WO2024046033A1

WO2024046033A1 - Signal transmission structure and manufacturing method

Info

Publication number: WO2024046033A1
Application number: PCT/CN2023/111327
Authority: WO
Inventors: 解旭彤; 周旭冉; 郭旭东; 张俊彪
Original assignee: 华为技术有限公司
Priority date: 2022-08-31
Filing date: 2023-08-04
Publication date: 2024-03-07
Also published as: CN117677029A

Abstract

A signal transmission structure (100) and a manufacturing method therefor. The signal transmission structure (100) comprises a first device (10), a second device (20), and a first grounding portion (30). The first device (10) and the second device (20) are disposed in a same signal layer (S1) or different signal layers (S1, S2) of a printed circuit board (200), and the first device (10) and the second device (20) are respectively located in two discrete grounds (60) in one or more signal layers. The first device (10) is configured to transmit a first signal to the second device (20). The first grounding portion (30) is arranged on the printed circuit board (200) and covers the two discrete grounds (60), and the first grounding portion (30) is configured to provide a complete reference ground when the second device (20) returns the first signal to the first device (10). Thus, the integrity of the reference ground of a sensitive signal is ensured, the impact of noise is greatly reduced, and the present invention is suitable for solving a signal integrity or electromagnetic problem caused by an incomplete reference layer of a sensitive signal.

Description

Signal transmission structure and production method

Cross-references to related applications

This application claims priority to the Chinese patent filed with the China Patent Office on August 31, 2022, with the application number 202211057543.8 and the application title "Signal Transmission Structure and Production Method", the entire content of which is incorporated into this application by reference.

Technical field

The present application relates to the field of signal transmission technology, and in particular, to a signal transmission structure and a manufacturing method.

Background technique

In a Printed Circuit Board (PCB), usually a signal can be sent from the driving end to the receiving end. After reaching the receiving end, the signal needs to return to the driving end, creating a current loop. The expression of the electric field strength of the signal is: E=0.3f2SI/L; among them, E represents the electric field strength of electromagnetic wave interference, f represents the signal frequency, I represents the signal size, S represents the loop area through which the signal flows, and L represents the test point and the loop. road distance. It can be seen from the above formula that the radiated electric field strength of the signal is proportional to the loop area of the signal. Therefore, by reducing the signal loop area, the radiation of the signal can be effectively reduced. In order to reduce the signal loop area, the existing board-level EMC design and wiring usually uses the power supply ground plane to be as complete as possible to provide an ideal reference plane for the signal and shorten the signal return path. As shown in Figure 1, the driving end 101 and the receiving end 102 is set in the signal layer 105, and the driving end 101 is connected to the receiving end 102 through the signal line 107. When the ground layer 106 provides a complete reference plane for the signal layer 105, the signal loop area composed of the signal direction and the signal return direction is the smallest, so that Minimize far-field radiation.

In some scenarios, as shown in Figure 2, when the signal line 107 crosses the gap on the reference ground plane, the signal backflow will bypass the gap and form a larger current loop, thereby causing the signal loop area to increase and the distance to the ground to be far away. Field radiation is enhanced and electromagnetic interference (EMI) performance is reduced.

Contents of the invention

This application provides a signal transmission structure and production method. This application can effectively reduce the loop area of signals and realize low-impedance return flow of sensitive signals. This application can solve electromagnetic problems caused by incomplete reference ground in high-speed signal wiring areas and ensure the integrity of signal transmission.

In a first aspect, the present application provides a signal transmission structure. The signal transmission structure may include a first device, a second device and a first ground portion. The first device and the second device may be disposed in the same signal layer or different signal layers of the printed circuit board, and the first device and the second device are respectively located in two first signals in the one or more signal layers. Discretely. The first device is used to transmit a first signal to the second device. A first ground portion is disposed on the printed circuit board and covers the two first discrete grounds. The ground portion is used to provide a signal when the second device recirculates the first signal to the first device. Provide a complete reference. This application aims to provide a way to achieve low-impedance ground return flow in a regional manner. This solution can ensure the integrity of the sensitive signal reference ground and greatly reduce the impact of ground noise. It is suitable for signal integrity or electromagnetic problems caused by incomplete reference layers of sensitive signals and is decoupled from the manufactured board.

As an optional implementation, the first ground part includes a contact array package LGA board, the first discrete ground is provided with a plurality of first pads, and the LGA board is provided with a plurality of second pads. , the plurality of second bonding pads are welded correspondingly to the plurality of first bonding pads to provide a complete reference ground for signal reflow between the second device and the first device. Based on this design, the LGA board has an off-board structure, which results in lower board costs and shorter processing time.

As an optional implementation manner, the first grounding part includes a steel sheet, and a plurality of third ground parts are discretely provided on the ground. A bonding pad, the steel sheet is used to connect the plurality of first bonding pads, and the steel sheet is used to provide a complete reference ground for signal reflow between the second device and the first device. Based on this design, there are more forms of steel plate prototyping, the implementation form is more flexible, the assembly is convenient, the cost is lower, and it is easy to disassemble.

As an optional implementation, the steel sheet is provided with one or more hollow areas, and the one or more hollow areas are used to prevent the steel sheet from contacting the one or more signal layers. device area contacts. Based on this design, it is possible to avoid contact between the steel sheet and the device area in the signal layer and avoid short circuit of the device.

As an optional implementation manner, the steel sheet is sunk corresponding to the first discrete position to form a plurality of welding portions, and the plurality of welding portions are correspondingly connected to the plurality of first pads. Based on this design, there are more forms of steel plate prototyping and the implementation form is more flexible.

As an optional implementation manner, the signal transmission structure further includes a conductive material, and the conductive material is pasted on a plurality of first pads on the two first discrete grounds. This can be applied to scenes such as curved surface structures, and has a wider scope of application.

As an optional implementation manner, the signal transmission structure further includes an insulator, and the insulator can isolate the conductive material from the device area, where the device area can include the area where the first device and the second device are located. Based on this design, short circuits in the device can be avoided.

As an optional implementation manner, the device area may also include an area where one or more devices other than the first device and the second device are located. Based on such a design, the present application can also prevent one or more devices other than the first device and the second device from being short-circuited.

As an optional implementation, the signal transmission structure further includes a third device, a fourth device and a second ground portion; the third device and the fourth device are provided in the same signal layer or in different signal layers. , the third device and the fourth device are respectively located at two second discrete places in the one or more signal layers; the third device is configured to transmit a second signal to the fourth device; The second ground portion is disposed on the printed circuit board and covers the two second discrete grounds, and the second ground portion is configured to return the second signal to the fourth device. The third device provides a complete reference ground.

As an optional implementation manner, the first device is connected to the second device through signal traces, where the signal traces may include but are not limited to clock lines, data lines, control lines or high-speed signal lines. at least one of them.

In a second aspect, the present application also provides a method for manufacturing a signal transmission structure. The signal transmission structure may include a printed circuit board and a first ground part, including: providing a printed circuit board, wherein the printed circuit board includes a or multiple signal layers; providing a first ground portion, disposing the first ground portion on the printed circuit board and covering the two first discrete grounds of the one or more signal layers; wherein, A first device and a second device are provided on the one or more signal layers. The first device and the second device are provided in the same signal layer or different signal layers. The first device and the third device are Two devices are respectively located on the two first discrete grounds, the second device is used to receive the first signal output by the first device, and the first ground portion is used to connect the first signal to the second device when the second device A signal provides a complete ground reference when flowing back to the first device. This application can provide a way to achieve low-impedance ground reflow in a regional manner. This solution can ensure the integrity of the sensitive signal reference ground and greatly reduce the impact of ground noise. It is suitable for signal integrity or electromagnetic problems caused by incomplete reference layers of sensitive signals and is decoupled from the manufactured board.

As an optional implementation manner, a first ground portion is provided, and the first ground portion is disposed on the printed circuit board and covers two first ground portions of the one or more signal layers. Discretely may include: providing an LGA board; forming a plurality of second bonding pads on the LGA board; connecting a plurality of second bonding pads on the LGA board to a plurality of first bonding pads on the first discrete ground. The disk is welded accordingly. Based on this design, the LGA board has an off-board structure, which results in lower board costs and shorter processing time.

As an optional implementation manner, a first ground portion is provided, and the first ground portion is disposed on the printed circuit board and covers two first ground portions of the one or more signal layers. Discretely may include: providing a steel sheet, sinking the steel sheet corresponding to the position of the first discrete ground to form a plurality of welded parts; connecting the plurality of welded parts with the first discrete ground A plurality of first pads are connected correspondingly. Based on this design, there are more forms of steel plate prototyping, the implementation form is more flexible, the assembly is convenient, the cost is lower, and it is easy to disassemble.

As an optional implementation manner, a first ground portion is provided, and the first ground portion is disposed on the printed circuit board and covers two first ground portions of the one or more signal layers. Discretely may include: providing a conductive material, and bonding the conductive material to a plurality of first pads on the first discrete ground. This can be applied to scenes such as curved surface structures, and has a wider scope of application.

As an optional implementation manner, the manufacturing method may further include: providing an insulator, and isolating the conductive material and the device area through the insulator. The device area may include an area where the first device and the second device are located. This prevents the device from short circuiting.

As an optional implementation manner, the device area may also include an area where one or more devices other than the first device and the second device are located.

As an optional implementation, the manufacturing method may further include: providing a second ground portion; disposing the second ground portion on the printed circuit board and covering the one or more signals two discrete layers; wherein, a third device and a fourth device are also provided on the one or more signal layers, and the third device and the fourth device are provided in the same signal layer or different signal layers. , the third device and the fourth device are respectively located at the two second discrete grounds, the fourth device is used to receive the second signal output by the third device, and the second ground portion is used to A complete reference ground is provided when the fourth device recirculates the second signal to the third device.

The signal transmission structure and production method provided by this application can achieve regional integrity through the outer structure. The signal transmission structure and production method of this application can ensure the integrity of the reference ground of sensitive signals, greatly reduce the impact of ground noise, and are suitable for signal integrity or electromagnetic problems caused by incomplete reference layers of sensitive signals, and decoupled from the manufactured board.

Description of drawings

Figure 1 is a schematic diagram of the signal loop of the complete reference plane signal routing.

Figure 2 is a schematic diagram of the signal loop after cleaning the wiring on the non-complete reference plane.

Figure 3 is another schematic diagram of the signal loop of the complete reference plane signal routing.

Figure 4 is a schematic structural diagram of a signal transmission structure according to an embodiment of the present application.

Figure 5 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 6 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 7 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 8 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 9 is a schematic structural diagram of a printed circuit board according to an embodiment of the present application.

Figure 10 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 11 is a schematic diagram comparing discrete and complete signals during signal transmission.

Figure 12 is another schematic diagram of comparison between discrete and complete signal transmission.

Figure 13 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 14 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 15 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 16 is another structural schematic diagram of the signal transmission structure according to the embodiment of the present application.

Figure 17 is another structural schematic diagram of a signal transmission structure according to an embodiment of the present application.

FIG. 18 is a flow chart of a method of manufacturing a signal transmission structure according to an embodiment of the present application.

FIG. 19 is another flowchart of a method of manufacturing a signal transmission structure according to an embodiment of the present application.

FIG. 20 is another flowchart of a method of manufacturing a signal transmission structure according to an embodiment of the present application.

FIG. 21 is another flowchart of a method of manufacturing a signal transmission structure according to an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the embodiments of the present application The technical solutions in the embodiments of the present application are clearly and completely described in the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

It should be noted that when an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element present at the same time. When an element is said to be "disposed on" another element, it can be placed directly on the other element or there may also be an intervening element present.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

At present, in the application process of high-speed circuit PCB boards, as the speed of integrated circuit switching and the density of PCB boards continue to increase, whether the signal can be completely sent from the sending end to the receiving end becomes a problem that high-speed circuit PCB boards need to face and consider. a key link. Among them, the reflow of high-speed signals is a key factor affecting signal integrity. Poor reflow processing of high-speed signals will cause the reflow signals to be affected by electromagnetic radiation, and the higher the rate of electromagnetic radiation, the more serious it will be, resulting in incomplete transmission of high-speed signals. , affecting signal integrity. It can be understood that signal integrity can refer to the quality of the signal in the circuit and the ability of the signal to respond according to the correct timing and voltage in the circuit.

For example, when a signal is transmitted on a printed circuit board, the signal flows from the driving end along the traces on the printed circuit board to the receiving end, and then from the receiving end along the ground plane through the shortest path or the path with the smallest impedance. The path leads back to the drive end. However, in one scenario, if the signal trace crosses the gap on the reference ground plane, the signal return path needs to be detoured, resulting in an increase in the signal loop area, enhanced far-field radiation, and poor electromagnetic interference (EMI) performance. reduce.

In order to cope with the above situation due to the increase in signal loop area, in a possible implementation, as shown in Figure 3, device 101 and device 102 are provided in the signal layer 103 of the printed circuit board, and the device 101 and the High-speed signals can be transmitted between devices 102 . The device 101 may be a driving end, and the device 102 may be a receiving end. Optionally, both the device 101 and the device 102 may be an integrated circuit (Integrated Circuit, IC) device. In order to realize the shortest path for signal return, a ground layer 104 can be provided in the inner layer of the printed circuit board in the scenario shown in FIG. 3 .

Wherein, the ground layer 104 is disposed below the signal layer 103, and the ground layer 104 is a complete reference ground. In this way, high-speed signals can flow from the device 101 along the wiring in the signal layer 103 to the device 102, and then from the device 102 along the ground layer 104 and return to the device through the shortest path. 101.

With such a design, the ground layer 104 can provide an ideal reference plane for signal transmission, shorten the signal return path, and minimize the signal loop area composed of the signal direction and the signal return direction, ensuring the integrity of high-speed signals with small noise tolerance. The reference layer can form a low-impedance return path, so it can solve the above-mentioned problems of increased radiation and reduced EMI performance caused by the increase in signal loop area.

However, in the implementation shown in Figure 3 above, an inner layer needs to be added to the printed circuit board to achieve a complete board. However, the board manufacturing process of this multi-layer board is very complicated and the cost is higher. It takes longer and has a greater impact on wiring density. This method is rarely used in actual board layout, which will reduce product competitiveness.

To this end, this application provides a signal transmission structure and a manufacturing method, which can achieve regional integrity through the outer structure. The embodiments of the present application can provide a nearby return path for signals, effectively reducing the signal loop area and realizing low-impedance return of high-speed signals. Embodiments of the present application can solve electromagnetic problems caused by incomplete reference ground in sensitive signal wiring areas, and can ensure the integrity of signal transmission.

Please refer to FIG. 4 , which is a schematic structural diagram of the signal transmission structure 100 according to an embodiment of the present application.

The signal transmission structure 100 in the embodiment of the present application can provide a large-area complete reference ground in the wiring area of sensitive signals, thereby achieving a low-impedance return ground. As shown in FIG. 4 , the signal transmission structure 100 can be disposed on the surface layer of the printed circuit board 200 . Specifically, the printed circuit board 200 may include a signal layer S1 and a ground plane G1, the ground plane G1 may be disposed on the lower surface of the signal layer S1. The ground plane G1 may be an incomplete reference ground.

The signal transmission structure 100 may include a first device 10 , a second device 20 and a ground portion 30 .

In this embodiment, the first device 10 can serve as a driving end, the second device 20 can serve as a receiving end, and the first device 10 can send a signal to the second device 20 . It can be understood that in other implementations, the first device 10 can serve as a receiving end and the second device 20 can serve as a driving end, that is, the second device 20 can send a signal to the first device 10 . Wherein, both the first device 10 and the second device 20 may be integrated circuit devices.

The first device 10 and the second device 20 may be disposed on the signal layer S1 of the printed circuit board 200 . In other words, in some possible scenarios, the first device 10 and the second device 20 may be provided in the same signal layer. The first device 10 can transmit one or more of clock signals, data signals, control signals or high-speed signals through the signal traces 40. These signals are collectively called sensitive signals, that is, those that need to be protected during printed circuit board wiring. Signal. to the second device 20 . It can be understood that, as an optional implementation manner, the signal wiring 40 may include but is not limited to one or more of clock lines, data lines, control lines or high-speed signal wiring.

As an optional implementation solution, the ground part 30 may be a conductive metal body.

It can be understood that in this embodiment, the ground portion 30 can be mounted on the surface of the printed circuit board 200 . The ground portion 30 can be mounted on the surface of the signal layer S1. For example, the ground portion 30 can be attached to the signal layer S1 and can be used to provide a complete reference ground for signal return flow between the first device 10 and the second device 20 . Specifically, the ground portion 30 may cover the wiring area of the signal wiring 40 in the signal layer S1. In other words, the ground portion 30 can provide a complete reference ground for signal return flow in some wiring areas of sensitive signals.

As shown in FIG. 4 , a sensitive signal can be emitted from the first device 10 and flow along the signal trace 40 to the second device 20 , and then from the second device 20 along the ground portion 30 reflow to the first device 10 . With such a design, the ground portion 30 in the embodiment of the present application does not have gap division, has a smaller area and is highly adapted to the sensitive signal wiring area, and can control the return path of the signal, thereby realizing the first The return path from device 10 to the second device 20 is the shortest and has the lowest return resistance.

Compared with the embodiment shown in Fig. 3, the embodiment shown in Fig. 4 has fewer board layers, is less costly, can shorten the board production time, is more flexible in implementation, and can be applied to more application scenarios. Improve product competitiveness.

Please refer to FIG. 5 , which is a schematic structural diagram of a signal transmission structure 100 according to another embodiment of the present application.

The difference from the signal transmission structure 100 shown in the embodiment of FIG. 4 is that, as shown in FIG. 5 , in this embodiment, the printed circuit board 200 may include multiple signal layers. For example, the printed circuit board 200 may include a signal layer S1, a ground plane G1, and a signal layer S2 that are stacked in sequence.

In this embodiment, the first device 10 may be disposed on the signal layer S1, and the second device 20 may be disposed on the signal layer S2. In other words, in some possible scenarios, the first device 10 and the second device 20 may be provided in different signal layers.

The signal transmission structure 100 may further include at least one via 401 and at least one via 403 .

Both the via hole 401 and the via hole 403 may have a cylindrical structure, and both the via hole 401 and the via hole 403 may be made of conductive materials, such as metal materials. The via hole 401 may penetrate the ground plane G1 to connect the first device 10 and the signal layer S2. Signal traces 40 may be provided in the signal layer S2. The first device 10 may be connected to the second device 20 through the via 401 and the signal trace 40 . The via hole 403 may penetrate the ground plane G1 to connect the first device 10 and the signal layer S2. The via hole 401 is a via hole used to transmit sensitive signals to the second device 20 , and the via hole 403 is a via hole used to return signals to the first device 10 .

As shown in Figure 5, in this embodiment, the ground portion 30 can be mounted on the surface of the signal layer S2, and can be used to provide signals between the first device 10 and the second device 20. The reflow provides a complete reference ground. Specifically, the ground portion 30 may cover the wiring area of the signal wiring 40 in the signal layer S2. Change In other words, the ground portion 30 can provide a complete reference ground for signal return in some wiring areas of sensitive signals.

Please refer to FIG. 6 , which is a schematic structural diagram of a signal transmission structure 100 according to another embodiment of the present application.

The difference from the signal transmission structure 100 shown in the embodiment of FIG. 4 is that, as shown in FIG. 6 , the signal transmission structure 100 may also include multiple devices. For example, in this embodiment, the signal transmission structure 100 may further include a third device 80 and a fourth device 90 . Wherein, the first device 10, the second device 20, the third device 80 and the fourth device 90 may all be disposed in the signal layer S1. It can be understood that only four devices (the first device 10 , the second device 20 , the third device 80 and the fourth device 90 ) are shown in FIG. 6 as an example for illustration. In other implementations, the number of devices may vary. Can be more than four. This application does not specifically limit this.

In this embodiment, the third device 80 can serve as a driving end, the fourth device 90 can serve as a receiving end, and the third device 80 can send a signal to the fourth device 90 . It can be understood that in other implementations, the third device 80 can serve as a receiving end, and the fourth device 90 can serve as a driving end, that is, the fourth device 90 can send a signal to the third device 80 .

As shown in FIG. 6 , the first device 10 and the second device 20 may be located on two discrete lands 60 respectively. The third device 80 and the fourth device 90 may be located on two discrete lands 62 respectively.

It can be understood that both the third device 80 and the fourth device 90 may be integrated circuit devices.

The third device 80 can transmit sensitive signals to the fourth device 90 through the signal trace 50 . The signal traces 50 may include at least one of a clock line, a data line, a control line or a high-speed signal trace.

In this embodiment, the signal transmission structure 100 may further include multiple ground parts. For example, the signal transmission structure 100 may include a ground portion 30 and a ground portion 70 . It can be understood that only two ground portions (ground portion 30 and ground portion 70 ) are shown in FIG. 6 as an example for illustration. In other implementations, the number of ground portions may be greater than two. This application does not specifically limit this.

As an optional implementation solution, the ground part 70 may be a conductive metal body.

It can be understood that in this embodiment, the ground portion 70 can be mounted on the surface of the printed circuit board 200 . For example, the ground portion 70 can be attached to the signal layer S1 and can be used to provide a complete reference ground for signal return flow between the third device 80 and the fourth device 90 . Specifically, the ground portion 70 may cover the wiring area of the signal wiring 50 in the signal layer S1. In other words, the ground portion 70 can provide a complete reference ground for signal return for some wiring areas of sensitive signals.

As shown in FIG. 6 , a sensitive signal may be emitted from the third device 80 and flow along the signal trace 50 to the fourth device 90 , and then from the fourth device 90 along the ground portion 70 reflow to the third device 80 . With such a design, the ground portion 70 in the embodiment of the present application does not have a gap separation, has a smaller area and is highly adapted to the sensitive signal wiring area, and can control the return path of the signal, thereby realizing the transmission from the third party. The return path from device 80 to the fourth device 90 is the shortest and has the lowest return resistance.

Compared with the embodiment shown in Figure 4, the embodiment shown in Figure 6 can be used for signal transmission scenarios between multiple devices, using multiple ground parts to provide a complete reference ground for signal transmission between these devices, achieving The form is more flexible and can be applied to more application scenarios, improving product competitiveness.

Referring to FIG. 7 , the following will illustrate the signal transmission structure 100 provided by the embodiment of the present application in conjunction with the drawings and actual application scenarios.

Please refer to FIG. 7 , which is a specific application scenario diagram of the signal transmission structure 100 according to an embodiment of the present application.

As shown in FIG. 7 , the signal transmission structure 100 may include a first device 10 , a second device 20 and a Land Grid Array (LGA) board 301 . That is, the grounding part in this embodiment can be implemented in the form of an LGA board.

The first device 10 and the second device 20 may be disposed in the signal layer S1.

The first device 10 can transmit sensitive signals to the second device 20 through the signal trace 40 . It can be understood that, as an optional implementation manner, the signal traces 40 may be sensitive signal traces. For example, the signal traces 40 may include sensitive signal traces such as clock lines, data lines, and control lines. At least one. In other words, at least one of sensitive signals such as clock signals, data signals, and control signals can be transmitted between the first device 10 and the second device 20 .

In this embodiment, the LGA board 301 may be disposed on the signal layer S1.

As an optional implementation manner, the LGA board 301 can be welded on the upper surface of the signal layer S1, and the LGA board 301 can be used to provide a connection between the first device 10 and the second device 20. The signal return provides a complete reference ground.

Specifically, the LGA board 301 may correspond to the wiring area of the signal wiring 40 in the signal layer S1. In other words, the LGA board 301 can provide a complete reference ground for signal return for some wiring areas of sensitive signals.

In a specific implementation process, a green oil layer may be provided on the side of the LGA board 301 away from the signal layer S1, where the green oil layer may play an insulating role. A plurality of bonding pads H1 may be provided on the side of the LGA board 301 close to the signal layer S1. For example, the bonding pad H1 may be a circular bonding pad. In other embodiments, the bonding pad H1 may also be a bonding pad of other shapes, which is not specifically limited in this embodiment of the present application.

Because at least one of sensitive signals such as a clock signal, a data signal, and a control signal is transmitted between the first device 10 and the second device 20 through the signal trace 40 . Therefore, in this embodiment, the wiring area between the first device 10 and the second device 20 can be used as a sensitive signal area.

As shown in FIG. 7 , in the signal layer S1 , the reference ground in the sensitive signal area between the first device 10 and the second device 20 is divided into a plurality of discrete grounds 60 , so that all The signal wiring between the first device 10 and the second device 20 does not have a complete reference ground, and the impedance of the loop path is relatively large. Wherein, a ground plane G1 is provided below the signal layer S1, and the ground plane G1 is a non-complete reference ground. As shown in FIG. 7 , the first device 10 and the second device 20 may be located at two discrete locations 60 respectively.

In this embodiment, the discrete ground 60 of the sensitive signal area may be provided with multiple pads H2. That is, the sensitive signal area may be provided with dense pads H2 on the discrete ground.

Referring to FIG. 7 , dense pads H2 may be provided on the discrete ground plane, and the pads H2 may be circular pads. Specifically, in the embodiment of the present application, the surface of the discrete land 60 can be scraped, and a plurality of circular pads H2 can be provided.

In some possible scenarios, the pads H2 on the sensitive signal area may be welded to the multiple pads H1 on the LGA board 301 . Among them, the pads H1 on the LGA board 301 are denser than the pads H2 on the signal layer S1, which can reduce the risk of false soldering and improve the welding yield between the signal layer S1 and the LGA board 301. , better reliability and consistency.

Please refer to FIG. 8 . In one embodiment, the signal layer S1 , the ground plane G1 , the signal layer S2 and the ground plane G2 may be stacked in sequence. Wherein, the pad H1 of the LGA board 301 is soldered to the pad H2 on the signal layer S1. The ground plane G2 may be an incomplete reference ground.

In one scenario, if the signal wiring of the signal layer S1 is too dense, it will affect the layout of the signal layer S1. In this case, signal wiring can be performed through the signal layer S2. The ground plane G2 may be configured to provide a reference ground for the signal layer S2. It can be understood that in some embodiments, the ground plane G2 may be a complete reference ground. In other embodiments, the ground plane G2 may also be a non-complete reference ground.

As shown in FIG. 8 , a signal may be emitted from the first device 10 , flow to the second device 20 along the signal trace 40 , and then flow back from the second device 20 along the LGA board 301 to the first device 10 . With such a design, the LGA board 301 in the embodiment of the present application has a complete reference ground, and there is no gap division. Therefore, in the embodiment of the present application, the LGA board 301 can be used to realize the connection from the first device 10 to the second device 10 . The device 20 has the shortest return path and the lowest return resistance, which can ensure the integrity of signal transmission.

Referring to FIG. 9 , the reference ground in the signal layer S1 is divided into discrete grounds by multiple gaps. A plurality of pads H2 are provided on the discrete ground. Multiple device regions 402 may also be provided in the signal layer S1 , and the device regions 402 may be close to the first device 10 or the second device 20 .

Referring to FIG. 10 , in order to prevent the LGA board 301 from contacting or colliding with other devices in the signal layer S1 , the LGA board 301 needs to avoid the device area 402 in the signal layer S1 . Therefore, this application implements The shape of the LGA board 301 in the example can be cut according to the actual size of the required area. That is, the LGA board 301 can cover the sensitive signal wiring area.

The embodiment of the present application can be in the form of adding an LGA board to the local area of the signal layer S1. Compared with the multi-layer board technology in the traditional solution, the LGA board of the embodiment of the present application has an off-board structure, which results in lower board material cost and shorter processing time. short.

In this embodiment, the LGA board 301 may cover the wiring area of the signal wiring 40 in the signal layer S1. In other words, this application can add a complete reference ground to the sensitive signal routing area, which is more targeted. It can be understood that the LGA can be a package with array-shaped electrode contacts on the bottom surface. Embodiments of this application can use LGA plate metal contact packaging to provide a complete reference ground for the reflow of high-speed signals. Among them, metal contacts can realize high-density grounding points and have the advantages of small size, low contact impedance and good electrical properties. They are suitable for application scenarios of high-speed signal transmission, that is, various types of sensitive signals.

Therefore, after the pad H2 of the signal layer S1 is welded to the pad H1 on the LGA board 301, the LGA board 301 with a complete reference ground can be placed on the outer layer of the printed circuit board 200. High-speed signal areas are connected discretely.

Based on the signal transmission structure 100 shown in the above embodiment of Figure 7, by using an LGA board to cover the sensitive signal routing area and providing a complete reference ground for the sensitive signal routing area, the first device 10 can be The reflow path between the second devices 20 is the shortest, which can effectively reduce the loop area of the signal, thereby realizing low impedance reflow of the signal, and can also solve the electromagnetic problem caused by the incomplete reference ground in the sensitive signal wiring area, ensuring the signal Transmission integrity.

Figure 11 is a schematic diagram comparing discrete and complete ground during signal transmission. Figure 12 is a comparative cross-sectional view of discrete and complete ground during signal transmission.

It can be seen from Figures 11 and 12 that after the signal emitted by the first device 10 flows to the second device 20, if the signal completely flows back to the first device 10, then the signal return path The shortest, and the return ground resistance is the smallest. If the signal flows back to the first device 10 discretely, the path for the signal to flow back is longer, and the impedance of the backflow is larger.

Please refer to FIG. 13 , which is another specific application scenario diagram of the signal transmission structure 100 according to an embodiment of the present application.

The difference from the signal transmission structure 100 shown in the embodiment of FIG. 7 is that in this embodiment, as shown in FIG. 13 , the signal transmission structure 100 may include a first device 10 , a second device 20 and a steel sheet 302 .

The difference from the LGA board 301 shown in the embodiment of FIG. 7 is that the steel sheet 302 does not need to be provided with a soldering pad. In other words, the steel sheet 302 can be mounted on the plurality of pads H2 of the signal layer S1.

As an optional implementation method, the steel sheet 302 may be provided with multiple hollow areas 303 . It can be understood that the hollow area 303 can enable the steel sheet 302 to avoid contact with other devices in the signal layer S1.

Referring to FIG. 14 , the signal layer S1 , the ground plane G1 , the signal layer S2 and the ground plane G2 may be stacked in sequence. The steel sheet 302 can be welded to the signal layer S1.

As shown in FIG. 14 , a sensitive signal can be emitted from the first device 10 and flow along the signal trace 40 to the second device 20 , and then from the second device 20 along the steel sheet 302 reflow to the first device 10 . With such a design, the steel sheet 302 in the embodiment of the present application has a complete reference ground and there is no gap division. Therefore, the embodiment of the present application can use the steel sheet 302 to realize the transition from the first device 10 to the second component. The second device 20 has the shortest return path and the lowest return resistance.

Please refer to FIG. 15 , which is a specific implementation form of the steel sheet 302 according to the embodiment of the present application. As shown in Figure 15, the steel sheets 302 may be steel sheets connected by a grid.

The steel sheet 302 can be sunk at a position corresponding to the discrete ground 60 of the signal layer S1, so that the discrete ground 60 of the sensitive signal area can be connected through the sunken part. For example, as shown in Figure 13, the inner frame portion of the steel sheet 302 can be sunk to form a welded portion 305 as shown in Figure 15. The welding portion 305 may correspond to the discrete ground 60 of the high-speed signal area in the signal layer S1. The steel sheet 302 can be connected to the pad H2 in the signal layer S1 through the sunken welding portion 305, so that the steel sheet 302 can be the first device. The signal loop between 10 and the second device 20 provides a complete reference ground.

Please refer to FIG. 16 , which is another specific implementation form of the steel sheet 302 according to the embodiment of the present application. As shown in Figure 16, the steel sheet 302 may be a steel sheet connected by cross beams.

The steel sheet 302 can be sunk at a position corresponding to the discrete ground 60 of the signal layer S1, so that the discrete ground 60 of the sensitive signal area can be connected through the sunken part. For example, as shown in FIG. 16 , the outer frame portion of the steel sheet 302 can be sunk to form a welded portion 305 as shown in FIG. 14 . The welding portion 305 may correspond to the discrete ground 60 of the sensitive signal area in the signal layer S1. The welding part 305 may be closer to the discrete points 60 of the sensitive signal area in the signal layer S1 than other parts of the steel sheet 302 . The steel sheet 302 can be connected to the pad H2 in the signal layer S1 through the sunken welding portion 305, so that the steel sheet 302 can be a signal between the first device 10 and the second device 20. The loop provides a complete reference ground.

It can be understood that the implementation form of the steel sheet 302 shown in Figure 15 and Figure 16 can be explained as an example. In other implementations, the steel sheet 302 can also be other implementation forms. In this regard, The embodiments of this application are not specifically limited.

Compared with the LGA plate 301 used in the embodiment of Figure 7, the steel sheet 302 used in the embodiment of Figure 13 has more patterns, and the implementation form is more flexible. In other words, the steel sheet 302 used in the embodiment of FIG. 13 can be configured in a corresponding shape according to the layout area and shape of the discrete ground 60 in the signal layer S1. For example, the steel sheet 302 can flexibly select the sinking area of the steel sheet, making assembly easy, lower cost, and easy to disassemble.

Please refer to FIG. 17 , which is another specific application scenario diagram of the signal transmission structure 100 according to an embodiment of the present application.

The difference from the signal transmission structure 100 shown in the embodiment of FIG. 7 is that in this embodiment, as shown in FIG. 17 , the signal transmission structure 100 may include a first device 10 , a second device 20 and a conductive material 306 . It can be understood that in this embodiment, the first device 10 and the second device 20 may be disposed in the signal layer S1. The signal layer S1 may be disposed on the ground plane G1, and the ground plane G1 is a non-complete reference ground.

A plurality of pads H3 may be provided on the signal layer S1. It can be understood that the pad H3 can be, but is not limited to, an inverted triangular pad, a circular pad, and a rectangular pad. As shown in Figure 17, the pad H3 may be in an inverted triangle shape.

The conductive material 306 may be disposed on the signal layer S1, and the conductive material 306 may be in contact with the pad H3. The conductive material 306 can provide a complete reference ground for signal backflow between the first device 10 and the second device 20 . The signal transmission structure 100 may also include a plurality of insulators 307 that may isolate the conductive material 306 from the device region 405 . The device area 405 may include an area where the first device 10 and the second device 20 are located. Optionally, the device region 405 also includes a region where one or more devices 308 other than the first device 10 and the second device 20 are located. Specifically, the insulator 307 can cover the first device 10 and the multiple devices 308 , and the insulator 307 can also cover the second device 20 and the multiple devices 308 . The insulator 307 can be used to insulate the conductive material 306 and the device 308 to prevent the device 308 from short circuiting.

The conductive material 306 can be implemented in the form of conductive auxiliary materials or metal spraying. For example, in an optional implementation, the conductive material 306 may be any one of copper sheet, conductive cloth laser engraving, conductive aluminum foil or conductive tape. In another optional implementation, silver paste can be sprayed on the insulator 307 to connect the pad H3. Based on such a design, the embodiments of the present application can be applied to scenes such as curved structures, and have a wider scope of application.

As shown in FIG. 17 , a sensitive signal can be emitted from the first device 10 and flow along the signal trace 40 to the second device 20 , and then from the second device 20 along the conductive material 306 reflow to the first device 10 . With such a design, the conductive material 306 in the embodiment of the present application has a complete reference ground, and there is no gap separation. Therefore, in the embodiment of the present application, the connection from the first device 10 to the second device 10 can be realized through the conductive material 306 Device 20 has the shortest return path and the lowest return resistance.

Please refer to Figure 18, which is a flow chart of a method for making a signal transmission structure according to an embodiment of the present application. This method can make a signal transmission structure on a printed circuit board. The flow chart of the method for making the signal transmission structure can include the following steps:

Step S181: Provide a printed circuit board.

Taking the printed circuit board 200 shown in FIG. 4 as an example, the printed circuit board 200 may include a signal layer S1 and a ground plane G1. The signal layer S1 is disposed on the ground plane G1. The signal layer S1 may be provided with a first device 10 and a second device 20 . The first device 10 may be connected to the second device 20 through signal traces 40 . The first device 10 may send a sensitive signal to the second device 20 . For example, the first device 10 may send at least one of a clock signal, a data signal, a control signal or a high-speed signal to the second device 20 .

Step S182: Form bonding pads at discrete locations on the signal layer of the printed circuit board.

Embodiments of the present application may form pads H2 at divided discrete locations on the surface of the printed circuit board 200 . For example, in this embodiment, a layer of copper can be brushed on the surface of the printed circuit board, and the excess part can be etched away, and then a solder resist layer can be added and solidified to form a soldering pattern, and a layer of tin can be brushed on the soldering pattern. paste to form the pad, i.e. forming pad H2.

Step S183: Provide a ground portion with a complete reference ground, and mount the ground portion on the pad to connect the ground portion to the discrete ground on the signal layer.

In this embodiment, the ground portion 30 may have a complete reference ground. The ground portion 30 is connected to the pad H2 of the signal layer S1, and the ground portion can provide a complete reference ground for signal reflow between the first device 10 and the second device 20. The ground portion 30 may correspond to the wiring area of the signal wiring 40 in the signal layer S1. In other words, the ground portion 30 can provide a complete reference ground for signal return flow in some wiring areas of sensitive signals.

With such a design, the ground portion 30 in the embodiment of the present application does not have a gap separation, has a smaller area and is highly adapted to the sensitive signal wiring area, and can achieve discrete connections to form a complete and gap-free connection. The divided reference ground can control the return path of the signal, thereby achieving the shortest return path and the lowest return impedance from the first device 10 to the second device 20 .

Please refer to Figure 19, which is a flow chart of a method for making a signal transmission structure according to another embodiment of the present application. The method may include the following steps:

Step S191: Provide a printed circuit board.

Taking the printed circuit board 200 shown in FIG. 7 as an example, the printed circuit board 200 may include a signal layer S1 and a ground plane G1. The signal layer S1 is disposed on the ground plane G1. The signal layer S1 may be provided with a first device 10 and a second device 20 . The first device 10 may be connected to the second device 20 through signal traces 40 . The first device 10 may send a signal to the second device 20 .

Step S192: Form bonding pads at discrete locations on the signal layer of the printed circuit board.

Step S193: Provide an LGA board.

Step S194: Form a bonding pad on the LGA board.

It can be understood that the LGA board format uses metal contact packaging to replace the traditional pin-like pins, and multiple pads can be provided at the bottom. In order to make the device as close to the circuit board as possible after soldering, it needs to be dried before soldering, then the stencil is opened to scrape the solder paste, and then reflow soldering is performed.

In this embodiment, multiple bonding pads H1 are provided on the LGA board 301, where the number of bonding pads H1 on the LGA board 301 is greater than the number of bonding pads H2 on the signal layer S1. In other words, the pads H1 on the LGA board 301 are denser.

Step S195: Weld the pads on the LGA board to the pads on the signal layer to connect the LGA board to the discrete ground on the signal layer.

In this embodiment, the pad H1 is set on the LGA board 301. The LGA board 301 has a complete reference ground and there is no gap division. The shortest reflow path from the first device 10 to the second device 20 can be achieved. and lowest return resistance.

Please refer to Figure 20, which is a flow chart of a method for making a signal transmission structure according to another embodiment of the present application. The method may include the following steps:

Step S201: Provide a printed circuit board.

Taking the printed circuit board 200 shown in FIG. 13 as an example, the printed circuit board 200 may include a signal layer S1 and a ground plane G1. The signal layer S1 is disposed on the ground plane G1. The signal layer S1 may be provided with a first device 10 and a second device 20 . The first device 10 may be connected to the second device 20 through signal traces 40 . The first device 10 may send a signal to the second device 20 .

Step S202: Form bonding pads at discrete locations on the signal layer of the printed circuit board.

Step S203: Provide a steel sheet.

Step S204: Mount the steel sheet on the pad of the signal layer to connect the steel sheet to a discrete ground on the signal layer.

The mounting process in this embodiment may include: 1. Identify the marking points of the printed circuit board 200 and the steel sheet 302 through optical instruments to complete precise positioning; use a scraper to demold the solder paste through the opening of the steel sheet. On the pads of the printed circuit board, after the printing process is completed, precise positioning is performed through the marking points of the printed circuit board 200; 3. Mount on the designated pads. Wherein, the steel sheet 302 can be sunk at discrete positions corresponding to the signal layer S1, so that the sensitive signal areas can be connected discretely through the sunk parts. For example, as shown in FIG. 16 , the inner frame portion of the steel sheet 302 can be sunk to form a welded portion 305 as shown in FIG. 16 . The welding portion 305 may correspond to a discrete ground of a sensitive signal area in the signal layer S1. The steel sheet 302 can be connected to the pad H2 in the signal layer S1 through the sunken welding portion 305, so that the steel sheet 302 can be a signal between the first device 10 and the second device 20. The loop provides a complete reference ground.

It can be understood that in this embodiment, the steel sheet 302 has a complete reference ground, which can discretely connect the wiring areas of sensitive signals, and can achieve the shortest return path and return impedance from the first device 10 to the second device 20 lowest.

Please refer to Figure 21, which is a flow chart of a method for making a signal transmission structure according to another embodiment of the present application. The method may include the following steps:

Step S211: Provide a printed circuit board.

Taking the printed circuit board 200 shown in FIG. 17 as an example, the printed circuit board 200 may include a signal layer S1 and a ground plane G1. The signal layer S1 is disposed on the ground plane G1. The signal layer S1 may be provided with a first device 10 and a second device 20 . The first device 10 may be connected to the second device 20 through signal traces 40 . The first device 10 may send a signal to the second device 20 .

Step S212: Form bonding pads at discrete locations on the signal layer of the printed circuit board.

Step S213: Provide an insulator.

Step S214: Cover the first device, the second device and other devices with an insulator.

The plurality of insulators 307 may isolate the conductive material 306 from the device region 405 . The device area 405 may include an area where the first device 10 and the second device 20 are located. Optionally, the device area 405 also includes one or more devices 308 in addition to the first device 10 and the second device 20 . Area.

Step S215: Provide a conductive material, and bond the conductive material to the pad in the sensitive signal wiring area of the signal layer, so that the conductive material connects to the discrete ground on the signal layer.

As shown in FIG. 17 , the conductive material 306 can be implemented in the form of conductive auxiliary materials or metal spraying. For example, in an optional implementation, the conductive material 306 may be any one of copper sheet, conductive cloth laser engraving, conductive aluminum foil or conductive tape. In another optional implementation, silver paste can be sprayed on the insulator 307 to connect the pad H3. The embodiments of the present application can be applied to scenes such as curved surface structures, and have a wider scope of application.

It can be understood that in the embodiments of this application, the conductive material after bonding will lose part of the conductive particles and conductive glue, resulting in poor sticking consistency; during the construction process, the material cannot be directly touched with hands, otherwise the surface of the conductive auxiliary material will be caused Dirt affects electrical conductivity.

Those of ordinary skill in the art should realize that the above embodiments are only used to illustrate the present application and are not used to limit the present application.

Claims

A signal transmission structure, characterized in that the signal transmission structure includes a first device, a second device and a ground portion;

The first device and the second device are arranged in the same signal layer or different signal layers of the printed circuit board, and the first device and the second device are respectively located in two of one or more signal layers. One discretely; the first device is used to transmit the first signal to the second device;

A first ground portion is provided on the printed circuit board and covers the two first discrete grounds. The ground portion is used to return the first signal to the first signal when the second device device provides a complete ground reference.
The signal transmission structure according to claim 1, characterized in that:

The first ground portion includes a contact array package LGA board. The first discrete ground is provided with a plurality of first pads. The LGA board is provided with a plurality of second pads. The plurality of second pads are Solder correspondingly to the plurality of first pads to provide a complete reference ground for signal reflow between the second device and the first device.
The signal transmission structure according to claim 1, characterized in that:

The first grounding part includes a steel piece, a plurality of first pads are provided discretely on the ground, the steel piece is used to connect the plurality of first pads, and the steel piece is used to provide the second The signal return flow between the device and the first device provides a complete reference ground.
The signal transmission structure according to claim 3, characterized in that:

The steel sheet is provided with one or more hollow areas, and the one or more hollow areas are used to enable the steel sheet to avoid contact with device areas in the one or more signal layers.
The signal transmission structure according to claim 3 or 4, characterized in that,

The steel sheet is sunk corresponding to the first discrete position to form a plurality of welding portions, and the plurality of welding portions are correspondingly connected to the plurality of first pads.
The signal transmission structure according to claim 1, characterized in that:

The signal transmission structure further includes a conductive material adhered to a plurality of first pads on the two first discrete grounds.
The signal transmission structure according to claim 6, characterized in that:

The signal transmission structure further includes an insulator, the insulator is used to isolate the conductive material from a device area, wherein the device area includes an area where the first device and the second device are located.
The signal transmission structure according to claim 7, characterized in that:

The device area also includes an area where one or more devices other than the first device and the second device are located.
The signal transmission structure according to any one of claims 1-8, characterized in that,

The signal transmission structure also includes a third device, a fourth device and a second ground portion;

The third device and the fourth device are arranged in the same signal layer or different signal layers, and the third device and the fourth device are respectively located in two second discrete signals in the one or more signal layers. ground; the third device is configured to transmit a second signal to the fourth device;

The second ground portion is disposed on the printed circuit board and covers the two second discrete grounds, and the second ground portion is configured to return the second signal to the fourth device. The third device provides a complete reference ground.
The signal transmission structure according to any one of claims 1-9, characterized in that,

The first device is connected to the second device through a signal trace, wherein the signal trace includes at least one of a clock line, a data line, a control line or a high-speed signal trace.
A method of manufacturing a signal transmission structure. The signal transmission structure includes a printed circuit board and a first ground part, which is characterized by including:

A printed circuit board is provided, wherein the printed circuit board includes one or more signal layers;

Provide a first ground portion, the first ground portion is disposed on the printed circuit board and covers the two first discrete grounds of the one or more signal layers;

Wherein, a first device and a second device are provided on the one or more signal layers, the first device and the second device are provided in the same signal layer or different signal layers, and the first device and the second device are The second device is respectively located at the two first discrete grounds, the second device is used to receive the first signal output by the first device, and the first ground portion is used to connect the first signal to the second device when the second device The first signal provides a complete reference ground when it flows back to the first device.
The method of manufacturing a signal transmission structure according to claim 11, wherein the first ground portion is provided on the printed circuit board and covers the one or Two first of the plurality of signal layers discretely include:

Provide an LGA board;

Form a plurality of second pads on the LGA board;

The plurality of second pads on the LGA board are correspondingly welded to the plurality of first pads on the first discrete ground.
The method of manufacturing a signal transmission structure according to claim 11, wherein the first ground portion is provided on the printed circuit board and covers the one or Two first of the plurality of signal layers discretely include:

Provide a steel piece;

Sinking the steel sheet corresponding to the position of the first discrete place to form a plurality of welded parts;

The plurality of welding parts are correspondingly connected to the plurality of first pads on the first discrete ground.
The method of manufacturing a signal transmission structure according to claim 11, wherein the first ground portion is provided on the printed circuit board and covers the one or Two first of the plurality of signal layers discretely include:

Provide a conductive material;

The conductive material is bonded to a plurality of first pads on the first discrete ground.
The manufacturing method of a signal transmission structure according to claim 14, characterized in that the manufacturing method further includes:

provide an insulator;

The conductive material is isolated from the device area by the insulator; wherein the device area includes the area where the first device and the second device are located.
The method of manufacturing a signal transmission structure according to claim 15, characterized in that:

The device area also includes an area where one or more devices other than the first device and the second device are located.
The manufacturing method of a signal transmission structure according to claim 11, characterized in that the manufacturing method further includes:

Provide a second grounding portion;

disposing the second ground portion on the printed circuit board and covering two discrete grounds of the one or more signal layers;

Wherein, a third device and a fourth device are also provided on the one or more signal layers, the third device and the fourth device are provided in the same signal layer or different signal layers, the third device and The fourth device is respectively located at the two second discrete grounds, the fourth device is used to receive the second signal output by the third device, and the second ground portion is used to connect the fourth device to the The second signal provides a complete reference ground when flowing back to the third device.