Circuit board assembly and communication device

Abstract

The present application relates to the technical field of communications, and specifically relates to a circuit board assembly and a communication device. The circuit board assembly comprises: a substrate; a circuit board, a gap being present between the substrate and the circuit board; a soldering structure, the soldering structure being located in the gap and connected to the substrate and the circuit board, wherein the soldering structure comprises a plurality of first soldering structures and a plurality of second soldering structures, the plurality of first soldering structures and the plurality of second soldering structures have one-to-one correspondence, and a partition member is arranged between each corresponding first soldering structure and second soldering structure so as to separate the corresponding first soldering structure from the corresponding second soldering structure; and a plurality of connecting members, wherein the plurality of connecting members can be supported between the substrate and the partition members and / or between the circuit board and the partition members. The circuit board assembly of the present application can overcome the soldering defects of solder bridge and open solder in the soldering process.

Description

Circuit board assembly and communication equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 24, 2023, with application number 202310917920.9 and application name “A circuit board assembly and communication equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a circuit board assembly and communication equipment. Background Art

[0003] Currently, surface mount technology (SMT) packaging has become a packaging form with great development potential. SMT packaging can be grid array (GA) packaging, which includes pin grid array (PGA) packaging and ball grid array (BGA) packaging. Among them, BGA packaging is the main chip packaging form in the current ICT industry, and the package and the circuit board (such as the printed circuit board, PCB) are usually soldered together using a ball planting and tin printing method. The ball planting method between the package and the circuit board uses a single solder ball structure, that is, a solder point on the package is soldered to a solder point on the circuit board to form a solder ball structure.

[0004] Due to the complexity of the package structure and the materials used, differences in the coefficient of thermal expansion (CTE) between different materials will affect the allowable combined deformation range of the package body and the circuit board. In other words, the tolerance of the solder balls between the package and the circuit board. Solder joints that exceed the solder ball tolerance will result in bridging and open soldering.

[0005] With the development of ICT equipment specifications, chip package sizes have increased significantly in recent years, with the industry trending towards single packages exceeding the target size of 100mm×100mm. As chip sizes increase, the die, fan-out package (FoP), and package dimensions within a single package are rapidly expanding. This results in significantly increased deformation of the die, FoP, and package under varying temperatures. Large, fine-pitch area array packages, in particular, are prone to insufficient tolerance when using conventional soldering methods (single-ball structures) with soldering. This increases the risk of quality defects at all levels of the assembly process, such as solder bridging or open solder joints.

[0006] Therefore, the conventional soldering method of ball planting and tin printing can no longer meet the welding requirements of large deformation. How to improve the tolerance of the solder balls between the package and the circuit board to achieve large-size and fine-pitch area array packages and circuit boards with large tolerance has become an urgent problem that needs to be solved.

[0007] Summary of the Invention

[0008] The embodiments of the present application provide a circuit board assembly and communications equipment that can address the issues of solder bridging and open solder joints between the package and the circuit board, which arise from the increasing thermal deformation of the chip as the chip size increases. The following describes the present application from multiple aspects, and the implementation methods and beneficial effects of the following aspects can be referenced in conjunction with each other.

[0009] In a first aspect, the present application provides a circuit board assembly. The specific circuit board assembly includes: a substrate; a circuit board, with a gap between the substrate and the circuit board; a soldering structure, located in the gap and providing electrical connection between the substrate and the circuit board; wherein the soldering structure includes a plurality of first soldering structures and a plurality of second soldering structures, the plurality of first soldering structures and the plurality of second soldering structures corresponding one to one, with a separator provided between each corresponding first soldering structure and second soldering structure to separate the corresponding first soldering structure from the second soldering structure; and a plurality of connectors, the plurality of connectors being capable of supporting between the substrate and the separator and / or between the circuit board and the separator.

[0010] The above-mentioned circuit board assembly introduces a new welding structure in the gap between the substrate (for example, including a BGA package) and the circuit board (for example, a printed circuit board, PCB), improves the traditional single-ball structure into a double-sided welding module (including a first welding structure and a second welding structure), and introduces a separator separating the first welding structure and the second welding structure of the double-sided welding module; the comprehensive thermal deformation of the substrate (for example, including a BGA package) and the circuit board (for example, a printed circuit board, PCB) can be decomposed into two parts, reducing the welding process capability required for the single-sided solder joint, improving the overall welding tolerance capability of the overall welding structure, preventing the problems of bridging and open soldering caused by the increase in the degree of thermal deformation of the chip with the increase in chip size during the welding process, and realizing large-tolerance assembly of large-size and fine-pitch area array packages (i.e., substrates) and circuit boards.

[0011] In addition, the circuit board assembly of the embodiment of the present application further includes a connector (also referred to as a spacer) supported between the substrate and the separator and / or between the circuit board and the separator. For example, the connector is supported between the substrate and the separator; or, the connector is supported between the circuit board and the separator; or, the connector is supported between the substrate and the separator, and also between the circuit board and the separator. Exemplarily, the connector is a metal post.

[0012] The functions of the connector include the following two: one is to control the minimum weld height, that is, to control the minimum weld height between the separator and the substrate (for example, the height of the weld at the two side edges and the middle position of the circuit board assembly), and the minimum weld height between the separator and the circuit board (for example, the height of the weld at the two side edges and the middle position of the circuit board assembly) to ensure that there will be no bridging during the welding process; the other function is to adjust the shape of the double-sided solder ball module by adjusting the thickness of the connector at the two side edges and the center of the circuit board assembly, so that the deformation trend of the separator matches the deformation trend of the substrate (for example, the substrate), so that the separator is located in the center of the substrate and the circuit board, and the solder ball tolerance capability is higher.

[0013] In a possible implementation of the first aspect, there is one separator, the multiple first welding structures and the multiple second welding structures share one separator, and the separator is deformable under the welding temperature environment.

[0014] It can be understood that by providing a separator between the first welding structure and the second welding structure, the comprehensive large thermal deformation of the substrate and the circuit board can be decomposed into two parts: the thermal deformation of the first part is the thermal deformation between the separator and the substrate, and the thermal deformation of the second part is the thermal deformation between the separator and the circuit board, so as to reduce the welding process capability required for the welding structure of either part of the two parts, improve the tolerance capability of the solder balls of the first welding structure or the second welding structure, and thus improve the tolerance capability of the solder balls of the overall welding structure. In addition, the separator of the embodiment of the present application can be made of rigid material or flexible material, and the separator can be deformed in a welding temperature environment (for example, 200°C to 245°C). Thus, the separator has a certain flexibility at high temperature, and the comprehensive thermal deformation of the substrate and the circuit board is matched by matching connectors of different thicknesses. For example, the thermal expansion coefficient of the separator needs to be between that of the substrate and the circuit board, so as to center the gap between the separator and the circuit board, decompose the comprehensive large thermal deformation of the coupling between the substrate and the circuit board into small thermal deformations of the upper and lower parts, and achieve the effect of large deformation welding.

[0015] In a possible implementation of the first aspect, there are at least two separators, and at least two first welding structures and two second welding structures are respectively provided on two sides of each separator.

[0016] It can be understood that the separator is divided, and each divided separator corresponds to a separation area. There are multiple first welding structures and multiple second welding structures in each separation area. After the cutting is completed, the degree of freedom of each separation area is higher, and the thermal expansion coefficient of the separator itself has less influence on the comprehensive thermal deformation of the substrate and the circuit board, which is conducive to improving the tolerance capability of the solder balls of the overall welding structure.

[0017] The embodiments of the present application do not limit the number of separators and the number of welding structures corresponding to each separator. For example, the number of separators includes four, or sixteen, and each separation area includes sixteen first welding structures and second welding structures, or four first welding structures and second welding structures.

[0018] In a possible implementation of the first aspect, a plurality of connectors are supported between the substrate and the separator and between the circuit board and the separator.

[0019] In one possible implementation of the first aspect, the connectors are distributed in the center region and / or edge region of the separator. Specifically, the connectors are distributed in both the center region and edge region of the separator; or, the connectors are distributed in the center region of the separator; or, the connectors are distributed in the edge region of the separator.

[0020] In a possible implementation of the first aspect above, two ends of the connector supported between the substrate and the separator are respectively connected to the separator and the substrate; two ends of the connector supported between the circuit board and the separator are respectively connected to the separator and the circuit board.

[0021] In a possible implementation of the first aspect, there are multiple separators, two adjacent separators are spaced apart, and a separator is provided between each corresponding first welding structure and second welding structure.

[0022] In a possible implementation of the first aspect, the first welding structure and the second welding structure are respectively provided with connecting pieces. For example, the connecting pieces are integrated with the first welding structure and the second welding structure.

[0023] In a possible implementation of the first aspect, two ends of the connector in the first welding structure are respectively connected to the separator and the substrate, and two ends of the connector in the second welding structure are respectively connected to the separator and the circuit board.

[0024] In a possible implementation of the first aspect above, a plurality of connectors are supported between the substrate and the separator; wherein each connector is supported between the first welding structure and the separator, and the heights of at least some of the connectors between the substrate and the separator are unequal so as to conform to the lower surface of the substrate. By constructing connectors with a certain gradient difference on the separator plate, conformation to the lower surface of the substrate is achieved. That is, the embodiment of the present application constructs a correction module (a connector with a certain gradient difference) on the separator to convert a large-scale deformation of the substrate (for example, including a chip) into a small-scale deformation or no deformation, thereby ensuring the welding of the substrate on the substrate with large thermal deformation. Exemplarily, the gradient difference of the connector in the embodiment of the present application is designed according to the deformation of the substrate.

[0025] In one possible implementation of the first aspect described above, the side of the separator proximal to the substrate is shaped like the lower surface of the substrate. Exemplarily, the upper surface of the separator is pre-formed by grinding to create the same deformation as the substrate. That is, in this embodiment of the application, the separator is processed to create an orthopedic module. Exemplarily, the lower side of the orthopedic module is flat. That is, the lower side of the separator (the surface facing the circuit board) is flat.

[0026] In a possible implementation of the first aspect, a plurality of connectors are supported between the circuit board and the separator; wherein the connectors are distributed in an edge area of ​​the separator, and two ends of the connectors are respectively connected to the separator and the circuit board.

[0027] In a possible implementation of the first aspect above, the first welding structure includes a first welding pad and a first solder ball provided on the substrate, and the second welding structure includes a second welding pad and a second solder ball provided on the circuit board; wherein, the first welding pad is located on the substrate, the first solder ball is electrically connected to the first welding pad, and the second welding pad is located on the circuit board, and the second solder ball is electrically connected to the second welding pad.

[0028] In one possible implementation of the first aspect, the pitch of the plurality of first soldering structures is less than 0.5 mm, and the pitch of the plurality of second soldering structures is less than 0.5 mm. That is, the circuit board assembly in the embodiment of the present application has a fine-pitch structure. However, the specific value of the pitch of the soldering structures in the present application is not limited and may also be other values, for example, greater than or equal to 0.5 mm.

[0029] In a possible implementation of the first aspect, the separator is provided with a plurality of through holes, an inner wall of each through hole is provided with a conductive medium, and the corresponding first welding structures are connected to the second welding structures through the conductive medium.

[0030] In a possible implementation of the first aspect, the substrate includes a package, and the package is a ball grid array (BGA) package.

[0031] In one possible implementation of the first aspect above, the package has a size of 40 mm × 40 mm or larger. That is, the circuit board assembly in the embodiment of the present application is a large-size package structure. However, the size of the package in the present application is not limited and may be other sizes, such as 50 mm × 50 mm, or 40 mm × 40 mm or smaller.

[0032] The second aspect of the present application provides another circuit board assembly, which includes a substrate; a circuit board, with a gap between the substrate and the circuit board; a welding structure, which is located in the gap and conducts electricity between the substrate and the circuit board; wherein the welding structure includes a plurality of first welding structures and a plurality of second welding structures, the plurality of first welding structures and the plurality of second welding structures correspond one to one, and each corresponding first welding structure and second welding structure shares a connecting member, and the connecting member connects the first welding structure and the second welding structure.

[0033] In the embodiments of the present application, a connector (e.g., a metal needle) is used to connect a first solder structure (e.g., a liquid solder ball that becomes a solid solder ball after soldering) and a second solder structure (e.g., a liquid solder ball that becomes a solid solder ball after soldering) to achieve a connection between a substrate and a circuit board. The wetting force between the connector and the liquid solder ball improves soldering tolerance. During the soldering process, as the temperature rises, the substrate (e.g., with a chip) will undergo thermal deformation. When the solder ball reaches the liquidus and melts, the concave area of ​​the substrate will penetrate the liquid solder ball and support it on the circuit board. The upturned area of ​​the substrate will form an elongated solder joint due to the wettability of the liquid solder ball and the metal needle, which also prevents the solder structure from bridging and opening during the soldering process.

[0034] In a possible implementation of the second aspect, the connecting member includes a metal needle.

[0035] In a possible implementation of the second aspect above, the first welding structure includes a first welding pad and a first solder ball provided on the substrate, and the second welding structure includes a second welding pad and a second solder ball provided on the circuit board; wherein, the first welding pad is located on the substrate, the first solder ball is electrically connected to the first welding pad, and the second welding pad is located on the circuit board, and the second solder ball is electrically connected to the second welding pad.

[0036] In a possible implementation of the second aspect, the substrate includes a package, and the package is a ball grid array (BGA) package.

[0037] In a possible implementation of the second aspect, the size of the package is 40 mm×40 mm or larger.

[0038] A third aspect of the present application provides another circuit board assembly, comprising a substrate; a circuit board, with a gap between the substrate and the circuit board; and a soldering structure located in the gap and electrically connecting the substrate and the circuit board; wherein the soldering structure comprises at least two stacked electroplating layers. In embodiments of the present application, the electroplating structure is electroplated multiple times on the upper base side to form a multilayer electroplating layer, thereby increasing the amount of tin in the solder joints, improving the soldering tolerance, achieving high-tolerance soldering, and preventing problems such as bridging and open soldering during the soldering process.

[0039] In a possible implementation of the third aspect above, the electroplating layer includes a first electroplating layer and a second electroplating layer, and the first electroplating layer and the second electroplating layer are spaced apart along the height direction; wherein, the outermost electroplating layer away from the substrate among the at least two stacked electroplating layers is the second electroplating layer, and the height direction is a direction perpendicular to the plane where the surface of the substrate is located.

[0040] In a possible implementation of the third aspect above, the welding structure further includes a barrier layer, and the barrier layer is provided between the first electroplating layer and the second electroplating layer.

[0041] In one possible implementation of the third aspect, the first electroplated layer includes Cu, the second electroplated layer includes Sn / SnAg, and the barrier layer includes Ni. The electroplated Cu acts as a spacer to control the minimum weld height and prevent soldering during the welding process.

[0042] In a possible implementation of the third aspect, the substrate includes a package, and the package is a ball grid array (BGA) package.

[0043] In a possible implementation of the third aspect, the size of the package is 40 mm×40 mm or larger.

[0044] A fourth aspect of the present application provides another communication device, comprising the circuit board assembly according to the first, second, and third aspects, as well as any possible implementations of the first, second, and third aspects, wherein the circuit board assembly is mounted within a housing of the communication device. For example, a slot is provided within the housing of the communication device, and a circuit board in the circuit board assembly is plugged into the slot within the housing to achieve electrical connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic structural diagram of a welding structure of a circuit board assembly in some embodiments;

[0046] FIG2 is a schematic diagram illustrating the tolerance capability of the soldering structure of a circuit board assembly in some embodiments, wherein FIG2(a) illustrates the tolerance capability of the soldering boundary of a single solder ball, and FIG2(b) illustrates the tolerance capability of the soldering boundary of a single solder ball;

[0047] FIG3 is a structural diagram 1 of the welding structure of the circuit board assembly provided in the first embodiment of the present application;

[0048] FIG4 is a schematic diagram showing the tolerance capability of the soldering structure of the circuit board assembly provided in the first embodiment of the present application;

[0049] FIG5 is a second structural diagram of the welding structure of the circuit board assembly provided in the first embodiment of the present application;

[0050] FIG6 (a) to (c) are process flow chart 1 of the soldering structure of the circuit board assembly provided in the first embodiment of the present application;

[0051] FIG. 7 (a) to (c) are a second process flow chart of the soldering structure of the circuit board assembly provided in the first embodiment of the present application;

[0052] FIG8 (a) and (b) are process flow chart 3 of the soldering structure of the circuit board assembly provided in the first embodiment of the present application;

[0053] FIG9 is a second structural diagram of the welding structure of the circuit board assembly provided in the second embodiment of the present application;

[0054] FIG10a is a first structural diagram of multiple separators of a welding structure of a circuit board assembly provided in a second embodiment of the present application;

[0055] FIG10 b is a second structural diagram of multiple separators of the welding structure of the circuit board assembly provided by the second embodiment of the present application;

[0056] FIG11 is a third structural diagram of the welding structure of the circuit board assembly provided in the second embodiment of the present application;

[0057] FIG12 is a third structural diagram of multiple separators of the welding structure of the circuit board assembly provided in the second embodiment of the present application;

[0058] FIG13 (a) to (g) are process flow charts of the soldering structure of the circuit board assembly provided in the second embodiment of the present application;

[0059] FIG14 is a structural diagram 1 of a welding structure of a circuit board assembly provided in a third embodiment of the present application;

[0060] FIG15 (a) to (d) are process flow chart 1 of the soldering structure of the circuit board assembly provided in the third embodiment of the present application;

[0061] FIG16 is a second structural diagram of the welding structure of the circuit board assembly provided in the third embodiment of the present application;

[0062] FIG17 (a) to (d) are a second process flow chart of the soldering structure of the circuit board assembly provided in the third embodiment of the present application;

[0063] FIG18 is a schematic structural diagram of a welding structure of a circuit board assembly provided in a fourth embodiment of the present application;

[0064] FIG19 (a) to (h) are process flow charts of the soldering structure of a circuit board assembly provided in the fourth embodiment of the present application;

[0065] FIG20 is a schematic structural diagram of a welding structure of a circuit board assembly provided in a fifth embodiment of the present application;

[0066] Figure 21 (a) to (i) are process flow charts of the welding structure of the circuit board assembly provided in the fifth embodiment of the present application. DETAILED DESCRIPTION

[0067] An embodiment of the present application provides a circuit board assembly including a substrate, a circuit board, and a welding structure, wherein the welding structure between the substrate and the circuit board is a double-sided solder ball structure, which replaces the traditional single-solder ball welding structure between the substrate and the circuit board. The double-sided solder ball structure improves the welding tolerance capability of the welding structure and solves the problems of bridging and open welding caused by the combined large thermal deformation of the coupling of the substrate and the circuit board during the welding process of the circuit board assembly.

[0068] The circuit board assembly provided in the embodiments of the present application is applied to communication equipment, which may include, but is not limited to, ICT (Information Communication Technology) such as base stations, servers, routers, switches, supercomputers, AI devices, and data centers. The circuit board assembly can be understood as a board-level assembly structure formed by assembling a packaging structure onto a carrier.

[0069] Among them, the circuit board assembly of the embodiment of the present application includes an assembly structure formed by assembling any package or structural part in the form of BGA (Bail Grid Array, BGA) to a carrier (such as the circuit board described later). For example, the package and structural part in the form of BGA can also be a BGA socket. Among them, the size of the package includes 14mm×14mm, or large size (40mm×40mm and above, such as 40mm×40mm, 50mm×50mm) large deformation surface array package. The circuit board assembly of the embodiment of the present application can also be applied to the assembly of other large deformation welding devices, such as large-size connectors, large deformation castle boards and LGA (Land Grid Array, grid array package) and other scenarios.

[0070] The present application uses a BGA package or structural component as an example for illustration. Referring to FIG1 , FIG1 illustrates a schematic diagram of a circuit board assembly. As shown in FIG1 , the circuit board assembly includes a substrate 10 and a circuit board 20. Exemplarily, the substrate 10 and the circuit board 20 are positioned relative to each other along the thickness direction of the circuit board assembly.

[0071] Substrate 10 can be understood as the package substrate in the aforementioned package structure. The package substrate is a carrier for semiconductor chip packaging, providing electrical connection, protection, support, heat dissipation, and assembly functions for the chip. The package structure can be formed by, for example, providing I / O (IN / OUT) pins on the back side of substrate 10 for electrical connection to circuit board 20, and packaging electronic devices such as chips on the front side of substrate 10.

[0072] In the embodiments of this application, a BGA package structure is used as an example for illustration. It is understood that a BGA is a surface mount package used in multi-pin LSIs (large-scale integrated circuits) in which spherical contacts are arrayed on the back of a substrate 10 as lead pins, and components such as chips are assembled on the front of the substrate 10.

[0073] The circuit board 20 can be understood as the aforementioned carrier, which can carry the substrate 10 and be assembled with the substrate 10, thereby achieving electrical interconnection with the substrate 10. Exemplarily, the circuit board 20 is a printed circuit board (PCB).

[0074] Exemplarily, the substrate 10 and circuit board 20 are assembled by soldering. Specifically, as shown in FIG1 , a plurality of first solder balls 101 are provided on the surface of the substrate 10 facing the circuit board 20, and a plurality of second solder balls 102 are provided on the surface of the circuit board 20 facing the substrate 10. The plurality of first solder balls 101 and the plurality of second solder balls 102 are provided in a one-to-one correspondence. Exemplarily, the first solder balls 101 are the spherical contacts described above that can serve as lead pins.

[0075] Typically, when soldering and assembling a substrate 10 and a circuit board 20, a first solder ball 101 and a second solder ball 102 are soldered together to form a single solder ball structure (i.e., a single solder ball structure). However, at room temperature, the substrate 10 and circuit board 20 may experience some warping, and this warping may vary with temperature during the soldering process. Figure 1 illustrates a schematic diagram of a soldering defect in a single solder ball structure during the soldering process between the substrate 10 and circuit board 20.

[0076] As shown in FIG. 1 , it is understood that due to the complexity of the packaging structure and the materials used, there are differences in the thermal expansion coefficients of different materials. When the thermal expansion coefficients of different materials are mismatched, the substrate 10 and the circuit board 20 will produce thermal deformation.

[0077] For example, referring to Figure 1, the two side edges of the substrate 10 are warped upward along the height direction (as shown in the X direction in Figure 1), and the two side edges of the circuit board 20 are bent downward along the height direction (as shown in the X direction in Figure 1), so that the gap between the substrate 10 and the circuit board 20 shows a trend of gradually increasing vertical height from the center area (as shown in the dotted line C area in Figure 1) to the edge area (as shown in the dotted line D area in Figure 1), that is, the vertical distance of the center area of ​​the gap between the substrate 10 and the circuit board 20 is the smallest, and the vertical distance of the edge area is the largest.

[0078] It should be noted that the thermal deformation structures of the substrate 10 and circuit board 20 shown in Figure 1 are not unique. For example, the two side edges of the substrate 10 may bend downward along the height direction (as shown in the X direction in Figure 1), while the two side edges of the circuit board 10 may warp upward along the height direction (as shown in the X direction in Figure 1). Alternatively, the two side edges of the substrate 10 and circuit board 20 may warp upward along the height direction (as shown in the X direction in Figure 1), etc.

[0079] During the soldering process between substrate 10 and circuit board 20, insufficient tolerance for a single solder ball structure can lead to a surge in quality risks and increased assembly difficulty, particularly when solder bridging and open solder joints occur simultaneously. Tolerance refers to the combined deformation range of substrate 10 and circuit board 20 that can be tolerated by the solder balls in a single solder ball structure. This value corresponds to the difference between the maximum and minimum solder joint heights. Exceeding the solder ball tolerance can lead to bridging and open solder joints.

[0080] Bridging can be understood as a soldering defect where two adjacent solder joints between the substrate 10 and the circuit board 20 are bridged during the soldering process, which electrically manifests as a short circuit. Open soldering can be understood as a soldering defect where no effective solder joint is formed between the substrate 10 and the circuit board 20, which electrically manifests as an open circuit. As shown in Figure 1, bridging occurs in the center area of ​​the substrate 10 and circuit board 20 (indicated by the dashed line C in Figure 1), and open soldering occurs in the edge areas of the substrate 10 and circuit board 20 (indicated by the dashed line D in Figure 1).

[0081] The following first analyzes the solder ball tolerance capability of a single solder ball structure between the substrate 10 and the circuit board 20 during the soldering process.

[0082] Figure 2 shows a schematic diagram of the tolerance capability analysis of a single solder ball structure. Figure 2 (a) shows a single solder ball structure with the solder ball at the soldering boundary, and Figure 2 (b) shows a single solder ball structure with the solder ball at the open solder boundary. In Figure 2 , dashed line G represents the top surface of circuit board 20, dashed line F represents the bottom surface of substrate 10 when adjacent solder balls are at the soldering boundary, and dashed line E represents the bottom surface of substrate 10 when the solder ball is at the open solder boundary.

[0083] As shown in (a) of Figure 2, when two adjacent solder balls of a single solder ball structure between the substrate 10 and the circuit board 20 are at the soldering boundary, the vertical height of the weld between the substrate 10 and the circuit board 20 reaches the minimum value (as shown by the height Hmin in (a) of Figure 2), that is, the minimum weld height is Hmin1.

[0084] As shown in (b) of Figure 2, when the solder ball of the single solder ball structure between the substrate 10 and the circuit board 20 is at the open soldering boundary, the vertical height of the weld between the substrate 10 and the circuit board 20 reaches the maximum value (as shown by the height Hmax in (b) of Figure 2), that is, the maximum weld height is Hmax1.

[0085] Then, the tolerance capability of the solder ball of the single solder ball structure is ΔH1 = Hmax1 - Hmin1.

[0086] As can be seen, the solder ball tolerance ΔH1 of a single solder ball structure is limited. As chip sizes increase, the thermal deformation of substrates also increases. The solder ball tolerance ΔH1 of a single solder ball structure cannot meet the assembly requirements and soldering quality of PCB assemblies with highly deformed substrates.

[0087] Therefore, the embodiment of the present application introduces a new solder joint structure (the double-sided solder ball module, correction module, pin structure and stacked solder joint structure described later) between the substrate and the circuit board, which improves the overall welding tolerance capability, can solve the welding defect problems caused by the mismatch of thermal expansion coefficients of the substrate 10 and the circuit board 20 (such as bridging and open soldering problems), meet the assembly requirements and welding quality of the circuit board assembly of the large deformation substrate, and ensure the high reliability of the circuit system of the circuit board assembly 100 during normal operation.

[0088] Double-sided solder ball module solution:

[0089] The specific structure of the circuit board assembly 100 including the double-sided solder ball module will be described below with reference to the accompanying drawings.

[0090] 3 , which shows a schematic structural diagram of a circuit board assembly 100 using a double-sided solder ball module as a soldering structure according to an embodiment of the present application.

[0091] As shown in Figure 3, the circuit board assembly 100 provided in an embodiment of the present application includes a substrate 10, a circuit board 20, and a soldering structure. A gap is provided between the substrate 10 and the circuit board 20, and the soldering structure is located in the gap. The soldering structure is used to conduct electricity between the substrate 10 and the circuit board 20. The soldering structure in the embodiment of the present application includes a plurality of first soldering structures 1 and a plurality of second soldering structures 2. The plurality of first soldering structures 1 and the plurality of second soldering structures 2 correspond one to one, i.e., one first soldering structure 1 is soldered to one second soldering structure 2.

[0092] Exemplarily, the substrate 10 includes a package. In the embodiment of the present application, the package is a large-size, fine-pitch ball grid array (BGA) package, wherein the pitch of the multiple first welding structures 1 is less than 0.5 mm, and the pitch of the multiple second welding structures 2 is less than 0.5 mm. The size of the package is 40 mm × 40 mm and above, for example, 40 mm × 40 mm, 50 mm × 50 mm.

[0093] For example, with continued reference to FIG3 , each first solder structure 1 includes a first solder pad 11 and a first solder ball 12 provided on the substrate 10, and each second solder structure 2 includes a second solder pad 21 and a second solder ball 22 provided on the circuit board 20. Each first solder pad 11 is located on the back side of the substrate 10, and multiple first solder pads 11 are spaced apart along the extension direction of the substrate 10 (as shown in the Y direction in FIG3 ). Each first solder pad 11 is provided with a first solder ball 12, and the first solder ball 12 is electrically connected to the first solder pad 11. Each second solder pad 21 is located on the front side of the circuit board 20, and multiple second solder pads 21 are spaced apart along the extension direction of the circuit board 20 (as shown in the Y direction in FIG3 ). Each second solder pad 21 may be provided with a second solder ball 22, and the second solder ball 22 is electrically connected to the second solder pad 21. It can be understood that the first solder ball 12 or the second solder ball 22 can be understood as a spherical contact distributed in the gap between the substrate 10 and the circuit board 20 when the substrate 10 and the circuit board 20 are assembled, that is, the welding material that can constitute the first welding structure 1 or the second welding structure 2.

[0094] Continuing to refer to Figure 3, a separator 30 is provided between each corresponding first welding structure 1 and second welding structure 2 to separate the corresponding first welding structure 1 and second welding structure 2. For example, the separator 30 is formed by processing a PCB board. The separator 30 is provided with a plurality of through holes 31, and the inner wall of each through hole 31 is provided with a conductive medium, and each corresponding first welding structure 1 and second welding structure 2 is connected through the conductive medium. Thus, the first welding structure 1, the second welding structure 2 and the separator 30 between the two in the embodiment of the present application constitute a double-sided solder ball module of the circuit board assembly 100. It can also be understood that after the first welding structure 1 and the second welding structure 2 are welded, two solder ball structures are formed, and the two solder ball structures are separated by the separator 30.

[0095] Referring to FIG. 3 , FIG. 3 shows that there is only one separator 30, and multiple first soldering structures 1 and multiple second soldering structures 2 share one separator 30. One separator 30 divides the gap between the substrate 10 and the circuit board 20 into a first gap A, and divides the gap between the substrate 10 and the circuit board 20 into a second gap B. Multiple first soldering structures 1 are arranged in the first gap A, and multiple second soldering structures 2 are arranged in the second gap B. The multiple first soldering structures 1 correspond one-to-one to the multiple second soldering structures 2.

[0096] The embodiment of the present application constructs a double-sided solder ball module (including a first soldering structure 1, a second soldering structure 2, and a separator 30 therebetween) to separate the combined large thermal deformation of the coupling between the substrate 10 (e.g., including a chip) and the circuit board 20 (e.g., a printed circuit board) into two smaller deformation parts, the upper and lower parts. This reduces the soldering process capability required for single-sided solder joints, improves the overall soldering tolerance capability, and prevents the soldering structure between the substrate 10 and the circuit board 20 from open solder joints and solder bridging during the soldering process. This allows for large-size, fine-pitch area array BGA packages (i.e., substrates) to be assembled with the circuit board with large tolerances.

[0097] Exemplarily, the separator 30 can be deformed under the welding temperature environment, and the welding temperature includes 200°C to 245°C, that is, the separator 30 of the embodiment of the present application can be rigid or flexible, and the separator 30 has a certain flexibility at high temperature, and the thermal expansion coefficient of the separator 30 needs to be between the substrate 10 and the circuit board 20, so as to have the effect of centering the separator 30 in the gap between the substrate 10 and the circuit board 20, and decomposing the comprehensive large thermal deformation coupled with the substrate 10 and the circuit board 20 into small thermal deformations of the upper and lower parts (that is, the first part is the thermal deformation between the separator 30 and the substrate 10, and the second part is the thermal deformation between the separator 30 and the circuit board 20), thereby realizing the effect of large deformation welding.

[0098] Continuing with reference to FIG3 , the double-sided solder ball module provided in an embodiment of the present application further includes a plurality of connectors 40. As shown in FIG3 , the plurality of connectors 40 are supported between the substrate 10 and the separator 30, and between the circuit board 20 and the separator 30. In some possible embodiments, the connectors 40 are supported between the substrate 10 and the separator 30; alternatively, the connectors 40 are supported between the circuit board 20 and the separator 30. Exemplarily, the connectors 40 are fixed between the substrate 10 and the separator 30, and between the circuit board 20 and the separator 30, by welding or electroplating.

[0099] The connector 40 provided in the embodiment of the present application mainly has the following two functions:

[0100] First, as shown by the dashed line C in Figure 1, when the vertical distance between the substrate 10 and the circuit board 20 is too small, adjacent solder joints may typically experience bridging. Therefore, the provision of connectors 40 between the substrate 10 and the separator 30, and between the circuit board 20 and the separator 30, effectively ensures a minimum support height between the substrate 10 and the circuit board 20 to prevent soldering defects such as bridging. This prevents the combined thermal deformation of the substrate 10 and the circuit board 20 during soldering, which increases with temperature and can lead to bridging between adjacent solder joints.

[0101] In other words, the connector 40 can control the minimum weld height between the substrate 10 and the circuit board 20, that is, control the minimum weld height between the separator 30 and the substrate 10 (for example, the height of the weld at the two side edges and the middle position of the circuit board assembly), and the minimum weld height between the separator 30 and the circuit board 20 (for example, the height of the weld at the two side edges and the middle position of the circuit board assembly), to ensure that there will be no bridging during the welding process.

[0102] Second, as shown in the dotted line D area in Figure 1, when the vertical distance between the substrate 10 and the circuit board 20 is too large, adjacent solder joints may open under normal circumstances. Therefore, in addition to providing a separator 30 between the first soldering structure 1 and the second soldering structure 2 on the substrate 10 and the circuit board 20, the embodiment of the present application also adjusts the vertical height of the connector 40 in different areas of the substrate 10 and the circuit board 20 (for example, the center area or the edge area) and adjusts the shape of the separator 30 so that the deformation trend of the separator 30, which is aggravated by temperature changes during the welding process, matches the deformation trend of the substrate 10, so that the separator 30 can be located in the middle of the gap between the substrate 10 and the circuit board 20, thereby improving the tolerance of the solder balls.

[0103] In other words, by adjusting the thickness of the connectors on both sides of the edge and the center of the circuit board assembly 100, the shape of the double-sided solder ball module is adjusted so that the deformation trend of the separator 30 matches the deformation trend of the substrate (such as the substrate 10), so that the separator 30 is located in the center of the substrate 10 and the circuit board 20, and the solder ball tolerance capability is higher.

[0104] The shape of the connector 40 in this embodiment has the possibility of being diversified. The cross-sectional shape of the connector 40 along its height direction (as shown in the X direction in FIG3 ) includes a combination of one or more of a U-shape, a rectangle, and an arc, and the height direction of the connector 40 is the direction perpendicular to the plane where the surface of the circuit board 20 is located. Exemplarily, the connector 40 can be cylindrical (as shown in FIG3 ), or the connector 40 can be U-shaped, or the connector 40 can be truncated cone-shaped, or the connector 40 can be spherical. It should be understood that the form of the connector 40 is not limited to the aforementioned shape, and any geometric shape that can play a supporting role and can be produced within the processable range can be used as the connector 40, and the embodiments of the present application do not limit this.

[0105] In some possible embodiments, the connector 40 may be an electronic component. For example, the electronic component may be a resistor or a capacitor. Alternatively, in some possible embodiments, the connector 40 may be a gasket. For example, the gasket may be made of one or more metal materials, such as a copper alloy. Alternatively, the gasket may be made of materials such as ceramics or plastic.

[0106] It should be noted that the possible types of the connector 40 are not limited to the above description. It can be any object with a high melting point that will not melt during the welding process and a supporting function. The embodiments of the present application do not limit this.

[0107] In addition, the height of each connector 40 has various possibilities for variation, and the actual height of the connector 40 is selected to ensure that adjacent solder joints do not experience bridging, while also avoiding the problem of open solder joints that fail to form effective solder joints. The height of each connector 40 can be designed according to actual conditions under the aforementioned conditions, which has strong flexibility and a wide range of applications.

[0108] The tolerance capability of the solder balls of the soldering structure of the double-sided solder ball module provided in the embodiment of the present application will be described below with reference to FIG. 4 and FIG. 5 .

[0109] Please refer to Figure 4, which shows a schematic diagram analyzing the tolerance capability of two solder balls in a double-sided solder ball module. The dashed line G represents the plane of the circuit board 20, the dashed line F represents the top surface of the substrate 10 when the adjacent solder balls of the first solder structure 1 and the second solder structure 2 are at the soldering boundary, and the dashed line E represents the top surface of the substrate 10 when the solder balls of the first solder structure 1 and the second solder structure 2 are at the soldering boundary.

[0110] As shown in (a) of Figure 4, when the adjacent first solder ball 12 and second solder ball 22 of the double solder ball welding structure between the substrate 10 and the circuit board 20 are at the soldering boundary, the vertical height of the weld between the substrate 10 and the circuit board 20 reaches the minimum value (as shown by the height Hmin2 in (a) of Figure 4), that is, the minimum weld height is Hmin2.

[0111] As shown in Figure 4(b), when the first solder ball 12 and second solder ball 22 of the dual-solder ball solder structure between substrate 10 and circuit board 20 are at the open solder boundary, the vertical height of the weld between substrate 10 and circuit board 20 reaches its maximum value (as indicated by height Hmax in Figure 4(b)). This means that the maximum weld height is Hmax. Therefore, the dual-solder ball tolerance in the double-sided solder ball module is ΔH2 = Hmax2 - Hmin2.

[0112] From (a) and (b) in FIG4 , it can be seen that the tolerance capability ΔH2 of the double solder balls in the double-sided solder ball module provided in the embodiment of the present application has been greatly improved, which is approximately twice the tolerance capability ΔH1 of the single solder ball, that is, ΔH2≈2ΔH1.

[0113] Please refer to Figure 5, which shows a schematic diagram of an M-shaped thermal deformation structure of the substrate 10 and circuit board 20. The central region of the substrate 10 is concave, while the edge regions show a trend of first rising and then bending downward, resulting in the greatest deformation. The central region of the circuit board 20 is also concave, while the edge regions show an upward curve, with the deformation of the circuit board 20 being less than that of the substrate 10. As a result, the vertical height of the gap between the substrate 10 and circuit board 20 exhibits an M-shaped variation, i.e., the gap is small in the central region and initially increases and then decreases in the edge regions.

[0114] It should be noted that the deformation of the substrate 10 and the circuit board 20 is not limited to the type shown in FIG5 , and may also be other types of deformation, such as W-shaped deformation, twisting deformation, etc. The embodiment of the present application uses the M-shaped deformation shown in FIG5 as an example for explanation.

[0115] Based on the above description and in combination with Figure 5, it can be seen that the double-sided solder ball module provided in the embodiment of the present application is provided with a separator 30 for separating the substrate 10 and the circuit board 20 between the substrate 10 and the circuit board 20 to separate the large thermal deformation, so as to separate the large deformation into small deformation between the substrate 10 and the separator 30 and small deformation between the circuit board 20 and the separator 30.

[0116] At the same time, the double-sided solder ball module provided in the embodiment of the present application also provides connectors 40 of different vertical heights between the substrate 10 and the separator 30, and between the circuit board 20 and the separator 30, according to the different deformation trends of the substrate 10 and the substrate 20, so that the deformation trend of the separator 30 aggravated by temperature changes during the welding process matches the deformation trend of the substrate 10, so that the separator can be located in the middle position of the gap between the substrate 10 and the circuit board 20, thereby improving the tolerance capability of the solder ball and preventing the problem of tin connection and desoldering caused by the increase in chip thermal deformation as the chip size increases during the welding process, thereby realizing a large-size and fine-pitch surface array BGA package (i.e., substrate) and a circuit board with a large tolerance.

[0117] Exemplarily, the central area and edge area of ​​the separator 30 are respectively distributed with connectors 40, but the present application is not limited to this. The connectors 40 can also be arranged in other areas of the separator 30. For example, the connectors 40 can also be arranged separately in the central area or edge area of ​​the separator 30, or in the first welding structure 1 and the second welding structure 2.

[0118] In the embodiment of the present application, before the substrate 10 and the circuit board 20 are soldered, the positions of the first solder balls 12 or the second solder balls 22 may include the following four situations:

[0119] (1) The first solder ball 12 and the second solder ball 22 are disposed on the upper and lower sides of the separator 30;

[0120] (2) The first solder ball 12 is disposed on the back side of the substrate 10 , and the second solder ball 22 is disposed on the lower side of the separator 30 ;

[0121] (3) The first solder ball 12 is disposed on the upper side of the separator 30 , and the second solder ball 22 is disposed on the front side of the circuit board 20 ;

[0122] (3) The first solder balls 12 are disposed on the back surface of the substrate 10 , and the second solder balls 22 are disposed on the front surface of the circuit board 20 .

[0123] In this embodiment, the soldering process of the circuit board assembly 100 is described by taking the case where the first solder ball 12 and the second solder ball 22 are disposed on the upper and lower sides of the separator 30 as an example.

[0124] The following will illustrate an example of the welding process flow of the circuit board assembly 100 when the number of the separator 30 in the embodiment of the present application is one with reference to FIG6 to FIG8 :

[0125] Example 1:

[0126] As shown in FIG6 , the manufacturing method of the circuit board assembly 100 provided in the embodiment of the present application specifically includes the following steps:

[0127] S1: Provide welding structure.

[0128] 6( a ), a double-sided solder ball module with first solder balls 12 and second solder balls 22 disposed on upper and lower sides of a spacer 30 is prepared and ready for soldering. Connectors 40 are disposed on both sides of the substrate 10 .

[0129] S2: Welding the welding structure to the substrate 10 .

[0130] 6 (b), the double-sided solder ball module (ie, soldering structure) is then soldered to the substrate 10 side, and the vertical height of the first gap A (ie, weld height) is adjusted by the connector 40 on the substrate 10 side.

[0131] S3: Soldering the soldering structure to the circuit board 20 .

[0132] 6 (c), the soldered substrate 10 and the double-sided solder ball module are invertedly soldered to the side of the circuit board 20 provided with the connector 40, and the substrate 10 and the circuit board 20 are soldered and assembled to form a circuit board assembly 100 with a double-sided solder ball module.

[0133] Example 2:

[0134] In Example 1, the double-sided solder ball module is first soldered to the side of the substrate 10, while in Example 2, the double-sided solder ball module is first soldered to the side of the circuit board 20. Specifically, referring to FIG7(a), connectors 40 are provided on both sides of the circuit board 20; referring to FIG7(b), the double-sided solder ball module (i.e., the soldering structure) is then soldered to the side of the circuit board 20, and the vertical height of the second gap B (i.e., the weld height) is adjusted by the connector 40 on the side of the circuit board 20; referring to FIG7(c), the soldered circuit board 20 and the double-sided solder ball module are then inverted and soldered to the side of the substrate 20 provided with the connector 40. The substrate 10 and the circuit board 20 are then soldered and assembled to form a circuit board assembly 100 with a double-sided solder ball module.

[0135] Example 3:

[0136] The difference between the welding process flow of Example 1 and Example 2 is that Example 3 first mounts the substrate 10, the double-sided solder ball module, and the circuit board 20 together. Specifically, referring to Figure 8(a), connectors 40 are provided on both sides of the substrate 10, and connectors 40 are provided on both sides of the circuit board 20. Referring to Figure 8(b), the double-sided solder ball module (i.e., the welding structure), the substrate 10 provided with the connectors 40, and the circuit board 20 provided with the connectors 40 are mounted together. The mounted double-sided solder ball module, substrate 10, and circuit board 20 are then furnace-welded at one time. The substrate 10 and circuit board 20 are welded and assembled to form a circuit board assembly 100 with a double-sided solder ball module.

[0137] The above embodiment has one separator 30 (as shown in FIG3 ). However, this application does not limit the number of separators 30. In some possible implementations, referring to FIG9 , the soldering structure provided in this embodiment of the application has at least two separators 30. This is equivalent to the embodiment shown in FIG9 , which divides one separator in the double-sided solder ball module shown in FIG3 into sections, with no limitation on the size or number of the sections.

[0138] 9 exemplarily shows two separators. Accordingly, the circuit board assembly 100 has two welding areas. The separator 30 on the left side of FIG. 9 corresponds to one welding area, and the separator 30 on the right side of FIG. 9 corresponds to the other welding area.

[0139] As shown in Figure 9, three first soldering structures 1 and three second soldering structures 2 are provided on either side of each separator 30. Furthermore, multiple connectors 40 are supported between the substrate 10 and the separator 30, and multiple connectors 40 are supported between the circuit board 20 and the separator 30. After separation, the connectors 40 control the minimum weld height of each soldering area of ​​the circuit board assembly to prevent solder bridging caused by excessively low weld heights.

[0140] For example, as shown in FIG9 , two separators 30 are symmetrically arranged, and connectors 40 are distributed in the edge area of ​​each separator 30. The two ends of the connector 40 supported between the substrate 10 and the separator 30 are respectively connected to the separator 30 and the substrate 10, and the two ends of the connector 40 supported between the circuit board 20 and the separator 30 are respectively connected to the separator 30 and the circuit board 20, so that the deformation trend of the separator 30, which is aggravated by temperature changes during the welding process, matches the deformation trend of the substrate 10, so that the separator 30 can be located in the middle of the gap between the substrate 10 and the circuit board 20, thereby improving the tolerance of the solder balls and preventing the problem of bridging and debonding caused by the increase in chip thermal deformation as the chip size increases during the welding process, thereby realizing a large-size and fine-pitch surface array BGA package (i.e., substrate 10) and the circuit board 20 with a large tolerance.

[0141] In some possible embodiments, a connector (not shown) is distributed in the central region of the separator 30 to maintain a certain vertical distance between the substrate 10 and the circuit board 20. This prevents the combined thermal deformation of the substrate 10 and the circuit board 20 from increasing with temperature during soldering, which could lead to bridging between adjacent solder joints. Specifically, distributing the connector in the central region of the separator 30 can control the minimum weld height, preventing bridging caused by excessively low weld heights.

[0142] It should be noted that the number of separators 30 in the embodiment of the present application is not limited to two. In other embodiments, the number of separators 30 may be three or more. Accordingly, the circuit board assembly 100 has three or more soldering areas. In other words, the number of soldering areas of the circuit board assembly 100 corresponds one-to-one to the number of separators 30.

[0143] For example, referring to FIG10a, there are four separators 30, and sixteen first welding structures 1 and second welding structures 2 are provided on both sides of each separator 30. FIG10a shows that the first solder balls 12 of the first welding structures 1 are provided on one side of the separator 30 corresponding to the substrate 10.

[0144] For another example, referring to FIG10b, the number of separators 30 can also be sixteen, with four first welding structures 1 and two second welding structures 2 provided on both sides of each separator 30. FIG10b also shows that the first solder balls 12 of the first welding structure 1 are provided on the side of the separator 30 corresponding to the substrate 10.

[0145] It can be understood that the number of the first welding structures 1 and the second welding structures 2 on both sides of each separator 30 shown in Figures 9 to 10b is not limited thereto, and can also be other numbers, such as four, five, six, eight, etc.

[0146] It is understood that the size of the separators 30 in the embodiment of the present application only needs to be reasonably distributed between the substrate 10 and the circuit board 20. In other words, the sizes of the multiple separators 30 can be the same or different and can be selected according to actual conditions. The embodiment of the present application does not impose strict restrictions on this.

[0147] In some possible embodiments, referring to Figures 11 and 12, the number of separators 30 in the welding structure provided in the embodiment of the present application is multiple, two adjacent separators 30 are arranged at intervals, and a separator 30 is provided between each corresponding first welding structure 1 and second welding structure 2.

[0148] 11 and 12 , each separator 30 is provided with a first welding structure 1 and a second welding structure 2 on the upper and lower sides. That is, FIG11 and FIG12 show the minimum segmentation unit.

[0149] In the smallest unit of the circuit board assembly 100, a connector 40 is provided in each of the first solder structure 1 and the second solder structure 2. The two ends of the connector 40 in the first solder structure 1 connect the separator 30 to the substrate 10, respectively. The two ends of the connector 40 in the second solder structure 2 connect the separator 30 to the circuit board 20, respectively. That is, in this embodiment, the connector 40 is located within the first solder ball 12 and the second solder ball 22.

[0150] It is understood that when the number of separators 30 is small (e.g., as shown in Figures 9 and 10), or the partition size of the separators 30 is large (e.g., as shown in Figure 9), it is necessary to connect the separators 30 with the substrate 10 and the circuit board 20 through connectors 40 to adjust the comprehensive thermal deformation of the substrate 10 and the circuit board 20. When the number of separators 30 is large (e.g., as shown in Figures 10b, 11, and 12), or the partition size of the separators 30 is small (e.g., as shown in Figures 11 and 12), the connectors 40 only need to ensure that the spacing between the substrate 10 and the circuit board 20 and the separators 30 is not too small to cause bridging. The comprehensive thermal deformation of the substrate 10 and the circuit board 20 is matched by the solder ball buoyancy of the first solder ball 12 and the second solder ball 22, thereby achieving wide tolerance soldering.

[0151] In other words, when the separation size of the separator 30 is smaller, the degree of freedom of each separator 30 is higher after the separation is completed, and the thermal expansion coefficient of the separator 30 itself has a smaller impact on the comprehensive thermal deformation of the substrate 10 and the circuit board 20, which is beneficial to improving the tolerance capability of the solder balls of the overall welding structure and ensuring the welding quality of the substrate 10 and the circuit board 20.

[0152] 13 , the following describes an example of the welding process of the circuit board assembly 100 when the size of the separator 30 of the embodiment of the present application is the smallest separator unit, that is, each separator 30 is provided with a first welding structure 1 and a second welding structure 2 on the upper and lower sides.

[0153] Referring to FIG13 (a), a whole undivided separator 30 is first provided. The separator 30 is provided with a plurality of through holes 31. The inner wall of each through hole 31 is provided with a conductive medium for conducting with the corresponding first welding structure 1 and the second welding structure 2 through the conductive medium.

[0154] Referring to (b) in Figure 13, balls are then planted on both sides of the entire separator 30, that is, multiple first solder balls 12 and multiple second solder balls 22 are respectively arranged on the upper and lower sides of the entire separator 30, one first solder ball 12 corresponds to one second solder ball 22, and each first welding structure 1 and each corresponding second welding structure 2 are connected through the conductive medium in the through hole 31 on the separator 30.

[0155] 13 ( c ), the entire separator 30 after ball implantation is then composited onto the intermediate member 50 , ie, the intermediate member 50 and the entire separator 30 are composited via the second solder balls 22 .

[0156] 13( d ), the entire separator 30 is then divided into a plurality of separators 30 , so that each of the divided separators 30 has a first welded structure 1 and a second welded structure 2 on its upper and lower sides. Exemplarily, the entire separator 30 is divided into the plurality of separators 30 using a laser cutting process.

[0157] Referring to FIG13(e), the side of the double-sided ball-bonded separators 30 that is not bonded to the intermediate member 50 (e.g., the side where the first solder balls 12 are located in FIG13(e)) is inverted and soldered to the substrate 10. The substrate 10 is provided with first solder pads 11 (not shown in FIG13), and the first solder balls 12 are soldered to the first solder pads 11 on the substrate 10.

[0158] 13( f ), the intermediate member 50 combined with the plurality of spacers 30 via the second solder balls 22 is removed.

[0159] Referring to FIG13(g), substrate 10 is finally inverted along with the multiple separators 30 soldered to its backside and then soldered to circuit board 20. Circuit board 20 is provided with second solder pads 21 (not shown in FIG13 ), and second solder balls 22 are soldered to second solder pads 2 on circuit board 20. Thus, substrate 10 and circuit board 20 are soldered and assembled, forming circuit board assembly 100 with a double-sided solder ball module.

[0160] It should be noted that no connectors 40 are set in the first solder balls 12 and the second solder balls 22 on the upper and lower sides of each separator 30 shown in Figure 13. Since the separators 30 under the minimum separation unit have a higher degree of freedom, the thermal expansion coefficient of the separator 30 itself has a smaller impact on the comprehensive thermal deformation of the substrate 10 and the circuit board 20. Therefore, a connector 40 is not set for each solder ball, which can reduce costs.

[0161] For example, in some embodiments, connectors 40 are provided in some of the first solder balls 12, while connectors 40 are not provided in some of the first solder balls 12; or, in some embodiments, connectors 40 are provided in some of the second solder balls 22, while connectors 40 are not provided in some of the second solder balls 22; or, in some embodiments, connectors 40 are provided in some of the first solder balls 12, while connectors 40 are not provided in some of the first solder balls 12, connectors 40 are provided in some of the second solder balls 22, while connectors 40 are not provided in some of the second solder balls 22.

[0162] For example, during the soldering process, a plurality of spacers 30 can be arranged in the middle position of the gap between the substrate 10 and the circuit board 20 to improve the tolerance of the solder balls and prevent the soldering structure from causing the solder joint to open due to the increase in the degree of thermal deformation of the chip as the chip size increases during the soldering process, thereby realizing a large-size and fine-pitch area array BGA package (i.e., the substrate 10) and the circuit board 20 with a large tolerance assembly.

[0163] In summary, by adopting the double-sided solder ball module welding structure solution, during the welding process of the circuit board assembly 100, the high-temperature deformation of the double-sided solder ball module divides the large comprehensive deformation into two small deformation parts, upper and lower. The tolerance capability of the upper and lower solder balls (the first solder ball 12 and the second solder ball 22) is used to achieve large tolerance welding, thereby solving the problems of bridging and open soldering caused by deformation during the welding process.

[0164] Orthopedic module solution:

[0165] The specific structure of the circuit board assembly 100 including the orthopedic module will be described below with reference to the accompanying drawings.

[0166] This embodiment converts the large-scale deformation of the chip into small-scale deformation or no deformation by constructing a correction module, thereby ensuring the soldering of the BGA with large thermal deformation on the board.

[0167] Refer to FIG. 14 , which shows a first structural diagram of a circuit board assembly 100 with an orthopedic module as a welding structure provided in an embodiment of the present application.

[0168] As shown in Figure 14, a circuit board assembly 10 provided in an embodiment of the present application includes a substrate 10, a circuit board 20, a separator 30, a first welding structure 1 and a second welding structure 2 located on the upper and lower sides of the separator 30, and a plurality of connecting parts 40 supported between the substrate 10 and the separator 30.

[0169] Specifically, each of the multiple connectors 40 located in the gap (i.e., first gap A) between the substrate 10 and the separator 30 is supported between the first solder ball 12 of the first solder structure 1 and the separator 30. Each connector 40 is electrically connected to the second solder ball 22 of the second solder structure 2 via the conductive medium within the through-hole 31 of the separator 30. At least some of the connectors 40 located between the substrate 10 and the separator 30 have unequal heights to conform to the lower surface of the substrate 10 (i.e., the back surface of the substrate 10 described above). Thus, the orthopedic module of the circuit board assembly 100 of the present embodiment includes the first solder ball 12, the second solder ball 11, multiple connectors 40 of unequal heights, and the separator 30.

[0170] By constructing a correction module, the thermal deformation of the substrate 10 side is absorbed, and the large-scale deformation of the substrate 10 (for example, including the chip) is converted into small-scale deformation or no deformation, ensuring the large thermal deformation BGA upper board welding.

[0171] For example, as shown in FIG14 , there is only one separator 30, and the substrate 10 exhibits a deformation trend with the center region concave downward and the edge regions warping upward. The height variation trend of the connector 40 located between the substrate 10 and the separator 30 (shown by curve C in FIG14 ) mimics the deformation trend of the substrate 10. In other words, the plurality of connectors 40 as a whole also exhibit a tendency with the center region concave downward and the edge regions warping upward.

[0172] As can be understood, referring to FIG. 14 , the circuit board assembly 100 of the present embodiment utilizes connectors 40 on separator 30, which exhibit the same height variation as substrate 10. This allows for the conversion of large-scale deformation of the chip (i.e., substrate 10) into small-scale or no deformation on the back side of separator 30 (i.e., the side closest to circuit board 20). For example, as shown in FIG. 14 , the back side of separator 30 remains unchanged, thereby preventing the solder joint from debonding during soldering, as the thermal deformation of the chip increases with chip size.

[0173] It should be noted that the deformation trend of the substrate 10 described above is not limited and can also exhibit other deformation trends, such as the M-shaped deformation trend shown in FIG5 , or a deformation trend in which the center region of the substrate 10 warps upward and the edges of the substrate 10 concave downward. Prior to welding, the deformation trend of the substrate 10 can be determined through simulation, and the height deformation trend of the connector 40 located between the substrate 10 and the separator 30 can be adjusted accordingly to align with the lower surface of the substrate 10.

[0174] Continuing with Figure 14 , multiple connectors 40 are distributed between the circuit board 20 and the separator 30 (i.e., in the second gap B). Figure 14 shows two connectors 40 spaced apart at the edge of the separator 30, with each connector 40 connecting the separator 30 and the circuit board 20 at its two ends. In this embodiment, the function of the connectors 40 between the circuit board 20 and the separator 30 is the same as that of the connectors 40 at the corresponding positions in the aforementioned double-sided solder ball module solution. For details, please refer to the above description and will not be repeated here.

[0175] In addition, the number of the separators 30 in the embodiment of the present application is not limited to one, and may also be arranged in the same manner as the separators 30 in the above-mentioned double-sided solder ball module solution, that is, dividing the entire separator into multiple separators.

[0176] The following will illustrate the soldering process of the circuit board assembly 100 shown in FIG14 with reference to FIG15 :

[0177] Referring to (a) in FIG15 , first, a plurality of connectors 40 of different heights are arranged on the side of the entire separator 30 close to the substrate 10, which are shaped to imitate the deformation trend of the substrate 10 during the welding process (as shown in (b) in FIG15 ), and tin is sprayed on the end of the connector 40 facing the substrate 10. As described above, the deformation trend of the substrate 10 can be obtained by simulation, so that the height deformation trend of the connector 40 located between the substrate 10 and the separator 30 can be set accordingly. A substrate 10 is provided with a first welding structure (including a first solder ball 12 and a first solder pad 11). Then, the separator 30 is mounted on the back side of the substrate 10. Among them, the connector 40 in the edge area of ​​the separator 30 is mounted on the first solder ball 12 on the substrate 10.

[0178] Referring to FIG. 15 ( b ), the mounted separator 30 is then furnace-welded together with the substrate 10 . The substrate 10 deforms as the welding temperature changes, and the multiple connectors 40 on the separator 30 are welded one-to-one with the multiple first solder balls 12 on the back of the substrate 10 .

[0179] 15( c ), balls are then planted on a side of the spacer 30 away from the substrate 10 , ie, a plurality of second solder balls 22 corresponding one-to-one to the plurality of first solder balls 12 are provided.

[0180] 15 (d), the spacer 30 after ball implantation is inverted and welded to the circuit board 20 to connect the substrate 10 and the circuit board 20. Thus, the substrate 10 and the circuit board 20 are welded and assembled to form a circuit board assembly 100 with a corrective module.

[0181] For example, the multiple connectors 40 of varying heights on the separator 30 include metal pillars, which can be implemented through electroplating, mounting, or implantation techniques. Furthermore, this application does not impose any specific restrictions on the height variation trend (or gradient) of the multiple connectors 40. The height variation trends of the multiple connectors 40 can be one, two, or more. The multiple connectors 40 can be arranged to cover the entire area of ​​the separator 30 (as shown in FIG. 14 ) or selectively arranged.

[0182] The orthopedic module of the embodiment of the present application is not limited to being realized by constructing a connector 40 with a certain gradient difference on the separator 30, but can also be realized by processing the separator 30 to construct the same deformation condition as the base plate.

[0183] Referring to FIG. 16 , FIG. 16 shows a schematic structural diagram of a circuit board assembly 100 in which the orthopedic module (formed by processing the separator 30 ) provided in an embodiment of the present application is used as a welding structure.

[0184] As shown in FIG16 , a circuit board assembly 10 provided in an embodiment of the present application includes a substrate 10, a circuit board 20, a separator 30, and first and second soldering structures 1 and 2 located on the upper and lower sides of the separator 30. The specific structures and connection methods of the first and second soldering structures 1 and 2 in the embodiment of the present application are similar to those of the first and second soldering structures 1 and 2 in the double-sided solder ball module, and are not further described herein.

[0185] The side of the separator 30 close to the substrate 10 is shaped like the lower surface of the substrate 10 (ie, the back surface of the substrate 10 mentioned above).

[0186] Exemplarily, as shown in Figure 16, the number of separators 30 is one, and the substrate 10 has a deformation trend of being concave in the central area and warping in the edge area. The change trend of the outer surface of the separator 30 on the side close to the substrate 10 is similar to the deformation trend of the substrate 10, that is, the outer surface of the separator 30 on the side close to the substrate 10 also shows a deformation trend of being concave in the central area and warping in the edge area.

[0187] As can be understood, referring to FIG. 16 , the circuit board assembly 100 of the present embodiment achieves this by creating a deformation trend similar to that of the substrate 10 on the side of the separator 30 closest to the substrate 10. This serves to transform large-scale deformation of the chip (i.e., substrate 10) into small-scale deformation or no deformation on the back side of the separator 30 (i.e., the side closest to the circuit board 20). For example, as shown in FIG. 16 , the back side of the separator 30 remains unchanged, thereby preventing the solder joint from opening during soldering due to the increased thermal deformation of the chip as the chip size increases.

[0188] It should also be noted that the deformation trend of the substrate 10 is not limited. For example, other deformation trends are possible, such as the M-shaped deformation trend shown in FIG5 , or the deformation trend of the substrate 10 with an upward warping center region and a downward concave edge region. Prior to welding, the deformation trend of the substrate 10 can be determined through simulation, and the side of the separator 30 closest to the substrate 10 can be processed accordingly to align with the lower surface of the substrate 10.

[0189] The following will illustrate the soldering process flow of the circuit board assembly 100 shown in FIG16 with reference to FIG17 :

[0190] Referring to Figure 17(a), a single-piece separator 30 is first provided. The outer surface of the separator 30, which is adjacent to the substrate 10, is contoured to the deformation tendency of the substrate 10 during soldering (as shown in Figure 17(b)). Tin is sprayed on the contoured surface of the separator 30. A substrate 10 is provided with a first solder structure (including a first solder ball 12 and a first solder pad 11). The separator 30 is then attached to the backside of the substrate 10.

[0191] Referring to FIG. 17 ( b ), the mounted separator 30 is then soldered together with the substrate 10 in a furnace. The substrate 10 deforms as the soldering temperature changes, and the separator 30 is soldered to the plurality of first solder balls 12 on the back side of the substrate 10 .

[0192] 17 ( c ), balls are then planted on a side of the separator 30 away from the substrate 10 , ie, a plurality of first solder balls 1 corresponding to the plurality of first solder balls 12 are provided.

[0193] 17 (d), the spacer 30 after ball implantation is inverted and welded to the circuit board 20 to connect the substrate 10 and the circuit board 20. Thus, the substrate 10 and the circuit board 20 are welded and assembled to form a circuit board assembly 100 with a corrective module.

[0194] For example, this can be achieved by grinding and preforming the outer surface of the separator 30 on the side close to the substrate 10, thereby creating the same deformation as the substrate 10. Alternatively, a micro-concave or micro-convex model (determined according to the deformation of the substrate 10) can be obtained through an integrated molding process, and then drilling and electroplating can be performed.

[0195] In summary, this implementation case converts the large-scale deformation of the chip into small-scale deformation or no deformation by constructing a correction module, ensuring the welding of the BGA with large thermal deformation on the board and solving the problems of bridging and open welding caused by deformation during the welding process.

[0196] Pin structure scheme:

[0197] The specific structure of the circuit board assembly 100 including the pin structure will be described below with reference to the accompanying drawings.

[0198] This embodiment improves the soldering tolerance capability through the wetting force of the metal needle and the liquid solder ball.

[0199] Refer to FIG. 18 , which shows a first structural diagram of a circuit board assembly 100 using a pin structure as a welding structure according to an embodiment of the present application.

[0200] 18 to 19 , an embodiment of the present application further provides a circuit board assembly 100 in which the soldering structure is a pin structure (ie, a connector is used to connect the first soldering structure 1 and the second soldering structure 2 ).

[0201] As shown in FIG18 , a circuit board assembly 100 provided in an embodiment of the present application includes a substrate 10, a circuit board 20, and a soldering structure. A gap is defined between the substrate 10 and the circuit board 20, and the soldering structure is located in the gap. The soldering structure is used to provide electrical continuity between the substrate 10 and the circuit board 20. The soldering structure includes a plurality of first soldering structures 1 and a plurality of second soldering structures 2, with the plurality of first soldering structures 1 corresponding to the plurality of second soldering structures 2.

[0202] For example, with continued reference to FIG18 , the first solder structure 1 includes a first solder pad 11 and a first solder ball 12 provided on the substrate 10, and the second solder structure 2 includes a second solder pad 21 and a second solder ball 22 provided on the circuit board 20. The first solder pad 11 is located on the back side of the substrate 10, with multiple first solder pads 11 spaced apart. Each first solder pad 11 may be provided with a first solder ball 12, and the first solder ball 12 is electrically connected to the first solder pad 11. The second solder pad 21 is located on the front side of the circuit board 20, with multiple second solder pads 21 spaced apart. Each second solder pad 21 may be provided with a second solder ball 22, and the second solder ball 22 is electrically connected to the second solder pad 21.

[0203] Continuing with reference to FIG18 , a connector 40 is shared within each corresponding first welding structure 1 and second welding structure 2. The connector 40 connects the first solder ball 12 of the first welding structure 1 and the second solder ball 22 of the second welding structure 2. The welding tolerance of the first solder ball 12 and the second solder ball 22 is improved by the wetting force of the connector 40 and the liquid solder ball during the welding process. That is, the wettability of the liquid solder ball and the connector 40 causes the first solder ball 12 and the second solder ball 22 to jointly form an elongated solder joint, thereby preventing the welding structure between the substrate 10 and the circuit board 20 from opening during the welding process.

[0204] It can be understood that during the welding process, as the temperature rises, the chip (i.e., substrate 10) undergoes thermal deformation. When the first solder ball 12 and the second solder ball 22 reach the liquidus and melt, as shown in Figure 18, the central area of ​​the substrate 10 is concave downward, so that the connector 40 can penetrate the liquid solder ball and support the side of the circuit board 20 close to the substrate 10, thereby preventing the soldering structure between the substrate 10 and the circuit board 20 from bridging during the welding process.

[0205] The following will illustrate an example of the welding process of the circuit board assembly 100 with a soldering structure having a pin structure according to an embodiment of the present application with reference to FIG19 :

[0206] As shown in FIG19 , the manufacturing method of the circuit board assembly 100 provided in the embodiment of the present application specifically includes the following steps:

[0207] 19( a ), tin is printed on the back side of the substrate 10 (ie, the side close to the soldering structure). Exemplarily, the material of the first solder balls 12 of the substrate 10 includes tin balls or tin columns.

[0208] 19( b ), a needle (ie, connector 40 ) is implanted in the first solder ball 12 of the substrate 10 through a mold 60 so that one end of the connector 40 is connected to the first solder ball 12 . Exemplarily, the mold 60 is a graphite mold.

[0209] 19( c ), after the substrate 10 with the implanted needles is furnace-welded, the mold 60 is removed.

[0210] 19( d ), tin is printed on the front side of the circuit board 20 (ie, the side close to the soldering structure).

[0211] 19( e ), a ball (ie, a second solder ball 22 ) is planted on the front surface of the circuit board 20 . Exemplarily, the material of the second solder ball 22 of the circuit board 20 includes a tin ball or a tin column.

[0212] 19( f ), the end of the second solder ball 22 of the circuit board 20 away from the circuit board 20 is leveled to facilitate the insertion of the other end of the connector 40 into the second solder ball 22 in a subsequent process.

[0213] 19 ( g ), the substrate 10 and the circuit board 20 are mounted so that the other end of the connector 40 on the substrate 10 is connected to the second solder ball 22 on the circuit board 20 .

[0214] Referring to FIG19(h), the mounted substrate 10, circuit board 20, and soldering structure are furnace-soldered so that the corresponding first soldering structures 1 and second soldering structures 2 share a common connector 40, thereby connecting the first soldering structures 1 and the second soldering structures 2. Thus, the substrate 10 and circuit board 20 are soldered and assembled, forming a circuit board assembly 100 with a pin structure.

[0215] It can be understood that in the above process flow, the process steps (a), (b), and (c) in Figure 19 can be performed simultaneously with the process steps (d), (e), and (f) in Figure 19 to improve production efficiency.

[0216] For example, the connector 40 in the embodiment of the present application comprises a metal pin. The material of the metal pin is not specifically limited in the present embodiment, and may be, for example, any one or more of copper, silver, or gold, which are good electrical conductors. The connection method between the connector 40 and the substrate 10 is not specifically limited in the present embodiment, and may be, for example, soldering, welding, or wire bonding.

[0217] In summary, the embodiment of the present application connects the substrate 10 and the circuit board 20 through a metal needle (connector 40), improves the welding tolerance capability through the wetting force of the metal needle and the liquid solder ball (the first solder ball 12 and the second solder ball 22), and solves the problems of bridging and open soldering caused by deformation during the welding process.

[0218] Laminated solder joint structure scheme:

[0219] The specific structure of the circuit board assembly 100 including the laminated solder joint structure will be described below with reference to the accompanying drawings.

[0220] This implementation case leverages the electroplating industry chain to perform multiple electroplating of Cu and Sn / SnAg on the substrate side to increase the amount of tin in the solder joints and achieve wide-tolerance welding.

[0221] Referring to FIG. 20 , FIG. 20 shows a first structural diagram of a circuit board assembly 100 using a laminated solder joint structure as a soldering structure according to an embodiment of the present application.

[0222] As shown in FIG20 , the circuit board assembly 100 provided in an embodiment of the present application includes a substrate 10, a circuit board 20, and a soldering structure. A gap is provided between the substrate 10 and the circuit board 20, and the soldering structure is located in the gap. The soldering structure is used to conduct electricity between the substrate 10 and the circuit board 20. The soldering structure includes at least two stacked electroplated layers. For example, as shown in FIG20 , the number of electroplated layers includes four layers. The embodiment of the present application does not impose any specific restrictions on the number of electroplated layers, and the number can be selected based on actual conditions.

[0223] By providing at least two stacked electroplating layers, the volume of the solder joints can be increased to increase the soldering tolerance of the soldering structure between the substrate 10 and the circuit board 20, thereby preventing the soldering structure between the substrate 10 and the circuit board 20 from opening during the soldering process.

[0224] In some possible implementations, with continued reference to FIG. 20 , the electroplating layer includes a first electroplating layer 71 and a second electroplating layer 72 , and the first electroplating layer 71 and the second electroplating layer 72 are spaced apart along a height direction (as shown in the X direction in FIG. 20 ).

[0225] Specifically, as shown in FIG20 , the outermost electroplated layer of the at least two stacked electroplated layers, which is farther from the substrate 10, is the second electroplated layer 72. The height direction (as indicated by the X direction in FIG20 ) is perpendicular to the plane of the surface of the substrate 10. The second electroplated layer 72 is connected to the circuit board 20, and the first electroplated layer 71 is connected to the substrate 10.

[0226] In addition, referring to FIG. 21 , in some possible implementations, the soldering structure of the circuit board assembly 100 provided in the embodiments of the present application further includes a barrier layer 73, which is disposed between the first electroplating layer 71 and the second electroplating layer 72. The barrier layer 73 can prevent the first electroplating layer 71 and the second electroplating layer 72 from reacting during soldering. For example, the first electroplating layer 71 is made of Cu, the second electroplating layer 72 is made of Sn / SnAg, and the barrier layer 73 is made of Ni.

[0227] It is understood that the present embodiment does not impose any specific restrictions on the materials of the first electroplating layer 71 and the second electroplating layer 72. It is sufficient that one of the two electroplating materials participates in soldering, while the other provides support to prevent solder bridging between the substrate 10 and the circuit board 20 during soldering. For example, in the present embodiment, the Cu electroplating layer controls the minimum spacing between the substrate 10 and the circuit board 20.

[0228] The following will illustrate an example of the soldering process of the circuit board assembly 100 with a soldering structure having a four-layer stacked solder joint structure according to an embodiment of the present application with reference to FIG. 21 :

[0229] As shown in FIG. 21 , the manufacturing method of the circuit board assembly 100 provided in the embodiment of the present application specifically includes the following steps:

[0230] Referring to FIG. 21 (a), a substrate 10 is received; referring to FIG. 21 (b), Cu is plated on the back side of the substrate 10 (i.e., the side close to the welding structure), i.e., the first electroplating layer 71. For example, the material of the first electroplating layer 71 of the substrate 10 includes Cu or Sn / SnAg; referring to FIG. 21 (c), Ni is deposited on the surface of the first electroplating layer 71, i.e., the barrier layer 73; referring to FIG. 21 (d), Sn / SnAg is deposited on the surface of the barrier layer 73, i.e., the first second electroplating layer 72; referring to FIG. 21 (e), the second electroplating layer 72 is continued. The surface of 72 is plated with Ni, i.e. the second barrier layer 73; referring to (f) in FIG21 , Cu is continuously plated on the surface of the second barrier layer 73, i.e. the second first electroplating layer 71; referring to (g) in FIG21 , Ni is continuously plated on the surface of the second first electroplating layer 71, i.e. the third barrier layer 73; referring to (h) in FIG21 , Sn / SnAg is continuously plated on the surface of the third barrier layer 73, i.e. the second second electroplating layer 72, which is also the outermost electroplating layer; referring to (i) in FIG21 , the substrate 10 is subjected to a reflow process to form a four-layer stacked electroplating layer structure.

[0231] In summary, the laminated solder joint structure of the embodiment of the present application mainly consists of electroplated Cu and electroplated Sn / SnAg. The number of electroplating layers is not limited (four layers are shown in FIG21 ), the starting electroplating layer can be Cu or Sn / SnAg, and the electroplating end layer is the Sn / SnAg layer involved in the welding. The electroplating material is not limited to Cu and Sn / SnAg. It is required that one of the two electroplating materials participates in welding and the other plays a supporting role. In order to avoid the reaction between the two materials during welding, an intermediate barrier layer can be added. For Cu and Sn / SnAg electroplating materials, Ni is selected as the barrier layer. By using the electroplating industry chain, the first electroplating layer 71 and the second electroplating layer 72 are electroplated multiple times on the side of the substrate 10 to increase the amount of solder tin in the solder joint structure, achieve large tolerance welding, and solve the problems of tin connection and open welding caused by deformation during welding.

[0232] In summary, the application embodiment improves the overall welding tolerance capability group by introducing a new solder joint structure (double-sided solder ball module, corrective module, pin structure and stacked solder joint structure) between the substrate and the circuit board, which can solve the welding defect problem (such as bridging and open soldering problems) caused by the mismatch of thermal expansion coefficients between the substrate and the circuit board, meet the assembly requirements and welding quality of the circuit board assembly of the large deformation substrate, and ensure the high reliability and temperature resistance of the circuit system of the circuit board assembly during normal operation.

Claims

1. A circuit board assembly, characterized in that: include: substrate; A circuit board, wherein a gap is provided between the substrate and the circuit board; A welding structure, the welding structure is located in the gap and conducts the substrate and the circuit board; wherein, The welding structure includes a plurality of first welding structures and a plurality of second welding structures, the plurality of first welding structures correspond to the plurality of second welding structures one by one, and a separator is provided between each corresponding first welding structure and second welding structure to separate the corresponding first welding structure from the second welding structure; A plurality of connectors can be supported between the substrate and the separator and / or between the circuit board and the separator.

2. The circuit board assembly according to claim 1, wherein: The number of the separator is one, the plurality of first welding structures and the plurality of second welding structures share one separator, and the separator is deformable under a welding temperature environment.

3. The circuit board assembly according to claim 1, wherein: The number of the separators is at least two, and at least two of the first welding structures and two of the second welding structures are respectively disposed on two sides of each separator.

4. The circuit board assembly according to claim 2 or 3, characterized in that: The plurality of connection members are supported between the substrate and the partition and between the circuit board and the partition.

5. The circuit board assembly according to claim 4, wherein: The connecting elements are respectively distributed in the central area and / or the edge area of ​​the partition.

6. The circuit board assembly according to claim 4 or 5, characterized in that: Two ends of the connecting member supported between the substrate and the separator are respectively connected to the separator and the substrate; two ends of the connecting member supported between the circuit board and the separator are respectively connected to the separator and the circuit board.

7. The circuit board assembly according to claim 1, wherein: There are a plurality of separators, and two adjacent separators are arranged at intervals, and one separator is provided between each corresponding first welding structure and second welding structure.

8. The circuit board assembly according to claim 7, wherein: The connecting members are respectively disposed in the first welding structure and the second welding structure.

9. The circuit board assembly according to claim 8, wherein: Two ends of the connecting member in the first welding structure are respectively connected to the separator and the substrate, and two ends of the connecting member in the second welding structure are respectively connected to the separator and the circuit board.

10. The circuit board assembly according to claim 2, wherein: The multiple connectors are supported between the substrate and the separator; wherein each connector is supported between the first welding structure and the separator, and at least part of the connectors between the substrate and the separator have unequal heights to conform to the shape of the lower surface of the substrate.

11. The circuit board assembly according to claim 2, wherein: The side of the partition close to the substrate is shaped like the lower surface of the substrate.

12. The circuit board assembly according to claim 10 or 11, characterized in that: The plurality of connectors are supported between the circuit board and the separator; wherein the connectors are distributed in the edge area of ​​the separator, and two ends of the connectors are respectively connected to the separator and the circuit board.

13. The circuit board assembly according to any one of claims 1 to 12, characterized in that: The first welding structure includes a first welding pad and a first welding ball provided on the substrate, and the second welding structure includes a second welding pad and a second welding ball provided on the circuit board; wherein, the first welding pad is located on the substrate, the first welding ball is electrically connected to the first welding pad, the second welding pad is located on the circuit board, and the second welding ball is electrically connected to the second welding pad.

14. The circuit board assembly according to any one of claims 1 to 13, characterized in that: The separator is provided with a plurality of through holes, and a conductive medium is provided on the inner wall of each through hole, and the corresponding first welding structure and the second welding structure are connected to each other through the conductive medium.

15. The circuit board assembly according to any one of claims 1 to 14, characterized in that: The substrate includes a package, and the package is a ball grid array (BGA) package.

16. A communication device, characterized in that: The communication device comprises a housing and a circuit board assembly according to any one of claims 1 to 15, wherein the circuit board assembly is installed in the housing.

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