This application relates to the field of electronic devices, and more specifically, to a circuit board assembly, an electronic device, and a method for processing a circuit board assembly.
As an electronic device needs to implement increasing functions, an increasing quantity of electronic components are disposed inside the electronic device. The electronic device may include a plurality of circuit boards, and each circuit board may be used to solder and fasten the electronic components. This soldering and fastening process may also be referred to as a soldering technology. To provide larger space for a battery and another function module, a transverse area (XY area) of the circuit board may be reduced through board on board (board on board, BoB) or package on package (package on package, PoP). To ensure connection reliability of the BOB and the PoP, a soldering region needs to be filled with underfill (underfill) materials or edge bond adhesive (edge bond adhesive) materials. This filling technology may also be referred to as a dispensing technology. However, a vertical height (a Z-direction height) for connecting the electronic component or the circuit board is very small (for example, only 40 μm). In addition, solder flux may remain on the circuit board. This is not conducive to effectively put a filling material between solder joints. Further, it is difficult to ensure mechanical reliability and environmental reliability of a circuit board assembly (printed circuit board assembly, PCBA).
This application provides a circuit board assembly, an electronic device, and a method for processing a circuit board assembly, to improve reliability of a connection between circuit boards, or between a circuit board and an electronic component.
According to a first aspect, an electronic device is provided, including: a first circuit board, including a first side surface and a first sidewall pad, where the first sidewall pad is disposed on the first side surface; a second circuit board, fastened to the first circuit board, where the first sidewall pad is located at a position close to the second circuit board; and sidewall solder, adhered to the first sidewall pad and the second circuit board.
Optionally, the electronic component further includes a power supply. The power supply is electrically connected to the first circuit board and the second circuit board.
A circuit board mentioned in this application may be a mainboard, a frame board, a daughterboard, a substrate of the electronic component, or the like.
A pad may also be referred to as a solder mask (solder mask). The pad may be disposed on the circuit board in an electroplating manner. A material of the pad may be a metal material such as copper.
A side surface of the circuit board may refer to a surface disposed in parallel to a height direction of the circuit board. For example, the frame board is a circuit board. The frame board may include a via for disposing the electronic component. A side surface of the frame board may include an inner wall of the via, and may further include an outer peripheral surface of the frame board. A surface that is perpendicular to the height direction of the circuit board and used to carry another circuit board or electronic component may be referred to as a horizontal plane of the circuit board. The circuit board may include an upper horizontal plane and a lower horizontal plane.
A solder ball may refer to a solder material connected between a horizontal plane of a circuit board 1 and a horizontal plane of a circuit board 2. The sidewall solder may refer to a solder material disposed on the side surface of the circuit board.
It should be understood that a conventional solder ball may be welded to a copper foil on the horizontal plane of the circuit board. In an embodiment of this application, the sidewall solder may also be adhered to the copper foil on the horizontal plane of the circuit board.
In this embodiment of this application, solder is formed on a side wall. In a case in which electrical properties of the circuit board assembly are not affected, a volume of the sidewall solder may be relatively large, so that relatively high connection strength can be implemented, and mechanical and environmental reliability of the circuit board assembly can be improved. In addition, because of the sidewall solder, a solder ball closest to a periphery of the circuit board can also be protected to some extent. This can delay breakdown of the circuit board assembly. In addition, a spacing between adjacent circuit boards hardly affects formation of the sidewall solder.
With reference to the first aspect, in some implementations of the first aspect, the second circuit board includes a second horizontal pad, and the second horizontal pad is disposed on a second horizontal plane that is of the second circuit board and close to the first circuit board. That the sidewall solder is adhered to the first sidewall pad and the second circuit board is specifically: The sidewall solder is adhered to the first sidewall pad and the second horizontal pad.
The second horizontal pad may be located at a position close to a second side surface of the second circuit board. The second side surface is disposed in parallel to the first side surface. The first side surface may be located on either side of the second side surface. The first side surface and the second side surface may also be coplanar.
In this embodiment of this application, the second horizontal pad is disposed, so that the sidewall solder is formed between the first sidewall pad and the second horizontal pad. Sizes, arrangement positions, and the like of the first circuit board and the second circuit board may not be limited, to adapt to more scenarios.
With reference to the first aspect, in some implementations of the first aspect, the second circuit board includes a second side surface and a second sidewall pad, the first side surface and the second side surface are located on a same side of the electronic device, and the second sidewall pad is disposed at a position that is on the second side surface and close to the first circuit board. That the sidewall solder is adhered to the first sidewall pad and the second circuit board is specifically: The sidewall solder is adhered to the first sidewall pad and the second sidewall pad.
In this embodiment of this application, a distance between the first side surface and the second side surface is relatively short. Consequently, it is difficult to put a filling material between the first circuit board and the second circuit board. Therefore, when the first side surface and the second side surface are fastened together by using the sidewall solder, a process solution for replacing the filling material may be provided.
With reference to the first aspect, in some implementations of the first aspect, the first sidewall pad further includes a sidewall groove, and the sidewall solder is adhered to a surface of the sidewall groove.
A sidewall groove on a sidewall pad may be implemented by using technologies such as laser cutting and a plurality of times of electroplating.
In this embodiment of this application, the sidewall groove is disposed on the sidewall pad, so that the sidewall solder can be adhered to the surface of the sidewall groove. Therefore, a contact area between the sidewall solder and the pad is increased. In addition, a total adhesion volume of the sidewall solder can be increased, so that connection reliability of the sidewall solder can be improved, and mechanical and environmental reliability of the circuit board assembly can be improved.
With reference to the first aspect, in some implementations of the first aspect, the sidewall groove includes a first bottom surface and a first groove wall, the first bottom surface is disposed in parallel to the first side surface, the first groove wall is connected between the first bottom surface and an outer surface of the first sidewall pad, and the first groove wall surrounds a periphery of the first bottom surface, or the first groove wall is located on one side of the first bottom surface.
For the sidewall groove that includes the first bottom surface and the first groove wall surrounding a periphery of the first bottom surface, a contact area between the sidewall pad and the sidewall solder is larger, a connection effect of the sidewall solder is better, and stronger mechanical and environmental reliability can be implemented.
With reference to the first aspect, in some implementations of the first aspect, the first circuit board further includes: a first horizontal pad, located on a first horizontal plane that is of the first circuit board and close to the second circuit board, and located at a position close to the first sidewall pad. The sidewall solder is further adhered to the first horizontal pad.
In this embodiment of this application, a horizontal pad is disposed on the circuit board, so that the contact area between the sidewall solder and the pad can be increased. In addition, the first horizontal pad is disposed, so that the sidewall solder may further fasten a side surface of the first circuit board and a horizontal plane of the second circuit board, thereby providing binding force in a plurality of directions. This is more suitable for a complex drop scenario.
With reference to the first aspect, in some implementations of the first aspect, the first horizontal pad is connected to the first sidewall pad to form a first pad.
In this embodiment of this application, the horizontal pad and the sidewall pad are connected as a whole, so that the sidewall solder is closely adhered to the pad. However, if the horizontal pad and the sidewall pad are spaced from each other, a cavity is prone to form among the sidewall solder, the horizontal pad, and the sidewall pad. This is not conducive to mechanical and environmental reliability of the sidewall solder.
With reference to the first aspect, in some implementations of the first aspect, the first horizontal pad further includes a horizontal groove, and the sidewall solder is adhered to a surface of the horizontal groove.
In this embodiment of this application, the horizontal groove is disposed on the horizontal pad, so that the sidewall solder can be adhered to the surface of the horizontal groove. Therefore, the contact area between the sidewall solder and the pad is increased. In addition, a total adhesion volume of the sidewall solder can be increased, so that connection reliability of the sidewall solder can be improved, and mechanical and environmental reliability of the circuit board assembly can be improved. Because there is a spacing between the horizontal pad and the side surface of the circuit board, it is relatively difficult to adhere the sidewall solder to the horizontal pad. Adhesion resistance of the sidewall solder to the horizontal pad can be reduced by adding the horizontal groove to the horizontal pad.
With reference to the first aspect, in some implementations of the first aspect, the horizontal groove includes a second bottom surface and a second groove wall, the second bottom surface is disposed in parallel to the first horizontal plane, the second groove wall is connected between the second bottom surface and an outer surface of the first horizontal pad, and the second groove wall surrounds a periphery of the second bottom surface, or the second groove wall is located on one side of second bottom surface.
For the horizontal groove that includes the second bottom surface and the second groove wall surrounding a periphery of the second bottom surface, a contact area between the horizontal pad and the sidewall solder is larger, a connection effect of the sidewall solder is better, and stronger mechanical and environmental reliability can be implemented.
With reference to the first aspect, in some implementations of the first aspect, one end that is of the first sidewall pad and far away from the second circuit board extends to a third horizontal plane, and the third horizontal plane is a horizontal plane that is of the first circuit board and far away from the second circuit board.
In this embodiment of this application, a height of the sidewall pad is increased, so that an electromagnetic shielding effect of the sidewall pad can be improved.
With reference to the first aspect, in some implementations of the first aspect, the first circuit board further includes a third side surface and a first groove. The first groove is located at a position close to the third side surface, and is located on the first horizontal plane that is of the first circuit board and close to the second circuit board. The electronic device further includes: a filling material, adhered between the first groove and the second circuit board.
With reference to the first aspect, in some implementations of the first aspect, the first circuit board further includes a third side surface, and the second circuit board further includes a first groove. The first groove is located at a position close to the third side surface, and is located on the second horizontal plane that is of the second circuit board and close to the first circuit board. The electronic device further includes: a filling material, adhered between the first groove and the first circuit board.
In this embodiment of this application, a groove is disposed, so that a contact area between the filling material and the circuit board can be increased, and a total adhesion volume of the filling material can be increased. This can implement relatively high connection strength, and helps improve mechanical and environmental reliability of the circuit board assembly. In addition, the filling material is disposed on a side surface of a circuit, so that the solder ball closest to the periphery of the circuit board can also be protected to some extent, thereby delaying breakdown of the circuit board assembly. In addition, a filling technology and a sidewall soldering technology may be combined to improve stability of a connection between circuit boards, which is more applicable to various scenarios.
With reference to the first aspect, in some implementations of the first aspect, the electronic device further includes an electronic component disposed in the first groove, and the filling material wraps the electronic component.
In this embodiment of this application, the electronic component is disposed in the groove, so that a quantity of electronic components that can be carried by the circuit board assembly can be increased without increasing space occupied by the circuit board assembly, and arrangement compactness of the electronic components can be improved. In other words, when the quantity of electronic components is fixed, the space occupied by the circuit board assembly can be reduced, and arrangement convenience of the electronic components can be improved.
According to a second aspect, an electronic device is provided, including: a first circuit board, including a first side surface; a second circuit board, fastened to the first circuit board and including a first groove, where the first groove is located at a position close to the first side surface, and is disposed on a second horizontal plane that is of the second circuit board and close to the first circuit board; and a filling material, adhered between the first circuit board and the first groove.
Optionally, the electronic device further includes a power supply. The power supply is electrically connected to the first circuit board and the second circuit board.
It should be noted that the second circuit board includes a third side surface disposed in parallel to the first side surface, and the first side surface and the third side surface are located on a same side of a circuit board assembly. In an example, the third side surface is located on a side that is of the first side surface and away from the first circuit board, and the second circuit board may be configured to carry a filling material. In an example, the third side surface is located on a side that is of the first side surface and close to the first circuit board, and the first circuit board may be configured to carry the filling material. Corresponding to the former, the first groove may carry the filling material, which is more conducive to planning a flow direction of the filling material.
A side surface of a circuit board may refer to a surface disposed in parallel to a height direction of the circuit board. For example, the frame board is a circuit board. The frame board may include a via for disposing the electronic component. A side surface of the frame board may include an inner wall of the via, and may further include an outer peripheral surface of the frame board. A surface that is perpendicular to the height direction of the circuit board and used to carry another circuit board or electronic component may be referred to as a horizontal plane of the circuit board. The circuit board may include an upper horizontal plane and a lower horizontal plane.
In this embodiment of this application, a groove is disposed, so that a contact area between the filling material and the circuit board can be increased, and a total adhesion volume of the filling material can be increased. This can implement relatively high connection strength, and helps improve mechanical and environmental reliability of the circuit board assembly. In addition, the filling material is disposed on a side surface of a circuit, so that a solder ball closest to a periphery of the circuit board can also be protected to some extent, thereby delaying breakdown of the circuit board assembly.
With reference to the second aspect, in some implementations of the second aspect, the first groove includes a bottom surface and a groove wall, the bottom surface is disposed in parallel to the second horizontal plane, the groove wall is connected between the bottom surface and the second horizontal plane, and the groove wall surrounds a periphery of the bottom surface, or the groove wall is located on one side of bottom surface.
For a groove that includes a bottom surface and a groove wall surrounding a periphery of the bottom surface, a contact area between the groove and the filling material is larger. Therefore, a connection effect of the filling material is better, and stronger mechanical and environmental reliability can be implemented.
With reference to the second aspect, in some implementations of the second aspect, the electronic device further includes an electronic component disposed in the first groove, and the filling material wraps the electronic component.
In this embodiment of this application, the electronic component is disposed in the groove, so that a quantity of electronic components that can be carried by the circuit board assembly can be increased without increasing space occupied by the circuit board assembly, and arrangement compactness of the electronic components can be improved. In other words, when the quantity of electronic components is fixed, the space occupied by the circuit board assembly can be reduced, and arrangement convenience of the electronic components can be improved.
With reference to the second aspect, in some implementations of the second aspect, the first circuit board further includes a third groove, the third groove is located at a position close to the first side surface, and is disposed on a first horizontal plane that is of the first circuit board and close to the second circuit board, and the filling material is adhered between the first groove and the third groove.
In this embodiment of this application, grooves are disposed on both the first circuit board and the second circuit board, so that a height for accommodating the filling material between the first circuit board and the second circuit board can be increased, a volume of the filling material can be increased, and a contact area between the filling material and each of the first circuit board and the second circuit board can be increased. This can implement relatively high connection strength, and helps improve mechanical and environmental reliability of the circuit board assembly.
According to a third aspect, a circuit board assembly is provided, including: a first circuit board, including a first side surface and a first sidewall pad, where the first sidewall pad is disposed on the first side surface; a second circuit board, fastened to the first circuit board, where the first sidewall pad is located at a position close to the second circuit board; and sidewall solder, adhered to the first sidewall pad and the second circuit board.
With reference to the third aspect, in some implementations of the third aspect, the second circuit board includes a second horizontal pad, and the second horizontal pad is disposed on a second horizontal plane that is of the second circuit board and close to the first circuit board. That the sidewall solder is adhered to the first sidewall pad and the second circuit board is specifically: The sidewall solder is adhered to the first sidewall pad and the second horizontal pad.
With reference to the third aspect, in some implementations of the third aspect, the second circuit board includes a second side surface and a second sidewall pad, the first side surface and the second side surface are located on a same side of the circuit board assembly, and the second sidewall pad is disposed at a position that is on the second side surface and close to the first circuit board. That the sidewall solder is adhered to the first sidewall pad and the second circuit board is specifically: The sidewall solder is adhered to the first sidewall pad and the second sidewall pad.
With reference to the third aspect, in some implementations of the third aspect, the first sidewall pad further includes a sidewall groove, and the sidewall solder is adhered to a surface of the sidewall groove.
With reference to the third aspect, in some implementations of the third aspect, the sidewall groove includes a first bottom surface and a first groove wall, the first bottom surface is disposed in parallel to the first side surface, the first groove wall is connected between the first bottom surface and an outer surface of the first sidewall pad, and the first groove wall surrounds a periphery of the first bottom surface, or the first groove wall is located on one side of the first bottom surface.
With reference to the third aspect, in some implementations of the third aspect, the first circuit board further includes: a first horizontal pad, located on a first horizontal plane that is of the first circuit board and close to the second circuit board, and located at a position close to the first sidewall pad. The sidewall solder is further adhered to the first horizontal pad.
With reference to the third aspect, in some implementations of the third aspect, the first horizontal pad is connected to the first sidewall pad to form a first pad.
With reference to the third aspect, in some implementations of the third aspect, the first horizontal pad further includes a horizontal groove, and the sidewall solder is adhered to a surface of the horizontal groove.
With reference to the third aspect, in some implementations of the third aspect, the horizontal groove includes a second bottom surface and a second groove wall, the second bottom surface is disposed in parallel to the first horizontal plane, the second groove wall is connected between the second bottom surface and an outer surface of the first horizontal pad, and the second groove wall surrounds a periphery of the second bottom surface, or the second groove wall is located on one side of second bottom surface.
With reference to the third aspect, in some implementations of the third aspect, one end that is of the first sidewall pad and far away from the second circuit board extends to a third horizontal plane, and the third horizontal plane is a horizontal plane that is of the first circuit board and far away from the second circuit board.
With reference to the third aspect, in some implementations of the third aspect, the first circuit board further includes a third side surface and a first groove. The first groove is located at a position close to the third side surface, and is located on the first horizontal plane that is of the first circuit board and close to the second circuit board. The circuit board assembly further includes: a filling material, adhered between the first groove and the second circuit board.
With reference to the third aspect, in some implementations of the third aspect, the first circuit board further includes a third side surface, and the second circuit board further includes a first groove. The first groove is located at a position close to the third side surface, and is located on the second horizontal plane that is of the second circuit board and close to the first circuit board. The circuit board assembly further includes: a filling material, adhered between the first groove and the first circuit board.
With reference to the third aspect, in some implementations of the third aspect, the circuit board assembly further includes an electronic component disposed in the first groove, and the filling material wraps the electronic component.
According to a fourth aspect, a circuit board assembly is provided, including: a first circuit board, including a first side surface; a second circuit board, fastened to the first circuit board and including a first groove, where the first groove is located at a position close to the first side surface, and is disposed on a second horizontal plane that is of the second circuit board and close to the first circuit board; and a filling material, adhered between the first circuit board and the first groove.
With reference to the fourth aspect, in some implementations of the fourth aspect, the first groove includes a bottom surface and a groove wall, the bottom surface is disposed in parallel to the second horizontal plane, the groove wall is connected between the bottom surface and the second horizontal plane, and the groove wall surrounds a periphery of the bottom surface, or the groove wall is located on one side of bottom surface.
With reference to the fourth aspect, in some implementations of the fourth aspect, the circuit board assembly further includes an electronic component disposed in the first groove, and the filling material wraps the electronic component.
With reference to the fourth aspect, in some implementations of the fourth aspect, the first circuit board further includes a third groove, the third groove is located at a position close to the first side surface, and is disposed on a first horizontal plane that is of the first circuit board and close to the second circuit board, and the filling material is adhered between the first groove and the third groove.
According to a fifth aspect, a method for processing a circuit board assembly is provided, including: an electroplating step, including: electroplating a first side surface of a first circuit board with a first sidewall pad; and a soldering step, including: soldering the first circuit board to a second circuit board, and performing soldering between the first sidewall pad and the second circuit board to form sidewall solder.
An embodiment of this application provides a soldering manner different from a conventional soldering technology, to implement a connection effect with higher strength.
With reference to the fifth aspect, in some implementations of the fifth aspect, the electroplating step further includes: electroplating a second side surface of the second circuit board with a second sidewall pad, where the second sidewall pad is located at a position close to the first sidewall pad, and the second side surface and the first side surface are disposed in parallel to each other, and are located on a same side of the circuit board assembly. The performing soldering between the first sidewall pad and the second circuit board to form sidewall solder includes: performing soldering between the first sidewall pad and the second sidewall pad to form the sidewall solder.
With reference to the fifth aspect, in some implementations of the fifth aspect, the electroplating step further includes: electroplating a second horizontal plane of the second circuit board with a second horizontal pad, where the second horizontal plane is a horizontal plane that is of the second circuit board and close to the first circuit board, and the second horizontal pad is located at the position close to the first sidewall pad. The performing soldering between the first sidewall pad and the second circuit board to form sidewall solder includes: performing soldering between the first sidewall pad and the second horizontal pad to form the sidewall solder.
With reference to the fifth aspect, in some implementations of the fifth aspect, the electroplating step further includes: electroplating a first horizontal plane of the first circuit board with a first horizontal pad, where the first horizontal plane is a horizontal plane that is of the first circuit board and close to the second circuit board. The performing soldering between the first sidewall pad and the second circuit board to form sidewall solder includes: performing soldering among the first sidewall pad, the first horizontal pad, and the second circuit board to form the sidewall solder.
With reference to the fifth aspect, in some implementations of the fifth aspect, the electroplating step further includes: electroplating the first horizontal pad to form a horizontal groove.
With reference to the fifth aspect, in some implementations of the fifth aspect, the electroplating step further includes: electroplating the first sidewall pad to form a sidewall groove.
The following describes technical solutions of this application with reference to accompanying drawings.
The electronic device 100 may be a device such as a mobile phone, a tablet computer, an electronic reader, a notebook computer, a digital camera, a vehicle-mounted device, or a wearable device. In the embodiment shown in
The electronic device 100 includes a housing 10, a display 20, and a circuit board assembly 30. The display 20 and the circuit board assembly 30 are installed on the housing 10. Specifically, the housing 10 includes a frame and a rear cover. The frame surrounds a periphery of the display 20 and a periphery of the rear cover. The display 20 and the rear cover are spaced from each other. A cavity formed among the display 20, the frame, and the rear cover is used to place the circuit board assembly 30. The electronic device 100 further includes a power supply 40 configured to supply power to the circuit board assembly 30. The power supply 40 may be, for example, a lithium-ion battery.
As shown in
The plurality of electronic components electrically connected to the plurality of PCBs may include, for example, a system-on-a-chip (system on chip, SOC) component 211, a double data rate (double data rate, DDR) memory 212, a primary power management unit (power management unit, PMU) 213, a radio frequency integrated circuit (radio frequency integrated circuit, RF IC) 214, a radio frequency power amplifier (radio frequency power amplifier, RF PA) 215, a wireless fidelity (wireless fidelity, Wi-Fi) chip 216, and a secondary PMU 218. The plurality of electronic components may be stacked and packaged to form a package on package (Package on Package, POP) component. As shown in
To ensure connection strength, a filling material 233 may be put between the circuit boards, or between the circuit board and the electronic component. A pattern filled with rectangles in
In conclusion, a total height of the electronic device is usually relatively thin. Therefore, a height of a solder joint between the circuit board and the electronic component is very small, and a height of a solder joint between the circuit boards is also very small, for example, only 40 μm. Consequently, it is difficult for the filling material to achieve effective adhesion, and it is difficult to ensure mechanical and environmental reliability of the circuit board assembly. Embodiments of this application provide a circuit board assembly, an electronic device, and a method for processing a circuit board assembly, to improve reliability of a connection between circuit boards, or between a circuit board and an electronic component, so as to ensure mechanical and environmental reliability of the circuit board assembly and the electronic device.
The circuit board assembly 300 may include a first circuit board 301 and a second circuit board 302. The second circuit board 302 may be fastened to the first circuit board 301 by using solder balls 311. In an example, the first circuit board 301 may be, for example, the frame board 202 in
The first circuit board 301 includes a first side surface 321 and a first sidewall pad 331. The first sidewall pad 331 is disposed at a position that is on the first side surface 321 and close to the second circuit board 302. The second circuit board 302 includes a second side surface 322 and a second sidewall pad 332. The first side surface 321 is disposed in parallel to the second side surface 322. The first side surface 321 and the second side surface 322 are located on a same side of the circuit board assembly 300. The second sidewall pad 332 is disposed at a position that is on the second side surface 322 and close to the first circuit board 301. First sidewall solder 312 is adhered to the first sidewall pad 331 and the second sidewall pad 332. Similarly, the first circuit board 301 includes a third side surface 323. A third sidewall pad 333 is disposed at a position that is on the third side surface 323 and close to the second circuit board 302. The second circuit board 302 includes a fourth side surface 324. The third side surface 323 is disposed in parallel to the fourth side surface 324. The third side surface 323 and the fourth side surface 324 are located on a same side of the circuit board assembly 300. A fourth sidewall pad 334 is disposed at a position that is on the fourth side surface 324 and close to the first circuit board 301. Second sidewall solder 313 is adhered to the third sidewall pad 333 and the fourth sidewall pad 334. The first sidewall solder 312 and the second sidewall solder 313 may fasten a side surface of the first circuit board 301 to a side surface of the second circuit board 302, so that the first circuit board 301 and the second circuit board 302 are fastened together.
It should be noted that, in this application, a pattern filled with slashes may represent a pad. The pad may also be referred to as a solder mask (solder mask). The pad may be disposed on the circuit board in an electroplating manner. A material of the pad may be a metal material, for example, copper.
It should be noted that a side surface of the circuit board may be a surface disposed in parallel to a height direction (for example, a Z direction indicated by an arrow in
It should be noted that, in this application, a solder ball may refer to a solder material connected between a horizontal plane of a circuit board 1 and a horizontal plane of a circuit board 2. Sidewall solder may refer to a solder material disposed on the side surface of the circuit board.
It can be known from a drop test of the circuit board assembly that, solder balls close to a periphery of the circuit board usually bear relatively large mechanical and environmental stresses, and solder balls close to the center of the circuit board usually bear relatively small mechanical and environmental stresses. Solder is formed on a side wall, so that a solder ball closest to the periphery of the circuit board can also be protected to some extent, thereby delaying breakdown of the circuit board assembly. In addition, a spacing between adjacent circuit boards hardly affects formation of the sidewall solder. Therefore, in a case in which electrical properties of the circuit board assembly are not affected, a volume of the sidewall solder may be relatively large, so that relatively high connection strength can be implemented, and mechanical and environmental reliability of the circuit board assembly can be improved.
The sidewall groove is disposed on the sidewall pad, so that sidewall solder can be adhered to a surface of the sidewall groove. Therefore, a contact area between the sidewall solder and the pad is increased. In addition, a total adhesion volume of the sidewall solder can be increased, so that connection reliability of the sidewall solder can be improved, and mechanical and environmental reliability of the circuit board assembly can be improved.
As shown in
It should be noted that the first circuit board 601 may include a first pad 651, and the first pad 651 includes the first sidewall pad 631 and the first horizontal pad 635, that is, the first sidewall pad 631 and the first horizontal pad 635 are connected as a whole. Similarly, the first circuit board 6oi may include a third pad 652, and the third pad 652 includes the third sidewall pad 633 and the third horizontal pad 636, that is, the third sidewall pad 633 and the third horizontal pad 636 are connected as a whole. The horizontal pad and the sidewall pad are connected as a whole, so that the sidewall solder is closely adhered to the pad. However, if the horizontal pad and the sidewall pad are spaced from each other, a cavity is prone to form among the sidewall solder, the horizontal pad, and the sidewall pad. This is not conducive to mechanical and environmental reliability of the sidewall solder.
The horizontal groove is disposed on the horizontal pad, so that sidewall solder can be adhered to the surface of the horizontal groove. Therefore, a contact area between the sidewall solder and a pad is increased. In addition, a total adhesion volume of the sidewall solder can be increased, so that connection reliability of the sidewall solder can be improved, and mechanical and environmental reliability of the circuit board assembly can be improved. Because there is a spacing between the horizontal pad and a side surface of the circuit board, it is relatively difficult to adhere the sidewall solder to the horizontal pad. Adhesion resistance of the sidewall solder to the horizontal pad can be reduced by adding the horizontal groove to the horizontal pad.
As shown in
It should be noted that the second circuit board 1102 may include a second pad 1153, and the second pad 1153 includes the second sidewall pad 1132 and the second horizontal pad 1137, that is, the second sidewall pad 1132 and the second horizontal pad 1137 are connected as a whole. Similarly, the second circuit board 1102 may include a fourth pad 1154, and the fourth pad 1154 includes the fourth sidewall pad 1134 and the fourth horizontal pad 1138, that is, the fourth sidewall pad 1134 and the fourth horizontal pad 1138 are connected as a whole. The foregoing has described beneficial effects of connecting the sidewall pad and the horizontal pad as a whole. Details are not described herein again.
With reference to the embodiments shown in
The circuit board assembly 1500 may include a first circuit board 1501 and a second circuit board 1502. The first circuit board 1501 may be fastened to the second circuit board 1502 by using solder balls 1511. In an example, the first circuit board 1501 may be, for example, the frame board 202 in
A first sidewall pad 1531 is disposed on a first side surface 1521 of the first circuit board 1501. A second horizontal pad 1537 is disposed on a second horizontal plane 1504 that is of the second circuit board 1502 and close to the first circuit board 1501. The second horizontal pad 1537 is located at a position close to the first side surface 1521. First sidewall solder 1512 is adhered to the first sidewall pad 1531 and the second horizontal pad 1537. Similarly, a third sidewall pad 1533 is disposed on a third side surface 1523 of the first circuit board 1501; a fourth horizontal pad 1538 is disposed on the second horizontal plane 1504 that is of the second circuit board 1502 and close to the first circuit board 1501; the fourth horizontal pad 1538 is located at a position close to the third side surface 1523; and second sidewall solder 1513 is adhered to the third sidewall pad 1533 and the fourth horizontal pad 1538. A pad may also be referred to as a solder mask (solder mask). The first sidewall solder 1512 and the second sidewall solder 1513 may fasten a side surface of the first circuit board 1501 to a horizontal plane of the second circuit board 1502, so that the second circuit board 1502 and the first circuit board 1501 are fastened together.
The second horizontal pad 1537 may be located at a position close to a second side surface 1522 of the second circuit board 1502. The second side surface 1522 is disposed in parallel to the first side surface 1521. The second side surface 1522 and the first side surface 1521 are located on a same side of the circuit board assembly 1500. The first side surface 1521 may be located on either side of the second side surface 1522. The first side surface 1521 and the second side surface 1522 may also be coplanar.
In an example, it is assumed that a first direction (an X direction indicated by an arrow in
In an example, it is assumed that a second direction (for example, may be a direction opposite to the X direction) is a direction that points from the periphery of the first circuit board 1501 to the center of the first circuit board 1501 and that is perpendicular to the first side surface 1521. The first side surface 1521 moves for a specific distance in the second direction, and may be coplanar with the second side surface 1522.
Similarly, the fourth horizontal pad 1538 may be located at a position close to a fourth side surface 1524 of the second circuit board 1502. The fourth side surface 1524 is disposed in parallel to the third side surface 1523. The fourth side surface 1524 and the third side surface 1523 are located on a same side of the circuit board assembly 1500. The third side surface 1523 may be located on either side of the fourth side surface 1524. The third side surface 1523 and the fourth side surface 1524 may also be coplanar.
It can be known from a drop test of the circuit board assembly that, solder balls close to a periphery of the circuit board usually bear relatively large mechanical and environmental stresses, and solder balls close to the center of the circuit board usually bear relatively small mechanical and environmental stresses. Solder is formed on a side wall, so that a solder ball closest to the periphery of the circuit board can also be protected to some extent, thereby delaying breakdown of the circuit board assembly. In addition, a spacing between adjacent circuit boards hardly affects formation of the sidewall solder. Therefore, in a case in which electrical properties of the circuit board assembly are not affected, a volume of the sidewall solder may be relatively large, so that relatively high connection strength can be implemented, and mechanical and environmental reliability of the circuit board assembly can be improved. In addition, compared with the circuit board assembly 300 shown in
With reference to the embodiment shown in
The circuit board assembly 1900 may include a plurality of circuit boards and a plurality of electronic components electrically connected to the circuit boards. The plurality of PCBs include a mainboard 1901, a frame board 1902, and a daughterboard 1903. The frame board 1902 may include vias 1933 for accommodating the electronic components. The daughterboard 1903 may be a pad land grid array (land grid array, LGA). The mainboard 1901, the frame board 1902, and the daughterboard 1903 are fastened together by using solder balls 1920, and the frame board 1902 is located between the mainboard 1901 and the daughterboard 1903. A drum pattern in
The plurality of electronic components electrically connected to the plurality of PCBs may include, for example, an SOC component 1911, a DDR memory 1912, a primary PMU 1913, an RF IC 1914, an RF PA 1915, a Wi-Fi chip 1916, a secondary PMU 1918, and a secondary PMU 1919. The SOC component 1911 may be stacked with the DDR memory 1912 to form a POP component 1917. A substrate 1904 of the POP component 1917 may be fastened, by using the solder balls 1920, on a side that is of the mainboard 1901 and away from the frame board 1902. The primary PMU 1913 may be fastened, by using the solder balls 1920, on a side that is of the mainboard 1901 and close to the frame board 1902, and extends into the via 1933 of the frame board 1902. All of the RF IC 1914, the RF PA 1915, and the Wi-Fi chip 1916 may be fastened, by using the solder balls 1920, on a side that is of the daughterboard 1903 and away from the mainboard 1901.
Optionally, the mainboard 1901 further includes a horizontal pad 1931 and a horizontal pad 1932. The frame board 1902 further includes a pad 1961 and a pad 1962. The pad 1961 may include a sidewall pad 1951, a horizontal pad 1935, and a horizontal pad 1937. The horizontal pad 1935 is located on a side that is of the frame board 1902 and close to the mainboard 1901, and the horizontal pad 1937 is located on a side that is of the frame board 1902 and close to the daughterboard 1903. The pad 1962 may include a sidewall pad 1952, a horizontal pad 1936, and a horizontal pad 1938. The horizontal pad 1936 is located on the side that is of the frame board 1902 and close to the mainboard 1901, and the horizontal pad 1938 is located on the side that is of the frame board 1902 and close to the daughterboard 1903. Sidewall solder 1971 may be adhered to the horizontal pad 1931, the sidewall pad 1951, and the horizontal pad 1935, and sidewall solder 1972 may be adhered to the horizontal pad 1932, the sidewall pad 1952, and the horizontal pad 1936, to enhance reliability of a connection between the mainboard 1901 and the frame board 1902.
Optionally, the daughterboard 1903 further includes a pad 1965 and a pad 1966. The pad 1965 may include a sidewall pad 1955 and a horizontal pad 1939. The pad 1966 may include a sidewall pad 1956 and a horizontal pad 1940. Sidewall solder 1973 may be adhered to the sidewall pad 1951, the horizontal pad 1937, the sidewall pad 1955, and the horizontal pad 1939, and sidewall solder 1974 may be adhered to the sidewall pad 1952, the horizontal pad 1938, the sidewall pad 1956, and the horizontal pad 1940, to enhance reliability of a connection between the frame board 1902 and the daughterboard 1903.
Optionally, the mainboard 1901 further includes a horizontal pad 1933 and a horizontal pad 1934. The substrate 1904 of the POP component 1917 further includes a pad 1967 and a pad 1968. The pad 1967 may include a sidewall pad 1957 and a horizontal pad 1941, and the pad 1968 may include a sidewall pad 1958 and a horizontal pad 1942. Sidewall solder 1975 may be adhered to the horizontal pad 1933, the sidewall pad 1957, and the horizontal pad 1941, and sidewall solder 1976 may be adhered to the horizontal pad 1934, the sidewall pad 1958, and the horizontal pad 1942, to enhance reliability of a connection between the mainboard 1901 and the POP component 1917.
It should be noted that the sidewall pad 1951, the horizontal pad 1935, and the horizontal pad 1937 that are disposed on the frame board 1902 may form a complete pad 1961. The sidewall pad 1952, the horizontal pad 1936, and the horizontal pad 1938 that are disposed on the frame board 1902 may form a complete pad 1962. In addition, the pad 1961 and the pad 1962 may wrap a periphery of the frame board 1902, which helps shield an electromagnetic signal of the PMU 1913.
An example in
The circuit board assembly 1900 may further include a screw hole 1981, a screw hole 1982, a screw hole 1983, and a screw hole 1984. The screw hole 1981, the screw hole 1982, the screw hole 1983, and the screw hole 1984 are respectively located at four corners of the frame board 1902. Therefore, the circuit board assembly 1900 may further include a plurality of screws (not shown in
The solder ball may be formed by using a conventional soldering technology. It can be learned from the examples shown in
2001: An electroplating step, including: electroplating a first side surface of a first circuit board with a first sidewall pad.
Optionally, the electroplating step further includes: electroplating a second side surface of a second circuit board with a second sidewall pad. The second sidewall pad is located at a position close to the first sidewall pad, and the second side surface and the first side surface are disposed in parallel to each other, and are located on a same side of the circuit board assembly.
Optionally, the electroplating step further includes: electroplating a third side surface of a first circuit board with a third sidewall pad.
Optionally, the electroplating step further includes: electroplating a fourth side surface of the second circuit board with a fourth sidewall pad. The fourth sidewall pad is located at a position close to the third sidewall pad, and the fourth side surface and the third side surface are disposed in parallel to each other, and are located on a same side of the circuit board assembly.
Optionally, the electroplating step further includes: electroplating a first horizontal plane of the first circuit board with a first horizontal pad. The first horizontal plane is a horizontal plane that is of the first circuit board and close to the second circuit board.
Optionally, the electroplating step further includes: electroplating a second horizontal plane of the second circuit board with a second horizontal pad. The second horizontal plane is a horizontal plane that is of the second circuit board and close to the first circuit board, and the second horizontal pad is located at the position close to the first sidewall pad.
Optionally, the electroplating step further includes: electroplating the first horizontal plane of the first circuit board with a third horizontal pad. The first horizontal plane is the horizontal plane that is of the first circuit board and close to the second circuit board, and the third horizontal pad is located at the position close to the third sidewall pad.
Optionally, the electroplating step further includes: electroplating the second horizontal plane of the second circuit board with a fourth horizontal pad. The second horizontal plane is the horizontal plane that is of the second circuit board and close to the first circuit board, and the fourth horizontal pad is located at a position close to the fourth sidewall pad.
Optionally, the electroplating step further includes: electroplating the first sidewall pad to form a sidewall groove.
Optionally, the electroplating step further includes: electroplating the second sidewall pad to form a sidewall groove.
Optionally, the electroplating step further includes: electroplating the third sidewall pad to form a sidewall groove.
Optionally, the electroplating step further includes: electroplating the fourth sidewall pad to form a sidewall groove.
Optionally, the electroplating step further includes: electroplating the first horizontal pad to form a horizontal groove.
Optionally, the electroplating step further includes: electroplating the second horizontal pad to form a horizontal groove.
Optionally, the electroplating step further includes: electroplating the third horizontal pad to form a horizontal groove.
Optionally, the electroplating step further includes: electroplating the fourth horizontal pad to form a horizontal groove.
2002: A soldering step, including: soldering the first circuit board to the second circuit board, and performing soldering between the first sidewall pad and the second circuit board to form first sidewall solder.
Optionally, the soldering step further includes: performing soldering between the first sidewall pad and the second sidewall pad to form the first sidewall solder.
Optionally, the soldering step further includes: performing soldering between the first sidewall pad and the second horizontal pad to form the first sidewall solder.
Optionally, the soldering step further includes: performing soldering among the first sidewall pad, the first horizontal pad, and the second sidewall pad to form the first sidewall solder.
Optionally, the soldering step further includes: performing soldering among the first sidewall pad, the first horizontal pad, the second sidewall pad, and the second horizontal pad to form the first sidewall solder.
Optionally, the soldering step further includes: performing soldering between the third sidewall pad and the fourth sidewall pad to form second sidewall solder.
Optionally, the soldering step further includes: performing soldering among the third sidewall pad, the third horizontal pad, and the fourth sidewall pad to form the second sidewall solder.
Optionally, the soldering step further includes: performing soldering among the third sidewall pad, the third horizontal pad, the fourth sidewall pad, and the fourth horizontal pad to form the second sidewall solder.
The circuit board assemblies shown in
The circuit board assembly 2100 may include a first circuit board 2101 and a second circuit board 2102. The first circuit board 2101 may be fastened to the second circuit board 2102 by using solder balls 2111. In an example, the first circuit board 2101 may be, for example, the frame board 202 in
The first circuit board 2101 includes a first side surface 2121. The second circuit board 2102 may include a first groove 2131. The first groove 2131 is disposed on a second horizontal plane 2104 that is of the second circuit board 2102 and close to the first circuit board 2101, and is located at a position close to the first side surface 2121. The circuit board assembly 2100 may include a filling material 2112. The filling material 2112 may be adhered between the first groove 2131 and the first circuit board 2101. Therefore, the first groove 2131 may accommodate the filling material 2112.
Similarly, the first circuit board 2101 includes a second side surface 2122. The second circuit board 2102 may include a second groove 2132. The second groove 2132 is disposed on the second horizontal plane 2104 that is of the second circuit board 2102 and close to the first circuit board 2101, and is located at a position close to the second side surface 2122. The filling material 2112 may be adhered between the second groove 2132 and the first circuit board 2101.
It should be noted that a side surface of a circuit board may refer to a surface disposed in parallel to a height direction of the circuit board. For example, a frame board is a circuit board. The frame board may include a via for disposing an electronic component. A side surface of the frame board may include an inner wall of the via, and may further include an outer peripheral surface of the frame board. A surface perpendicular to the height direction of the circuit board may be referred to as a horizontal plane of the circuit board. The circuit board may include an upper horizontal plane and a lower horizontal plane. The horizontal plane of the circuit board may be used to carry another circuit board or electronic component.
It should be noted that, in the example shown in
It can be known from a drop test of the circuit board assembly that, solder balls close to a periphery of the circuit board usually bear relatively large mechanical and environmental stresses, and solder balls close to the center of the circuit board usually bear relatively small mechanical and environmental stresses. The filling material is disposed on a side surface of a circuit, so that a solder ball closest to a periphery of the circuit board can also be protected to some extent, thereby delaying breakdown of the circuit board assembly. In addition, a groove is disposed, so that a contact area between the filling material and the circuit board can be increased, and a total adhesion volume of the filling material can be increased. This can implement relatively high connection strength, and helps improve mechanical and environmental reliability of the circuit board assembly.
It should be noted that the first groove 2131 may include a bottom surface 2191 and a groove wall 2192. The bottom surface 2191 is disposed in parallel to the second horizontal plane 2104 of the second circuit board 2102, and the groove wall 2192 may be connected between the bottom surface 2191 and the second horizontal plane 2104. As shown in
It can be learned from the embodiment shown in
The circuit board assembly 3100 may include a plurality of circuit boards and a plurality of electronic components electrically connected to the circuit boards. The plurality of PCBs include a mainboard 3101, a frame board 3102, and a daughterboard 3103. The frame board 3102 may include vias 3133 for accommodating the electronic components. The daughterboard 3103 may be a pad land grid array (land grid array, LGA). The mainboard 3101, the frame board 3102, and the daughterboard 3103 are fastened together by using solder balls 3140, and the frame board 3102 is located between the mainboard 3101 and the daughterboard 3103. A drum pattern in
The plurality of electronic components electrically connected to the plurality of PCBs may include, for example, an SOC component 3111, a DDR memory 3112, a primary PMU 3113, an RF IC 3114, an RF PA 3115, a Wi-Fi chip 3116, a secondary PMU 3118, and a secondary PMU 3119. The SOC component 3111 may be stacked with the DDR memory 3112 to form a POP component 3117. A substrate 3104 of the POP component 3117 may be fastened, by using the solder balls 3140, on a side that is of the mainboard 3101 and away from the frame board 3102. The PMU 3113 may be fastened, by using the solder balls 3140, on a side that is of the mainboard 3101 and close to the frame board 3102, and extends into the via 3133 of the frame board 3102. All of the RF IC 3114, the RF PA 3115, and the Wi-Fi chip 3116 may be fastened, by using the solder balls 3140, on a side that is of the daughterboard 3103 and away from the mainboard 3101.
Optionally, the mainboard 3101 further includes a groove 3121 and a groove 3122.
The frame board 3102 further includes a groove 3123 and a groove 3124. Reliability of a connection between the mainboard 3101 and the frame board 3102 may be enhanced by adhering a filling material 3141 between the groove 3121 and the groove 3123 and adhering the filling material 3141 between the groove 3122 and the groove 3124. Optionally, a capacitor 3151 may be disposed in the groove 3121. Optionally, a capacitor 3152 may be disposed in the groove 3122. Optionally, a capacitor 3153 may be disposed in the groove 3123. Optionally, a capacitor 3154 may be disposed in the groove 3124. A size of the mainboard 3101 is generally slightly larger than a size of the frame board 3102. Therefore, optionally, a groove on the mainboard 3101 may include a bottom surface and a groove wall, the groove wall surrounds a periphery of the bottom surface, and the groove wall is connected between the bottom surface and a horizontal plane of the mainboard 3101. A groove on the frame board 3102 may include a bottom surface and a groove wall, the groove wall is located on one side of the bottom surface, and the groove wall is connected between the bottom surface and a horizontal plane of the frame board 3102.
Optionally, the frame board 3102 further includes a groove 3125 and a groove 3126. The daughterboard 3103 further includes a groove 3127 and a groove 3128. Reliability of a connection between the frame board 3102 and the daughterboard 3103 may be enhanced by adhering the filling material 3141 between the groove 3125 and the groove 3127 and adhering the filling material 3141 between the groove 3126 and the groove 3128. Optionally, a capacitor 3155 may be disposed in the groove 3125. Optionally, a capacitor 3156 may be disposed in the groove 3126. Optionally, a capacitor 3157 may be disposed in the groove 3127. Optionally, a capacitor 3158 may be disposed in the groove 3128.
Optionally, the mainboard 3101 further includes a groove 3129 and a groove 3130. The substrate 3104 of the POP component 3117 further includes a groove 3131 and a groove 3132. Reliability of a connection between the mainboard 3101 and the POP component 3117 may be enhanced by adhering the filling material 3141 between the groove 3129 and the groove 3131 and adhering the filling material 3141 between the groove 3130 and the groove 3132. Optionally, a capacitor 3159 may be disposed in the groove 3129. Optionally, a capacitor 3160 may be disposed in the groove 3130. Optionally, a capacitor 3161 may be disposed in the groove 3131. Optionally, a capacitor 3162 may be disposed in the groove 3132.
It should be noted that a groove 3223 and a groove 3224 for adhering a filling material are disposed on a side that is of the frame board 3202 and away from the daughterboard 3203, as shown in
In a first aspect, a mainboard 3301 further includes a horizontal pad 3331 and a groove 3321. A frame board 3302 further includes a pad 3361 and a groove 3322. The pad 3361 may include a sidewall pad 3332 and a horizontal pad 3333. Sidewall solder 3371 may be adhered to the horizontal pad 3331, the sidewall pad 3332, and the horizontal pad 3333, and a filling material 3320 may be adhered to the groove 3321 and the groove 3322, to enhance reliability of a connection between the mainboard 3301 and the frame board 3302. Optionally, a capacitor 3351 may be disposed in the groove 3321. Optionally, a capacitor 3352 may be disposed in the groove 3322. A size of the mainboard 3301 is generally slightly larger than a size of the frame board 3302. Therefore, optionally, a groove on the mainboard 3301 may include a bottom surface and a groove wall, the groove wall surrounds a periphery of the bottom surface, and the groove wall is connected between the bottom surface and a horizontal plane of the mainboard 3301. A groove on the frame board 3302 may include a bottom surface and a groove wall, the groove wall is located on one side of the bottom surface, and the groove wall is connected between the bottom surface and a horizontal plane of the frame board 3302.
In a second aspect, the frame board 3302 further includes a pad 3362 and a groove 3323. The pad 3362 may include a sidewall pad 3334 and a horizontal pad 3335. A daughterboard 3303 further includes a pad 3363 and a groove 3324. The pad 3363 may include a sidewall pad 3336 and a horizontal pad 3337. Sidewall solder 3372 may be adhered to the sidewall pad 3334, the horizontal pad 3335, the sidewall pad 3336, and the horizontal pad 3337, and the filling material 3320 may be adhered to the groove 3323 and the groove 3324, to enhance reliability of a connection between the frame board 3302 and the daughterboard 3303. Optionally, a capacitor 3353 may be disposed in the groove 3323. Optionally, a capacitor 3354 may be disposed in the groove 3324.
In a third aspect, a mainboard 3301 further includes a horizontal pad 3338 and a groove 3325. A substrate 3304 of a POP component 3317 further includes a pad 3364 and a groove 3326. The pad 3364 may include a sidewall pad 3339 and a horizontal pad 3340. Sidewall solder 3373 may be adhered to the horizontal pad 3338, the sidewall pad 3339, and the horizontal pad 3340, and the filling material 3320 may be adhered to the groove 3325 and the groove 3326, to enhance reliability of a connection between the mainboard 3301 and the POP component 3317. Optionally, a capacitor 3355 may be disposed in the groove 3325. Optionally, a capacitor 3356 may be disposed in the groove 3326.
It should be noted that the pad 3361 and the pad 3362 disposed on the frame board 3302 are two different pads. Therefore, random flow of sidewall solder on a side surface of the frame board 3302 can be limited, to improve shape consistency of the sidewall solder.
The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.
Number | Date | Country | Kind |
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201911317190.9 | Dec 2019 | CN | national |
This application is a National Stage of International Application No. PCT/CN2020/124790, filed on Oct. 29, 2020, which claims priority to Chinese Patent Application No. 201911317190.9, filed on Dec. 19, 2019, both of which are hereby incorporated by reference in their entireties
Filing Document | Filing Date | Country | Kind |
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PCT/CN2020/124790 | 10/29/2020 | WO |