Circuit board assembly and electronic device
Patent Information
- Application Number
- PCT/CN2026/079095
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-20
- Filing Date
- 2026-02-13
- Publication Date
- 2026-08-27
Smart Images
Figure CN2026079095_27082026_PF_FP_ABST
Abstract
Description
Circuit board assemblies and electronic equipment
[0001] Cross-references to related applications
[0002] This application claims priority to Chinese Patent Application No. 202510188826.3, filed in China on February 20, 2025, the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application belongs to the field of electronic equipment technology, specifically relating to a circuit board assembly and an electronic device. Background Technology
[0004] As chip design becomes increasingly integrated, with multi-functional modules designed on a single wafer, such as System-on-Chips (SoCs), the size of the encapsulated chips is growing, leading to higher risks related to soldering reliability. To address the mechanical stress issues affecting chip soldering reliability, a backfill adhesive is typically applied after soldering to reinforce the chip and the printed circuit board (PCB).
[0005] In related technologies, as chips pursue ultimate performance, the heat generated by the chip's computing units during operation is also increasing, leading to higher overall chip temperatures. During the transition between operation and sleep states, the heating and cooling processes cause the solder paste at the bottom of the chip to expand and contract, generating alternating thermal stress. Over long periods, this stress can lead to solder ball fatigue and breakage, affecting the lifespan and performance of the chip and circuit board components. Summary of the Invention
[0006] The purpose of this application is to provide a circuit board assembly and electronic device that can solve the problem in the related art where the service life and performance of circuit board assemblies and chips are affected by solder ball breakage.
[0007] In a first aspect, embodiments of this application provide a circuit board assembly, including a printed circuit board, a chip, solder balls, and an adhesive. The solder balls and the adhesive are disposed between the printed circuit board and the chip to connect the printed circuit board and the chip. The chip includes a first region and a second region. The first region is located outside the second region and is a region close to the edge of the chip. The second region includes a heat source region. The adhesive is located in the first region.
[0008] Secondly, embodiments of this application also provide an electronic device, including a housing and a circuit board assembly as described in the first aspect, the circuit board assembly being disposed within the housing.
[0009] In this embodiment, the chip includes a heat source area located in the second region, and the adhesive is located in the first region. This means the adhesive can avoid the heat source area of the chip, thus preventing temperature fluctuations in the heat source area of the second region from affecting the adhesive in the first region. This avoids strain caused by thermal expansion and contraction of the adhesive due to temperature changes, which could lead to the solder balls being stretched. Consequently, the solder balls are prevented from cracking or breaking due to stretching, effectively extending their lifespan. This, in turn, helps extend the lifespan of the chip and circuit board assembly, ensuring the performance of the circuit board assembly and the electronic devices using the circuit board assembly. Attached Figure Description
[0010] Figure 1 is a schematic diagram of one of the circuit board assemblies provided in an embodiment of this application;
[0011] Figure 2 is a second schematic diagram of a circuit board assembly provided in an embodiment of this application;
[0012] Figure 3 is a third schematic diagram of a circuit board assembly provided in an embodiment of this application;
[0013] Figure 4 is one of the schematic diagrams of the flow of adhesive in a circuit board assembly during the dispensing process according to an embodiment of this application;
[0014] Figure 5 is a second schematic diagram of the flow of adhesive in a circuit board assembly during the dispensing process according to an embodiment of this application;
[0015] Figure 6 is a schematic diagram of the solder ball arrangement design in a circuit board assembly provided in an embodiment of this application;
[0016] Figure 7 is a partial structural schematic diagram of a circuit board assembly provided in an embodiment of this application;
[0017] Figure 8 is a schematic diagram of the structure of a circuit board assembly in the related technology. Detailed Implementation
[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0019] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0020] The circuit board assembly provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0021] Please refer to Figures 1 to 7. The circuit board assembly provided in this embodiment includes a printed circuit board 10, a chip 20, solder balls 30, and adhesive 40 (shown as the gray area surrounded by black lines in Figure 1). The solder balls 30 and the adhesive 40 are disposed between the printed circuit board 10 and the chip 20 to connect the printed circuit board 10 and the chip 20. The chip 20 includes a first region 21 and a second region 22. The first region 21 is located outside the second region 22 and is a region close to the edge of the chip 20. The second region 22 includes a heat source area. The adhesive 40 is located in the first region 21.
[0022] Understandably, the chip 20 integrates multiple functional modules on a wafer and is packaged into a single functional device; for example, the chip 20 can be a system-on-a-chip (SoC). The printed circuit board 10 is used to carry electronic components and for soldering. The solder balls 30 can be solder balls, which solidify after melting and are used to solder the chip 20 onto the printed circuit board 10, thus connecting the chip 20 and the printed circuit board 10. The adhesive 40 can be a substance capable of bonding, such as a curable glue, used to bond the chip 20 and the printed circuit board 10, also serving to connect the chip 20 and the printed circuit board 10.
[0023] In this embodiment, by providing solder balls 30 and adhesive 40 between the chip 20 and the printed circuit board 10, the connection performance between the chip 20 and the printed circuit board 10 can be effectively enhanced, and the stability of the chip 20 on the printed circuit board 10 can be increased.
[0024] Please refer to Figures 2 and 3 for details. The chip 20 includes a first region 21 (shown as the gray area surrounded by black lines in Figures 2 and 3, where the dashed circle in Figure 3 indicates no solder balls) and a second region 22 (the white area not surrounded by black lines in Figures 2 and 3). The first region 21 is located outside the second region 22. For example, the second region 22 can be understood as the middle region of the chip 20, and the first region 21 is the region other than the second region 22. The first region 21 can be understood as the edge region of the chip 20.
[0025] The solder balls 30 connect the printed circuit board 10 and the chip 20, which can be understood as the solder balls 30 being located on one side of the chip 20. The chip 20 includes a heat source area located in the second region 22. It should be noted that the heat source area can be understood as an area on the chip 20 that generates heat, such as an area on the chip 20 where electronic devices such as capacitors and resistors are mounted, or an area of the chip 20 near functional components (such as a camera) or a battery within an electronic device.
[0026] In this embodiment, the chip 20 includes a first region 21 and a second region 22, with the heat source region located in the second region 22 and the adhesive 40 located in the first region 21. That is, the adhesive 40 can avoid the heat source region of the chip 20. Therefore, the temperature rise and fall of the heat source region located in the second region 22 will not affect the adhesive 40 located in the first region 21. This avoids the strain caused by the thermal expansion and contraction of the adhesive 40 due to temperature rise and fall, which would cause the solder balls 30 to be pulled. This also avoids the solder balls 30 from cracking or breaking due to being pulled, thereby effectively improving the lifespan of the solder balls 30. This also helps to improve the lifespan of the chip 20 and the circuit board assembly, thereby ensuring the performance of electronic devices using the circuit board assembly.
[0027] Optionally, the area of the heat source region is less than or equal to the area of the second region 22. For example, the entire second region 22 can be a heat source region, or a portion of the second region 22 can be a heat source region. The size and location of the heat source region can be determined based on the mounting position of the electronic devices on the chip 20 and / or the mounting position of the functional devices within the electronic device. In this embodiment, the heat source region is located in the second region 22, while the adhesive 40 is located in the first region 21. Therefore, temperature fluctuations in the heat source region located in the second region 22 will not affect the adhesive 40 located in the first region 21, thus effectively improving the lifespan of the solder balls 30.
[0028] In some embodiments, the solder ball density in the first region 21 of the chip 20 is greater than that in the second region 22, meaning the solder balls 30 in the first region 21 of the chip 20 are arranged more densely. For example, referring to Figures 4 and 5, the adhesive 40 is a curable adhesive (shown as the gray area surrounded by black lines in Figure 5). The curable adhesive can be applied to a local area (e.g., an edge area) of the chip 20 using a local dispensing method. Since the solder balls 30 in the first region 21 are arranged more densely, during the dispensing process, the curable adhesive, under the action of surface tension, generates capillary flow between the solder balls 30. The curable adhesive will preferentially flow towards the direction and area where the solder balls 30 are more densely arranged (as indicated by the arrows formed by the black lines in Figures 4 and 5), meaning the curable adhesive will preferentially flow in the first region 21. In this way, by setting the arrangement density of the solder balls 30 in the first region 21 to be denser, it is possible to ensure that the adhesive 40 flows and solidifies in the first region 21, thereby preventing the adhesive 40 from flowing to the second region 22 where the heat source area is located. This also prevents the temperature rise and fall of the heat source area from affecting the adhesive 40 in the first region 21, that is, the adhesive 40 will not undergo thermal expansion and contraction. This also prevents the solder balls 30 from being pulled and broken, thus effectively ensuring the stability and service life of the solder balls 30, which in turn helps to improve the service life of the chip 20 and the circuit board assembly.
[0029] Optionally, the adhesive 40 is a curable glue, such as a curable resin glue, which is applied to the solder balls 30 in the first region 21 by dispensing.
[0030] For example, the curable adhesive is applied from the edge of the chip 20 via dispensing. Under surface tension, it flows through the solder balls 30 via capillary action. Because the solder balls 30 in the first region 21 are more densely packed, the curable adhesive preferentially flows and cures in the direction and area where the solder balls 30 are more densely packed (i.e., the first region 21), ultimately curing and filling the spaces between the solder balls 30 in the first region 21. In this embodiment, the first region 21 can also be understood as the area covered by the curable adhesive, or the first region 21 can be larger than the area covered by the curable adhesive, meaning the first region 21 can also include areas not covered by the curable adhesive.
[0031] Referring to Figure 6, in some embodiments, the area where the second region 22 connects to the first region 21 includes a first connection area 221 (the dashed circle in Figure 5 indicates that no solder balls are provided), and the first connection area 221 is not provided with solder balls 30.
[0032] In related technologies, such as as shown in Figure 8, the solder balls 30 on the chip 20 are typically arranged in an array, that is, the solder balls 30 on the chip 20 are distributed in a row × b column manner (where a and b are both integers greater than 1). In this embodiment of the application, as shown in Figure 6, the second region 22 includes a first connection area 221 connected to the first region 21. For example, the first connection area 221 is one or more rows, and / or one or more columns in the second region 22 that are connected to (or can also be understood as adjacent to) the first region 21. The first connection area 221 is not provided with solder balls 30, that is, one or more rows in the second region 22 that are connected to the first region 21 are not provided with solder balls 30, and / or one or more columns in the second region 22 that are connected to the first region 21 are not provided with solder balls 30. In other words, the second region 22 can be understood as including areas where the entire row and / or the entire column are not provided with solder balls 30 (for example, the area represented by the dashed box A in Figure 6). Therefore, during the dispensing process of adhesive 40, the capillary flow effect of adhesive 40 will cause adhesive 40 to preferentially flow to the first region 21 where solder balls 30 are more densely arranged. Since solder balls 30 are not set in the first connection region 221, adhesive 40 can be prevented from flowing to the first connection region 221 where solder balls 30 are not set during the dispensing process. This prevents adhesive 40 from flowing to the second region 22 during the dispensing process, ensuring that adhesive 40 is finally set in the first region 21.
[0033] Optionally, the second region 22 includes an on-chip capacitor region, such as a second on-chip capacitor (LSC) region 224, which is adjacent to the first connection region 221. It should be noted that the second on-chip capacitor region 224 is the area on the chip 20 where capacitors are provided. Capacitors generate heat during operation, and the heat source region may include the second on-chip capacitor region 224. Referring to Figures 2 and 6, the second on-chip capacitor region 224 is adjacent to the first connection region 221, and the first connection region 221 does not have solder balls 30. This effectively prevents the adhesive 40 from flowing to the first connection region 221 during dispensing, and even less likely to flow to the second on-chip capacitor region 224 adjacent to the first connection region 221. Therefore, the heat generated by the second on-chip capacitor region 224 will not affect the adhesive 40, thus effectively ensuring the stability of the solder balls 30.
[0034] Referring to Figures 6 and 7, in some embodiments, the solder balls 30 located in the first region 21 (shown as the gray area surrounded by black lines in Figure 7) are arranged at equal intervals with a first spacing (d1 shown in Figure 7); the region where the second region 22 connects to the first region 21 includes a second connection region 222 (the dashed circle in Figure 6 indicates that no solder balls are provided), the solder balls 30 located in the second connection region 222 are not arranged at equal intervals, and the spacing between the solder balls 30 located in the second connection region 222 includes a second spacing (d2 shown in Figure 7), the second spacing being greater than the first spacing.
[0035] The second connection area 222 can also be understood as the area adjacent to the first area 21, or as the edge area of the second area 22. The spacing between the solder balls 30 located in the second connection area 222 includes a second spacing. The solder balls 30 in the second connection area 222 are not equally spaced, that is, the spacing between the solder balls 30 in the second connection area 222 includes at least two different spacings. For example, it may include a first spacing and a second spacing. That is, the spacing between some solder balls 30 in the second connection area 222 is the first spacing, and the spacing between other solder balls 30 is the second spacing. The second spacing is greater than the first spacing, and the solder balls 30 located in the first region 21 are arranged at equal intervals with the first spacing. This results in the second connection region 222 including a region where the solder ball 30 arrangement density is less than that of the first region 21. As a result, during the dispensing process of the adhesive 40, the capillary flow effect of the adhesive 40 will cause the adhesive 40 to preferentially flow to the first region 21 where the solder ball 30 arrangement density is greater, preventing the adhesive 40 from flowing to the second connection region 222 where the solder ball 30 arrangement density is less during the dispensing process. This prevents the adhesive 40 from flowing to the second region 22 during the dispensing process, ensuring that the adhesive 40 is ultimately placed in the first region 21.
[0036] Optionally, the spacing between the solder balls 30 located in the second connection area 222 further includes a third spacing, which is greater than or less than the second spacing and greater than the first spacing. Since the solder balls 30 in the first region 21 are arranged at equal intervals with the first spacing, and the spacing between the solder balls 30 in the second connection area 222 includes a second spacing and a third spacing that are greater than the first spacing, it can be ensured that the arrangement density of the solder balls 30 in the second connection area 222 is less than that in the first region 21. This helps to prevent the adhesive 40 from flowing into the second connection area 222 during the dispensing process, that is, it can prevent the adhesive 40 from flowing into the second region 22, which includes the heat source area, during the dispensing process.
[0037] In some embodiments, the third spacing is greater than the second spacing. Understandably, the second spacing is greater than the first spacing, and the third spacing is greater than the second spacing. This arrangement results in a sparser arrangement density of solder balls 30 in the second connection area 222 compared to the solder ball 30 arrangement density in the first area 21, thereby preventing the adhesive 40 from flowing into the second connection area 222 during dispensing, and effectively preventing the adhesive 40 from flowing into the second area 22, which includes the heat source area, during dispensing.
[0038] It should be noted that the spacing between the solder balls 30 located in the second connection area 222 may also include a fourth spacing, a fifth spacing, etc., which are greater than the second spacing, so that the arrangement density of the solder balls 30 located in the second connection area 222 is much smaller than the arrangement density of the solder balls 30 located in the first area 21, effectively preventing the adhesive 40 from flowing to the second connection area 222 during the dispensing process, that is, effectively preventing the adhesive 40 from flowing to the second area 22, which includes the heat source area, during the dispensing process.
[0039] Referring to Figure 6, the second region 22 includes an on-chip capacitor region, such as a first on-chip capacitor region 223, which is adjacent to the second connection region 222. It should be noted that the first on-chip capacitor region 223 can be understood as an area on the chip 20 where capacitors are disposed, and the heat source region may include the first on-chip capacitor region 223. The first on-chip capacitor region 223 is adjacent to the second connection region 222, and the spacing of the solder balls 30 in the second connection region 222 includes a second spacing, which is greater than the first spacing. Therefore, the arrangement density of the solder balls 30 in the second connection region 222 is less than the arrangement density of the solder balls 30 in the first region 21. This effectively prevents the adhesive 40 from flowing to the second connection region 222 during dispensing, and even less likely to flow to the first on-chip capacitor region 223 adjacent to the second connection region 222. Consequently, the heat generated by the first on-chip capacitor region 223 will not affect the adhesive 40, thus effectively ensuring the stability of the solder balls 30.
[0040] Optionally, the second region 22 includes at least one of the first connection regions 221, and / or the second region 22 includes at least one of the second connection regions 222.
[0041] For example, the second region 22 may include both the first connection region 221 and the second connection region 222, or it may include only the first connection region 221, or only the second connection region 222; wherein the number of the first connection regions 221 may be one or more, and the number of the second connection regions 222 may be one or more, thereby making the arrangement density of the solder balls 30 in the second region 22 sparser than the arrangement density of the solder balls 30 in the first region 21, which can more effectively prevent the adhesive 40 from flowing to the second region 22 during the dispensing process.
[0042] Understandably, since both the first connecting area 221 and the second connecting area 222 are areas where the second region 22 connects to (or are understood as adjacent to) the first region 21, i.e., both the first connecting area 221 and the second connecting area 222 are edge areas of the second region 22, it is possible to prevent the adhesive 40 from flowing into the first connecting area 221 and / or the second connecting area 222 during the dispensing process. In other words, it is possible to prevent the adhesive 40 from flowing into the middle area of the second region 22 during the dispensing process. For example, the heat source area can be located in the middle area of the second region 22, thereby preventing the temperature rise and fall of the heat source area from affecting the adhesive 40 in the first region 21. This effectively prevents the adhesive 40 from pulling the solder balls 30 due to thermal expansion and contraction, ensuring the stability and service life of the solder balls 30. It should be noted that the solder balls 30 located in the middle area of the second region 22 can be evenly spaced, for example, evenly spaced with a first spacing.
[0043] In some embodiments, the first region 21 includes the area located at the corner of the chip 20. The solder balls 30 located in the first region 21 are arranged at equal intervals with a first spacing, meaning the solder balls 30 in the corner area of the chip 20 are arranged at equal intervals with a first spacing. The first connection area 221 is not provided with solder balls 30 (as shown by the upper row of dashed circles in Figure 6 and the area shown by dashed box A on the right). The spacing of the solder balls 30 located in the second connection area 222 includes a second spacing greater than the first spacing. It can be understood that the first connection area 221 and the second connection area 222 are configured with a reduction in the number of solder balls 30, while the solder balls 30 in the corner area of the chip 20 are configured without a reduction in the number of solder balls 30 (as shown by dashed box B in Figure 6). Since the adhesive 40 will preferentially flow to the area where the solder balls 30 are more densely arranged during the dispensing process, this setting can also make the adhesive 40 flow to the corner area of the chip 20 during the dispensing process, thereby reducing the mechanical stress in the corner area of the chip 20 through the adhesive 40.
[0044] This application also provides an electronic device, which includes a housing and the circuit board assembly described in the above embodiments, wherein the circuit board assembly is disposed within the housing. It should be noted that this electronic device includes all the technical features of the circuit board assembly described in the above embodiments and achieves the same technical effects; therefore, to avoid repetition, it will not be described again here.
[0045] Optionally, the electronic device includes, but is not limited to, products equipped with circuit board components such as mobile phones, tablets, and smart wearable devices.
[0046] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.
Claims
1. A circuit board assembly comprising: The circuit board, chip, solder balls, and adhesive are disposed between the circuit board and the chip to connect the circuit board and the chip. The chip includes a first region and a second region. The first region is located outside the second region and is a region close to the edge of the chip. The second region includes a heat source area. The adhesive is located in the first region.
2. The wiring board assembly according to claim 1, wherein, The solder ball density in the first region is greater than that in the second region, and the adhesive fills the spaces between the solder balls in the first region.
3. The wiring board assembly according to claim 2, wherein, The area where the second region connects to the first region includes a first connection area, which is not equipped with solder balls.
4. The circuit board assembly according to claim 3, wherein, The solder balls located in the first region are arranged at equal intervals with a first spacing. The area where the second region connects to the first region includes a second connection area. The solder balls in the second connection area are arranged at non-equal intervals. The spacing between the solder balls in the second connection area includes a second spacing, which is greater than the first spacing.
5. The circuit board assembly according to claim 4, wherein, The spacing between the solder balls in the second connection area also includes a third spacing, which is greater than or less than the second spacing and is greater than the first spacing.
6. The circuit board assembly according to claim 4, wherein, The second region includes an on-chip capacitor region, which is adjacent to the second connection region or the first connection region.
7. The circuit board assembly according to claim 6, wherein, The on-chip capacitor region is located in the heat source region.
8. The circuit board assembly according to claim 4, wherein, The second region includes at least one of the first connection regions, and / or the second region includes at least one of the second connection regions.
9. The circuit board assembly according to any one of claims 1-8, wherein, The area of the heat source region is less than or equal to the area of the second region.
10. An electronic device comprising a housing and a circuit board assembly as claimed in any one of claims 1-9, the circuit board assembly being disposed within the housing.