Packaging structures, electronic devices and their fabrication methods

Abstract

This application provides a packaging structure including a packaging substrate and a chip. The packaging substrate includes a packaging surface and a bottom surface disposed opposite each other. The chip is disposed on the packaging surface, and N pads are disposed on the bottom surface. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. When the above packaging structure is assembled with a circuit board, the solder balls corresponding to the reinforcing pads deform under heat and connect with each other to form large-volume solder balls covering the reinforcing pads. The large-volume solder balls have better fatigue strength. After the packaging structure and circuit board are assembled, during temperature cycling tests or use, the large-volume solder balls can uniformly distribute the stress they bear, making them less prone to fatigue cracks and breakage, effectively improving the board-level reliability of the assembled packaging structure and circuit board. This application also provides an electronic device and its manufacturing method.

Description

[0001] This application is a divisional application. The original application has the application number 201980094673.9 and the original application date is March 29, 2019. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of packaging technology, and in particular to a packaging structure, electronic device and its manufacturing method. Background Technology

[0003] In existing chip packaging structures, ball grid arrays (BGAs) are generally used to fix the package structure to components such as circuit boards or chips. However, with the trend of miniaturization in chip packaging components, the diameter of solder balls is getting smaller and smaller. During the use of chip packaging components, due to the large difference in the coefficients of thermal expansion between the packaging substrate and the circuit board, the solder balls are easily subjected to repeated stretching or compression, resulting in fatigue failure, breakage at the solder joints, and affecting the reliability of the chip packaging components. Summary of the Invention

[0004] This application provides a packaging structure, an electronic device, and a method for manufacturing the same, to improve the board-level reliability and fatigue life of the electronic device.

[0005] This application provides a packaging structure for use in electronic devices. The packaging structure includes a packaging substrate and a chip. The packaging substrate includes a packaging surface and a bottom surface disposed opposite each other. The chip is disposed on the packaging surface, and the bottom surface has N pads. At least two adjacent pads with the same electrical properties are connected and conductively connected through a conductive sheet to form a reinforced pad. Wherein, N is greater than or equal to 2.

[0006] When the packaging structure described in this application embodiment is assembled with the circuit board, the solder balls on the adjacent solder pads in the reinforcing solder pads melt when heated, and the solder flows into the conductive sheet to connect the adjacent solder balls to form a large-volume solder ball. The large-volume solder ball has better fatigue strength and can evenly distribute the fatigue stress, which is beneficial to improving the board-level reliability after the circuit board and packaging substrate are assembled.

[0007] In some embodiments, the bottom surface includes a central area, an edge area located around the central area, and a connection area connecting the central area and the edge area. The distance between the pads in the edge area and the pads in the central area is greater than the distance between the pads in the connection area and the pads in the central area. The reinforcing pads are arranged in the edge area.

[0008] During temperature cycling tests or use after the packaging structure is assembled with the circuit board, the solder balls in the edge area, which is furthest from the center area, bear the greatest fatigue stress. In this embodiment, the reinforcing pads are arranged in the edge area of ​​the packaging substrate. After the circuit board and the packaging structure are assembled, large-volume solder balls are formed on the reinforcing pads. Since the large-volume solder balls have good fatigue strength, they are not easy to crack and break under fatigue stress, thus improving the board-level reliability of the packaging structure and the circuit board after assembly.

[0009] In some embodiments, the surface of the conductive sheet facing the same direction as the bottom surface is a rough surface. That is, the surface of the conductive sheet facing away from the packaging substrate is a rough surface, in order to increase the contact area between the large-volume solder balls located on the reinforcing pad and the reinforcing pad, thereby increasing the bonding force between the large-volume solder balls and the reinforcing pad, and thus increasing the bonding force between the large-volume solder balls and the packaging substrate.

[0010] In some embodiments, along a direction perpendicular to the bottom surface, the height of one of the reinforcing pads is greater than the height of the other pads. During assembly of the package structure with the circuit board, the solder balls on the reinforcing pads are connected to each other, such that the deformation of the solder balls on the reinforcing pads is greater than that on the other pads. The larger height of the reinforcing pads ensures that the solder balls corresponding to them can be fully connected to the reinforcing pads during assembly, guaranteeing a consistent pressing height of the package substrate onto the circuit board and resulting in uniform stress between the package substrate and the circuit board.

[0011] The conductive sheet includes two oppositely arranged connection ends that are respectively connected to the two pads. In a direction perpendicular to one connection end to the other connection end, the width of the conductive sheet is less than or equal to the radial dimension of the pad. This not only prevents the conductive sheet from connecting and conducting electricity with the pads around the reinforcing pad, thus preventing short circuits, but also prevents large solder balls on the reinforcing pad from contacting and conducting electricity with other solder balls around it after the package structure is assembled with the circuit board, ensuring the normal operation of the circuit board and the electronic device.

[0012] In one embodiment of this application, the N pads have the same radial dimension. When fabricating the packaging substrate, it is not necessary to separately set pads of different sizes, simplifying the process of setting the N pads on the bottom surface and thus reducing the manufacturing time of the packaging structure.

[0013] In another embodiment of this application, the radial dimension of the pad located in the edge region is larger than the radial dimension of the pad located in the center region and the connection region. After the package structure is assembled with the circuit board, the size of the solder ball connected to the pad in the edge region is larger than the size of the solder ball connected to the pad in other regions, which avoids the solder ball connected to the pad in the edge region from breaking due to fatigue stress, and further improves the board-level reliability of the package structure after it is assembled with the circuit board.

[0014] In some embodiments, the bottom surface includes a mounting area, which comprises a central area, an edge area, and a connecting area. The mounting area is rectangular, and the corner positions of the mounting area are the edge areas. The corner position is the corner region of the mounting area furthest from the center of the mounting area. The mounting area includes four corner regions, i.e., the mounting area includes four edge regions. In this embodiment, the specific range of the corner regions can be divided according to actual needs.

[0015] The edge region contains at least two reinforcing pads. After the package structure is assembled with the circuit board, the pads located in the edge region are connected to at least two large-volume solder balls, further increasing the board-level reliability of the assembled package structure and circuit board.

[0016] Furthermore, the edge region includes a first boundary and a second boundary connected to the first boundary. At least one of the at least two reinforcing pads is distributed along the first boundary, with its length direction being the same as the extension direction of the first boundary. At least one of the at least two reinforcing pads is distributed along the second boundary, with its length direction being the same as the extension direction of the second boundary. After the package structure is assembled with the circuit board, each boundary of the edge region has at least one large-volume solder ball connecting the circuit board and the package substrate, improving the fatigue strength of the edge region of the package substrate in both directions.

[0017] In some embodiments, a solder resist layer is provided on the bottom surface, and N openings are formed on the solder resist layer that expose the bottom surface. Each opening contains a solder pad, and a conductive sheet is disposed on the solder resist layer between two solder pads. Alternatively, the solder resist layer and the conductive sheet have a connecting port that exposes the bottom surface and connects the two openings at the corresponding positions, and the conductive sheet is embedded in the connecting port.

[0018] The solder mask layer covers the area on the bottom surface that does not require soldering. This not only prevents short circuits caused by contact between pads with different electrical properties on the packaging substrate, but also protects the packaging substrate and extends its service life.

[0019] In one embodiment of this application, the conductive sheet and the surface of the bottom surface facing the same direction are flush with the surface of the pad in the reinforcing pad. During assembly of the package structure with the circuit board, the solder formed by the melting of adjacent solder balls on the reinforcing pad can flow on the surface of the conductive sheet, allowing two adjacent solder balls to connect to each other and form a large-volume solder ball.

[0020] In another embodiment of this application, the conductive sheet is bent toward the packaging substrate, that is, the surface of the conductive sheet facing the same direction as the bottom surface is a bent surface that bends toward the packaging substrate. When the packaging structure is assembled with the circuit board, the solder on the pads connected to the conductive sheet, after being heated and melted, flows more easily to the surface of the conductive sheet, which is beneficial for two adjacent solder balls with the same electrical properties to connect with each other to form a large-volume solder ball.

[0021] In some embodiments, a partition is provided on the conductive sheet of the reinforcing pad, the partition separating the two pads connected by the conductive sheet to separate the solder balls formed on the reinforcing pad, preventing the cracks of the solder balls located on both sides of the partition from spreading and connecting, and avoiding the breakage of large-volume solder balls located on the reinforcing pad.

[0022] Furthermore, the partition includes a fixed end and a free end disposed opposite to each other. The fixed end is fixed to the conductive sheet, and the width of the free end gradually decreases along the direction from the fixed end to the free end. During assembly of the package structure with the circuit board, the partition is located between two solder balls on the pads connected to the conductive sheet. The free end cooperates with the solder balls, reducing the spacing between the solder balls on both sides of the partition. This makes it easier for adjacent solder balls to connect together to form a large-volume solder ball when deformed by heat.

[0023] This application provides an electronic device, which includes a circuit board and any of the above-described packaging structures. The packaging substrate is mounted on the mounting surface of the circuit board. An auxiliary solder ball is provided on the mounting surface at a position corresponding to the reinforcing pad. The auxiliary solder ball covers the reinforcing pad and connects the reinforcing pad and the circuit board. A solder ball is provided on the mounting surface at a position corresponding to the pad, and the solder ball connects the pad and the circuit board.

[0024] In this embodiment of the electronic device, a large auxiliary solder ball is connected between the circuit board and the packaging substrate. The large auxiliary solder ball has good fatigue strength. When the electronic device is subjected to temperature cycling test or used, the auxiliary solder ball can uniformly distribute fatigue stress without easily cracking and failing, thereby improving the board-level reliability of the electronic device and extending its service life.

[0025] The auxiliary solder ball is formed by the thermal deformation and connection of solder balls on at least two adjacent pads of the reinforcing pad during encapsulation. During the assembly of the electronic device, the solder formed by the melting of the solder balls on the reinforcing pad flows on the surface of the conductive sheet, connecting two adjacent solder balls to form the auxiliary solder ball.

[0026] In some embodiments, a partition protrudes from the conductive sheet of the reinforcing pad, or a partition is provided on the mounting surface at a position corresponding to the conductive sheet, and the partition is embedded in the auxiliary solder ball connected to the reinforcing pad. During temperature cycling testing or use of the electronic device, the partition prevents the propagation and communication of cracks in the auxiliary solder ball located on both sides of the partition, thereby improving the fatigue life of the auxiliary solder ball.

[0027] The mounting surface has N auxiliary pads corresponding one-to-one with the pads. An auxiliary conductive sheet is located on the mounting surface at a position corresponding to the conductive sheet of the reinforcing pad. The auxiliary conductive sheet connects and conducts electricity between two adjacent auxiliary pads to form an auxiliary pad. An auxiliary solder ball is fixedly connected to the auxiliary pad and the reinforcing pad. The auxiliary conductive sheet increases the contact area between the auxiliary solder ball and the circuit board, improving the bonding strength between the auxiliary solder ball and the circuit board, thereby enhancing the bonding stability between the packaging substrate and the circuit board.

[0028] Furthermore, the surface of the auxiliary conductive sheet facing the same direction as the mounting surface is a rough surface to increase the contact area between the auxiliary conductive sheet and the auxiliary solder ball, and to increase the contact area between the auxiliary solder ball and the auxiliary pad, thereby improving the bonding stability between the auxiliary solder ball and the circuit board.

[0029] Furthermore, the radial dimensions of the plurality of auxiliary pads are the same, and the auxiliary conductive sheet includes two fixed ends that are arranged opposite to each other and respectively connected to the two auxiliary pads. In a direction perpendicular to one of the fixed ends toward the other fixed end, the width of the auxiliary conductive sheet is less than or equal to the radial dimension of the auxiliary pad, so as to prevent the auxiliary conductive sheet from connecting and conducting with the other adjacent auxiliary pads, and avoid short circuit problems.

[0030] In some embodiments, a solder resist layer is provided on the mounting surface, and the solder resist layer has N openings that expose the mounting surface. Each opening contains an auxiliary pad, and an auxiliary conductive piece is disposed on the solder resist layer between two auxiliary pads. Alternatively, the solder resist layer has a connecting window at a position corresponding to the auxiliary conductive piece, exposing the mounting surface and connecting the two openings, with the auxiliary conductive piece embedded in the connecting window. The solder resist layer covers areas on the mounting surface that do not require soldering, preventing short circuits between circuits on the circuit board and preventing oxidation of metal conductors, thus protecting the circuit board and preventing damage. Furthermore, the solder resist layer surrounds the auxiliary pads and the reinforcing pads, preventing the solder from flowing freely on the mounting surface after the solder balls melt, thus avoiding short circuits caused by connections between auxiliary pads with different electronic properties.

[0031] In some embodiments, a partition protrudes from the auxiliary conductive sheet, and the partition is embedded within the auxiliary solder ball connected to the auxiliary pad. During temperature cycling tests or use of the electronic device, the partition prevents the propagation and connection of cracks in the portions of the auxiliary solder ball located on both sides of the partition, thereby improving the fatigue life of the auxiliary solder ball.

[0032] The partition is completely embedded within the auxiliary solder ball and is located between the two auxiliary pads connected by the auxiliary conductive sheet. The partition includes two opposing sides facing the two auxiliary pads connected by the auxiliary conductive sheet. Solder formed by the melting of solder balls corresponding to the two auxiliary pads flows through the partition and connects with each other, forming auxiliary solder balls with the partition embedded inside. The partition prevents the propagation and connection of cracks generated in the portions of the auxiliary solder balls located on both sides of the partition, thereby improving the fatigue life of the auxiliary solder balls.

[0033] Furthermore, the partition includes a fixed end and a free end disposed opposite to each other. The fixed end is used to fix the partition to the packaging substrate or the circuit board. Along the direction from the fixed end to the free end, the width of the free end gradually decreases to reduce the spacing between the solder balls located on both sides of the partition, so that the two connected solder balls can be more easily connected together when they are deformed by heat.

[0034] This application also provides a method for manufacturing an electronic device, used to manufacture the electronic device described in any of the above claims, comprising: N pads are formed on the bottom surface of the packaging substrate, wherein at least two adjacent pads with the same electrical properties are connected and conductive through a conductive sheet to form a reinforced pad; A solder ball is formed on each of the aforementioned pads; The packaging substrate is mounted on the mounting surface, such that all N solder balls are in contact with the circuit board. The packaging substrate and the circuit board are heated and pressurized to fix the solder balls to the circuit board, wherein at least two adjacent solder balls on each reinforcing pad are deformed by heat and connected to each other to form auxiliary solder balls covering the reinforcing pad; The solder balls and the auxiliary solder balls are used to fix the packaging substrate to the circuit board.

[0035] The preparation method described in this application describes setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form a reinforcing pad. Solder formed by the melting of at least two adjacent solder balls on each reinforcing pad flows on the conductive sheet, connecting the adjacent solder balls to form a larger auxiliary solder ball. The larger auxiliary solder ball has higher fatigue strength and can uniformly withstand larger fatigue stress, which is beneficial to improving the board-level reliability of the electronic device and thus extending the fatigue life of the electronic device.

[0036] The N pads have the same radial dimension. Forming the N pads eliminates the need for multiple steps to separately set pads with different radial dimensions, simplifying the process of setting the pads on the bottom surface of the packaging substrate and saving packaging substrate manufacturing time.

[0037] The N solder balls have the same radial dimension. This method avoids the need for multiple high-temperature reflows due to different solder ball sizes, simplifying the ball placement process and saving process time on the packaging substrate.

[0038] In one embodiment of this application, before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: A partition is formed on the mounting surface of the circuit board at a position corresponding to the conductive sheet; During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the partition is located between the two solder balls on the two pads connected to the conductive sheet; During the heating and pressurization process of the packaging substrate and the circuit board, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0039] In another embodiment of this application, after forming a solder ball on each of the pads, the preparation method further includes: forming a partition on the conductive sheet, the partition being located between two solder balls on two pads connected to the conductive sheet; During the heating and pressurization process of the packaging substrate and the circuit board, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0040] In a third embodiment of this application, before forming a solder ball on each of the pads, the preparation method further includes: forming a partition on the conductive sheet, the partition being located between two pads connected to the conductive sheet; During the process of forming a solder ball on each of the said pads, the partition is located between the two solder balls on the two said pads; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0041] In a fourth embodiment of this application, before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: N auxiliary pads are formed on the mounting surface of the circuit board, wherein the N auxiliary pads have the same radial dimension, and auxiliary conductive sheets are formed on the mounting surface at positions corresponding to the conductive sheets. The auxiliary conductive sheets connect and conduct two adjacent auxiliary pads to form reinforced auxiliary pads. During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the N solder balls contact the N auxiliary pads on the circuit board one by one; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, at least two adjacent solder balls on each reinforcing pad are deformed by heat and connected to each other to form auxiliary solder balls covering the reinforcing auxiliary pad and the reinforcing pad.

[0042] In the preparation method described in this application embodiment, N solder balls correspond one-to-one with N auxiliary pads, and each solder ball is fixed on one of the auxiliary pads. Under the premise that the radial dimensions of the N auxiliary pads are the same, the size of the solder ball matched with each auxiliary pad is also the same. This avoids the process of needing multiple high-temperature reflows for ball placement due to different solder ball sizes. This not only simplifies the ball placement process, but also avoids the problem that the intermetallic compounds generated by the reaction between the solder balls initially formed on the auxiliary pads and the auxiliary pads during multiple high-temperature reflows grow too quickly, thus affecting the connection stability between the solder balls and the auxiliary pads.

[0043] Before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: forming a partition on the auxiliary conductive sheet, wherein the partition is located between two auxiliary pads connected to the auxiliary conductive sheet; During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the partition is located between the two solder balls corresponding to the two auxiliary pads; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0044] In the packaging structure and electronic device described in this application embodiment, the reinforcing pad is formed by connecting and conducting at least two adjacent pads with the same electrical properties on the bottom surface of the packaging substrate using the conductive sheet. During the assembly of the electronic device, adjacent solder balls on the reinforcing pad are connected to each other through the conductive sheet to form a large-volume auxiliary solder ball when deformed by heat. The large-volume auxiliary solder ball has better fatigue strength and can uniformly distribute the fatigue stress it bears, thereby increasing the board-level reliability of the electronic device and extending the service life of the electronic device. Attached Figure Description

[0045] Figure 1 This is a top view of the packaging structure described in the embodiments of this application; Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the encapsulation structure along the AA direction. Figure 3 yes Figure 1 An enlarged schematic diagram of the reinforced pads in the package structure shown. Figure 4 This is a top view schematic diagram of the second embodiment of the packaging structure described in this application; Figure 5 yes Figure 4 The diagram shows a cross-sectional view of the encapsulation structure along the BB direction. Figure 6 This is a top view schematic diagram of the third embodiment of the packaging structure described in this application; Figure 7 yes Figure 6 The diagram shows a cross-sectional view of the encapsulation structure along the CC direction. Figure 8 yes Figure 6 The diagram shows the relationship between the partition and the solder balls in the packaging structure shown. Figure 9 yes Figure 6 An enlarged schematic diagram of one embodiment of the partition in the encapsulation structure shown; Figure 10 This is a schematic cross-sectional view of the electronic device provided in the embodiments of this application; Figure 11 yes Figure 10 A magnified schematic diagram of region E in the electronic device shown; Figure 12 yes Figure 10 A top view of the circuit board structure in the electronic device shown. Figure 13 yes Figure 12 A schematic diagram of the cross-sectional structure of the circuit board along the FF direction is shown. Figure 14 yes Figure 12 An enlarged schematic diagram of the auxiliary pads in the circuit board shown. Figure 15 This is a cross-sectional structural schematic diagram of a second embodiment of the electronic device described in this application; Figure 16 This is a cross-sectional structural schematic diagram of a third embodiment of the electronic device described in this application; Figure 17 yes Figure 16 A top view of the circuit board structure in the electronic device shown. Figure 18 yes Figure 17 A schematic diagram of the cross-sectional structure of the circuit board along the GG direction is shown. Figure 19 This is a cross-sectional structural diagram of the fourth embodiment of the electronic device described in this application; Figure 20 yes Figure 19 A top view of the circuit board structure in the electronic device shown. Figure 21 yes Figure 20 A schematic diagram of the cross-sectional structure of the circuit board along the HH direction is shown. Figure 22 yes Figure 20 An enlarged schematic diagram of the reinforced auxiliary pads in the circuit board shown. Figure 23 This is a cross-sectional structural schematic diagram of the fifth embodiment of the electronic device described in this application; Figure 24 yes Figure 23 A top view of the circuit board structure in the electronic device shown. Figure 25 yes Figure 24 A schematic diagram of the cross-sectional structure of the circuit board along direction II; Figure 26 This is a schematic diagram of the process flow for the fabrication method of the electronic device provided in the embodiments of this application. Detailed Implementation The embodiments of this application will now be described with reference to the accompanying drawings.

[0046] Please see Figure 1 and Figure 2This application provides a packaging structure 100, which includes a packaging substrate 10 and a chip 20. The packaging substrate 10 includes a packaging surface 110 and a bottom surface 111 disposed opposite to each other, and the chip 20 is disposed on the packaging surface 110. N pads 12 are disposed on the bottom surface 111, and at least two adjacent pads 12 with the same electrical properties are connected by a conductive sheet 13 to form a reinforced pad 14. Here, N is a natural number greater than or equal to 2. It should be understood that the same electrical properties of two pads mean that the two pads receive the same electrical signal, for example, both pads are grounded or both pads are connected to a power source.

[0047] In this embodiment, when the package structure 100 is assembled with the circuit board, the solder balls on two adjacent solder pads 12 in the reinforcing pad 14 deform under heat, and the melted solder flows on the conductive sheet 13, causing the two adjacent solder balls to connect with each other to form a large-volume solder ball. This large-volume solder ball connects the reinforcing pad 14 and the circuit board. During temperature cycling tests or use after the package structure 100 and the circuit board are assembled, the large-volume solder ball has better fatigue strength and can more evenly distribute the fatigue stress it bears, making it less prone to cracking and breakage, thus improving the board-level reliability of the package structure 100 and the circuit board after assembly.

[0048] Re-reference Figure 1The bottom surface 111 includes a central area 1111a, an edge area 1111b located around the central area 1111a, and a connecting area 1111c connecting the central area 1111a and the edge area 1111b. The distance between the pads 12 in the edge area 1111b and the pads 12 in the central area 1111a is greater than the distance between the pads 12 in the connecting area 1111c and the pads 12 in the central area 1111a. Reinforcing pads 14 are arranged in the edge area 1111b. That is, the area in the mounting area 1111 that is farthest from the central area 1111a is the edge area 1111b, and the reinforcing pads 14 are arranged in the area in the mounting area 1111 that is farthest from the central area 1111a. It is important to understand that, generally speaking, after the circuit board and the package structure are assembled, during temperature cycling tests or use, when the circuit board and the package substrate undergo thermal expansion and contraction, the fatigue stress borne by the solder balls between the circuit board and the package substrate gradually increases along the direction from the center area to the edge area. The solder balls connected to the pads in the edge area are more prone to fatigue cracks due to the higher fatigue stress, leading to solder joint failure between the circuit board and the package substrate. In the embodiment of this application, the package structure 100 has a reinforcing pad 14 located in the edge area 1111b, which is furthest from the center area 1111a. After the package structure 100 is assembled with the circuit board, large-volume solder balls are formed on the reinforcing pad 14 in the edge area 1111b. These large-volume solder balls have high fatigue strength, effectively alleviating the fatigue stress they bear and preventing the solder balls in the edge area 1111b from cracking and breaking due to excessive fatigue stress. This improves the board-level reliability of the package structure 100 after assembly with the circuit board and extends the fatigue life of the package structure 100 after assembly with the circuit board. It is understood that the structure of the reinforced pad described in the embodiments of this application can be applied to any other substrate that needs to be soldered to the solder ball via the pad, and is not limited to the package substrate, but can also be applied to the circuit board.

[0049] In this embodiment, the bottom surface 111 includes a mounting area 1111, which includes a central area 1111a, an edge area 1111b, and a connecting area 1111c. Specifically, the mounting area 1111 is rectangular, and the corners of the mounting area 1111 are the edge areas 1111b. The corners of the mounting area 1111 are the corners furthest from the center of the mounting area 1111, and the rectangular mounting area 1111 includes four corner areas; that is, in this embodiment, the mounting area 1111 includes four edge areas 1111b. Further, the center of the mounting area 1111 is the central area 1111a, and the area between the center and the corners is the connecting area 1111c. It is understood that the specific ranges of the central area 1111a, the edge areas 1111b, and the connecting area 1111c can be divided according to actual needs, and this embodiment does not strictly limit this. It should be noted that in other embodiments of this application, the mounting area may also be other shapes such as triangle, pentagon, hexagon or circle, and the number of edge areas may vary depending on the shape of the mounting area.

[0050] Re-reference Figure 2 N pads 12 are evenly spaced and arranged in an array within the mounting area 1111, and each pad 12 has a solder ball 30. In this embodiment, all N pads 12 are circular pads, and the radial dimensions of the N pads 12 are the same, that is, the radial dimensions of the pads 12 arranged in the central area 1111a, the edge area 1111b, and the connection area 1111c are all the same. Therefore, in the process of preparing the packaging substrate, it is not necessary to set pads of different sizes separately, which simplifies the process of setting N pads 12 on the bottom surface 111 and correspondingly reduces the process time of the packaging structure 100. Generally, pads and solder balls are used together. The radial dimensions of N pads 12 are the same, and the radial dimensions of N solder balls 30 connected to the N pads 12 are also the same. This simplifies the ball placement process of the N solder balls 30, avoids the need for multiple high-temperature reflow processes due to different solder ball sizes, and avoids the problem of excessive growth of intermetallic compounds between the solder balls 30 and the pads 12, which reduces the bonding force between the solder balls 30 and the packaging substrate 10.

[0051] It should be noted that in other embodiments, the radial dimensions of the pads arranged in the three regions of the center region, edge region, and connection region may also be different. For example, the radial dimension of the pads located in the edge region may be greater than the radial dimension of the pads located in the center region and the connection region. After the package structure is assembled with the circuit board, the volume of the solder ball connecting the pads and the circuit board in the edge region will be correspondingly larger than the solder ball size in other regions, further improving the board-level reliability after the package structure is assembled with the circuit board.

[0052] Furthermore, at least two adjacent pads 12 with the same electrical properties are arranged within the edge region 1111b of the mounting area 1111 to ensure that at least one reinforcing pad 14 is arranged within the edge region 1111b. Next, in order to facilitate understanding of the package structure 100 shown in the embodiments of this application, a specific description will be given using an example of 12 pads 12 arranged within the edge region 1111b.

[0053] Re-reference Figure 1 In this embodiment, a reinforcing pad 14 is arranged within each edge region 1111b. The reinforcing pad 14 is formed by connecting and conducting two adjacent pads 12 with the same electrical properties through a conductive sheet 13. Specifically, the edge region 1111b includes a first boundary b1 and a second boundary b2 connected to the first boundary b1. The length direction of the reinforcing pad 14 is set at an angle to both the first boundary b1 and the second boundary b2, and it is located at the position furthest from the center region 1111a in the edge region 1111b. When the package structure 100 is assembled with the circuit board, the large-volume solder ball connecting the package substrate 10 and the circuit board is located at the position furthest from the center region 1111a. It will not produce fatigue cracks and break when subjected to large fatigue stress, thus improving the board-level reliability of the package structure 100 after assembly with the circuit board. It is understood that in other embodiments of this example, the reinforcing pads in each edge region may be distributed along the first boundary or the second boundary, and the length direction may be the same as the extension direction of the first boundary or the second boundary, so as to improve the board-level reliability of the package structure and the circuit board after assembly in the extension direction of the first boundary or the second boundary.

[0054] It should be noted that in other embodiments, among the multiple pads with the same electrical properties arranged in the edge area, each pair of adjacent pads can be connected by conductive sheets to form a reinforced pad. For example, three adjacent pads can be connected together by two conductive sheets to form a reinforced pad, or four adjacent pads can be connected together by three conductive sheets to form a reinforced pad. When the package structure is assembled with the circuit board, a larger solder ball is formed between the reinforced pad and the circuit board to further extend the fatigue life after the package structure and circuit board are assembled.

[0055] Furthermore, along the direction perpendicular to the bottom surface 111, the height of two pads 12 in the reinforcing pads 14 is the same as the height of pads 12 in other locations, to further simplify the fabrication process of the package structure 100. Of course, in other embodiments, the height of the pads in the reinforcing pads can be greater than the height of pads in other locations along the direction perpendicular to the bottom surface. It should be understood that during the assembly of the package structure with the circuit board, adjacent solder balls on the reinforcing pads deform due to heat and connect with each other to form a large-volume solder ball. The deformation amount of the solder ball on each pad in the reinforcing pads will be greater than the deformation amount of the solder ball on pads in other locations. By increasing the height of the pads in the reinforcing pads, the solder balls on the reinforcing pads can be fully connected to the pads on the circuit board during assembly, ensuring a consistent pressure drop height between the package substrate and the circuit board, and ensuring uniform stress between the package substrate and the circuit board.

[0056] Please refer to the following: Figure 3 In this embodiment, the conductive sheet 13 of the reinforcing pad 14 is connected to the opposite sides of the two pads 12. Specifically, the conductive sheet 13 includes two oppositely arranged connection ends 131 that are respectively connected to the two pads 12. Along the direction perpendicular to one connection end 131 to the other connection end 131 (i.e., perpendicular to the extension direction of the conductive sheet 13), the width of the conductive sheet 13 is less than or equal to the radial dimension of the pad 12. This not only prevents the conductive sheet 13 from connecting and conducting with other pads 12 within the edge area 1111b, causing a short circuit, but also prevents the large-volume solder balls on the reinforcing pad 14 from contacting and conducting with the solder balls 30 on other surrounding pads 12 after the package structure 100 is assembled with the circuit board, ensuring the normal operation of the package structure 100 after assembly with the circuit board. In this embodiment, the conductive sheet 13 is made of the same material as the pad 12 and is formed simultaneously with the pad 12 under the same process. It is understood that in other embodiments, the conductive sheet and the pad may be made of different materials, or may be formed sequentially under different processes, as long as the conductive sheet can connect and conduct the two pads.

[0057] Furthermore, the surface 132 of the conductive sheet 13 facing the same direction as the bottom surface 111 is flush with the surface of the pad 12 in the reinforcing pad 14, that is, the surface 132 of the conductive sheet 13 facing away from the packaging substrate 10 is flush with the surface of the pad 12 in the reinforcing pad 14 facing away from the packaging substrate 10. During the assembly of the package structure 100 with the circuit board, the solder formed by the melting of the solder balls 30 on the reinforcing pad 14 can flow on the surface 132 of the conductive sheet 13, allowing two adjacent solder balls 30 to connect to each other to form a large-volume solder ball. In this embodiment, the surface 132 of the conductive sheet 13 facing the same direction as the bottom surface 111 is a rough surface, that is, the surface 132 of the conductive sheet 13 facing away from the packaging substrate 10 is a rough surface, to increase the contact area between the large-volume solder ball on the reinforcing pad 14 and the reinforcing pad 14, increasing the bonding force between the large-volume solder ball and the reinforcing pad 14, and thus increasing the bonding force between the package structure 100 and the circuit board.

[0058] In other embodiments, the conductive sheet can also be bent toward the packaging substrate, that is, the conductive sheet and the bottom surface facing the same direction are bent surfaces toward the packaging substrate. When the packaging structure is assembled with the circuit board, the solder on the pads connected to the conductive sheet melts when heated and flows more easily to the surface of the conductive sheet, which is beneficial for two adjacent solder balls to connect with each other to form a large volume solder ball.

[0059] Re-reference Figure 1 The bottom surface 111 also includes a non-mounting area 1112 surrounding the mounting area 1111. A solder resist layer 112 is provided on the bottom surface 111, covering both the non-mounting area 1112 and areas within the mounting area 1111 that do not require soldering. This not only prevents short circuits between areas of the bottom surface 111 that require soldering but also protects the packaging substrate 10. For details, please refer to [link / reference needed]. Figure 3 The solder mask layer 112 has N openings 1121 exposing the bottom surface 111. Each opening 1121 contains a solder pad 12. A connecting port 1122, exposing the bottom surface 111 and connecting two openings 1121, is also provided on the solder mask layer 112 at a corresponding position to the conductive sheet 13. The conductive sheet 13 is embedded in the connecting port 1122. The solder mask layer 112 surrounds the solder pads 12 and the reinforcing solder pads 14. During assembly of the package structure 100 with the circuit board, it prevents the solder formed by the melting of the solder balls 30 from flowing freely on the bottom surface 111, thus avoiding short circuits caused by short circuits between solder pads 12 with different electrical properties. It should be noted that in other embodiments, the conductive sheet may also be located on the solder mask layer between two solder pads.

[0060] The opening 1121 is circular, matching the shape of the pad 12, and its radial dimension is smaller than that of the pad 12 (dashed line portion), allowing for precise control of the solder ball 30 position during the ball-mounting process. The connecting opening 1122 is rectangular, matching the shape of the conductive sheet 13, and its width is smaller than the width of the conductive sheet 13 (width along the direction perpendicular to the extension of the conductive sheet 13), allowing for precise control of the solder flow area on the conductive sheet 13 during assembly of the package structure 100 with the circuit board. It is understood that in other embodiments of this example, the radial dimension of the opening may be greater than or equal to the radial dimension of the pad, and the width of the connecting opening may be greater than or equal to the width of the conductive sheet, reserving sufficient space for the flow of solder formed after the solder ball melts upon heating on the pad and conductive sheet.

[0061] In this embodiment, the packaging substrate 10 is electrically connected to the circuit board via pads 12 on its bottom surface 111, and is connected to the chip 20 via the packaging surface 110 to realize electrical signal transmission between the circuit board and the chip 20. Specifically, the packaging substrate 10 is a structure composed of three stacked layers: a first add-on layer 11a, a core layer 11b, and a second add-on layer 11c. The surface of the second add-on layer 11c facing away from the core layer 11b is the packaging surface 110. The chip 20 is soldered to the packaging surface 110 via solder balls 31 and is electrically connected to the packaging substrate 10 via wires 22.

[0062] Furthermore, the package structure 100 also includes a passive component 40 and a heat sink 50. The passive component 40 is disposed on the package surface 110 and spaced apart from the chip 20. The passive component 40 is an electronic component such as a resistor or capacitor. The heat sink 50 covers the package surface 110 and forms a receiving cavity 501 with the package substrate 10, in which both the chip 20 and the passive component 40 are housed. The heat sink 50 is made of metal, which not only conducts away the heat generated by the chip 20 and the passive component 40 in a timely manner, but also prevents the chip 20 and the passive component 40 from being interfered with by electromagnetic signals generated by external components.

[0063] In a second embodiment of the packaging structure 100 described in this application, the difference from the first embodiment is that at least two reinforcing pads 14 are arranged within the edge region 1111b. After the packaging structure 100 is assembled with the circuit board, the pads 12 arranged within the edge region 1111b are connected to at least two large-volume solder balls to further increase the board-level reliability of the package structure 100 after assembly with the circuit board. Specifically, at least one of the at least two reinforcing pads 14 is distributed along the first boundary b1, with its length direction being the same as the extension direction of the first boundary b1. At least one of the at least two reinforcing pads 14 is distributed along the second boundary b2, with its length direction being the same as the extension direction of the second boundary b2. After the packaging structure 100 is assembled with the circuit board, at least one large-volume solder ball is connected between the packaging structure 100 and the circuit board on each boundary of the edge region 1111b, improving the fatigue strength in the extension direction of the two boundaries in the edge region 1111b.

[0064] Please refer to the specific embodiments. Figure 4 and Figure 5 Six reinforcing pads 14 are arranged within the edge region 1111b. Each reinforcing pad 14 is formed by connecting two adjacent pads 12 with the same electrical properties through a conductive sheet 13. Three reinforcing pads 14 are distributed along the first boundary b1, with two pads located on the outermost side of the edge region 1111b away from the central region 1111a and spaced apart along the direction of the first boundary b1. One reinforcing pad 14 is located on the inner side of the edge region 1111b closer to the central region 1111a. The other three reinforcing pads 14 are distributed along the second boundary b2, with two pads located on the outermost side of the edge region 1111b away from the central region 1111a and spaced apart along the direction of the second boundary b2. One reinforcing pad 14 is located on the inner side of the edge region 1111b closer to the central region 1111a. The packaging structure 100 shown in this embodiment has two layers of reinforcing pads 14 along the first boundary b1 and the second boundary b2 of the edge region 1111b to further increase the board-level reliability of the packaging structure 100 after assembly with the circuit board. It should be noted that in other embodiments, reinforcing pads arranged at an angle to the first and second boundaries along their length can also be arranged in the edge region. This application embodiment does not strictly limit the arrangement of the reinforcing pads in the edge region.

[0065] In a third embodiment of the packaging structure 100 described in this application, based on either of the above two embodiments, a partition is protruding from the conductive sheet of the reinforcing pad. For specific embodiments, please refer to... Figure 6 and Figure 7The position and number of reinforcing pads adopt the design of Embodiment 2. Specifically, a partition 15 protrudes from the conductive sheet 13 of the reinforcing pad 14, and the partition 15 separates the two pads 12 connected by the conductive sheet 13 to separate the solder balls formed on the reinforcing pad 14. After the package structure 100 is assembled with the circuit board, the partition 15 is embedded in the large-volume solder balls located on the reinforcing pad 14 to prevent the cracks generated on the solder ball portions located on both sides of the partition 15 in the reinforcing pad 14 from propagating and connecting, thereby improving the fatigue life of the large-volume solder balls and thus improving the board-level reliability of the package structure 100 after assembly with the circuit board.

[0066] Furthermore, the partition 15 includes two opposing sides 151, each facing the two pads 12 connected to the conductive sheet 13. That is, the partition 15 separates the two solder balls 30 located on the two pads 12 of the reinforcing pad 14, and the length direction of the partition 15 is perpendicular to the extending direction of the conductive sheet 13. This prevents cracks in the large-volume solder ball portion located on the reinforcing pad 14 from propagating through the partition 15 and causing the large-volume solder ball to break. Please refer to [further details omitted]. Figure 8 Along one side 151 toward the other side 151, the width 'a' of the partition 15 is less than or equal to the distance between the two solder balls 30 located on the two pads 12. Along the direction parallel to the bottom surface 111, the length 'c' of the partition 15 is less than the radial diameter 'D' of the solder balls 30. Along the direction perpendicular to the bottom surface 111, the height 'b' of the partition 15 is less than the radial diameter 'D' of the solder balls 30. This allows the solder formed by the heat deformation of the solder balls 30 on both sides of the partition 15 to connect with adjacent solder balls 30 via the partition 15, forming a large-volume solder ball covering the partition 15. In this embodiment, the partition 15 can be made of conductive or insulating material; this application does not specifically limit this.

[0067] It should be noted that in other embodiments of this application, such as Figure 9 As shown, the partition 15 includes a fixed end 15a and a free end 15b disposed opposite to each other. The fixed end 15a is fixed to the conductive sheet 13. Along the direction from the fixed end 15a to the free end 15b, the width of the free end 15b gradually decreases to reduce the distance between the solder balls located on both sides of the partition 15, making it easier for adjacent solder balls to connect together to form a large-volume solder ball when they deform due to heat. Specifically, the free end 15b includes two side surfaces 151a located on two side surfaces 151. The side surfaces 151a cooperate with the solder balls located on both sides of the partition 15, that is, the side surfaces 151 are arc-shaped surfaces, and the center of the side surface 151a coincides with the center of the solder ball. The two side surfaces 151a are in contact with and fit against the spherical surfaces of the solder balls 30 located on both sides of the partition 15, so as to reduce the distance between the solder balls 30 located on both sides of the partition 15, thereby helping adjacent solder balls 30 to connect together to form a large-volume solder ball when they deform due to heat.

[0068] Please see Figure 10 This application provides an electronic device 1000. The electronic device 1000 includes a package structure 100 and a circuit board 200 as described in any of the above embodiments. In this embodiment, two reinforcing pads 14 are located within an edge region 1111b and are distributed along the first boundary b1 and the second boundary b2 of the edge region 1111b, respectively. Specifically, a package substrate 10 is mounted on a mounting surface 201 of the circuit board 200. An auxiliary solder ball 31 is provided at a position on the mounting surface 201 corresponding to the reinforcing pad 14. The auxiliary solder ball 31 covers the reinforcing pad 14 and connects it to the circuit board 200. A solder ball 30 is provided at a position on the mounting surface 201 corresponding to the pad 12, and the solder ball 30 connects it to the pad 12. The auxiliary solder ball 31 is formed by the thermal deformation and connection of solder balls 30 on at least two adjacent pads 12 of the reinforcing pad 14 during packaging.

[0069] In this embodiment of the application, a large auxiliary solder ball 31 is provided between the packaging substrate 10 and the circuit board 200 of the electronic device 1000. The large auxiliary solder ball 31 has good fatigue strength. When the electronic device 1000 is subjected to temperature cycling test or used, the auxiliary solder ball 31 can evenly distribute the fatigue stress it bears without easily cracking or breaking, thereby improving the board-level reliability of the electronic device 1000 and extending the fatigue life of the electronic device 1000.

[0070] Please refer to the following: Figure 11 The reinforcing pad 14 is located within the edge region 1111b, and the auxiliary solder ball 31 is fixedly connected to the reinforcing pad 14, connecting the reinforcing pad 14 and the circuit board 200. In this embodiment, the reinforcing pad 14 is formed by connecting two adjacent pads 12 with the same electrical properties through a conductive sheet 13. When the two solder balls 30 on the two adjacent pads 12 are heated and melted, the resulting solder flows on the conductive sheet 13, connecting the two adjacent solder balls to form a large-volume auxiliary solder ball 31. Specifically, the auxiliary solder ball 31 includes a first part 31a located on the two pads 12 and a second part 31b located on the conductive sheet 13. The first part 31a is fixedly connected to the pad 12 and the circuit board 200, and the second part 31b is connected between the two first parts 31a and is fixedly connected to the conductive sheet 13 and the circuit board 200.

[0071] Re-reference Figure 12 and Figure 13N auxiliary pads 211 are spaced apart on the mounting surface 201, and each of the N auxiliary pads 211 corresponds one-to-one with one of the N pads 12. In this embodiment, all N auxiliary pads 211 are circular pads, and the radial dimensions of the N auxiliary pads 211 are the same. This eliminates the need to set auxiliary pads 211 of different sizes when fabricating the circuit board 200, simplifying the fabrication process of the N auxiliary pads 211 and saving the fabrication time of the circuit board 200. Generally, pads and solder balls are used in combination, and the sizes of the pads and solder balls are adapted to each other. When the same solder ball is used in combination with both auxiliary pads 211 and pads 12, the radial dimensions of the auxiliary pads 211 and pads 12 are the same. It is understood that in other embodiments of this application, the radial dimension of each auxiliary pad may also vary with the radial dimension of its corresponding pad, and this embodiment does not specifically limit this.

[0072] In the assembly of the electronic device 1000 shown in this embodiment, the package structure 100 is mounted on the mounting surface 201 of the circuit board 200. The N solder balls 30 on the package substrate 10 contact the N auxiliary pads 211 on the circuit board 200 one by one. When the package structure 100 and the circuit board 200 are heated and pressurized, the solder balls 30 react with the auxiliary pads 211 to generate intermetallic compounds, thereby connecting the solder balls 30 with the auxiliary pads 211. At this time, the solder formed by the thermal deformation of two adjacent solder balls 30 on each reinforcing pad 14 flows on the conductive sheet 13, causing the two solder balls 30 to connect with each other to form an auxiliary solder ball 31 covering the reinforcing pad 14. Finally, the auxiliary solder ball 31 and the remaining solder balls 30 are cured, thus realizing the fixed connection between the circuit board 200 and the package structure 100.

[0073] Furthermore, a solder resist layer 202 is provided on the mounting surface 201. The solder resist layer 202 has N openings 2021 that expose the mounting surface 201, and each opening 2021 embeds an auxiliary solder pad 211. Specifically, the solder resist layer 202 covers areas on the mounting surface 201 that do not require soldering. This not only prevents short circuits between traces on the circuit board 200 but also prevents oxidation of the metal conductors, protecting the circuit board 200, preventing damage, and thus extending its lifespan. The solder resist layer 202 surrounds the auxiliary solder pads 211, preventing the solder formed by the melting of the solder balls 30 from flowing freely on the mounting surface 201 and causing short circuits between auxiliary solder pads 211 with different electrical properties. Please refer to [link to relevant documentation]. Figure 14In this embodiment, the radial dimension of the window 2021 is larger than the radial dimension of the auxiliary pad 211, reserving a certain space for the flow of solder formed after the solder ball 30 melts upon heating on the auxiliary pad 211. Furthermore, in other embodiments, the radial dimension of the window may be less than or equal to the radial dimension of the auxiliary pad to precisely control the position of the solder flow during the soldering process; this application does not specifically limit this.

[0074] Please see Figure 15 In a second embodiment of the electronic device 1000 described in this application, the difference from the above embodiment is that a partition 15 protrudes from the conductive sheet 13 of the reinforcing pad 14, and the partition 15 is embedded in the auxiliary solder ball 31 connected to the reinforcing pad 14. During temperature cycling testing or use of the electronic device 1000, the partition 15 prevents the propagation and communication of cracks in the portions of the auxiliary solder ball 31 located on both sides of the partition 15, thereby improving the fatigue life of the auxiliary solder ball 31. Specifically, the partition 15 is completely embedded in the second portion 31b of the auxiliary solder ball 31, that is, the partition 15 is completely embedded in the auxiliary solder ball 31, so as to prevent cracks in one first portion 31a from propagating into the other first portion 31a or communicating with cracks in the other first portion 31a, thereby preventing the auxiliary solder ball 31 from breaking and extending the fatigue life of the auxiliary solder ball 31.

[0075] Furthermore, the partition 15 is located between the two solder pads 12 connected by the conductive sheet 13. The partition 15 includes two opposing sides 151, which face the two solder pads 12 connected by the conductive sheet 13, respectively. That is, the length direction of the partition 15 is perpendicular to the extension direction of the conductive sheet 13. During the assembly of the electronic device 1000, the partition 15 is located between two solder balls 30 on the two solder pads 12, and the two sides 151 face the two solder balls (e.g., ...). Figure 8 As shown, the solder formed by the thermal deformation and melting of two solder balls flows through the partition 15 and connects with each other to form an auxiliary solder ball 31 embedded in the partition 15. Specifically, along the direction from one side 151 to the other side 151, the width a of the partition 15 is less than or equal to the distance between the two solder balls located on the two pads 12; along the direction parallel to the bottom surface 111, the length c of the partition 15 is less than the radial diameter D of the solder ball; and along the direction perpendicular to the bottom surface 111, the height b of the partition 15 is less than the radial diameter D of the solder ball, so that the solder formed after the solder balls are thermally deformed can connect with adjacent solder balls via the partition 15.

[0076] In one alternative implementation, such as Figure 9As shown, the partition 15 includes a fixed end 15a and a free end 15b disposed opposite to each other. The fixed end 15a is fixed to the conductive sheet 13, and the width of the free end 15b gradually decreases along the direction from the fixed end 15a to the free end 15b. The partition 15 is located between two adjacent solder balls 30. The gradually decreasing width of the free end 15b reduces the spacing between the solder balls 30 located on both sides of the partition 15, making it easier for the two adjacent solder balls 30 to connect together when deformed by heat to form an auxiliary solder ball 31 covering the partition 15. Specifically, the free end 15b includes two side surfaces 151a located on two side surfaces 151. The side surfaces 151a cooperate with the solder balls 30, that is, the side surfaces 151a are arc-shaped surfaces, and the center of the ball of the side surface 151a coincides with the center of the ball of the solder ball. The two side surfaces 151a respectively contact and fit with the spherical surfaces of the solder balls 30 located on both sides of the partition plate 15, so as to further reduce the distance between the solder balls 30 on both sides of the partition plate 15, which is conducive to the connection of two adjacent solder balls 30 to form auxiliary solder balls 31 during the subsequent heat deformation process.

[0077] Please see Figures 16 to 18 In a third embodiment of the electronic device 1000 described in this application, the difference from the second embodiment is that a partition 15 is provided on the mounting surface 201 at a position corresponding to the conductive sheet 13. The partition 15 is embedded in the auxiliary solder ball 31 connected to the reinforcing pad 14. During temperature cycling testing or use of the electronic device 1000, the partition 15 prevents the expansion and connection of cracks located on both sides of the partition 15 in the auxiliary solder ball 31, thereby improving the fatigue life of the auxiliary solder ball 31.

[0078] Please see Figures 19 to 21 In the fourth embodiment of the electronic device 1000 described in this application, the difference from the above three embodiments is that an auxiliary conductive sheet 212 is provided on the mounting surface 201 at the position corresponding to the conductive sheet 13 of the reinforcing pad 14. The auxiliary conductive sheet 212 connects and conducts to two adjacent auxiliary pads 211 to form a reinforcing auxiliary pad 213. An auxiliary solder ball 31 is fixedly connected to the reinforcing auxiliary pad 213 and the reinforcing pad 14. The mounting surface 201 includes a corner area 2011 corresponding to the edge area 1111b, and the reinforcing auxiliary pads 213 are arranged within the corner area 2011. During the assembly process of the electronic device 1000, the solder balls 30 corresponding to the two auxiliary pads 211 connected to the auxiliary conductive sheet 212 melt after being heated, and the resulting solder flows and connects simultaneously on the auxiliary conductive sheet 212 and the conductive sheet 13 to connect the two solder balls 30 to each other to form a large-volume auxiliary solder ball 31. In this embodiment, the auxiliary conductive sheet 212 increases the contact area between the auxiliary solder ball 31 and the circuit board 200, improves the bonding force between the auxiliary solder ball 31 and the circuit board 200, and thus improves the bonding stability between the circuit board 200 and the package structure 100.

[0079] Please refer to the following: Figure 22The auxiliary conductive sheet 212 in the reinforced auxiliary pad 213 is connected to the opposite sides of the two auxiliary pads 211. Specifically, the auxiliary conductive sheet 212 includes two oppositely arranged fixed ends 2121 respectively connected to the two auxiliary pads 211. Along the direction perpendicular to one fixed end 2121 to the other fixed end 2121 (along the extension direction perpendicular to the auxiliary conductive sheet 212), the width d of the auxiliary conductive sheet 212 is less than or equal to the radial dimension of the auxiliary pad 211, to prevent the auxiliary conductive sheet 212 from connecting and conducting with adjacent auxiliary pads 211, thus avoiding short circuits. The surface of the auxiliary conductive sheet 212 facing the same direction as the mounting surface 201 is a rough surface to increase the contact area between the auxiliary solder ball 31 and the auxiliary conductive sheet 212, and to increase the contact area between the auxiliary solder ball 31 and the reinforced auxiliary pad 213, thereby improving the bonding stability between the auxiliary solder ball 31 and the circuit board 200.

[0080] In this embodiment, a connecting window 2022 is provided on the solder resist layer 202 at a position corresponding to the auxiliary conductive sheet 212, exposing the mounting surface 201 and connecting the two openings 2021. The auxiliary conductive sheet 212 is embedded in the connecting window 2022 to prevent the solder from flowing freely on the mounting surface 201 after the solder ball melts due to heat, thus preventing short circuits caused by the connection between auxiliary pads 211 with different electrical properties. Specifically, the width of the connecting window 2022 is greater than the width of the auxiliary conductive sheet 212 (the dimension along the extension direction perpendicular to the auxiliary conductive sheet 212), reserving a certain space for the flow of solder formed after the solder ball 30 melts due to heat on the auxiliary conductive sheet 212. In addition, in other embodiments, the width of the connecting window may be less than or equal to the width of the auxiliary conductive sheet to accurately control the flow area of ​​solder on the auxiliary conductive sheet during packaging. This application embodiment does not specifically limit this.

[0081] Please see Figures 23 to 25 In the fifth embodiment of the electronic device 1000 described in this application, the difference from the fourth embodiment is that a partition 15 is protruding on the auxiliary conductive sheet 212, and the partition 15 is embedded in the auxiliary solder ball 31 connected to the auxiliary solder pad 213, so as to prevent the portion of the auxiliary solder ball 31 located on both sides of the partition 15 from generating cracks and extending the fatigue life of the auxiliary solder ball 31.

[0082] Please see Figure 26 This application also provides a method for manufacturing an electronic device, used to manufacture the electronic device 1000 shown in the first embodiment above. The manufacturing method includes: Step S1: N pads are formed on the bottom surface of the packaging substrate. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. In this step, the N pads have the same radial dimension, eliminating the need for multiple steps to separately set pads with different radial dimensions. This simplifies the process of setting the pads on the bottom surface of the packaging substrate. Furthermore, the conductive sheet is formed simultaneously with the N pads, eliminating the need for a separate conductive sheet fabrication process and saving packaging substrate manufacturing time.

[0083] Step S2: Form a solder ball on each of the aforementioned pads. Specifically, N solder balls are formed one-to-one on N of the aforementioned pads, and the N solder balls have the same radial dimension. In this step, a reflow process is used to implant the solder balls onto the pads. During the reflow process, the solder of the solder ball reacts with the pad to generate an intermetallic compound, thereby achieving the implantation of the solder ball onto the pad. Generally, assuming that the radial dimensions of the N aforementioned pads are the same, the size of the solder ball used with each of the aforementioned pads is also the same. The identical radial dimensions of the N solder balls avoid the need for multiple high-temperature reflows for solder ball implantation due to different solder ball sizes. This not only simplifies the solder ball implantation process but also avoids the problem of the intermetallic compound initially formed between the solder ball and the pad growing too rapidly during multiple high-temperature reflows, which could affect the stability of the connection between the solder ball and the pad.

[0084] In this embodiment, step S11 is also included between step S1 and step S2.

[0085] Step S11: A solder resist layer is formed on the bottom surface of the packaging substrate. The solder resist layer has N openings, and N solder pads are formed one-to-one within each of the N openings. A connecting port is formed at a position on the solder resist layer corresponding to the conductive sheet, connecting two of the openings, and the conductive sheet is formed within the connecting port.

[0086] In this embodiment, before step S3, the preparation method further includes step S21.

[0087] Step S21: N auxiliary pads are formed on the mounting surface of the circuit board. The N auxiliary pads have the same radial dimension, eliminating the need for multiple steps to separately set auxiliary pads with different radial dimensions. This simplifies the process of setting the N auxiliary pads on the mounting surface of the circuit board and saves manufacturing time. Specifically, a solder resist layer is formed on the mounting surface of the circuit board, and the solder resist layer has N openings that expose the mounting surface. The N auxiliary pads are formed one by one within each of the N openings.

[0088] Step S3: The packaging substrate is mounted on the mounting surface of the circuit board, so that all N solder balls are in contact with the circuit board. Specifically, the packaging substrate is mounted on the mounting surface, so that each of the N solder balls is in contact with one of the N auxiliary pads. In this embodiment, before step S3, appropriate solder is applied to the auxiliary pads corresponding to the reinforcing pads, so that during the subsequent heat deformation of the solder balls, they together form large-volume solder balls located on the reinforcing pads.

[0089] Step S4 involves heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the circuit board. At least two adjacent solder balls on each reinforcing pad deform due to heat and connect with each other to form auxiliary solder balls covering the reinforcing pad. In this step, each solder ball reacts with the auxiliary pad it contacts to generate an intermetallic compound, connecting each solder ball to each auxiliary pad. Furthermore, after at least two adjacent solder balls on each reinforcing pad deform due to heat, molten solder flows on the conductive sheet, causing the solder of adjacent solder balls to connect with each other to form auxiliary solder balls.

[0090] Step S5: The solder balls and auxiliary solder balls are cured to fix the package substrate to the circuit board. Specifically, the solder balls and auxiliary solder balls are cooled to cure them.

[0091] The preparation method described in this application describes setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form a reinforcing pad. Solder formed by the melting of at least two adjacent solder balls on each reinforcing pad flows on the conductive sheet, connecting the adjacent solder balls to form a larger auxiliary solder ball. The large auxiliary solder ball has higher fatigue strength and can uniformly withstand larger fatigue stress, which is beneficial to improving the board-level reliability of electronic devices and thus extending the fatigue life of electronic devices.

[0092] This application provides another method for manufacturing an electronic device, used to manufacture the electronic device 1000 shown in the second embodiment above. The manufacturing method includes: Step S1: N pads are formed on the bottom surface of the packaging substrate. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. In this step, the N pads have the same radial dimension, eliminating the need for multiple steps to separately set pads with different radial dimensions. This simplifies the process of setting the pads on the bottom surface of the packaging substrate. Furthermore, the conductive sheet is formed simultaneously with the N pads, eliminating the need for a separate conductive sheet fabrication process and saving packaging substrate manufacturing time.

[0093] Step S2: Form a solder ball on each of the aforementioned pads. Specifically, N solder balls are formed one-to-one on N of the aforementioned pads, and the N solder balls have the same radial dimension. In this step, a reflow process is used to implant the solder balls onto the pads. During the reflow process, the solder of the solder ball reacts with the pad to generate an intermetallic compound, thereby achieving the implantation of the solder ball onto the pad. Generally, assuming that the radial dimensions of the N aforementioned pads are the same, the size of the solder ball used with each of the aforementioned pads is also the same. The identical radial dimensions of the N solder balls avoid the need for multiple high-temperature reflows for solder ball implantation due to different solder ball sizes. This not only simplifies the solder ball implantation process but also avoids the problem of the intermetallic compound initially formed between the solder ball and the pad growing too rapidly during multiple high-temperature reflows, which could affect the stability of the connection between the solder ball and the pad.

[0094] In this embodiment, steps S11 and S12 are further included between steps S1 and S2.

[0095] Step S11: A solder resist layer is formed on the bottom surface of the packaging substrate. The solder resist layer has N openings, and N solder pads are formed one-to-one within each of the N openings. A connecting port is formed at a position on the solder resist layer corresponding to the conductive sheet, connecting two of the openings, and the conductive sheet is formed within the connecting port.

[0096] Step S12: A partition is formed on the conductive sheet, the partition being located between the two pads connected to the conductive sheet.

[0097] It should be noted that in other embodiments, solder balls may be formed on the pads first, and then the separator may be formed on the conductive sheet, i.e., step S2 may be performed first, and then step S12 may be performed. This application does not specifically limit this.

[0098] In this embodiment, before step S3, the preparation method further includes step S21.

[0099] Step S21: N auxiliary pads are formed on the mounting surface of the circuit board. The N auxiliary pads have the same radial dimension, eliminating the need for multiple steps to separately set auxiliary pads with different radial dimensions. This simplifies the process of setting the N auxiliary pads on the mounting surface of the circuit board and saves manufacturing time. Specifically, a solder resist layer is formed on the mounting surface of the circuit board, and the solder resist layer has N openings that expose the mounting surface. The N auxiliary pads are formed one by one within each of the N openings.

[0100] Step S3: The packaging substrate is mounted on the mounting surface, so that all N solder balls are in contact with the circuit board. Specifically, the packaging substrate is mounted on the mounting surface, so that each of the N solder balls is in contact with one of the N auxiliary pads. In this embodiment, before step S3, appropriate solder is applied to the auxiliary pads corresponding to the reinforcing pads, so that during the subsequent heat deformation of the solder balls, they together form large-volume solder balls located on the reinforcing pads.

[0101] Step S4 involves heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the circuit board. At least two adjacent solder balls on each reinforcing pad deform due to heat and connect with each other to form auxiliary solder balls covering the reinforcing pad. In this step, each solder ball reacts with each auxiliary pad to generate an intermetallic compound, connecting each solder ball to each auxiliary pad. Furthermore, two solder balls located on either side of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0102] Step S5: The solder balls and auxiliary solder balls are cured to fix the package substrate to the circuit board. Specifically, the solder balls and auxiliary solder balls are cooled to cure them.

[0103] The preparation method described in this application involves setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form reinforced pads. A partition is set on the conductive sheet. Solder formed by the melting of solder balls located on both sides of the partition flows on the conductive sheet and passes through the partition, connecting adjacent solder balls to form a large-volume auxiliary solder ball embedded with the partition. The large-volume auxiliary solder ball has high fatigue strength and can uniformly withstand large fatigue stress. Moreover, the partition can prevent the crack propagation or connection of the portion of the auxiliary solder ball located on both sides of the partition, which is beneficial to extending the fatigue life of the auxiliary solder ball and improving the board-level reliability of the electronic device.

[0104] This application provides a third method for manufacturing an electronic device, used to manufacture the electronic device 1000 shown in the third embodiment above. The manufacturing method includes: Step S1: N pads are formed on the bottom surface of the packaging substrate. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. In this step, the N pads have the same radial dimension, eliminating the need for multiple steps to separately set pads with different radial dimensions. This simplifies the process of setting the pads on the bottom surface of the packaging substrate. Furthermore, the conductive sheet is formed simultaneously with the N pads, eliminating the need for a separate conductive sheet fabrication process and saving packaging substrate manufacturing time.

[0105] Step S2: Form a solder ball on each of the aforementioned pads. Specifically, N solder balls are formed one-to-one on N of the aforementioned pads, and the N solder balls have the same radial dimension. In this step, a reflow process is used to implant the solder balls onto the pads. During the reflow process, the solder of the solder ball reacts with the pad to generate an intermetallic compound, thereby achieving the implantation of the solder ball onto the pad. Generally, assuming that the radial dimensions of the N aforementioned pads are the same, the size of the solder ball used with each of the aforementioned pads is also the same. The identical radial dimensions of the N solder balls avoid the need for multiple high-temperature reflows for solder ball implantation due to different solder ball sizes. This not only simplifies the solder ball implantation process but also avoids the problem of the intermetallic compound initially formed between the solder ball and the pad growing too rapidly during multiple high-temperature reflows, which could affect the stability of the connection between the solder ball and the pad.

[0106] In this embodiment, step S11 is also included between step S1 and step S2.

[0107] Step S11: A solder resist layer is formed on the bottom surface of the packaging substrate. The solder resist layer has N openings, and N solder pads are formed one-to-one within each of the N openings. A connecting port is formed at a position on the solder resist layer corresponding to the conductive sheet, connecting two of the openings, and the conductive sheet is formed within the connecting port.

[0108] In this embodiment, before step S3, the preparation method further includes step S21.

[0109] Step S21: Form N auxiliary pads on the mounting surface of the circuit board. Specifically, step S21 includes steps S211 to S212. Step S211: N auxiliary pads are formed on the mounting surface of the circuit board. The N auxiliary pads have the same radial dimension, eliminating the need for multiple steps to separately set auxiliary pads with different radial dimensions. This simplifies the process of setting the N auxiliary pads on the mounting surface of the circuit board and saves manufacturing time. Specifically, a solder resist layer is formed on the mounting surface of the circuit board, and the solder resist layer has N openings that expose the mounting surface. The N auxiliary pads are formed one by one within each of the N openings.

[0110] Step S212: A partition is formed on the mounting surface of the circuit board at a position corresponding to the conductive sheet. The partition is located between two auxiliary pads corresponding to the two pads connected to the conductive sheet.

[0111] It should be noted that in other embodiments, in step S21, a partition can be formed on the mounting surface of the circuit board first, and then an auxiliary pad can be formed. That is, step S212 can be performed first, and then step S211 can be performed. This application embodiment does not specifically limit this.

[0112] Step S3: Mount the packaging substrate onto the mounting surface, ensuring that all N solder balls are in contact with the circuit board. Specifically, mount the packaging substrate onto the mounting surface, ensuring that each of the N solder balls is in contact with one of the N auxiliary pads. The spacer is located between two solder balls on two pads connected to the conductive sheet. In this embodiment, prior to step S3, appropriate solder is applied to auxiliary pads corresponding to the reinforcing pads, so that during subsequent heat deformation of the solder balls, it forms a large-volume solder ball on the reinforcing pad.

[0113] Step S4 involves heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the circuit board. At least two adjacent solder balls on each reinforcing pad deform due to heat and connect with each other to form auxiliary solder balls covering the reinforcing pad. In this step, each solder ball reacts with each auxiliary pad to generate an intermetallic compound, connecting each solder ball to each auxiliary pad. Furthermore, two solder balls located on either side of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0114] Step S5: The solder balls and auxiliary solder balls are cured to fix the package substrate to the circuit board. Specifically, the solder balls and auxiliary solder balls are cooled to cure them.

[0115] The preparation method described in this application involves setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form reinforced pads. A partition is set on the circuit board at a position corresponding to the conductive sheet. During the heating and pressurization process of the packaging structure and the circuit board, the solder balls located on both sides of the partition melt and the resulting solder flows on the conductive sheet and passes through the partition, connecting adjacent solder balls to form a large-volume auxiliary solder ball embedded with the partition. The large-volume auxiliary solder ball has high fatigue strength and can uniformly withstand large fatigue stress. Moreover, the partition can prevent the crack propagation or connection of the portion of the auxiliary solder ball located on both sides of the partition, which is beneficial to extending the fatigue life of the auxiliary solder ball and improving the board-level reliability of the electronic device.

[0116] This application provides a method for manufacturing a fourth electronic device, used to manufacture the electronic device shown in the fourth embodiment above. The manufacturing method includes: Step S1: N pads are formed on the bottom surface of the packaging substrate. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. In this step, the N pads have the same radial dimension, eliminating the need for multiple steps to separately set pads with different radial dimensions. This simplifies the process of setting the pads on the bottom surface of the packaging substrate. Furthermore, the conductive sheet is formed simultaneously with the N pads, eliminating the need for a separate conductive sheet fabrication process and saving packaging substrate manufacturing time.

[0117] Step S2: Form a solder ball on each of the aforementioned pads. Specifically, N solder balls are formed one-to-one on N of the aforementioned pads, and the N solder balls have the same radial dimension. In this step, a reflow process is used to implant the solder balls onto the pads. During the reflow process, the solder of the solder ball reacts with the pad to generate an intermetallic compound, thereby achieving the implantation of the solder ball onto the pad. Generally, assuming that the radial dimensions of the N aforementioned pads are the same, the size of the solder ball used with each of the aforementioned pads is also the same. The identical radial dimensions of the N solder balls avoid the need for multiple high-temperature reflows for solder ball implantation due to different solder ball sizes. This not only simplifies the solder ball implantation process but also avoids the problem of the intermetallic compound initially formed between the solder ball and the pad growing too rapidly during multiple high-temperature reflows, which could affect the stability of the connection between the solder ball and the pad.

[0118] In this embodiment, step S11 is also included between step S1 and step S2.

[0119] Step S11: A solder resist layer is formed on the bottom surface of the packaging substrate. The solder resist layer has N openings, and N solder pads are formed one-to-one within each of the N openings. A connecting port is formed at a position on the solder resist layer corresponding to the conductive sheet, connecting two of the openings, and the conductive sheet is formed within the connecting port.

[0120] In this embodiment, before step S3, the preparation method further includes step S21.

[0121] Step S21: N auxiliary pads are formed on the mounting surface of the circuit board. The N auxiliary pads have the same radial dimension, and auxiliary conductive sheets are formed on the mounting surface at positions corresponding to the conductive sheets. The auxiliary conductive sheets connect adjacent auxiliary pads to form reinforced auxiliary pads. Specifically, a solder resist layer is formed on the mounting surface of the circuit board. The solder resist layer has N openings that expose the mounting surface. The N auxiliary pads are formed within these N openings. A connecting window is formed on the solder resist layer at a position corresponding to the auxiliary conductive sheet, connecting two openings and exposing the mounting surface. The auxiliary conductive sheet is formed within the connecting window. In step S21, the N auxiliary pads have the same radial dimension, eliminating the need for multiple steps to separately set auxiliary pads with different radial dimensions. This simplifies the process of setting the N auxiliary pads on the mounting surface of the circuit board. Furthermore, the auxiliary conductive sheets are formed simultaneously with the auxiliary pads, eliminating the need for an additional process to form the auxiliary conductive sheets and saving circuit board manufacturing time.

[0122] Step S3: The packaging substrate is mounted on the mounting surface of the circuit board, so that all N solder balls are in contact with the circuit board. Specifically, the packaging substrate is mounted on the mounting surface, so that each of the N solder balls is in contact with one of the N auxiliary pads. In this embodiment, before step S3, appropriate solder is applied to the reinforcing auxiliary pads to form large-volume solder balls together with the solder balls located on the reinforcing pads during the subsequent heat deformation of the solder balls.

[0123] Step S4 involves heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the circuit board. At least two adjacent solder balls on each reinforcing pad deform due to heat and connect with each other to form auxiliary solder balls covering the reinforcing pad. In this step, each solder ball reacts with each auxiliary pad to generate an intermetallic compound, connecting each solder ball to each auxiliary pad. After at least two adjacent solder balls on each reinforcing pad deform due to heat, molten solder flows on the conductive sheet and the auxiliary conductive sheet, causing the solder of adjacent solder balls to connect with each other to form a large-volume auxiliary solder ball covering the reinforcing auxiliary pad and the reinforcing pad.

[0124] Step S5: The solder balls and auxiliary solder balls are cured to fix the package substrate to the circuit board. Specifically, the solder balls and auxiliary solder balls are cooled to cure them.

[0125] The preparation method described in this application involves setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form a reinforcing pad. An auxiliary conductive sheet is set on the mounting surface of the circuit board at a position corresponding to the conductive sheet. The auxiliary conductive sheet connects and conducts at least two adjacent auxiliary pads to form a reinforcing auxiliary pad. Solder formed by the melting of at least two adjacent solder balls on each reinforcing pad flows on the conductive sheet and the auxiliary conductive sheet, connecting adjacent solder balls to form auxiliary solder balls covering the reinforcing pad and the reinforcing auxiliary pad. The large-volume auxiliary solder balls have higher fatigue strength and can uniformly withstand larger fatigue stress, which is beneficial to improving the board-level reliability of electronic devices and thus extending the fatigue life of electronic devices.

[0126] This application provides a method for manufacturing a fifth type of electronic device, used to manufacture the electronic device shown in the fifth embodiment above. The manufacturing method includes: Step S1: N pads are formed on the bottom surface of the packaging substrate. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. In this step, the N pads have the same radial dimension, eliminating the need for multiple steps to separately set pads with different radial dimensions. This simplifies the process of setting the pads on the bottom surface of the packaging substrate. Furthermore, the conductive sheet is formed simultaneously with the N pads, eliminating the need for a separate conductive sheet fabrication process and saving packaging substrate manufacturing time.

[0127] Step S2: Form a solder ball on each of the aforementioned pads. Specifically, N solder balls are formed one-to-one on N of the aforementioned pads, and the N solder balls have the same radial dimension. In this step, a reflow process is used to implant the solder balls onto the pads. During the reflow process, the solder of the solder ball reacts with the pad to generate an intermetallic compound, thereby achieving the implantation of the solder ball onto the pad. Generally, assuming that the radial dimensions of the N aforementioned pads are the same, the size of the solder ball used with each of the aforementioned pads is also the same. The identical radial dimensions of the N solder balls avoid the need for multiple high-temperature reflows for solder ball implantation due to different solder ball sizes. This not only simplifies the solder ball implantation process but also avoids the problem of the intermetallic compound initially formed between the solder ball and the pad growing too rapidly during multiple high-temperature reflows, which could affect the stability of the connection between the solder ball and the pad.

[0128] In this embodiment, step S11 is also included between step S1 and step S2.

[0129] Step S11: A solder resist layer is formed on the bottom surface of the packaging substrate. The solder resist layer has N openings, and N solder pads are formed one-to-one within each of the N openings. A connecting port is formed at a position on the solder resist layer corresponding to the conductive sheet, connecting two of the openings, and the conductive sheet is formed within the connecting port.

[0130] In this embodiment, before step S3, the preparation method further includes steps S21 and S22.

[0131] Step S21: N auxiliary pads are formed on the mounting surface of the circuit board. The N auxiliary pads have the same radial dimension, and auxiliary conductive sheets are formed on the mounting surface at positions corresponding to the conductive sheets. The auxiliary conductive sheets connect adjacent auxiliary pads to form reinforced auxiliary pads. Specifically, a solder resist layer is formed on the mounting surface of the circuit board. The solder resist layer has N openings that expose the mounting surface. The N auxiliary pads are formed within these N openings. A connecting window is formed on the solder resist layer at a position corresponding to the auxiliary conductive sheet, connecting two openings and exposing the mounting surface. The auxiliary conductive sheet is formed within the connecting window. In step S21, the N auxiliary pads have the same radial dimension, eliminating the need for multiple steps to separately set auxiliary pads with different radial dimensions. This simplifies the process of setting the N auxiliary pads on the mounting surface of the circuit board. Furthermore, the auxiliary conductive sheets are formed simultaneously with the auxiliary pads, eliminating the need for an additional process to form the auxiliary conductive sheets and saving circuit board manufacturing time.

[0132] Step S22: A partition is formed on the auxiliary conductive sheet, the partition being located between the two auxiliary pads connected to the auxiliary conductive sheet.

[0133] Step S3: The packaging substrate is mounted on the mounting surface of the circuit board, so that all N solder balls are in contact with the circuit board. Specifically, the packaging substrate is mounted on the mounting surface, so that each of the N solder balls is in contact with one of the N auxiliary pads. The partition is located between two solder balls corresponding to two auxiliary pads. In this embodiment, before step S3, appropriate solder is applied to the auxiliary pads to form large-volume solder balls together with the solder balls during subsequent heat deformation.

[0134] Step S4 involves heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the circuit board. Specifically, at least two adjacent solder balls on each reinforcing pad deform due to heat and connect with each other to form auxiliary solder balls covering the reinforcing pad. Each solder ball reacts with each auxiliary pad to generate an intermetallic compound, connecting each solder ball to each auxiliary pad. Two solder balls located on either side of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

[0135] Step S5: The solder balls and auxiliary solder balls are cured to fix the package substrate to the circuit board. Specifically, the solder balls and auxiliary solder balls are cooled to cure them.

[0136] The preparation method described in this application involves setting a conductive sheet on the bottom surface of the packaging substrate. The conductive sheet connects and conducts at least two adjacent electrical pads to form a reinforcing pad. An auxiliary conductive sheet is set on the mounting surface of the circuit board at a position corresponding to the conductive sheet. The auxiliary conductive sheet connects and conducts at least two adjacent auxiliary pads to form a reinforcing auxiliary pad. A partition is set on the auxiliary conductive sheet. Solder formed by the melting of at least two adjacent solder balls on each reinforcing pad flows on the conductive sheet and the auxiliary conductive sheet and passes through the partition, connecting adjacent solder balls to form an auxiliary solder ball embedded with the partition. The large-volume auxiliary solder ball has high fatigue strength and can uniformly withstand large fatigue stress. Moreover, the partition can prevent the crack propagation or connection of the portion of the auxiliary solder ball located on both sides of the partition, which is beneficial to extending the fatigue life of the auxiliary solder ball, improving the board-level reliability of the electronic device, and thus extending the fatigue life of the electronic device.

[0137] In the packaging structure 100 and the electronic device 1000 described in this application embodiment, at least two adjacent pads 12 with the same electrical properties on the bottom surface 111 of the packaging substrate 10 are connected and made conductive by a conductive sheet 13 to form a reinforcing pad 14. During the soldering process of the electronic device 1000, at least adjacent solder balls on the reinforcing pad 14 are connected to each other through the conductive sheet 13 when they are deformed by heat to form a large-volume auxiliary solder ball 30. The large-volume auxiliary solder ball 30 has better fatigue strength, can evenly disperse the fatigue stress it bears and is not easy to generate cracks, thereby increasing the board-level reliability of the electronic device 1000 and extending the service life of the electronic device 1000.

[0138] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A packaging structure, characterized in that, The device includes a packaging substrate and a chip. The packaging substrate includes a packaging surface and a bottom surface disposed opposite to each other. The bottom surface includes a central area, an edge area located around the central area, and a connection area connecting the central area and the edge area. The chip is disposed on the packaging surface. The bottom surface has N pads. At least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad. The distance between the pads in the edge area and the pads in the central area is greater than the distance between the pads in the connection area and the pads in the central area. The reinforcing pads are arranged in the edge area. A partition is protruding from the conductive sheet of the reinforcing pad. The partition separates the two pads connected by the conductive sheet to separate the solder balls formed on the reinforcing pad. The partition is elongated, with its length direction perpendicular to the extension direction of the conductive sheet. The width of the partition is less than or equal to the distance between the two solder balls on the two pads. The length and height of the partition are both less than the radial diameter of the solder balls on the pads.

2. The packaging structure according to claim 1, characterized in that, The surface of the conductive sheet that faces the same direction as the bottom surface is a rough surface.

3. The packaging structure according to claim 1 or 2, characterized in that, Along a direction perpendicular to the bottom surface, the height of the reinforcing pad is greater than the height of the other pads.

4. The packaging structure according to any one of claims 1-3, characterized in that, The conductive sheet includes two oppositely arranged connection ends that are respectively connected to the two pads. In a direction perpendicular to one connection end to the other connection end, the width of the conductive sheet is less than or equal to the radial dimension of the pad.

5. The packaging structure according to any one of claims 1-4, characterized in that, The radial dimensions of the N pads are the same.

6. The packaging structure according to claim 1, characterized in that, The radial dimension of the pad located in the edge region is greater than the radial dimension of the pad located in the center region and the connection region.

7. The packaging structure according to claim 1, characterized in that, The bottom surface includes an installation area, which includes a central area, an edge area, and a connecting area. The installation area is rectangular, and the corner of the installation area is the edge area.

8. The packaging structure according to claim 7, characterized in that, At least two of the aforementioned reinforcing pads are arranged within the edge region.

9. The packaging structure according to claim 8, characterized in that, The edge region includes a first boundary and a second boundary connected to the first boundary. At least one of the at least two reinforcing pads is distributed along the first boundary and its length direction is the same as the extension direction of the first boundary. At least one of the at least two reinforcing pads is distributed along the second boundary and its length direction is the same as the extension direction of the second boundary.

10. The packaging structure according to any one of claims 1-9, characterized in that, The bottom surface is provided with a solder resist layer, and the solder resist layer has N openings that expose the bottom surface. Each opening is embedded with a solder pad. The conductive sheet is disposed on the solder resist layer between two solder pads. Alternatively, the solder resist layer and the conductive sheet have a connecting port that exposes the bottom surface and connects the two openings at the corresponding positions. The conductive sheet is embedded in the connecting port.

11. The packaging structure according to claim 1, characterized in that, The partition includes a fixed end and a free end arranged opposite to each other. The fixed end is fixed to the conductive sheet, and the width of the free end gradually decreases along the direction from the fixed end to the free end.

12. An electronic device, characterized in that, The invention includes a circuit board and a packaging structure according to any one of claims 1-11, wherein the packaging substrate is mounted on the mounting surface of the circuit board, and an auxiliary solder ball is provided at a position on the mounting surface corresponding to the reinforcing pad, the auxiliary solder ball covering the reinforcing pad and connecting the reinforcing pad and the circuit board, and a solder ball is provided at a position on the mounting surface corresponding to the pad, the solder ball connecting the pad and the circuit board.

13. The electronic device according to claim 12, characterized in that, The auxiliary solder ball is formed by solder balls on at least two adjacent pads of the reinforcing pad being heated and deformed and connected to each other during encapsulation.

14. The electronic device according to claim 12 or 13, characterized in that, A partition is provided on the mounting surface at the position corresponding to the conductive sheet, and the partition is embedded in the auxiliary solder ball connected to the reinforcing pad.

15. The electronic device according to claim 12 or 13, characterized in that, The mounting surface is provided with N auxiliary pads that correspond one-to-one with the pads. An auxiliary conductive sheet is provided on the mounting surface at the position corresponding to the conductive sheet of the reinforcing pad. The auxiliary conductive sheet connects two adjacent auxiliary pads to form a reinforcing auxiliary pad. The auxiliary solder ball is fixedly connected to the reinforcing auxiliary pad and the reinforcing pad.

16. The electronic device according to claim 15, characterized in that, The surface of the auxiliary conductive sheet that faces the same direction as the mounting surface is a rough surface.

17. The electronic device according to claim 15 or 16, characterized in that, The N auxiliary pads have the same radial dimension. The auxiliary conductive sheet includes two fixed ends that are arranged opposite to each other and respectively connected to the two auxiliary pads. In a direction perpendicular to one of the fixed ends toward the other fixed end, the width of the auxiliary conductive sheet is less than or equal to the radial dimension of the auxiliary pad.

18. The electronic device according to any one of claims 15-17, characterized in that, The mounting surface is provided with a solder resist layer, and the solder resist layer has N openings that expose the mounting surface. Each opening is embedded with an auxiliary pad. An auxiliary conductive sheet is disposed on the solder resist layer between two auxiliary pads. Alternatively, the solder resist layer and the auxiliary conductive sheet have a connecting window that exposes the mounting surface and connects the two openings, and the auxiliary conductive sheet is embedded in the connecting window.

19. The electronic device according to any one of claims 15-18, characterized in that, The auxiliary conductive sheet has a protruding partition, which is embedded in the auxiliary solder ball connected to the auxiliary solder pad.

20. The electronic device according to claim 14 or 19, characterized in that, The partition is completely embedded in the auxiliary solder ball, and the partition is located between the two pads connected by the conductive sheet. The partition includes two opposing sides, which face the two pads connected by the conductive sheet respectively.

21. The electronic device according to claim 14, 19 or 20, characterized in that, The partition includes a fixed end and a free end disposed opposite to each other. The fixed end is used to fix the partition to the packaging substrate or the circuit board. The width of the free end gradually decreases along the direction from the fixed end to the free end.

22. A method for manufacturing an electronic device, used to manufacture the electronic device according to any one of claims 12-21, characterized in that, include: N pads are formed on the bottom surface of the packaging substrate, wherein at least two adjacent pads with the same electrical properties are connected by a conductive sheet to form a reinforcing pad; A solder ball is formed on each of the aforementioned pads; The packaging substrate is mounted on the mounting surface of the circuit board, so that all N solder balls are in contact with the circuit board; The packaging substrate and the circuit board are heated and pressurized to fix the solder balls to the circuit board, wherein at least two adjacent solder balls on each reinforcing pad are deformed by heat and connected to each other to form auxiliary solder balls covering the reinforcing pad; The solder balls and the auxiliary solder balls are used to fix the packaging substrate to the circuit board.

23. The preparation method according to claim 22, characterized in that, The radial dimensions of the N pads are the same.

24. The preparation method according to claim 22 or 23, characterized in that, The radial dimensions of the solder balls on each of the aforementioned pads are identical.

25. The preparation method according to any one of claims 22-24, characterized in that, Before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: A partition is formed on the mounting surface of the circuit board at a position corresponding to the conductive sheet; During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the partition is located between the two solder balls on the two pads connected to the conductive sheet; During the heating and pressurization process of the packaging substrate and the circuit board, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

26. The preparation method according to any one of claims 22-24, characterized in that, After forming a solder ball on each of the pads, the preparation method further includes: forming a partition on the conductive sheet, the partition being located between two solder balls on two pads connected to the conductive sheet; During the heating and pressurization process of the packaging substrate and the circuit board, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

27. The preparation method according to any one of claims 22-24, characterized in that, Before forming a solder ball on each of the said solder pads, the preparation method further includes: forming a partition on the conductive sheet, the partition being located between two said solder pads connected to the conductive sheet; During the process of forming a solder ball on each of the said pads, the partition is located between the two solder balls on the two said pads; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

28. The preparation method according to any one of claims 22-24, characterized in that, Before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: N auxiliary pads are formed on the mounting surface of the circuit board, wherein the N auxiliary pads have the same radial dimension, and auxiliary conductive sheets are formed on the mounting surface at positions corresponding to the conductive sheets, and the auxiliary conductive sheets connect two adjacent auxiliary pads to form reinforced auxiliary pads; During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the N solder balls contact the N auxiliary pads on the circuit board one by one; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, at least two adjacent solder balls on each reinforcing pad are deformed by heat and connected to each other to form auxiliary solder balls covering the reinforcing auxiliary pad and the reinforcing pad.

29. The preparation method according to claim 26, characterized in that, Before mounting the packaging substrate onto the mounting surface of the circuit board, the preparation method further includes: forming a partition on the auxiliary conductive sheet, the partition being located between two auxiliary pads connected to the auxiliary conductive sheet; During the process of mounting the packaging substrate onto the mounting surface of the circuit board, the partition is located between the two solder balls corresponding to the two auxiliary pads; During the process of heating and pressurizing the packaging substrate and the circuit board to fix the solder balls to the pads, the two solder balls located on both sides of the partition deform due to heat and connect with each other to form auxiliary solder balls covering the partition.

Images