the first signal and the second signal of the differential pair signal.

[0029] For the forming method of the via group on the circuit board of the present invention, step S5 can be adopted. A part of the material of the grounding plating layer 32 is removed along the thickness direction of the board body 1, and a complete circle of the grounding plating layer 32 is divided into a plurality of grounding traces 33. Each grounding trace 33 can provide a signal return path for the signal carried by the adjacent differential via 2, so that one grounding via 3 can provide a return path for multiple signals, which is equivalent to that one grounding via 3 can realize the functions of multiple grounding vias 3 in the prior art, so as to further reduce the number of vias.

[0030] Of course, step S5 can also not be adopted, and a complete circle of the grounding plating layer 32 in the grounding base hole 31 can be directly used as the conductive medium of the grounding via 3, that is, the grounding via 3 is an integral structure.

[0031] For the forming method of the via group on the circuit board of the present invention, a part of the material of a complete circle of the differential plating layer 22 on the hole wall of the differential base hole 21 is removed to obtain a plurality of differential traces 23 spaced from each other. Each differential trace 23 can connect differential signals. The grounding via 3 is arranged adjacent to the differential via 2. The grounding via 3 can cooperate with the multiple differential traces 23 in the differential via 2 to meet the impedance requirements of the differential signal, so that one differential via 2 and the grounding via 3 can at least complete the layer change operation of one differential pair signal.

[0032] When a via in the prior art is a whole and four vias need to be set to complete the layer change of a differential pair signal, the present invention can complete the layer change of at least one differential pair signal through a differential via 2 and a grounding via 3, so as to reduce the number of vias required for the layer change of the differential pair signal, which is beneficial to ensuring the strength of the circuit board, reducing the possibility of the circuit board failing due to a large number of vias under the action of external force and stress, and also reducing the damage of the differential base hole 21 to the conductive copper foil on the circuit layer 12, which is beneficial to ensuring the current-carrying capacity of the circuit layer 12.

[0033] The via group formed by the grounding via 3 and the differential via 2 of the circuit board 1 is used to electrically connect the circuit layers 12 of different layers and realize the cross-layer transmission of differential signals. The specific application of the circuit board 1 with this via group can be a multi-layer PCB board, an HDI (High Density Interconnector), which is used for the connection and signal transmission of electronic components, or a substrate for packaging chips.

[0034] In one embodiment, as Figure 1 and Figure 3 shown, step S2 includes: S21: Drill a differential base hole 21 with a triangular cross-sectional shape along the thickness direction of the to-be-drilled area of the board body 1; S22: Drill a grounding base hole 31 beside one hole wall of the differential base hole 21.

[0035] Compared with the circular differential base hole 21, the differential base hole 21 with a triangular cross-sectional shape has a smaller cross-sectional area and occupies less space, which is more beneficial to ensuring the strength of the circuit board, further reducing the damage of the differential base hole 21 to the conductive copper foil on the circuit layer 12, and is more beneficial to ensuring the current-carrying capacity of the circuit layer 12.

[0036] In one embodiment, step S3 includes: Remove the materials at both ends of the corners and the middle position of the side wall adjacent to the grounding base hole 31 on the differential plating 22 along the thickness direction of the board body 1, and obtain two differential traces 23 spaced apart on the hole wall of the differential via 2 adjacent to the grounding base hole 31.

[0037] The two differential traces 23 connecting a differential pair signal are located on one hole wall of the differential base hole 21 close to the grounding base hole 31, and the distances between the two differential traces 23 and the grounding base hole 31 are the same or close, which is beneficial to ensuring that the lengths of the differential signal transmission line pairs are equal to optimize the matching of differential impedance.

[0038] In one embodiment, step S22 includes: A ground base hole 31 with a triangular cross-sectional shape is drilled beside a hole wall of the differential base hole 21; wherein, the adjacent hole walls between the ground base hole 31 and the differential base hole 21 are parallel.

[0039] In one embodiment, step S5 includes: Removing the materials at both ends of the corners of the side wall of the ground plating 32 close to the differential plating 22 along the thickness direction of the board body 1; wherein, a ground trace 33 extending along the thickness direction of the board body 1 is formed on the hole wall of the ground base hole 31 close to the differential base hole 21.

[0040] After removing the materials at both ends of the corners of the side wall of the ground plating 32 close to the differential plating 22, the entire ring of the ground plating 32 of the common ground via 3 is divided into two ground traces 33. Among them, a ground trace 33 is formed on the hole wall of the ground base hole 31 close to the differential base hole 21, and two differential traces 23 are arranged on the hole wall of the differential base hole 21 adjacent to the ground base hole 31. Therefore, the two differential traces 23 are parallel to the ground trace 33 of the ground base hole 31 close to the differential base hole 21, so that the distances between the two differential traces 23 and the ground trace 33 are the same everywhere, which is more conducive to ensuring that the lengths of the differential signal transmission line pairs are equal, and is also more conducive to simulating and calculating the differential impedance to obtain a matching differential impedance.

[0041] In one embodiment, step S4 includes: At least two dividing holes 4 are machined along the thickness direction of the board body 1. During the formation of the dividing holes 4, part of the material of the differential plating 22 is removed to obtain a plurality of differential traces 23 that are spaced apart and extend along the thickness direction of the board body 1.

[0042] By machining the dividing holes 4 to remove part of the material on the differential plating 22, the machining method is simple and it is convenient to control the removal amount of the differential plating 22.

[0043] In one embodiment, as Figure 3 shown, in step S5, part of the material on the ground plating 32 is removed by machining the dividing holes 4 to obtain a plurality of spaced-apart ground traces 33.

[0044] In one embodiment, the dividing holes 4 are machined by laser cutting, laser drilling or mechanical drilling.

[0045] In other embodiments, chemical etching can be used to remove part of the material of the differential plating 22 along the thickness direction of the board body 1 to obtain the above-mentioned differential traces 23. Of course, chemical etching can also be used to remove part of the material on the ground plating 32 along the thickness direction of the board body 1 to obtain a plurality of spaced-apart ground traces 33.

[0046] In one embodiment, in step S2, a differential base hole 21 or a ground base hole 31 is drilled in the board body 1 by means of laser drilling or mechanical drilling.

[0047] In another embodiment, as Figure 5 shown, step S2 includes: S23: Drill a first differential base hole and a second differential base hole with a triangular cross-section along the thickness direction of the area to be drilled on the board body 1; S24: Drill a ground base hole 31 with a triangular cross-section between the first differential base hole and the second differential base hole; wherein, the adjacent hole walls between the ground base hole 31 and the first differential base hole are parallel, and the adjacent hole walls between the ground base hole 31 and the second differential base hole are parallel.

[0048] In another embodiment, step S5 includes: Remove the materials at the three corners of the ground plating 32 along the thickness direction of the board body 1 to obtain three ground traces 33 that are spaced apart from each other and extend along the thickness direction of the board body 1; wherein, one of the ground traces 33 is formed on the hole wall of the ground base hole 31 parallel to the first differential base hole, and the other ground trace 33 is formed on the hole wall of the ground base hole 31 parallel to the second differential base hole.

[0049] Divide the entire circle of the ground plating 32 into three spaced ground traces 33. One ground trace 33 is used in cooperation with the differential trace 23 in the first differential via 24 to meet the impedance requirements of the differential signal carried by the differential trace 23 in the first differential via 24. Another ground trace 33 is used in cooperation with the differential trace 23 in the second differential via 25 to meet the impedance requirements of the differential signal carried by the differential trace 23 in the second differential via 25, so that the first differential via 24 and the second differential via 25 share a ground via 3, further reducing the number of vias on the circuit board and further reducing the space occupied by the vias.

[0050] In one embodiment, the board body 1 is a multilayer board, including two substrates 11 and three circuit layers 12. The three circuit layers 12 include two signal layers and one ground layer. The ground layer is located between the two substrates 11. The two signal layers are respectively arranged on the two side surfaces of the board body 1 in the thickness direction. At this time, the differential base hole 21 is a through hole penetrating the board body 1, the ground base hole 31 is a first-order hole, the ground trace 33 is electrically connected to the ground layer, and the differential trace 23 is electrically connected to the signal layer.

[0051] In other embodiments, the circuit board can be a six-layer board, an eight-layer board, etc., and the differential base holes 21 can be blind holes or buried holes on the circuit board. When the differential base holes 21 are buried holes on the circuit board, the substrate 11 through which the differential base holes 21 penetrate can be laminated first to obtain the board body 1. After processing the differential vias 2 and the ground vias 3 on the board body 1 by the above steps, other substrates 11 and circuit layers 12 are laminated on the board body 1 so that the differential base holes 21 are in the form of buried holes on the circuit board.

[0052] In other embodiments, the board body 1 can include a substrate 11 and circuit layers 12 provided on both surface sides in the thickness direction of the substrate 11. Ground lines are arranged at positions close to the differential lines on one side of the circuit layer 12. The ground traces 33 are electrically connected to the ground lines, and the differential traces 23 are electrically connected to the differential lines.

[0053] In addition, according to the method for forming a via group on the circuit board in any of the above embodiments, a circuit board can be processed.

[0054] As Figure 2 shown, the circuit board includes a via group and a board body 1. The board body 1 includes circuit layers 12 and substrates 11 stacked on top of each other. The via group penetrates at least one substrate 11. The via group includes at least one differential via 2 and at least one ground via 3 disposed adjacent to the differential via 2.

[0055] As Figure 3 shown, the differential via 2 includes a differential base hole 21 and a plurality of differential traces 23 spaced around the differential base hole 21 on the hole wall of the differential base hole 21. The ground via 3 includes a ground base hole 31 and at least one ground trace 33 provided on the hole wall of the ground base hole 31.

[0056] The ground traces 33 and the differential traces 23 extend in the thickness direction of the board body 1. Each differential trace 23 can be electrically connected to a differential signal on the circuit layer 12, and each ground trace 33 can be electrically connected to a ground signal on the circuit layer 12 so that one via group can transmit at least one differential pair signal.

[0057] The ground via 3 is disposed adjacent to the differential via 2 to provide a signal return path for the signal carried by the differential trace 23, reduce the influence of the signal return path on the impedance of the signal, facilitate maintaining the continuity of the signal impedance, and can also eliminate the electromagnetic field radiation between the first signal and the second signal of the differential pair signal.

[0058] Compared with the existing entire via, in the circuit board of the present invention, a plurality of mutually spaced differential traces 23 are arranged in the differential base hole 21 to form a differential via 2. Each differential trace 23 can connect a differential signal, so that at least one differential via 2 can electrically connect a differential pair signal, enabling one differential via 2 and a ground via 3 to achieve the function of changing layers of differential pair signals that originally required four vias, thereby reducing the number of vias on the circuit board, reducing the occupied space of the vias, reducing the possibility of the circuit board failing due to external force and stress, and also reducing the damage of the differential base hole 21 to the conductive copper foil on the circuit layer 12, which is beneficial to ensuring the current-carrying capacity of the circuit layer 12.

[0059] In one embodiment, as Figure 3 shown, the cross-sectional shape of the differential base hole 21 is triangular.

[0060] Compared with the common circular via, the cross-sectional area of the triangular differential base hole 21 is smaller and the occupied space is smaller, so as to further reduce the occupied space of the vias on the circuit board.

[0061] In one embodiment, two spaced differential traces 23 are arranged on the hole wall of the differential base hole 21 adjacent to the ground base hole 31. One differential trace 23 can electrically connect the first signal of a differential pair signal, and the other differential trace 23 can electrically connect the second signal of a differential pair signal.

[0062] The two differential traces 23 connecting a differential pair signal are located on the same hole wall of the differential base hole 21 close to the ground base hole 31, and the distances between the two differential traces 23 and the ground base hole 31 are the same or close, which is beneficial to ensuring that the lengths of the differential signal transmission line pairs are equal to optimize the matching of differential impedance.

[0063] Moreover, the two differential traces 23 connecting a differential pair signal only occupy one hole wall of the differential via 2, reducing the occupied space, so that differential traces 23 can also be arranged on the remaining hole walls of the differential via 2, enabling one differential via 2 to connect more differential signals and further improving the utilization rate of the differential via 2.

[0064] In one embodiment, as Figure 4 shown, the ground base hole 31 and the differential base hole 21 are mirror-distributed, and the cross-sectional outer shape of the ground base hole 31 and the cross-sectional outer shape of the differential base hole 21 are inscribed in a circle. It can be seen that in the present invention, two vias can be processed in the space where originally only one circular via could be processed, and the space utilization rate is relatively high.

[0065] In one embodiment, as Figure 3As shown, the cross-sectional shape of the grounding base hole 31 is triangular. The adjacent hole walls between the grounding base hole 31 and the differential base hole 21 are parallel. A grounding trace 33 is provided on the hole wall of the grounding base hole 31 adjacent to the differential base hole 21, such that the two differential traces 23 are parallel to the grounding trace 33 of the grounding base hole 31 close to the differential base hole 21, and the distances between the two differential traces 23 and the grounding trace 33 are the same everywhere, which is more conducive to ensuring that the lengths of the differential signal transmission line pairs are equal and is also more conducive to simulating and calculating the differential impedance to obtain a matched differential impedance.

[0066] In one embodiment, at each differential via 2, a dividing hole 4 is provided between any two adjacent differential traces 23, and the dividing hole 4 penetrates the hole wall of the differential base hole 21 along the thickness direction of the board body 1. The plating on a common via is a complete circle. By drilling the dividing hole 4, part of the material on the complete circle of plating is removed to obtain multiple spaced differential traces 23. The drilling process is simple and it is convenient to control the amount of material removed.

[0067] In one embodiment, as Figure 3 shown, dividing holes 4 are provided at both end corners and the middle position of the side wall of the differential plating 22 close to the grounding base hole 31.

[0068] In one embodiment, dividing holes 4 are provided at both end corners of the side wall of the grounding plating 32 close to the differential base hole 21.

[0069] In another embodiment, as Figure 5 shown, the via group includes two differential vias 2, namely a first differential via 24 and a second differential via 25, and a grounding via 3 is provided between the first differential via 24 and the second differential via 25.

[0070] Two spaced grounding traces 33 are provided on the hole wall of the grounding base hole 31, namely a first grounding trace 34 and a second grounding trace 35. The first grounding trace 34 is provided on the side wall of the grounding base hole 31 adjacent to the first differential via 24, and the second grounding trace 35 is provided on the side wall of the grounding base hole 31 adjacent to the second differential via 25.

[0071] The complete circle of grounding plating 32 is divided into three spaced grounding traces 33. One grounding trace 33 is used in cooperation with the differential trace 23 in the first differential via 24 to meet the impedance requirements of the differential signal carried by the differential trace 23 in the first differential via 24, and another grounding trace 33 is used in cooperation with the differential trace 23 in the second differential via 25 to meet the impedance requirements of the differential signal carried by the differential trace 23 in the second differential via 25, such that the first differential via 24 and the second differential via 25 share a grounding via 3, so as to further reduce the number of vias on the circuit board and further reduce the space occupied by the vias.

[0072] In another embodiment, as Figure 5 shown, the first differential via 24 and the second differential via 25 are symmetrically distributed with respect to the first symmetry axis. There are two grounding vias 3, and the two grounding vias 3 are symmetrically distributed with respect to the second symmetry axis. The first symmetry axis is perpendicular to the second symmetry axis.

[0073] Four sets of parallel planes are formed between the two grounding vias 3 and the first differential via 24 and the second differential via 25. In each set of parallel planes, the above-mentioned grounding traces 33 are provided on the hole walls of the grounding vias 3 close to the first differential via 24 and the second differential via 25. Correspondingly, two differential traces 23 are provided on the hole walls of the first differential base hole and the second differential base hole close to the grounding base hole 31. The first differential base hole, the second differential base hole and the two grounding base holes 31 are used in cooperation to be able to transmit four differential pair signals.

[0074] In other embodiments, the cross-sectional shape of the differential base hole 21 can be square, circular, hexagonal, etc.

[0075] In other embodiments, the cross-sectional shape of the grounding base hole 31 can be square, circular, hexagonal, etc.

[0076] In other embodiments, only one grounding trace 33 can be provided on the grounding base hole 31. At this time, the grounding trace is a whole-circle plating layer, that is, the grounding via 3 is a common through-hole with an integral structure.

[0077] In other embodiments, for a differential base hole 21 with a triangular cross-sectional shape, one differential trace 23 can be provided on one hole wall of the differential base hole 21, and one differential trace 23 can be provided on the other hole wall of the differential base hole 21.

[0078] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for forming a via group on a circuit board, characterized in that: The molding method comprises: Obtaining a board body (1); wherein the board body (1) comprises a circuit layer (12) and a substrate (11) which are stacked; Drilling a differential base hole (21) in the to-be-drilled area of ​​the plate body (1) along the thickness direction thereof, and drilling a grounding base hole (31) at a position adjacent to the differential base hole (21); A circle of grounding plating (32) is formed on the hole wall of the grounding base hole (31), and a circle of differential plating (22) is formed on the hole wall of the differential base hole (21); Removing part of the material of the differential plating layer (22) along the thickness direction of the board body (1) to obtain a plurality of differential traces (23) spaced apart from each other and extending along the thickness direction of the board body (1) to form differential vias (2); And / or, part of the material of the grounding plating layer (32) is removed along the thickness direction of the board body (1) to obtain a grounding trace (33) extending along the thickness direction of the board body (1) and close to the differential trace (23), so as to form a grounding via (3).

2. The method for forming a via group on a circuit board according to claim 1, characterized in that: The method comprises drilling a differential base hole (21) in the to-be-drilled area of ​​the plate body (1) along the thickness direction thereof, and drilling a grounding base hole (31) at a position adjacent to the differential base hole (21), comprising: Drilling a differential basic hole (21) having a triangular cross-sectional shape in the area to be drilled of the plate body (1) along the thickness direction thereof; A grounding base hole (31) is drilled on the side of a hole wall of the differential base hole (21).

3. The method for forming a via group on a circuit board according to claim 2, characterized in that: The method comprises removing part of the material of the differential plating layer (22) along the thickness direction of the board body (1) to obtain a plurality of differential traces (23) spaced apart from each other and extending along the thickness direction of the board body (1) to form a differential via (2), comprising: The material at the corners and the middle position of the side wall adjacent to the grounding base hole (31) on the differential plating layer (22) is removed along the thickness direction of the board body (1), thereby obtaining two differential traces (23) separated on the hole wall of the differential via hole (2) adjacent to the grounding base hole (31).

4. The method for forming a via group on a circuit board according to claim 3, characterized in that: The method of drilling a grounding base hole (31) beside a hole wall of the differential base hole (21) comprises: A grounding base hole (31) having a triangular cross-sectional shape is drilled on the side of a hole wall of the differential base hole (21); wherein the grounding base hole (31) is parallel to the adjacent hole wall between the differential base holes (21).

5. The method for forming a via group on a circuit board according to claim 4, characterized in that: The method of removing part of the material of the grounding plating layer (32) along the thickness direction of the board body (1) to obtain a grounding trace (33) extending along the thickness direction of the board body (1) and close to the differential trace (23) to form a grounding via (3) comprises: The material at the corners at both ends of the side wall of the grounding plating layer (32) close to the differential plating layer (22) is removed along the thickness direction of the board body (1), and a grounding trace (33) extending along the thickness direction of the board body (1) is formed on the hole wall of the grounding base hole (31) close to the differential base hole (21).

6. The method for forming a via group on a circuit board according to claim 1, characterized in that: The method comprises drilling a differential base hole (21) in the to-be-drilled area of ​​the plate body (1) along the thickness direction thereof, and drilling a grounding base hole (31) at a position adjacent to the differential base hole (21), comprising: Drilling a first differential basic hole and a second differential basic hole having a triangular cross-sectional shape in the area to be drilled of the plate body (1) along the thickness direction thereof; The grounding base hole (31) having a triangular cross-sectional shape is drilled between the first differential base hole and the second differential base hole; wherein the grounding base hole (31) is parallel to adjacent hole walls between the first differential base holes, and the grounding base hole (31) is parallel to adjacent hole walls between the second differential base holes.

7. The method for forming a via group on a circuit board according to claim 6, characterized in that: The method of removing part of the material of the grounding plating layer (32) along the thickness direction of the board body (1) to obtain a grounding trace (33) extending along the thickness direction of the board body (1) and close to the differential trace (23) to form a grounding via (3) comprises: The material at the three corners of the grounding plating layer (32) is removed along the thickness direction of the plate body (1) to obtain three grounding traces (33) that are spaced apart from each other and extend along the thickness direction of the plate body (1); wherein one of the grounding traces (33) is formed on a hole wall of the grounding base hole (31) parallel to the first differential base hole, and the other grounding trace (33) is formed on a hole wall of the grounding base hole (31) parallel to the second differential base hole.

8. The method for forming a via group on a circuit board according to any one of claims 1 to 7, characterized in that: The method comprises removing part of the material of the differential plating layer (22) along the thickness direction of the board body (1) to obtain a plurality of differential traces (23) spaced apart from each other and extending along the thickness direction of the board body (1) to form a differential via (2), comprising: At least two split holes (4) are machined along the thickness direction of the board body (1); in the process of forming the split holes (4), part of the material of the differential plating layer (22) is removed to obtain a plurality of differential traces (23) that are spaced apart from each other and extend along the thickness direction of the board body (1).

9. The method for forming a via group on a circuit board according to claim 8, characterized in that: The segmentation holes (4) are processed by laser cutting, laser drilling or mechanical drilling.

10. A circuit board, characterized in that: The board body (1) comprises a via hole group and a board body (1), wherein the board body (1) comprises a circuit layer (12) and a substrate (11) arranged in a stacked manner, the via hole group passes through at least one of the substrates (11), and the via hole group comprises at least one differential via hole (2) and at least one grounding via hole (3) arranged adjacent to the differential via hole (2); The differential via (2) comprises a differential base hole (21) and a plurality of differential traces (23) arranged on the hole wall of the differential base hole (21) at intervals around the differential base hole (21); the grounding via (3) comprises a grounding base hole (31) and at least one grounding trace (33) arranged on the hole wall of the grounding base hole (31); The ground traces (33) and the differential traces (23) extend along the thickness direction of the board body (1); each of the differential traces (23) can be electrically connected to a differential signal on the circuit layer (12); and each of the ground traces (33) can be electrically connected to a ground signal on the circuit layer (12), so that one of the via groups can transmit at least one differential pair signal.

11. The circuit board according to claim 10, characterized in that: The cross-sectional shape of the differential base hole (21) is a triangle.

12. The circuit board according to claim 11, characterized in that: Two differential traces (23) are arranged at intervals on the hole wall of the differential base hole (21) adjacent to the ground base hole (31), wherein one differential trace (23) can be electrically connected to a first signal of a differential pair signal, and the other differential trace (23) can be electrically connected to a second signal of a differential pair signal.

13. The circuit board according to claim 12, characterized in that: The cross-sectional shape of the grounding base hole (31) is triangular, the grounding base hole (31) is parallel to the adjacent hole wall between the differential base hole (21), and the grounding trace (33) is arranged on the hole wall of the grounding base hole (31) adjacent to the differential base hole (21).

14. The circuit board according to claim 10, characterized in that: The via group comprises two differential vias (2), namely a first differential via (24) and a second differential via (25), and the ground via (3) is arranged between the first differential via (24) and the second differential via (25); Two spaced ground traces (33) are arranged on the hole wall of the ground base hole (31), which are a first ground trace (34) and a second ground trace (35); the first ground trace (34) is arranged on the side wall of the ground base hole (31) adjacent to the first differential via (24); and the second ground trace (35) is arranged on the side wall of the ground base hole (31) adjacent to the second differential via (25).

15. The circuit board according to any one of claims 10 to 14, characterized in that: At each of the differential via holes (2), a split hole (4) is provided between any two adjacent differential traces (23), and the split hole (4) penetrates the hole wall of the differential base hole (21) along the thickness direction of the board body (1).

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