CN117677029A - Signal transmission structure and manufacturing method - Google Patents

Abstract

The application discloses a signal transmission structure and a manufacturing method, wherein the signal transmission structure can comprise a first device, a second device and a first grounding part. The first device and the second device are disposed in the same signal layer or different signal layers of the printed circuit board, the first device and the second device being located discretely in two of the one or more signal layers, respectively. The first device is configured to transmit a first signal to the second device. The first ground is disposed over the printed circuit board and overlies the two discrete grounds, the ground being configured to provide a complete reference ground when the second device reflows the first signal to the first device. The signal transmission structure and the manufacturing method can ensure the integrity of the sensitive signal reference, greatly reduce the noise influence, and are suitable for signal integrity or electromagnetic problems caused by incomplete sensitive signal reference layers.

Description

Signal transmission structure and manufacturing method

Technical Field

The present disclosure relates to the field of signal transmission technologies, and in particular, to a signal transmission structure and a manufacturing method thereof.

Background

In a printed circuit board (Printed Circuit Board, PCB), typically a signal can be sent from a driving end to a receiving end, after reaching the receiving end, the signal needs to be returned to the driving end, creating a current loop. The electric field strength expression of the signal is: e=0.3f2si/L; wherein 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 distance between the test point and the loop. As can be seen from the above equation, the radiated electric field intensity of the signal is proportional to the loop area of the signal, so that the radiation of the signal can be effectively reduced by reducing the loop area of the signal. In order to reduce the area of the signal loop, the conventional board-level EMC design is usually designed to make the power ground plane as complete as possible, provide an ideal reference plane for the signal, and shorten the signal return path, as shown in fig. 1, the driving end 101 and the receiving end 102 are disposed in the signal layer 105, the driving end 101 is connected to the receiving end 102 through the signal line 107, and when the local flat layer 106 provides the complete reference plane for the signal layer 105, the area of the signal loop formed by the signal direction and the signal return direction is minimum, so that the far-field radiation is minimum.

In some scenarios, as shown in fig. 2, when the signal line 107 crosses the slot on the reference ground plane, the signal return will bypass the slot, forming a larger current loop, resulting in an increased signal loop area, increased far field radiation, and reduced electromagnetic interference (Electromagnetic Interference, EMI) performance.

Disclosure of Invention

The application provides a signal transmission structure and a manufacturing method, which can effectively reduce the loop area of signals and realize low-impedance backflow of sensitive signals. The method and the device can solve the electromagnetic problem caused by incomplete reference ground of the high-speed signal wiring area, and ensure the integrity of signal transmission.

In a first aspect, the present application provides a signal transmission structure that may include a first device, a second device, and a first ground. The first device and the second device may be disposed in the same signal layer or in different signal layers of the printed circuit board, the first device and the second device being located at two first discretizations of the one or more signal layers, respectively. The first device is configured to transmit a first signal to the second device. The first grounding part is arranged on the printed circuit board and covers the two first discrete grounds, and the grounding part is used for providing complete reference ground when the second device reflows the first signal to the first device. The present application aims to provide a way to regionally achieve low impedance ground reflow. The scheme can ensure the integrity of the reference ground of the sensitive signal, greatly reduce the influence of ground noise, and is suitable for decoupling with the manufactured plate due to the signal integrity or electromagnetic problem caused by the incomplete reference layer of the sensitive signal.

As an alternative implementation, 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, and the plurality of second pads are soldered corresponding to the plurality of first pads so as to provide a complete reference ground for signal reflow between the second device and the first device. Based on such design, the LGA board is of an off-board structure, the cost of the board is lower, and the processing time is shorter.

As an alternative implementation manner, the first grounding portion includes a steel sheet, and the plurality of first pads are discretely disposed, the steel sheet is used for connecting the plurality of first pads, and the steel sheet is used for providing complete reference ground for signal reflow between the second device and the first device. Based on such design, the form of drawing a design of steel sheet is more, and implementation form is more nimble, and convenient assembling, cost are lower to convenient dismantlement.

As an alternative implementation, the steel sheet is provided with one or more hollowed-out areas for avoiding contact with device areas in the one or more signal layers. Based on the design, the steel sheet can be prevented from being contacted with a device area in the signal layer, and short circuit of the device is avoided.

As an alternative implementation, the steel sheet is sunk corresponding to the first discrete positions to form a plurality of welded parts, and the plurality of welded parts are correspondingly connected with the plurality of first bonding pads. Based on the design, the steel sheet is more in design form and more flexible in implementation form.

As an alternative implementation, the signal transmission structure further comprises a conductive material adhered to the plurality of first pads on the two first discrete lands. Therefore, the method is applicable to curved surface structures and other scenes, and the application range is wider.

As an alternative implementation manner, the signal transmission structure further includes an insulator, and the insulator may isolate the conductive material from the device region, where the device region may include a region where the first device and the second device are located. Based on such a design, short circuits of the device can be avoided.

As an alternative implementation, the device region may further include a region where one or more devices other than the first device and the second device are located. Based on such a design, the present application may also avoid shorting of one or more devices other than the first device and the second device.

As an alternative implementation manner, the signal transmission structure further comprises a third device, a fourth device and a second grounding part; 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 positioned at two second discretes in the one or more signal layers; the third device is configured to transmit a second signal to the fourth device; the second ground is disposed over the printed circuit board and overlies the two second discrete grounds, the second ground being configured to provide a complete reference ground when the fourth device reflows the second signal to the third device.

As an alternative implementation, the first device is connected to the second device through a signal trace, where the signal trace may include, but is not limited to, at least one of a clock line, a data line, a control line, or a high speed signal trace.

In a second aspect, the present application further provides a method for manufacturing a signal transmission structure, where the signal transmission structure may include a printed circuit board and a first grounding portion, including: providing a printed circuit board, wherein the printed circuit board comprises one or more signal layers; providing a first grounding part, wherein the first grounding part is arranged on the printed circuit board and covers two first discrete lands of the one or more signal layers; the first device and the second device are arranged in the same signal layer or different signal layers, the first device and the second device are respectively positioned at the two first discretes, the second device is used for receiving a first signal output by the first device, and the first grounding part is used for providing a complete reference ground when the second device reflows the first signal to the first device. The present application can provide a way to regionally achieve low impedance ground reflow. The scheme can ensure the integrity of the reference ground of the sensitive signal, greatly reduce the influence of ground noise, and is suitable for decoupling with the manufactured plate due to the signal integrity or electromagnetic problem caused by the incomplete reference layer of the sensitive signal.

As an alternative implementation manner, the providing a first grounding portion, where the first grounding portion is disposed on the printed circuit board and covers two first discrete areas of the one or more signal layers may include: providing an LGA board; forming a plurality of second pads on the LGA board; and correspondingly welding a plurality of second bonding pads on the LGA board with a plurality of first bonding pads on the first discrete ground. Based on such design, the LGA board is of an off-board structure, the cost of the board is lower, and the processing time is shorter.

As an alternative implementation manner, the providing a first grounding portion, where the first grounding portion is disposed on the printed circuit board and covers two first discrete areas of the one or more signal layers may include: providing a steel sheet, sinking the steel sheet corresponding to the first discrete positions to form a plurality of welding parts; the plurality of solder joints are correspondingly connected with the plurality of first pads on the first discrete ground. Based on such design, the form of drawing a design of steel sheet is more, and implementation form is more nimble, and convenient assembling, cost are lower to convenient dismantlement.

As an alternative implementation manner, the providing a first grounding portion, where the first grounding portion is disposed on the printed circuit board and covers two first discrete areas of the one or more signal layers may include: a conductive material is provided and bonded to the first plurality of first pads on the first discrete ground. Therefore, the method is applicable to curved surface structures and other scenes, and the application range is wider.

As an alternative implementation manner, the manufacturing method may further include: an insulator is provided and the conductive material is isolated from the device region by the insulator. The device region may include a region where the first device and the second device are located. This prevents the device from shorting.

As an alternative implementation manner, the device region may further include a region where one or more devices other than the first device and the second device are located.

As an alternative implementation manner, the manufacturing method may further include: providing a second grounding part; disposing the second ground over the printed circuit board and overlying two discrete ones of the one or more signal layers; and the second grounding part is used for providing complete reference ground when the fourth device reflows the second signals to the third device.

The signal transmission structure and the manufacturing method can achieve region integrity through the outer layer structure. The signal transmission structure and the manufacturing method can ensure the integrity of the sensitive signal reference ground, greatly reduce the influence of ground noise, are suitable for signal integrity or electromagnetic problems caused by incomplete sensitive signal reference layers, and are decoupled from the manufactured plate.

Drawings

Fig. 1 is a schematic diagram of a signal loop of a complete reference plane signal trace.

Fig. 2 is a schematic diagram of a signal loop of a non-complete reference plane washed-out trace.

Fig. 3 is another schematic diagram of a signal loop of a complete reference plane signal trace.

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

Fig. 5 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 6 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 7 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 8 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

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

Fig. 10 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 11 is a schematic diagram of a discrete and complete comparison of signal transmissions.

Fig. 12 shows another contrast diagram in discrete and complete form for signal transmission.

Fig. 13 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 14 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 15 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

Fig. 16 is another structural schematic diagram of a signal transmission structure of an embodiment of the present application.

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

Fig. 18 is a flowchart of a method for fabricating a signal transmission structure according to an embodiment of the present application.

Fig. 19 is another flowchart of a method for fabricating a signal transmission structure according to an embodiment of the present application.

Fig. 20 is another flowchart of a method for fabricating a signal transmission structure according to an embodiment of the present application.

Fig. 21 is another flowchart of a method for fabricating a signal transmission structure according to an embodiment of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present.

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

At present, in the application process of the high-speed circuit PCB, along with the continuous increase of the speed of an integrated circuit switch and the density of the PCB, whether a signal can be completely sent from a sending end to a receiving end becomes a key link to be faced and considered by the high-speed circuit PCB. The high-speed signal is a key factor affecting the signal integrity, poor processing of the high-speed signal can lead to the influence of electromagnetic radiation on the reflow signal, and the higher the electromagnetic radiation rate is, the more serious the electromagnetic radiation rate is, so that the high-speed signal cannot be completely transmitted, and the signal integrity is affected. It is understood that signal integrity may refer to the quality of a signal in a circuit, the ability of a signal to respond in the circuit with the correct timing and voltage.

For example, when the signal is transmitted on the printed circuit board, the signal flows from the driving end, flows to the receiving end along the trace on the printed circuit board, and then flows from the receiving end to the driving end along the ground plane, and returns to the driving end through the shortest path or the path with the smallest impedance. However, in one scenario, if the signal trace crosses a slot in the reference ground plane, the signal return path needs to bypass, resulting in increased signal loop area, increased far field radiation, and reduced electromagnetic interference (Electromagnetic Interference, EMI) performance.

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

The ground layer 104 is disposed below the signal layer 103, and the ground layer 104 is a complete reference ground. Such that high speed signals may flow from the device 101, along traces in the signal layer 103, to the device 102, and back from the device 102 to the device 101 along the ground layer 104 via a shortest path.

With such a design, the ground layer 104 can provide an ideal reference plane for signal transmission, shorten the signal return path, minimize the signal loop area formed by the signal direction and the signal return direction, ensure that the high-speed signal with small noise margin has a complete reference layer, and form a low-impedance return path, so as to solve the problems of radiation enhancement, EMI performance reduction and the like caused by the increase of the signal loop area.

However, in the implementation shown in fig. 3, an inner layer needs to be added to the printed circuit board to realize the whole board is complete, but the manufacturing process of the multi-layer board is very complex, the cost is higher, the manufacturing time is longer, the influence on the wiring density is larger, and the method is less adopted in the actual wiring board, so that the product competitiveness is reduced.

For this purpose, the present application provides a signal transmission structure and a manufacturing method, and the region integrity can be achieved by the outer layer structure. The embodiment of the application can provide a return path for the signal nearby, effectively reduce the loop area of the signal and realize low-impedance return of the high-speed signal. The embodiment of the application can solve the electromagnetic problem caused by incomplete reference ground of the sensitive signal wiring area, and can ensure the integrity of signal transmission.

Referring to fig. 4, a schematic structural diagram of a signal transmission structure 100 according to an embodiment of the present application is shown.

The signal transmission structure 100 in the embodiment of the present application can provide a large-area complete reference ground in the routing area of the sensitive signal, so as to realize low-impedance reflow ground. As shown in fig. 4, the signal transmission structure 100 may be disposed on a 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, and the ground plane G1 may be disposed on a lower surface of the signal layer S1. Wherein, 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 30.

In this embodiment, the first device 10 may be used as a driving end, the second device 20 may be used as a receiving end, and the first device 10 may send a signal to the second device 20. It will be appreciated that in other implementations, the first device 10 may act as a receiving terminal and the second device 20 may act as a driving terminal, i.e. the second device 20 may 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 at a 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 may transmit one or more of clock signals, data signals, and control signals or high-speed signals, collectively referred to as sensitive signals, i.e., signals that need to be protected when the printed circuit board is routed through the signal trace 40. To the second device 20. It is to be appreciated that the signal traces 40 may include, as an alternative implementation, one or more of clock lines, data lines, and control lines or high-speed signal traces.

As an alternative implementation, the grounding portion 30 may be a conductive metal body.

It will be appreciated that in this embodiment, the grounding portion 30 may be attached to the surface layer of the printed circuit board 200. The ground portion 30 may be attached to the surface of the signal layer S1. For example, the ground 30 may be attached to the signal layer S1 and may be used to provide a complete reference ground for signal return between the first device 10 and the second device 20. Specifically, the grounding portion 30 may cover the routing area of the signal routing 40 in the signal layer S1. In other words, the ground 30 may provide a complete reference ground for signal return for a partial trace area of the sensitive signal.

As shown in fig. 4, a sensitive signal may emanate from the first device 10 and flow along the signal trace 40 to the second device 20 and back from the second device 20 to the first device 10 along the ground 30. By adopting such a design, the grounding portion 30 in the embodiment of the application has no slit division, has smaller area and is highly adapted to the sensitive signal routing area, and can control the reflow path of the signal, thereby realizing the shortest reflow path and the lowest reflow impedance from the first device 10 to the second device 20.

Compared with the embodiment shown in fig. 3, the embodiment shown in fig. 4 has fewer plate layers, lower cost, shorter plate making time, more flexible realization form, and suitability for more application scenes, and improves the product competitiveness.

Please refer to fig. 5, which is a schematic 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, the printed circuit board 200 may include a plurality of signal layers in this embodiment. For example, the printed circuit board 200 may include a signal layer S1, a ground plane G1, and a signal layer S2 stacked in this order.

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 comprise at least one via 401 and at least one via 403.

The via 401 and the via 403 may each have a cylindrical structure, and the via 401 and the via 403 may each be made of a conductive material, such as a metal material. The via 401 may extend through the ground plane G1 to connect the first device 10 and the signal layer S2. The signal layer S2 may have signal traces 40 disposed therein. The first device 10 may be connected to the second device 20 through the via 401 and the signal trace 40. The via 403 may extend through the ground plane G1 to connect the first device 10 and the signal layer S2. The via 401 is a via for transmitting a sensitive signal to the second device 20, and the via 403 is a via for reflowing a signal to the first device 10.

As shown in fig. 5, in this embodiment, the grounding portion 30 may be attached to the surface of the signal layer S2, and may be used to provide a complete reference ground for signal return between the first device 10 and the second device 20. Specifically, the grounding portion 30 may cover the routing area of the signal routing 40 in the signal layer S2. In other words, the ground 30 may provide a complete reference ground for signal return for a partial trace area of the sensitive signal.

Referring to fig. 6, a schematic structural diagram of a signal transmission structure 100 according to another embodiment of the present application is shown.

The signal transmission structure 100 is different from the embodiment shown in fig. 4 in that the signal transmission structure 100 may further include a plurality of devices as shown in fig. 6. 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 be disposed in the signal layer S1. It will be appreciated that only four devices (first device 10, second device 20, third device 80, and fourth device 90) are shown for illustration in fig. 6, and that in other implementations, the number of devices may be greater than four. The present application is not particularly limited thereto.

In this embodiment, the third device 80 may be used as a driving end, the fourth device 90 may be used as a receiving end, and the third device 80 may send a signal to the fourth device 90. It will be appreciated that in other implementations, the third device 80 may act as a receiving side and the fourth device 90 may act as a driving side, i.e., the fourth device 90 may 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 is understood that the third device 80 and the fourth device 90 may each be integrated circuit devices.

The third device 80 may transmit a sensitive signal to the fourth device 90 via the signal trace 50. The signal traces 50 may include at least one of clock lines, data lines, and control lines or high-speed signal traces, among others.

In this embodiment, the signal transmission structure 100 may further include a plurality of grounding portions. For example, the signal transmission structure 100 may include a ground 30 and a ground 70. It will be appreciated that only two ground portions (ground portions 30, 70) are shown in fig. 6 for illustration, and that in other implementations, the number of ground portions may be greater than two. The present application is not particularly limited thereto.

As an alternative implementation, the grounding portion 70 may be a conductive metal body.

It will be appreciated that in this embodiment, the grounding portion 70 may be attached to the surface layer of the printed circuit board 200. For example, the ground 70 may be attached to the signal layer S1 and may be used to provide a complete reference ground for signal return between the third device 80 and the fourth device 90. Specifically, the grounding portion 70 may cover the routing area of the signal routing 50 in the signal layer S1. In other words, the ground 70 may provide a complete reference ground for signal return for a partial trace area of the sensitive signal.

As shown in fig. 6, a sensitive signal may emanate from the third device 80 and flow along the signal trace 50 to the fourth device 90 and then back from the fourth device 90 to the third device 80 along the ground 70. With such a design, the grounding portion 70 in the embodiment of the present application has no split situation, has a smaller area and is highly adapted to the sensitive signal routing area, so that the reflow path of the signal can be controlled, and the shortest reflow path and the lowest reflow impedance from the third device 80 to the fourth device 90 are realized.

Compared with the embodiment shown in fig. 4, the embodiment shown in fig. 6 can provide complete reference ground for signal transmission between a plurality of devices by adopting a plurality of grounding parts for the signal transmission between the devices, so that the implementation form is more flexible, the method can be suitable for more application scenes, and the product competitiveness is improved.

Referring to fig. 7, a signal transmission structure 100 provided in an embodiment of the present application will be illustrated in the following with reference to the accompanying drawings and practical application scenarios.

Referring to fig. 7, a specific application scenario diagram of a signal transmission structure 100 according to an embodiment of the present application is shown.

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. I.e. the grounding in this embodiment may be realized in the form of an LGA board.

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

The first device 10 may transmit a sensitive signal to the second device 20 via the signal trace 40. It will be appreciated that as an alternative implementation, the signal trace 40 may be a sensitive signal trace, for example, the signal trace 40 may include at least one of a clock line, a data line, and a control line. In other words, at least one of the sensitive signals of the clock signal, the data signal, the control signal, etc. may 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 alternative implementation, the LGA board 301 may be soldered on the upper surface of the signal layer S1, and the LGA board 301 may be used to provide a complete reference ground for signal reflow between the first device 10 and the second device 20.

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

In a specific implementation, a green oil layer may be disposed on a side of the LGA board 301 away from the signal layer S1, where the green oil layer may serve as an insulation function. The LGA board 301 may be provided with a plurality of pads H1 on a side close to the signal layer S1. The pad H1 may be a circular pad, and in other embodiments, the pad H1 may be a pad with another shape, which is not specifically limited in this embodiment.

Since at least one of the sensitive signals clock signal, data signal and control signal is transmitted between the first device 10 and the second device 20 via the signal trace 40. Thus, in this embodiment, the routing area between the first device 10 and the second device 20 may 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 the impedance of the loop path is large because the signal trace between the first device 10 and the second device 20 is not completely referenced to the ground. Wherein, a ground plane G1 is disposed below the signal layer S1, and the ground plane G1 is an incomplete reference ground. As shown in fig. 7, the first device 10 and the second device 20 may be located at two discrete sites 60, respectively.

In this embodiment, the discrete lands 60 of the sensitive signal area may be provided with a plurality of pads H2. I.e. the sensitive signal areas may be discretely provided with dense pads H2.

Referring to fig. 7, dense pads H2 may be disposed on the discrete ground plane, wherein the pads H2 may be circular pads. Specifically, embodiments of the present application may provide for a plurality of circular pads H2 by scraping off the surface of the discretely 60.

In some possible scenarios, these pads H2 on the sensitive signal area may be soldered to pads H1 on the LGA board 301. The bonding pads H1 on the LGA board 301 are denser than the bonding pads H2 on the signal layer S1, so that the risk of cold joint can be reduced, the welding yield of the signal layer S1 and the LGA board 301 is improved, and the reliability and consistency are better.

Referring 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 order. 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 traces of the signal layer S1 are too dense, the layout of the signal layer S1 will be affected, and at this time, signal wiring may 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 will be appreciated that in some embodiments, the ground plane G2 may be a complete reference to ground. In other embodiments, the ground plane G2 may also be a non-complete reference ground.

As shown in fig. 8, signals may be emitted from the first device 10 and flow along the signal traces 40 to the second device 20 and back from the second device 20 to the first device 10 along the LGA board 301. With such a design, the LGA board 301 in the embodiments of the present application has a complete reference ground, and no gap division exists, so that the embodiments of the present application can implement the shortest reflow path and the lowest reflow impedance from the first device 10 to the second device 20 through the LGA board 301, and 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 a plurality of slits. The plurality of pads H2 are discretely provided. The signal layer S1 may further include a plurality of device regions 402, where the device regions 402 may be adjacent 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 region 402 in the signal layer S1. Thus, the shape of the LGA board 301 in embodiments of the present application may be tailored to the actual size of the desired area. I.e. the LGA board 301 may cover the sensitive signal routing area.

According to the embodiment of the application, the LGA board is added in the local area of the signal layer S1, compared with the multilayer board technology in the traditional scheme, the LGA board is of an off-board structure, the board cost is lower, and the processing time is shorter.

In this embodiment, the LGA board 301 may cover the routing area of the signal routing 40 in the signal layer S1. In other words, the method and the device can add complete reference ground to the sensitive signal routing area, so that the method and the device are more specific. It is understood that the LGA may be a package that has array-like electrode contacts fabricated on the bottom surface. Embodiments of the present application may employ an LGA board metal contact package to provide a complete reference ground for reflow of high speed signals. The metal contact can realize high-density grounding points, has the advantages of small volume, low contact impedance, good electrical performance and the like, and is suitable for application scenes of high-speed signals, namely various sensitive signal transmission.

Thus, after bonding pads H2 of the signal layer S1 with bonding pads H1 on the LGA board 301, the LGA board 301 with its complete ground reference can be discretely connected in the high speed signal area on the outer layer of the printed circuit board 200.

Based on the signal transmission structure 100 shown in the embodiment of fig. 7, the LGA board is used to cover the sensitive signal routing area and provide a complete reference ground for the sensitive signal routing area, so that a return path between the first device 10 and the second device 20 can be shortest, a loop area of a signal can be effectively reduced, low impedance return of the signal can be further realized, an electromagnetic problem caused by incomplete reference ground of the sensitive signal routing area can be solved, and signal transmission integrity is ensured.

Fig. 11 is a schematic diagram showing a discrete and complete comparison of signal transmission. Fig. 12 is a cross-sectional view of a signal transmission using discrete and complete comparisons.

As can be seen from fig. 11 and 12, after the signal from the first device 10 flows to the second device 20, if the signal flows back to the first device 10 completely, the path of the signal flow back is shortest and the impedance of the flow back ground is smallest. If the signal passes discretely back to the first device 10, the path of signal back flow is longer and the back flow ground impedance is greater.

Referring to fig. 13, another specific application scenario diagram of the signal transmission structure 100 according to an embodiment of the present application is shown.

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 may not need to be provided with pads. In other words, the steel sheet 302 may be attached to the plurality of pads H2 of the signal layer S1.

As an alternative implementation, the steel sheet 302 may be provided with a plurality of hollowed-out areas 303. It can be appreciated that the hollowed-out area 303 may 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 sequentially stacked. Wherein, the steel sheet 302 may be welded on the signal layer S1.

As shown in fig. 14, a sensitive signal may be emitted from the first device 10 and flow along the signal trace 40 to the second device 20 and then back from the second device 20 to the first device 10 along the steel sheet 302. With such a design, the steel sheet 302 in the embodiment of the present application has a complete reference ground and no gap division exists, and thus, the embodiment of the present application can achieve the shortest reflow path and the lowest reflow resistance from the first device 10 to the second device 20 through the steel sheet 302.

Referring to FIG. 15, a specific implementation of a steel sheet 302 according to an embodiment of the present application is shown. As shown in fig. 15, the steel sheets 302 may be steel sheets connected by a grid.

The steel sheet 302 may be sunk at a position corresponding to the discrete lands 60 of the signal layer S1, so that the discrete lands 60 of the sensitive signal area may be communicated through the sunk portions. For example, as shown in fig. 13, the inner frame portion of the steel sheet 302 may be submerged to form a welded portion 305 as shown in fig. 15. The weld 305 may correspond to the discrete lands 60 of the high speed signal region in the signal layer S1. The steel sheet 302 may be connected to the pad H2 in the signal layer S1 through the submerged solder 305, so that the steel sheet 302 may provide a complete reference ground for the signal loop between the first device 10 and the second device 20.

Referring to FIG. 16, another embodiment of a steel sheet 302 according to an embodiment of the present application is shown. As shown in fig. 16, the steel plates 302 may be steel plates connected by a beam.

The steel sheet 302 may be sunk at a position corresponding to the discrete lands 60 of the signal layer S1, so that the discrete lands 60 of the sensitive signal area may be communicated through the sunk portions. For example, as shown in fig. 16, the outer frame portion of the steel sheet 302 may be submerged to form a welded portion 305 as shown in fig. 14. The welds 305 may correspond to the discrete lands 60 of the sensitive signal area in the signal layer S1. Wherein the weld 305 may be closer to the discrete lands 60 of the sensitive signal area in the signal layer S1 than to other portions of the steel sheet 302. The steel sheet 302 may be connected to the pad H2 in the signal layer S1 through the submerged solder 305, so that the steel sheet 302 may provide a complete reference ground for the signal loop between the first device 10 and the second device 20.

It will be appreciated that the implementation of the steel sheet 302 shown in fig. 15 and 16 may be illustrated as an example, and in other implementations, the steel sheet 302 may be implemented in other manners, which is not specifically limited to the embodiments of the present application.

Compared to the LGA board 301 used in the embodiment of FIG. 7, the embodiment of FIG. 13 uses more design forms of steel sheet 302, which is more flexible to implement. In other words, the steel sheet 302 employed in the embodiment of fig. 13 may be correspondingly provided with a steel sheet shape according to the layout area and shape of the discretely 60 in the signal layer S1. For example, the steel sheet 302 may be flexible in selecting the sinking area of the steel sheet, easy to assemble, less costly, and easy to disassemble.

Referring to fig. 17, another specific application scenario diagram of the signal transmission structure 100 according to an embodiment of the present application is shown.

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 will be appreciated 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 a ground plane G1, the ground plane G1 being an incomplete reference ground.

The signal layer S1 may be provided with a plurality of pads H3. It is understood that the pads H3 may be, but are not limited to, inverted triangle pads, circular pads, and rectangular pads. As shown in fig. 17, the pad H3 may have 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. Wherein the conductive material 306 may provide a complete reference ground for signal reflow between the first device 10 and the second device 20. The signal transmission structure 100 may further include a plurality of insulators 307, the plurality of insulators 307 may isolate the conductive material 306 from the device region 405. The device region 405 may include a region where the first device 10 and the second device 20 are located. Optionally, the device region 405 further 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 may cover the first device 10 and the plurality of devices 308, and the insulator 307 may also cover the second device 20 and the plurality of devices 308. The insulator 307 may be used to insulate the conductive material 306 from the device 308 to prevent shorting of the device 308.

The conductive material 306 may be implemented in the form of a conductive auxiliary material or a metal spray. For example, in an alternative implementation, the conductive material 306 may be any one of copper sheet, conductive cloth laser etched, conductive aluminum foil, or conductive tape. In another alternative implementation, silver paste may be sprayed on the insulator 307 to connect the pads H3. Based on the design, the embodiment of the application can be suitable for scenes such as curved surface structures, and the application range is wider.

As shown in fig. 17, a sensitive signal may emanate from the first device 10 and flow along the signal trace 40 to the second device 20 and back from the second device 20 to the first device 10 along the conductive material 306. With such a design, the conductive material 306 in the embodiments of the present application has a complete reference ground, and there is no gap split, so the embodiments of the present application can achieve the shortest reflow path and the lowest reflow impedance from the first device 10 to the second device 20 through the conductive material 306.

Referring to fig. 18, a flowchart of a method for manufacturing a signal transmission structure according to an embodiment of the present application may manufacture a signal transmission structure on a printed circuit board, where the flowchart of the method for manufacturing a signal transmission structure may include the following steps:

Step S181: a printed circuit board is provided.

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 being disposed on the ground plane G1, and the signal layer S1 may be provided with a first device 10 and a second device 20. Wherein the first device 10 may be connected to the second device 20 via a signal trace 40. The first device 10 may send a sensitive signal to the second device 20. For example, the first device 10 may issue at least one of a clock signal, a data signal, and a control signal or a high-speed signal to the second device 20.

Step S182: pads are formed at discrete locations on a signal layer of a printed circuit board.

Embodiments of the present application may form pads H2 at discrete locations that are segmented on the surface layer of the printed circuit board 200. For example, in this embodiment, a layer of copper may be brushed on the surface of the printed circuit board, the redundant portion is etched away, then a solder mask layer is added and cured to form a solder pattern, and a layer of solder paste is brushed on the solder pattern to form a pad, namely, a pad H2.

Step S183: a grounding part with complete reference ground is provided, and the grounding part is attached to the bonding pad so as to realize the discrete ground on the grounding part connection signal layer.

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

By adopting such a design, the grounding part 30 in the embodiment of the application has no slit segmentation, has smaller area and is highly adapted to the sensitive signal routing area part, and can realize discrete connection, form complete reference ground without slit segmentation, thereby controlling the reflow path of signals and further realizing the shortest reflow path and the lowest reflow impedance from the first device 10 to the second device 20.

Referring to fig. 19, a flowchart of a method for manufacturing a signal transmission structure according to another embodiment of the present application may include the following steps:

step S191: a printed circuit board is provided.

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 being disposed on the ground plane G1, and the signal layer S1 may be provided with a first device 10 and a second device 20. Wherein the first device 10 may be connected to the second device 20 via a signal trace 40. The first device 10 may send a signal to the second device 20.

Step S192: pads are formed at discrete locations on a signal layer of a printed circuit board.

Embodiments of the present application may form pads H2 at discrete locations that are segmented on the surface layer of the printed circuit board 200. For example, in this embodiment, a layer of copper may be brushed on the surface of the printed circuit board, the redundant portion is etched away, then a solder mask layer is added and cured to form a solder pattern, and a layer of solder paste is brushed on the solder pattern to form a pad, namely, a pad H2.

Step S193: an LGA board is provided.

Step S194: and forming a bonding pad on the LGA board.

It will be appreciated that the LGA board is formed using a metal contact package instead of conventional pin-shaped pins, and that the bottom thereof may be provided with a plurality of pads. In order to enable the device to be close to the circuit board as much as possible after the device is welded, the device is required to be dried before welding, then the steel mesh is opened to scrape solder paste, and then reflow soldering is carried out.

In this embodiment, a plurality of pads H1 are disposed on the LGA board 301, wherein the number of pads H1 on the LGA board 301 is greater than the number of pads H2 on the signal layer S1. In other words, the pads H1 on the LGA board 301 are more densely packed.

Step S195: and welding the bonding pads on the LGA board and the bonding pads on the signal layer to realize the discrete connection of the LGA board and the signal layer.

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

Referring to fig. 20, a flowchart of a method for manufacturing a signal transmission structure according to another embodiment of the present application may include the following steps:

step S201: a printed circuit board is provided.

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 being disposed on the ground plane G1, and the signal layer S1 may be provided with a first device 10 and a second device 20. Wherein the first device 10 may be connected to the second device 20 via a signal trace 40. The first device 10 may send a signal to the second device 20.

Step S202: pads are formed at discrete locations on a signal layer of a printed circuit board.

Embodiments of the present application may form pads H2 at discrete locations that are segmented on the surface layer of the printed circuit board 200. For example, in this embodiment, a layer of copper may be brushed on the surface of the printed circuit board, the redundant portion is etched away, then a solder mask layer is added and cured to form a solder pattern, and a layer of solder paste is brushed on the solder pattern to form a pad, namely, a pad H2.

Step S203: a steel sheet is provided.

Step S204: and attaching the steel sheet to the bonding pad of the signal layer to realize discrete connection of the steel sheet on the signal layer.

The mounting process in this embodiment may include: 1. identifying marking points of the printed circuit board 200 and the steel sheet 302 through an optical instrument to finish accurate positioning; demolding the solder paste on the bonding pad of the printed circuit board through the opening of the steel sheet by using a scraper, and accurately positioning through the marking point of the printed circuit board 200 after the printing process is finished; 3. is attached to the designated pad. Wherein the steel sheet 302 may be sunk at discrete positions corresponding to the signal layer S1, so that the sensitive signal areas may be discretely connected by the sunk portions. For example, as shown in fig. 16, the inner frame portion of the steel sheet 302 may be submerged to form a welded portion 305 as shown in fig. 16. The welds 305 may correspond to discrete areas of sensitive signal in the signal layer S1. The steel sheet 302 may be connected to the pad H2 in the signal layer S1 through the submerged solder 305, so that the steel sheet 302 may provide a complete reference ground for the signal loop between the first device 10 and the second device 20.

It will be appreciated that in this embodiment, where the steel sheet 302 has a complete reference ground, discrete communication of trace areas of the sensitive signal may be achieved, with the shortest return path from the first device 10 to the second device 20 and the lowest return impedance.

Referring to fig. 21, a flowchart of a method for manufacturing a signal transmission structure according to another embodiment of the present application may include the following steps:

step S211: a printed circuit board is provided.

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 being disposed on the ground plane G1, and the signal layer S1 may be provided with a first device 10 and a second device 20. Wherein the first device 10 may be connected to the second device 20 via a signal trace 40. The first device 10 may send a signal to the second device 20.

Step S212: pads are formed at discrete locations on a signal layer of a printed circuit board.

Embodiments of the present application may form pads H2 at discrete locations that are segmented on the surface layer of the printed circuit board 200. For example, in this embodiment, a layer of copper may be brushed on the surface of the printed circuit board, the redundant portion is etched away, then a solder mask layer is added and cured to form a solder pattern, and a layer of solder paste is brushed on the solder pattern to form a pad, namely, a pad H2.

Step S213: an insulator is provided.

Step S214: the insulator is covered on the first device, the second device and other devices.

The plurality of insulators 307 may isolate the conductive material 306 from the device region 405. The device region 405 may include a region where the first device 10 and the second device 20 are located. Optionally, the device region 405 further includes a region where one or more devices 308 other than the first device 10 and the second device 20 are located.

Step S215: providing a conductive material, and bonding the conductive material to a bonding pad of a sensitive signal routing area in the signal layer to realize discrete connection of the conductive material on the signal layer.

As shown in fig. 17, the conductive material 306 may be implemented in the form of a conductive auxiliary material or a metal spray. For example, in an alternative implementation, the conductive material 306 may be any one of copper sheet, conductive cloth laser etched, conductive aluminum foil, or conductive tape. In another alternative implementation, silver paste may be sprayed on the insulator 307 to connect the pads H3. The embodiment of the application can be suitable for scenes such as curved surface structures, and the application range is wider.

It can be understood that in the embodiment of the present application, a part of conductive particles and conductive adhesive will be lost from the conductive material after bonding, resulting in poor bonding consistency; in the construction process, the material cannot be directly contacted by hands, otherwise, the surface of the conductive auxiliary material is dirty to influence the conductivity.

Those of ordinary skill in the art will realize that the foregoing embodiments are merely illustrative of the present application and are not intended to be limiting.

Claims (17)

1. A signal transmission structure, characterized in that the signal transmission structure comprises a first device, a second device and a grounding part;

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 positioned at two first discretes in one or more signal layers; the first device is used for transmitting a first signal to the second device;

and the first grounding part is arranged on the printed circuit board and covers the two first discretes and is used for providing complete reference ground when the second device reflows the first signal to the first device.

2. The signal transmission structure according to claim 1, wherein,

The first ground includes a contact array package (LGA) board having a first plurality of first pads disposed discretely and a second plurality of pads disposed to be soldered to the first plurality of pads to provide a complete reference ground for signal reflow between the second device and the first device.

3. The signal transmission structure according to claim 1, wherein,

the first grounding portion comprises a steel sheet, a plurality of first bonding pads are arranged on the discrete ground, the steel sheet is used for connecting the plurality of first bonding pads, and the steel sheet is used for providing complete reference ground for signal backflow between the second device and the first device.

4. The signal transmission structure according to claim 3, wherein,

the steel sheet is provided with one or more hollowed-out areas, and the one or more hollowed-out areas are used for enabling the steel sheet to avoid contact with device areas in the one or more signal layers.

5. The signal transmission structure according to claim 3 or 4, wherein,

the steel sheet is sunk at a position corresponding to the first discrete to form a plurality of welding parts, and the plurality of welding parts are correspondingly connected with the plurality of first bonding pads.

6. The signal transmission structure according to claim 1, wherein,

the signal transmission structure further includes a conductive material adhered to the plurality of first pads on the two first discrete lands.

7. The signal transmission structure according to claim 6, wherein,

the signal transmission structure further comprises an insulator for isolating the conductive material from a device region, wherein the device region comprises regions where the first device and the second device are located.

8. The signal transmission structure according to claim 7, wherein,

the device region further includes a region where one or more devices other than the first device and the second device are located.

9. The signal transmission structure according to any one of claims 1 to 8, wherein,

the signal transmission structure further comprises a third device, a fourth device and a second grounding part;

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 positioned at two second discretes in the one or more signal layers; the third device is configured to transmit a second signal to the fourth device;

The second ground is disposed over the printed circuit board and overlies the two second discrete grounds, the second ground being configured to provide a complete reference ground when the fourth device reflows the second signal to the third device.

10. The signal transmission structure according to any one of claims 1 to 9, wherein,

the first device is connected with the second device through a signal wire, wherein the signal wire comprises at least one of a clock wire, a data wire, a control wire or a high-speed signal wire.

11. A method for manufacturing a signal transmission structure, the signal transmission structure including a printed circuit board and a first ground portion, the method comprising:

providing a printed circuit board, wherein the printed circuit board comprises one or more signal layers;

providing a first grounding part, wherein the first grounding part is arranged on the printed circuit board and covers two first discrete lands of the one or more signal layers;

the first device and the second device are arranged in the same signal layer or different signal layers, the first device and the second device are respectively positioned at the two first discretes, the second device is used for receiving a first signal output by the first device, and the first grounding part is used for providing a complete reference ground when the second device reflows the first signal to the first device.

12. The method of claim 11, wherein providing a first ground portion, disposing the first ground portion over the printed circuit board and overlying two first discrete ones of the one or more signal layers comprises:

providing an LGA board;

forming a plurality of second pads on the LGA board;

and correspondingly welding a plurality of second bonding pads on the LGA board with a plurality of first bonding pads on the first discrete ground.

13. The method of claim 11, wherein providing a first ground portion, disposing the first ground portion over the printed circuit board and overlying two first discrete ones of the one or more signal layers comprises:

providing a steel sheet;

sinking the steel sheet at positions corresponding to the first discrete positions to form a plurality of welding parts;

the plurality of solder joints are correspondingly connected with the plurality of first pads on the first discrete ground.

14. The method of claim 11, wherein providing a first ground portion, disposing the first ground portion over the printed circuit board and overlying two first discrete ones of the one or more signal layers comprises:

Providing a conductive material;

the conductive material is bonded to a plurality of first pads on the first discrete ground.

15. The method of manufacturing a signal transmission structure according to claim 14, further comprising:

providing an insulator;

isolating the conductive material from the device region by the insulator; the device region comprises a region where the first device and the second device are located.

16. The method of manufacturing a signal transmission structure according to claim 15, wherein,

the device region further includes a region where one or more devices other than the first device and the second device are located.

17. The method of manufacturing a signal transmission structure according to claim 11, further comprising:

providing a second grounding part;

disposing the second ground over the printed circuit board and overlying two discrete ones of the one or more signal layers;

and the second grounding part is used for providing complete reference ground when the fourth device reflows the second signals to the third device.