Circuit board assembly and electronic equipment

Abstract

The invention discloses a circuit board assembly and electronic equipment, and belongs to the technical field of electronic equipment. The circuit board assembly comprises a printed circuit board, a chip, a solder ball and an adhesive, the solder ball and the adhesive are arranged between the printed circuit board and the chip so as to connect the printed circuit board and the chip, the chip comprises a first area and a second area, the first area is located on the periphery of the second area, and the second area is located on the periphery of the second area. The first area is an area close to the edge of the chip, the second area comprises a heat source area, and the adhesive is located in the first area.

Description

Technical Field

[0001] This application belongs to the technical field of electronic devices, and particularly relates to a circuit board assembly and an electronic device. Background Art

[0002] As the integration degree of chip design is getting higher and higher, multi-functional module designs are on the same wafer, such as a System on Chip (SoC). Therefore, the size of the chip after plastic encapsulation is getting larger and larger, and the risk of welding reliability is getting higher and higher. To solve the problem of mechanical stress in chip welding reliability applications, underfill glue is usually applied after chip welding to reinforce the chip and the Printed Circuit Board (PCB).

[0003] In related technologies, as chips pursue extreme performance, the heat generated by the chip's arithmetic units during operation is also getting higher and higher, and the overall temperature of the chip is getting higher and higher. When the chip undergoes temperature rise and fall during the operation and sleep change process, the underfill glue at the bottom of the chip expands and contracts accordingly, generating alternating thermal stress. Under long-term action, the solder balls fatigue and break, affecting the service life and performance of the chip and the circuit board assembly. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a circuit board assembly and an electronic device, which can solve the problem that the service life and performance of the circuit board assembly and the chip are affected due to the breakage of solder balls in related technologies.

[0005] To solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, the 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 on the periphery of the second region, and the first region is the region close to the edge of the chip. The second region includes a heat source area, and the adhesive is located in the first region.

[0007] In a second aspect, the embodiments of this application further provide an electronic device, including a housing and the circuit board assembly as described in the first aspect. The circuit board assembly is disposed inside the housing.

[0008] In the embodiment of the present application, the chip includes a heat source area, the heat source area is located in the second area, and the adhesive is located in the first area. That is, the adhesive can avoid the heat source area of the chip. Furthermore, the temperature rise and fall of the heat source area located in the second area will not affect the adhesive located in the first area, and it can avoid the pulling force on the solder balls caused by the thermal expansion and contraction of the adhesive due to temperature rise and fall. It can also avoid the cracking or breaking of the solder balls due to being pulled, thereby effectively improving the lifespan of the solder balls, contributing to improving the service life of the chip and the circuit board assembly, ensuring the performance of the circuit board assembly of the chip, and thus ensuring the performance of the electronic device using the circuit board assembly. Description of the Drawings

[0009] Figure 1 is one of the structural schematic diagrams of a circuit board assembly provided by an embodiment of the present application;

[0010] Figure 2 is another structural schematic diagram of a circuit board assembly provided by an embodiment of the present application;

[0011] Figure 3 is yet another structural schematic diagram of a circuit board assembly provided by an embodiment of the present application;

[0012] Figure 4 is one of the flow schematic diagrams of the adhesive during the dispensing process in a circuit board assembly provided by an embodiment of the present application;

[0013] Figure 5 is another flow schematic diagram of the adhesive during the dispensing process in a circuit board assembly provided by an embodiment of the present application;

[0014] Figure 6 is the layout design schematic diagram of the solder balls in a circuit board assembly provided by an embodiment of the present application;

[0015] Figure 7 is the partial structural schematic diagram of a circuit board assembly provided by an embodiment of the present application;

[0016] Figure 8 is the structural schematic diagram of a circuit board assembly in the related art. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0018] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0019] The circuit board assembly provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0020] Please refer to Figures 1 to 7 The circuit board assembly provided in the embodiment of the present application includes a printed circuit board 10, a chip 20, a solder ball 30 and an adhesive 40. The solder ball 30 and the adhesive 40 are arranged 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 area 21 and a second area 22. The first area 21 is located at the periphery of the second area 22, and the first area 21 is an area close to the edge of the chip 20. The second area 22 includes a heat source area. The adhesive 40 is located in the first area 21.

[0021] It can be understood that the chip 20 integrates multiple functional modules on a wafer and packages them into an integral functional device. For example, the chip 20 can be a system chip. The printed circuit board 10 is used to carry electronic components and realize welding. The solder ball 30 can be a solder ball, which is solidified after being molten, and is used to solder the chip 20 on the printed circuit board 10, so as to connect the chip 20 and the printed circuit board 10. The adhesive 40 can be a substance that can achieve bonding, such as curable glue, which is used to bond the chip 20 and the printed circuit board 10, and also plays the role of connecting the chip 20 and the printed circuit board 10.

[0022] In the embodiment of the present application, 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.

[0023] Please refer to Figure 2 and Figure 3 The chip 20 includes a first region 21 ( Figure 2 and Figure 3 The middle grey area shows Figure 3The dashed circle indicates that no solder balls are provided) and the second region 22 ( Figure 2 and Figure 3 the white region in), the first region 21 is located on the periphery of the second region 22. For example, the second region 22 can be understood as the middle region of the chip 20, the first region 21 is the region other than the second region 22, and the first region 21 can be understood as the edge region of the chip 20.

[0024] Among them, the solder balls 30 connect the printed circuit board 10 and the chip 20, and it can be understood that solder balls 30 are provided on one side of the chip 20. Among them, the chip 20 includes a heat source area, and the heat source area is located in the second region 22. It should be noted that the heat source area can be understood as the area on the chip 20 that generates heat. For example, the area on the chip 20 where electronic devices such as capacitors and resistors are installed, or the area on the chip 20 close to functional devices (such as cameras) or batteries in the electronic device.

[0025] In the embodiment of the present application, the chip 20 includes a first region 21 and a second region 22, and the heat source area is located in the second region 22. The adhesive 40 is located in the first region 21, that is, the adhesive 40 can avoid the heat source area of the chip 20. Furthermore, the temperature rise and fall of the heat source area in the second region 22 will not affect the adhesive 40 located in the first region 21, and it can also avoid the pulling force on the solder balls 30 caused by the thermal expansion and contraction of the adhesive 40 due to the temperature rise and fall. It can also avoid the cracking or breaking of the solder balls 30 due to being pulled, thereby effectively improving the service life of the solder balls 30, and also helping to improve the service life of the chip 20 and the circuit board assembly, thereby ensuring the performance of the electronic device using the circuit board assembly.

[0026] Optionally, the area of the heat source area is less than or equal to the area of the second region 22. For example, the entire second region 22 can be the heat source area, or a certain part of the second region 22 can be the heat source area. The size and position of the heat source area can be determined according to the installation position of the electronic devices on the chip 20 and / or the installation position of the functional devices in the electronic device. In the embodiment of the present application, the heat source area is located in the second region 22, and the adhesive 40 is located in the first region 21. Furthermore, the temperature rise and fall of the heat source area in the second region 22 will not affect the adhesive 40 located in the first region 21, and it can also effectively improve the service life of the solder balls 30.

[0027] In some embodiments, the arrangement density of the solder balls 30 in the first region 21 of the chip 20 is greater than the arrangement density of the solder balls 30 in the second region 22, that is, the solder balls 30 in the first region 21 of the chip 20 are arranged more densely. Exemplarily, please refer to Figure 4 and Figure 5, the adhesive 40 is a curable glue. The curable glue can be applied in a local area (such as the edge area) of the chip 20 by means of local dispensing. The solder balls 30 in the first area 21 are arranged more densely. Then, during the dispensing process, under the action of surface tension, the curable glue generates capillary effect flow between the soldered solder balls 30, and the curable glue will preferentially flow in the direction and area where the solder balls 30 are arranged more densely (as shown in Figure 4 and Figure 5 by the arrows). That is, the curable glue will preferentially flow in the first area 21. In this way, by setting the arrangement density of the solder balls 30 in the first area 21 to be more dense, it can be ensured that the adhesive 40 flows and cures in the first area 21, thereby preventing the adhesive 40 from flowing to the second area 22 where the heat source area is provided, and thus avoiding the influence of the temperature rise and fall of the heat source area on the adhesive 40 in the first area 21. That is, the adhesive 40 will not undergo thermal expansion and contraction, and the phenomenon of pulling on the solder balls 30 resulting in the fracture of the solder balls 30 can be avoided, thereby effectively ensuring the stability and service life of the solder balls 30, and also helping to improve the service life of the chip 20 and the circuit board assembly.

[0028] Optionally, the adhesive 40 is a curable glue, such as a curable resin glue. The curable glue is filled between the solder balls 30 in the first area 21 by means of dispensing.

[0029] Exemplarily, the curable glue is dispensed from the edge of the chip 20 by means of dispensing, and can generate capillary effect and flow between the soldered solder balls 30 under the action of surface tension. Since the arrangement density of the solder balls 30 in the first area 21 is more dense, the curable glue will preferentially flow and finally cure in the direction and area where the solder balls 30 are arranged more densely (that is, the first area 21), and finally cure and fill between the solder balls 30 in the first area 21. In the embodiments of the present application, the first area 21 can also be understood as the area covered by the curable glue, or the first area 21 can be larger than the area covered by the curable glue, that is, the first area 21 can also include an area where the curable glue is not covered.

[0030] Please refer to Figure 6 , in some embodiments, the area where the second area 22 is connected to the first area 21 includes a first connection area 221 ( Figure 5 the dotted circle in

[0031] represents that no solder ball is provided), and no solder ball 30 is provided in the first connection area 221. Figure 8As shown, the solder balls 30 on the chip 20 are usually arranged in an array, that is, the solder balls 30 on the chip 20 are arranged in the form of a rows × b columns (both a and b are integers greater than 1). In the embodiments of the present application, as Figure 6 shown, the second region 22 includes a first connection region 221 connected to the first region 21. For example, the first connection region 221 is one or more rows and / or one or more columns in the second region 22 that are connected (or can also be understood as adjacent) to the first region 21. No solder balls 30 are provided in the first connection region 221, that is, no solder balls 30 are provided in one or more rows in the second region 22 that are connected to the first region 21, and / or no solder balls 30 are provided in one or more columns in the second region 22 that are connected to the first region 21. That is, it can be understood that the second region 22 includes a region where no solder balls 30 are provided in the entire row and / or entire column (such as Figure 6 the region represented by the dashed box A shown in

[0032] . Thus, during the dispensing process of the adhesive 40, the capillary flow effect of the adhesive 40 will cause the adhesive 40 to preferentially flow towards the first region 21 where the solder balls 30 are more densely arranged. Since no solder balls 30 are provided in the first connection region 221, it is possible to avoid the adhesive 40 flowing towards the first connection region 221 where no solder balls 30 are provided during the dispensing process, thereby avoiding the adhesive 40 flowing into the second region 22 during the dispensing process, and ensuring that the adhesive 40 is finally disposed in the first region 21. Figure 2 and Figure 6 , optionally, the second region 22 includes an on-chip capacitor region, such as a second on-chip capacitor (Land Side Capacitance, LSC) region 224, and the second on-chip capacitor region 224 is adjacent to the first connection region 221. It should be noted that the second on-chip capacitor region 224 is a region on the chip 20 where capacitors are provided. Heat will be generated during the operation of the capacitors, and the heat source region may include the second on-chip capacitor region 224. Please refer to

[0033] Please refer to Figure 6 and Figure 7 . In some embodiments, the solder balls 30 in the first region 21 are arranged at equal intervals with a first pitch ( Figure 7 the d1 shown in Figure 6The dashed circles in the figure indicate that no solder balls are provided). The solder balls 30 located in the second connection area 222 are arranged at unequal intervals, and the intervals between the solder balls 30 located in the second connection area 222 include a second interval ( Figure 7 as shown as d2 in the figure), and the second interval is greater than the first interval.

[0034] Among them, the second connection area 222 can also be understood as the area where the second area 22 is adjacent to the first area 21, or the edge area of the second area 22. The intervals between the solder balls 30 located in the second connection area 222 include a second interval, and the solder balls 30 in the second connection area 222 are arranged at unequal intervals, that is, the intervals between the solder balls 30 in the second connection area 222 include at least two different intervals. For example, it can include a first interval and a second interval, that is, the interval between some of the solder balls 30 in the second connection area 222 is the first interval, and the interval between another part of the solder balls 30 is the second interval. The second interval is greater than the first interval, and the solder balls 30 in the first area 21 are arranged at equal intervals with the first interval. Furthermore, it makes the second connection area 222 include an area where the arrangement density of the solder balls 30 is less than that of the first area 21. Thus, during the dispensing process of the adhesive 40, the capillary flow effect of the adhesive 40 will cause the adhesive 40 to preferentially flow towards the first area 21 where the arrangement density of the solder balls 30 is greater, avoiding the adhesive 40 from flowing towards the second connection area 222 where the arrangement density of the solder balls 30 is smaller during the dispensing process, thereby avoiding the adhesive 40 from flowing towards the second area 22 during the dispensing process and ensuring that the adhesive 40 is finally disposed in the first area 21.

[0035] Optionally, the intervals between the solder balls 30 located in the second connection area 222 further include a third interval, the third interval is greater than or less than the second interval, and the third interval is greater than the first interval. Since the solder balls 30 in the first area 21 are arranged at equal intervals with the first interval, and the intervals between the solder balls 30 in the second connection area 222 include the second interval and the third interval that are greater than the first interval, this can ensure that the arrangement density of the solder balls 30 in the second connection area 222 is less than that of the solder balls 30 in the first area 21, thereby helping to avoid the adhesive 40 from flowing towards the second connection area 222 during the dispensing process, that is, it can avoid the adhesive 40 from flowing towards the second area 22 including the heat source area during the dispensing process.

[0036] In some embodiments, the third pitch is greater than the second pitch. It can be understood that the second pitch is greater than the first pitch, and the third pitch is greater than the second pitch. Such an arrangement makes the arrangement density of the solder balls 30 in the second connection region 222 sparser than that of the solder balls 30 in the first region 21, thereby preventing the adhesive 40 from flowing to the second connection region 222 during the dispensing process, and effectively preventing the adhesive 40 from flowing to the second region 22 including the heat source region during the dispensing process.

[0037] It should be noted that the pitch between the solder balls 30 in the second connection region 222 may further include a fourth pitch, a fifth pitch, etc. that are greater than the second pitch, so that the arrangement density of the solder balls 30 in the second connection region 222 is much smaller than that of the solder balls 30 in the first region 21, effectively preventing the adhesive 40 from flowing to the second connection region 222 during the dispensing process, that is, effectively preventing the adhesive 40 from flowing to the second region 22 including the heat source region during the dispensing process.

[0038] Please refer to Figure 6 , the second region 22 includes an on-chip capacitor region, such as a first on-chip capacitor region 223, and the first on-chip capacitor region 223 is adjacent to the second connection region 222. It should be noted that the first on-chip capacitor region 223 can be understood as the region on the chip 20 where capacitors are provided, 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 pitch of the solder balls 30 in the second connection region 222 includes a second pitch, and the second pitch is greater than the first pitch. Furthermore, the arrangement density of the solder balls 30 in the second connection region 222 is less than that of the solder balls 30 in the first region 21, thereby effectively preventing the adhesive 40 from flowing to the second connection region 222 during the dispensing process, and it is even less likely to flow to the first on-chip capacitor region 223 adjacent to the second connection region 222. Therefore, the heat generated by the first on-chip capacitor region 223 will not affect the adhesive 40, effectively ensuring the stability of the solder balls 30.

[0039] 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.

[0040] Exemplarily, the second region 22 may simultaneously include the above-mentioned first connection region 221 and second connection region 222, or may only include the first connection region 221, or only include 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, so that the arrangement density of the solder balls 30 in the second region 22 is sparser than that of the solder balls 30 in the first region 21, and it is possible to more effectively prevent the adhesive 40 from flowing into the second region 22 during the dispensing process.

[0041] It can be understood that since both the first connection region 221 and the second connection region 222 are regions where the second region 22 is connected to (or adjacent to) the first region 21, that is, both the first connection region 221 and the second connection region 222 are edge regions of the second region 22, so that it is possible to prevent the adhesive 40 from flowing into the first connection region 221 and / or the second connection region 222 during the dispensing process, that is, it is possible to prevent the adhesive 40 from flowing into the middle region of the second region 22. For example, the heat source region may be provided in the middle region of the second region 22, so that it is possible to avoid the influence of the temperature rise and fall of the heat source region on the adhesive 40 in the first region 21, and effectively prevent the phenomenon that the adhesive 40 pulls 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 region of the second region 22 may be arranged at equal intervals, for example, arranged at equal intervals with a first interval.

[0042] In some embodiments, the first region 21 includes a region at the corners of the chip 20. Among them, the solder balls 30 in the first region 21 are arranged at equal intervals with a first interval, that is, the solder balls 30 in the corner region of the chip 20 are arranged at equal intervals with a first interval, and no solder balls 30 are provided in the first connection region 221 (such as Figure 6 the area shown by the whole row of dotted circles on the upper side and the area shown by the dotted box A on the right side), and the pitch of the solder balls 30 in the second connection region 222 includes a second pitch greater than the first pitch. It can be understood that the settings of the first connection region 221 and the second connection region 222 for the solder balls 30 are ball-reducing settings, and the solder balls 30 in the corner region of the chip 20 are set as non-ball-reducing settings (such as Figure 6 the area shown by the dotted box B). Based on the fact that the adhesive 40 will preferentially flow into the region where the solder balls 30 are arranged more densely during the dispensing process, such a setting method can make the adhesive 40 flow into the corner region of the chip 20 during the dispensing process, so as to reduce the mechanical stress in the corner region of the chip 20 through the adhesive 40.

[0043] An embodiment of the present application further provides an electronic device, which includes a housing and the circuit board assembly described in the above embodiment, and the circuit board assembly is disposed in the housing. It should be noted that this electronic device includes all the technical features of the circuit board assembly in the above embodiment and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0044] Optionally, the electronic device includes, but is not limited to, products equipped with a circuit board assembly such as a mobile phone, a tablet computer, and a smart wearable device.

[0045] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them belong to the protection scope of the present application.

Claims

1. A circuit board assembly, characterized in that: The invention comprises a printed circuit board, a chip, a solder ball and an adhesive, wherein the solder ball and the adhesive are arranged between the printed circuit board and the chip to connect the printed circuit board and the chip, the chip comprises a first area and a second area, the first area is located at the periphery of the second area, and the first area is an area close to the edge of the chip, the second area comprises a heat source area, and the adhesive is located in the first area.

2. The circuit board assembly according to claim 1, characterized in that: The arrangement density of the solder balls located in the first region is greater than the arrangement density of the solder balls located in the second region, and the adhesive is filled between the solder balls in the first region.

3. The circuit board assembly according to claim 2, characterized in that: The area where the second area is connected to the first area includes a first connection area, and no solder ball is disposed in the first connection area.

4. The circuit board assembly according to claim 3, characterized in that: The solder balls located in the first area are arranged at equal intervals at a first interval; The area where the second area is connected to the first area includes a second connection area, the solder balls in the second connection area are arranged at non-equidistant intervals, and the intervals between the solder balls in the second connection area include a second interval, which is greater than the first interval.

5. The circuit board assembly according to claim 4, characterized in that: The spacing between the solder balls located in the second connection area further includes a third spacing, the third spacing is greater than or less than the second spacing, and the third spacing is greater than the first spacing.

6. The circuit board assembly according to claim 4, characterized in that: The second region includes an on-chip capacitor region, and the on-chip capacitor region is adjacent to the second connection region or the first connection region.

7. The circuit board assembly according to claim 6, characterized in that: The on-chip capacitor region is located in the heat source region.

8. The circuit board assembly according to claim 4, characterized in that: The second region includes at least one of the first connection areas, and / or the second region includes at least one of the second connection areas.

9. The circuit board assembly according to any one of claims 1 to 8, characterized in that: The area of ​​the heat source zone is smaller than or equal to the area of ​​the second region.

10. An electronic device, characterized in that: The electronic device comprises a housing and a circuit board assembly as claimed in any one of claims 1 to 9, wherein the circuit board assembly is arranged in the housing.

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