Circuit board assembly and electronic device

Abstract

The present application provides a circuit board assembly and an electronic device. The circuit board assembly comprises a circuit board, a chip module, and a heat dissipation member, wherein the chip module and the heat dissipation member are stacked on the circuit board, the chip module and the circuit board are electrically connected by means of solder balls, and the heat dissipation member is in thermally conductive connection with the chip module; and the circuit board assembly further comprises a thermally conductive adhesive and a thermally conductive member, wherein in the planar direction of the circuit board, a part of the thermally conductive adhesive fills the gap between the chip module and the circuit board and is in contact with the solder balls, the other part of the thermally conductive adhesive is located outside the chip module, the thermally conductive member extends in the thickness direction of the circuit board, and the thermally conductive member is configured to be separately in thermally conductive connection with the heat dissipation member and the other part of the thermally conductive adhesive. In the circuit board assembly of the present application, the thermally conductive connection between the chip module and the heat dissipation member is achieved by means of the contact between the solder balls and the thermally conductive adhesive and the contact between the thermally conductive adhesive and the thermally conductive member, and the thermal resistance between the chip module and the heat dissipation member is reduced by means of the thermally conductive member and the thermally conductive adhesive, thereby improving the heat dissipation efficiency of the circuit board assembly of the present application.

Description

Circuit board assemblies and electronic devices

[0001] This application claims priority to Chinese Patent Application No. 202411550303.0, filed with the China National Intellectual Property Administration on October 31, 2024, entitled "Circuit Board Assembly and Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of electronic technology, specifically to a circuit board assembly and an electronic device. Background Technology

[0003] In electronic devices, circuit board assemblies typically use heat sinks to dissipate heat from the chips within them. However, due to the high thermal resistance between the chip and the heat sink, when the heat generated by the chip during operation is excessive, it is difficult to transfer the heat to the heat sink in time, leading to abnormal temperatures in the circuit board assembly and affecting the operating efficiency of the electronic device. Summary of the Invention

[0004] This application provides a circuit board assembly and an electronic device, which achieves thermally conductive connection between the heat sink and the solder balls of the chip module through thermally conductive adhesive and thermally conductive components, thereby reducing the thermal resistance between the heat sink and the chip module and improving heat dissipation efficiency.

[0005] In a first aspect, this application provides a circuit board assembly, which includes a circuit board, a chip module, and a heat sink. The chip module and the heat sink are stacked on the circuit board, and the chip module and the circuit board are connected by solder balls. The heat sink is thermally connected to the chip module.

[0006] The circuit board assembly also includes thermally conductive adhesive and thermal conductive components. Along the planar direction of the circuit board, a portion of the thermally conductive adhesive fills the gap between the chip module and the circuit board and contacts the solder balls. Another portion of the thermally conductive adhesive is located outside the chip module. The thermal conductive components extend along the thickness direction of the circuit board and are used to thermally connect with the heat sink and another portion of the thermally conductive adhesive, respectively.

[0007] The circuit board assembly provided in this application places the chip module between the heat sink and the circuit board along the thickness direction of the circuit board. A portion of the thermally conductive adhesive is filled between the chip module and the circuit board, while the other portion of the thermally conductive adhesive is located outside the chip module and thermally connected to one end of the thermally conductive adhesive. The other end of the thermally conductive adhesive, along the thickness direction of the circuit board, is thermally connected to the heat sink. This allows the heat generated by the chip module during operation to be sequentially transferred to the heat sink via the solder balls of the chip module, the thermally conductive adhesive, and the thermally conductive adhesive. During the fabrication process of the circuit board assembly provided in this application, a portion of the thermally conductive adhesive filled between the circuit board and the chip module overflows along the plane of the circuit board; the other portion of the thermally conductive adhesive is the overflowing thermally conductive adhesive between the circuit board and the chip module.

[0008] The circuit board assembly provided in this application achieves thermally conductive connection between the chip module and the heat sink through the contact between the solder balls and the thermally conductive adhesive, and the contact between the thermally conductive adhesive and the thermally conductive component. The thermal resistance between the chip module and the heat sink is reduced by the thermally conductive component and the thermally conductive adhesive, thereby improving the heat dissipation efficiency of the circuit board assembly in this application.

[0009] In one implementation, the thermal conductive element is made of a colloid and is also used to adhere to the sidewall of the chip module, wherein: the thermal conductive element connects to the heat sink by adhering to the sidewall of the heat sink. Alternatively, the thermal conductive element extends from the bottom surface of the chip module by adhering to the heat sink to connect to the heat sink.

[0010] In this implementation, the heat-conducting component is attached to the sidewall of the chip module, allowing the heat generated by the chip module during operation to be transferred from the sidewall to the heat-conducting component. The circuit board assembly of this application uses the heat-conducting component to attach to the heat sink, ensuring that the heat transferred to the heat-conducting component is transferred to the heat sink.

[0011] In one implementation, a portion of the thermally conductive adhesive is made of the same material as another portion of the thermally conductive adhesive, while the material of the thermally conductive component is different from that of the other portion of the thermally conductive adhesive.

[0012] In one implementation, one part of the thermally conductive adhesive is made of a different material than another part, while the thermally conductive component is made of the same material as another part of the thermally conductive adhesive.

[0013] In this implementation, the thermal conductive component and another part of the thermal conductive adhesive are integrated. Along the plane of the circuit board, a part of the thermal conductive adhesive is flush with the sidewall of the chip module and in contact with the thermal conductive component.

[0014] In one implementation, the material of the thermally conductive component is the same as the material of another part of the thermally conductive adhesive, and the material of one part of the thermally conductive adhesive includes multiple adhesive materials, at least one of which is the same as the material of the thermally conductive component.

[0015] In this implementation, the thermal conductive component and another part of the thermal conductive adhesive are integrated. Along the thickness direction of the circuit board, part of the thermal conductive component fills the space between the chip module and the circuit board and contacts a part of the thermal conductive adhesive.

[0016] In one implementation, along the thickness direction of the circuit board, one end of the thermally conductive component extends into another portion of the thermally conductive adhesive, while the other end of the thermally conductive component extends toward the heat sink. The other end of the thermally conductive component contacts the sidewall of the heat sink to thermally connect to it. Alternatively, the other end of the thermally conductive component contacts the bottom surface of the heat sink that extends out of the chip module to thermally connect to it.

[0017] In this implementation, the heat-conducting component is made of a solid material. One end of the heat-conducting component absorbs and transfers the heat transferred from the solder balls to the heat-conducting adhesive through the other part extending into the thermally conductive adhesive. The circuit board assembly of this application ensures that the heat transferred to the heat-conducting component is transferred to the heat sink through contact between the heat-conducting component and the heat sink.

[0018] In one implementation, the heat-conducting component contacts the sidewall of the chip module along the plane of the circuit board.

[0019] In this implementation, the heat generated by the chip module during operation can be transferred from the sidewall of the chip module to the heat-conducting component, and then from the heat-conducting component to the heat sink. This increases the heat exchange area between the chip module and the heat-conducting component, thereby improving the heat dissipation efficiency of the circuit board assembly in this application.

[0020] In one implementation, the chip module includes a first surface and multiple sidewalls. The first surface has solder balls protruding from it, and each sidewall is connected to the first surface. The multiple sidewalls include a first sidewall located between a portion of thermally conductive adhesive and another portion of thermally conductive adhesive along the plane of the circuit board. The other portion of the thermally conductive adhesive is located on one side of the first sidewall of the chip module. Multiple thermally conductive elements are present, and these elements are located on one side of the first sidewall of the chip module.

[0021] In this implementation, along the planar direction of the circuit board, the thermally conductive adhesive extends from the first sidewall of the chip module to the outside of the chip module to form another portion of the thermally conductive adhesive. Multiple thermally conductive components respectively contact this other portion of the thermally conductive adhesive to increase the contact area between the other portion of the thermally conductive adhesive and the thermally conductive components. This improves the heat dissipation efficiency of the circuit board assembly of this application.

[0022] In one implementation, there are multiple first sidewalls. There are also multiple heat-conducting components, with multiple heat-conducting components arranged on one side of each first sidewall of the chip module.

[0023] In this implementation, along the planar direction of the circuit board, the thermally conductive adhesive extends from each of the first sidewalls to the outside of the chip module in different directions to form another part of the thermally conductive adhesive. The other part of the thermally conductive adhesive is thermally connected to the heat sink through multiple thermally conductive components located on different sides of the chip module.

[0024] In one implementation, another portion of the thermally conductive adhesive surrounds the chip module. The thermally conductive component is used to surround the chip module.

[0025] In this implementation, there are multiple heat-conducting components, which are spaced apart and surround the chip module. Alternatively, the heat-conducting components are ring-shaped and surround the chip module.

[0026] In one implementation, the thermal conductivity of the thermally conductive adhesive is greater than that of air, and the thermal conductivity of the thermally conductive adhesive is greater than that of the circuit board.

[0027] In one implementation, the thermal conductivity of the heat-conducting component is greater than that of air, and the thermal conductivity of the heat-conducting component is greater than that of the circuit board.

[0028] In one implementation, the material of the heat-conducting component includes epoxy resin and filler material, wherein the filler material of the heat-conducting component includes alumina and / or aluminum nitride.

[0029] In this implementation, the material of the thermally conductive component is a colloid, the matrix material of the thermally conductive component is epoxy resin, and the filler material of the thermally conductive component includes aluminum oxide and / or aluminum nitride. In the circuit board assembly manufacturing process of this application, the thermally conductive component is formed by filling aluminum oxide and / or aluminum nitride into the epoxy resin.

[0030] In one implementation, the thermally conductive adhesive material includes epoxy resin and filler material, wherein the filler material of the thermally conductive adhesive includes alumina and / or silicon oxide.

[0031] In this implementation, the matrix material of the thermally conductive adhesive is epoxy resin, and the filler material of the thermally conductive component includes alumina and / or silicon oxide. During the preparation of the thermally conductive adhesive, alumina and / or silicon oxide can be filled into the epoxy resin to form the thermally conductive adhesive.

[0032] In one implementation, the chip module includes two stacked chips connected by a second solder ball, wherein: a second thermally conductive adhesive is filled between the two chips, and the second thermally conductive adhesive is used to thermally connect with the second solder ball and the thermally conductive component respectively.

[0033] In this implementation, the second thermally conductive adhesive can transfer the heat from the two chips to the second solder balls during operation to the thermally conductive component, and then from the thermally conductive component to the heat sink to achieve heat dissipation. This, combined with the thermally conductive adhesive, further reduces the thermal resistance between the chip module and the heat sink, further improving the heat dissipation efficiency of the circuit board assembly in this application.

[0034] In one implementation, each chip includes a thermally conductive surface, and the two thermally conductive surfaces of the two chips face each other along the thickness direction of the circuit board. The areas of the two thermally conductive surfaces of the two chips are equal. Along the plane direction of the circuit board, a second thermally conductive adhesive is flush with the sidewalls of the two chips and in contact with the thermally conductive component.

[0035] In one implementation, the two chips include a first chip and a second chip. The area of ​​the thermally conductive surface of the first chip is larger than that of the thermally conductive surface of the second chip. A portion of the second thermally conductive adhesive is located between the first chip and the second chip, and another portion of the second thermally conductive adhesive is located outside the second chip and in contact with a thermally conductive component. The material of the portion of the second thermally conductive adhesive is the same as the material of the other portion of the second thermally conductive adhesive, while the material of the thermally conductive component is different from the material of the other portion of the second thermally conductive adhesive.

[0036] In one implementation, a portion of the second thermally conductive adhesive is made of a different material than another portion of the second thermally conductive adhesive, while the material of the second thermally conductive component is the same as that of another portion of the second thermally conductive adhesive.

[0037] In one implementation, the material of the heat-conducting component is the same as the material of another part of the second thermally conductive adhesive, and the material of a part of the second thermally conductive adhesive includes a variety of second adhesive materials, and at least one of the multiple second adhesive materials is made of the same material as the heat-conducting component.

[0038] In one implementation, each chip includes a thermally conductive surface, and the two thermally conductive surfaces of two chips face each other along the thickness direction of the circuit board. At least one thermally conductive surface includes a heat dissipation pad, which is used to extend into the interior of the chip and thermally connect with the heat-generating unit of the chip. A second thermally conductive adhesive or thermally conductive component is also used to thermally connect the heat dissipation pad.

[0039] In this implementation, along the thickness direction of the circuit board, one end of the heat dissipation pad is located inside the chip and thermally connected to the chip's heat-generating unit, while the other end of the heat dissipation pad protrudes from the chip's thermally conductive surface and is thermally connected to a thermally conductive component or a second thermally conductive adhesive. The heat generated by the chip with the heat dissipation pad during operation can also be transferred to the thermally conductive component or the second thermally conductive adhesive via the heat dissipation pad, thereby transferring it to the heat sink. This further reduces the thermal resistance between the heat sink and the chip module, further improving the heat dissipation efficiency of the circuit board assembly in this application.

[0040] In one implementation, the thermal conductivity of the second thermally conductive adhesive is greater than that of air.

[0041] In one implementation, the two chips include a first chip and a second chip. The area of ​​the heat-conducting surface of the first chip is larger than that of the heat-conducting surface of the second chip. The heat dissipation pad is located on the heat-conducting surface of the first chip. Along the thickness direction of the circuit board, the projection of the second chip on the heat-conducting surface of the first chip is not covered.

[0042] In this implementation, along the planar direction of the circuit board, a portion of the second thermally conductive adhesive is located between the first and second chips, and another portion of the second thermally conductive adhesive is located outside the second chip and in contact with the thermally conductive component. A thermal pad is located outside the second chip and in contact with the other portion of the second thermally conductive adhesive. And / or, the thermal pad is located outside the second chip and in contact with the thermally conductive component.

[0043] In one implementation, a thermal pad is located between two chips and spaced apart from second solder balls. The thermal pad contacts a second thermally conductive adhesive to thermally connect the second thermally conductive adhesive.

[0044] In one implementation, the chip module includes a first chip and a second chip, which are connected by a second solder ball. The area of ​​the heat-conducting surface of the first chip is larger than that of the heat-conducting surface of the second chip. The heat-dissipating pad is located on the heat-conducting surface of the first chip and is spaced apart from the second chip. The heat-dissipating pad is in contact with the heat-conducting component.

[0045] In this implementation, the heat generated by the first chip during operation is sequentially transferred to the heat sink through the heat dissipation pad and the thermal conductive component. This reduces the thermal resistance between the heat sink and the first chip, thereby improving the heat dissipation efficiency of the circuit board assembly in this application.

[0046] In one implementation, the heat dissipation pad is made of copper.

[0047] In one implementation, the chip module includes a first chip and a second chip, which are connected by a second solder ball. Along the thickness direction of the circuit board, the first chip is closer to the circuit board than the second chip, and the second chip is thermally connected to a heat sink. The material of the surface of the second chip facing the heat sink includes metal.

[0048] In this implementation, the heat generated during the operation of the second chip and the heat transferred by the second chip can be transferred to the heat sink through the surface of the second chip facing the heat sink. The material of the surface of the second chip facing the heat sink includes metal, which can reduce the thermal resistance between the second chip and the heat sink and improve the heat dissipation efficiency of the circuit board assembly of this application.

[0049] In one implementation, the chip module includes a chip that is connected to the circuit board via solder balls, wherein the chip is thermally connected to a heat sink on the surface of the circuit board away from the circuit board along the thickness direction.

[0050] In one implementation, along the thickness direction of the circuit board, the surface of the circuit board facing the chip module includes a second heat dissipation pad. One end of the second heat dissipation pad extends into the interior of the circuit board, and the other end of the second heat dissipation pad protrudes from the surface of the circuit board facing the chip module. The other end of the second heat dissipation pad is thermally connected to a thermally conductive component, or the other end of the second heat dissipation pad is spaced from solder balls along the plane of the circuit board and thermally connected to thermally conductive adhesive.

[0051] In this implementation, some of the heat generated during the chip module's operation is transferred to the circuit board via solder balls, and the circuit board also generates heat during operation. The second heat dissipation pad is used to transfer the heat from the circuit board to the thermally conductive component or thermally conductive adhesive, so that the thermally conductive component or thermally conductive adhesive can transfer the heat to the heat sink. This further improves the heat dissipation efficiency of the circuit board assembly in this application.

[0052] In one implementation, the heat sink includes a heat sink and a shield. Along the thickness direction of the circuit board, the shield is attached to the surface of the heat sink facing the chip module. The projection of the shield covers the chip module, thermal adhesive, and thermal conductive component. The outer edge of the shield includes a protrusion that extends toward the circuit board and is fixedly connected to the circuit board. The protrusion at least surrounds the chip module and the thermal conductive component.

[0053] In this implementation, the protrusions of the shielding cover contact the circuit board and surround the chip module to shield the propagation of electromagnetic waves and prevent electromagnetic waves from affecting the operation of the chip module. This ensures the stable operation of the circuit board assembly of this application. During the operation of the circuit board assembly of this application, the heat transferred by the chip module through the thermally conductive adhesive and thermally conductive components is transferred to the heat sink through the shielding cover, and the heat sink dissipates the heat.

[0054] In one implementation, the heat sink is made of graphite.

[0055] In one implementation, the circuit board assembly further includes a baffle wall fixed to the circuit board and extending toward the heat sink. Along the plane of the circuit board, the baffle wall and the chip module are spaced apart from each other, and another part of the thermally conductive adhesive and the thermally conductive component are located between the chip module and the baffle wall.

[0056] In this implementation, along the plane of the circuit board, the baffle is used to restrict the flow range of another portion of the thermally conductive adhesive. When the material of the thermally conductive component is a gel, the baffle is also used to restrict the flow range of the thermally conductive component to facilitate its fabrication.

[0057] In one implementation, another portion of the thermally conductive adhesive surrounds the chip module along the plane of the circuit board. Multiple baffles are used to surround the thermally conductive adhesive. Alternatively, the baffles are annular and used to surround the thermally conductive adhesive.

[0058] In this implementation, a baffle is used to surround the thermally conductive adhesive to further restrict its flow range. When the material of the thermally conductive component is a gel, the baffle is also used to surround the thermally conductive component to further restrict its flow range.

[0059] In one implementation, the height of the baffle along the thickness direction of the circuit board is less than or equal to the distance between the heat sink and the circuit board.

[0060] In this implementation, along the thickness direction of the circuit board, the end of the baffle away from the substrate contacts the surface of the heat sink facing the circuit board, or the end of the baffle away from the substrate is thermally connected to the surface of the heat sink facing the circuit board. This allows the heat generated by the chip module during operation to be transferred to the baffle through the thermally conductive component and thermally conductive adhesive, and then transferred from the baffle to the heat sink. This further reduces the thermal resistance between the chip module and the heat sink, and further improves the heat dissipation efficiency of the circuit board in this application.

[0061] In one implementation, there are multiple baffles, and at least some of the baffles are thermally connected to the heat sink and a heat transfer line in the circuit board along the thickness direction of the circuit board. Each heat transfer line extends along the plane of the circuit board and is connected to a heat-generating unit in the chip module through solder balls.

[0062] In this implementation, based on the conductivity between the heat-generating units within the chip module and the heat transfer lines within the circuit board, a portion of the baffle is thermally connected to the heat transfer lines of the heat-generating units. This allows the heat generated by the heat-generating units within the chip module to be sequentially transferred to the baffle through the solder balls and the heat transfer lines of the circuit board, and then to the heat sink via the baffle. This further reduces the thermal resistance between the chip module and the heat sink, thereby further improving the heat dissipation efficiency of the circuit board assembly in this application.

[0063] In one implementation, the barrier is made of metal; and / or, the circuit board assembly further includes components mounted on the surface of the circuit board on which the chip module is mounted, with another portion of the thermal conductive material and thermal adhesive located between the chip module and the components, the components forming the barrier.

[0064] In one implementation, the retaining wall is made of copper.

[0065] In one implementation, the circuit board assembly includes a second thermal conductive element made of a colloid. Along the thickness direction of the circuit board, the second thermal conductive element is used to fill the mounting gap between the baffle and the heat sink to achieve a thermally conductive connection between the baffle and the heat sink.

[0066] In one implementation, the circuit board assembly includes a second thermal conductive element made of a colloid. Along the thickness direction of the circuit board, the second thermal conductive element is used to fill the mounting gap between the heat sink and the chip module.

[0067] In this implementation, the chip module is thermally connected to the heat sink via a second thermally conductive component. The heat generated by the chip module during operation can also be transferred to the heat sink via the second thermally conductive component. This further reduces the thermal resistance between the chip module and the heat sink, improving the heat dissipation efficiency of the circuit board assembly in this application.

[0068] In one implementation, the material of the heat-conducting component is a colloid, and the material of the second heat-conducting component is the same as that of the heat-conducting component.

[0069] In a second aspect, an electronic device includes a housing and a circuit board assembly, the circuit board assembly being housed within the housing.

[0070] The electronic device of this application includes the circuit board assembly provided by any of the above implementations, and the heat generated during its operation can be transferred to the heat sink in sequence through the thermally conductive adhesive and the thermally conductive component, so as to reduce the thermal resistance between the heat sink and the chip module and thus improve the heat dissipation efficiency. Attached Figure Description

[0071] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0072] Figure 1 is a cross-sectional structural diagram of the electronic device provided in an embodiment of this application;

[0073] Figure 2 is a partial cross-sectional structural diagram of the electronic device provided in the embodiment of this application;

[0074] Figure 3 is a schematic diagram of the circuit board assembly provided in an embodiment of this application;

[0075] Figure 4 is a cross-sectional view of the circuit board assembly provided in an embodiment of this application;

[0076] Figure 5 is a schematic diagram of the circuit board assembly provided in one embodiment of this application;

[0077] Figure 6 is a schematic diagram of the circuit board assembly provided in this application embodiment in another embodiment;

[0078] Figure 7 is another structural schematic diagram of the circuit board assembly provided in an embodiment of this application;

[0079] Figure 8 is a top cross-sectional view of the circuit board assembly provided in one embodiment of this application.

[0080] Figure 9 is a cross-sectional view of the circuit board assembly provided in an embodiment of this application;

[0081] Figure 10 is a top cross-sectional view of the circuit board assembly provided in an embodiment of this application in another embodiment;

[0082] Figure 11 is a top cross-sectional view of the circuit board assembly provided in another embodiment of this application;

[0083] Figure 12 is a top cross-sectional view of the circuit board assembly provided in another embodiment of this application.

[0084] Figure 13 is a cross-sectional structural diagram of the circuit board assembly provided in one embodiment of the present application;

[0085] Figure 14 is another structural schematic diagram of the circuit board assembly provided in the embodiment of this application;

[0086] Figure 15 is a schematic diagram of the dispensing of the first chip of the circuit board assembly provided in the embodiment of this application;

[0087] Figure 16 is a schematic diagram of the dispensing of the second chip of the circuit board assembly provided in the embodiment of this application;

[0088] Figure 17 is a cross-sectional view of the circuit board assembly provided in this application embodiment in another embodiment;

[0089] Figure 18 is a cross-sectional view of the circuit board assembly provided in another embodiment of this application;

[0090] Figure 19 is a cross-sectional view of the internal structure of the chip in the circuit board assembly provided in the embodiment of this application;

[0091] Figure 20 is another cross-sectional view of the internal structure of the chip in the circuit board assembly provided in the embodiment of this application;

[0092] Figure 21 is a top view of the chip module of the circuit board assembly provided in the embodiment of this application;

[0093] Figure 22 is another cross-sectional view of the internal structure of the chip in the circuit board assembly provided in the embodiment of this application;

[0094] Figure 23 is another cross-sectional view of the internal structure of the chip in the circuit board assembly provided in the embodiment of this application;

[0095] Figure 24 is a schematic diagram of the internal structure of the circuit board assembly provided in the embodiment of this application;

[0096] Figure 25 is another schematic diagram of the internal structure of the circuit board assembly provided in the embodiment of this application;

[0097] Figure 26 is another structural schematic diagram of the circuit board assembly provided in the embodiment of this application;

[0098] Figure 27 is a schematic diagram of the retaining wall structure of the circuit board assembly provided in the embodiment of this application;

[0099] Figure 28 is another structural schematic diagram of the retaining wall of the circuit board assembly provided in the embodiment of this application;

[0100] Figure 29 is a partial top view of the circuit board assembly provided in an embodiment of this application;

[0101] Figure 30 is another partial top view of the circuit board assembly provided in an embodiment of this application;

[0102] Figure 31 is another structural schematic diagram of the retaining wall of the circuit board assembly provided in the embodiment of this application;

[0103] Figure 32 is another structural schematic diagram of the retaining wall of the circuit board assembly provided in the embodiment of this application;

[0104] Figure 33 is another schematic diagram of the internal structure of the circuit board assembly provided in the embodiment of this application. Detailed Implementation

[0105] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0106] Please refer to Figure 1, which shows a cross-sectional structural diagram of the electronic device provided in an embodiment of this application.

[0107] As shown in Figure 1, the electronic device provided in this application includes a housing 201 and a circuit board assembly 100. The circuit board assembly 100 is the remaining structure of the area highlighted by the dashed line in Figure 1, excluding the middle plate 2012 of the housing 201. In this embodiment, the housing 201 houses and protects the circuit board assembly 100. The circuit board assembly 100 processes received instructions and controls the modules of the electronic device to perform corresponding functions based on these instructions. The electronic device provided in this application is one of a computer, a mobile phone, a tablet, or a wearable device.

[0108] In one embodiment, as shown in FIG1, the housing 201 includes an outer frame 2011 and a middle plate 2012. The middle plate 2012 is housed within the outer frame 2011 and fixed to the inner surface of the outer frame 2011. Along the thickness direction of the middle plate 2012, the opening between the middle plate 2012 and the outer frame 2011 is spaced apart, and the middle plate 2012 is used to cooperate with the outer frame 2011 to form a receiving cavity. The circuit board assembly 100 is at least partially housed within the receiving cavity.

[0109] In one embodiment, as shown in FIG1, the electronic device provided in this application further includes a screen 202 and a battery 203. A housing 201 is used to fix the screen 202 and to accommodate the battery 203 and the circuit board assembly 100. The screen 202 is fixed to the opening of the outer frame 2011 and covers the opening of the outer frame 2011.

[0110] The middle plate 2012 is used to form a receiving cavity on the side of the middle plate 2012 away from the screen 202, in conjunction with the outer frame 2011. The battery 203 is housed within the receiving cavity and is in communication with the circuit board assembly 100. A portion of the circuit board assembly 100 is housed within the receiving cavity, and another portion of the circuit board assembly 100 passes through the middle plate 2012 to communicate with the screen 202. The circuit board assembly 100 and the battery 203 are fixed to the middle plate 2012 at a distance. The battery 203 provides the electrical energy required for the electronic device to operate. The circuit board assembly 100 controls the information displayed on the screen 202.

[0111] Please refer to Figure 2, which shows a partial cross-sectional view of the electronic device provided in an embodiment of this application. Figure 2 is a cross-sectional view of the circular area marked with a dashed line in Figure 1.

[0112] As shown in Figures 1 and 2, in one embodiment, the electronic device provided in this application further includes a first heat sink 2041 and a second heat sink 2042. Along the thickness direction of the middle plate 2012, the first heat sink 2041 is located between the middle plate 2012 and the screen 202, and is fixed to the surface of the middle plate 2012 facing the screen 202. The second heat sink 2042 is fixed to the bottom surface of the outer frame 2011 opposite to the middle plate 2012. The thickness direction of the middle plate 2012 is parallel to the thickness direction of the circuit board 10. Along the thickness direction of the circuit board 10, the surfaces of opposite sides of the circuit board assembly 100 are thermally connected to the first heat sink 2041 and the second heat sink 2042, respectively. The heat generated when the circuit board assembly 100 is in operation is transferred to the first heat sink 2041 and the second heat sink 2042, respectively, and the first heat sink 2041 and the second heat sink 2042 dissipate heat from the circuit board assembly 100.

[0113] That is, the first heat sink 2041 and the second heat sink 2042 are used to dissipate heat from the circuit board assembly 100. In one embodiment, as shown in Figures 1 and 2, the projections of the first heat sink 2041 and the second heat sink 2042 on the middle plate 2012 also cover the battery 203, and the first heat sink 2041 and the second heat sink 2042 are also used to dissipate heat from the battery 203.

[0114] In one embodiment, as shown in Figures 1 and 2, the electronic device provided in this application further includes a heat spreader 205. Along the thickness direction of the circuit board 10, the heat spreader 205 is attached to the first heat sink 2041 and the circuit board assembly 100, respectively. The heat spreader 205 is used to cooperate with the first heat sink 2041 to dissipate heat from the circuit board assembly 100 and improve the heat dissipation efficiency of the circuit board assembly 100. This ensures the working efficiency of the electronic device of this application.

[0115] In this embodiment, the electronic device dissipates heat from the circuit board 10 via a first heat sink 2041 and a second heat sink 2042 on opposite sides of the circuit board assembly 100. In another embodiment, the electronic device includes a heat sink located on one side of the circuit board assembly 100 along the thickness direction of the circuit board 10 and thermally connected to the circuit board assembly 100 to dissipate heat from the circuit board assembly 100. The heat sink can be positioned on the side of the circuit board assembly 100 where heat generation is relatively high to improve the heat dissipation efficiency of the circuit board assembly 100.

[0116] In one embodiment, as shown in FIG2, the circuit board assembly 100 provided in this application includes a circuit board 10 and a chip module 20. The circuit board 10 is fixed to the surface of the middle plate 2012 opposite to the screen 202. The chip module 20 is mounted on the surface of the circuit board 10 opposite to the middle plate 2012 and is electrically connected to the circuit board 10 through solder balls 21. The chip module 20 is thermally connected to the second heat sink 2042. The chip module 20 is electrically connected to the battery 203 through the circuit board 10. The chip in the chip module 20 includes a system-on-chip (SOC). The SOC is used to receive electrical signals output by the battery 203 and process the electrical signals based on user input commands to control the operation of various components 1001 mounted on the circuit board 10. The SOC is also used to control the screen 202 to display corresponding display content based on user input commands.

[0117] During the operation of a system-on-a-chip (SoC), the SoC generates heat. The electronic device of this application connects a second heat sink 2042 to the chip module 20 through thermal conductivity. This allows the heat generated by the SoC within the chip module 20 to dissipate outwards via the second heat sink 2042, preventing the chip module 20 from reaching its over-temperature protection threshold and causing thermal throttling, which would otherwise result in stuttering and frame drops on the screen 202. This ensures the operational efficiency of the electronic device and guarantees a superior user experience.

[0118] In one embodiment, the circuit board assembly 100 provided in this application further includes a heat sink 30, with the chip module 20 and the heat sink 30 stacked on the circuit board 10. Specifically, along the thickness direction of the circuit board 10, one end of the heat sink 30 is thermally connected to the chip module 20, and the other end of the heat sink 30 is attached to the second heat sink 2042. When the chip module 20 is working, the heat generated by the chip module 20 can be dissipated to the outside through the heat sink 30. The heat sink 30 can also transfer the absorbed heat from the chip module 20 to the second heat sink 2042 to achieve heat dissipation for the chip module 20.

[0119] In one embodiment, the circuit board 10 is a double-layer circuit board, the middle plate 2012 includes through holes, and the circuit board 10 is fixed on the middle plate 2012 and covers the through holes. The circuit board assembly 100 provided in this application also includes a plurality of components 1001, each component 1001 being mounted on the circuit board 10. At least some of the components 1001 are mounted on the circuit board 10 and exposed on the surface of the through holes along the thickness direction of the circuit board 10. In one embodiment, some of the components 1001 are mounted on the same surface of the circuit board 10 as the chip module 20, and another portion of the components 1001 are mounted on the surface of the circuit board 10 opposite to the chip module 20. Each component 1001 is electrically connected to the chip module 20, and the chip module 20 is used to control the operation of each component 1001.

[0120] As shown in Figure 2, the components 1001 mounted on the surface of the circuit board 10 facing the screen 202 are thermally connected to the first heat sink 2041. During the operation of the circuit board assembly 100, the heat generated by the various components 1001 mounted on the surface of the circuit board 10 facing the screen 202 is absorbed by the first heat sink 2041. This achieves heat dissipation for the various components 1001.

[0121] The heat generated by the chip module 20 during operation is transferred to the second heat sink 2042 and also via the circuit board 10 to the first heat sink 2041, whereby the first heat sink 2041 dissipates heat from the chip module 20. In other words, the first heat sink 2041 and the second heat sink 2042 of the electronic device of this application cooperate to dissipate heat from the chip module 20.

[0122] In this embodiment, the circuit board 10 is configured as a double-layer circuit board to facilitate the placement of components 1001 and chip modules 20 on opposite surfaces of the circuit board 10, thereby making the structure of the circuit board assembly 100 of this application compact. In another embodiment, the circuit board 10 is a single-layer circuit board, with all components 1001 and chip modules 20 spaced apart on the surface of the circuit board 10 opposite to the screen 202.

[0123] In one embodiment, as shown in FIG2, the components 1001 mounted on the surface of the circuit board 10 facing the screen 202 include at least one of resistors and capacitors.

[0124] In one embodiment, the first heat sink 2041 is made of graphite.

[0125] In one embodiment, the material of the second heat sink 2042 is graphite.

[0126] In one embodiment, the circuit board assembly 100 of this application further includes thermally conductive adhesive 40 and thermally conductive element 50. Along the planar direction of the circuit board 10, a portion of the thermally conductive adhesive 40 fills the gap between the chip module 20 and the circuit board 10 and contacts the solder ball 21. Another portion of the thermally conductive adhesive 40 is located outside the chip module 20. The thermally conductive element 50 extends along the thickness direction of the circuit board 10 and is used for thermally conductive connection with the heat sink 30 and another portion of the thermally conductive adhesive 40, respectively.

[0127] For ease of description, a portion of the thermally conductive adhesive 40 is defined as the first thermally conductive part 41, and the other portion of the thermally conductive adhesive 40 is defined as the second thermally conductive part 42.

[0128] Please refer to Figure 3 for a schematic diagram of the circuit board assembly 100 provided in this embodiment of the application. Figure 3 shows the circuit board assembly 100 (highlighted by dashed lines in Figure 2) after being rotated 180°. For ease of description, the structure of the circuit board 10 facing away from the chip module 20 is omitted in Figure 3. In subsequent figures, the structure of the circuit board 10 facing away from the chip module 20 is also omitted.

[0129] Specifically, as shown in Figure 3, along the thickness direction of the circuit board 10, the chip module 20 is located between the heat sink 30 and the circuit board 10. Solder balls 21 protrude from the surface of the chip module 20 facing the circuit board 10, and the solder balls 21 are used for electrical connection between the chip module 20 and the circuit board 10. This enables the chip module 20 to conduct electricity with the circuit board 10.

[0130] When the chip module 20 is operating, the heat-generating units inside the chip module 20 generate heat. This heat dissipates outwards, causing the temperature of the chip module 20's casing and solder balls 21 to rise. Since the casing of the chip module 20 is typically made of plastic, while the solder balls 21 are typically made of metal to enable conductivity between the chip module 20 and the circuit board 10, the thermal conductivity of the plastic is lower than that of the metal. Therefore, the heat generated by the chip module 20 during operation is primarily transferred outwards through the solder balls 21. In other words, the solder balls 21 of the chip module 20 are essentially the main heat source exposed to the outside environment.

[0131] In this embodiment, the first heat-conducting part 41 fills the gap between the chip module 20 and the circuit board 10 and contacts the solder balls 21, while the second heat-conducting part 42 is located outside the chip module 20. When the chip module 20 is operating, the first heat-conducting part 41 absorbs the heat released by the solder balls 21 through contact with them, and the second heat-conducting part 42 absorbs the heat absorbed by the first heat-conducting part 41, thereby transferring the heat from the solder balls 21 to the outside of the chip module 20. That is, the thermally conductive adhesive 40 absorbs the heat transferred through the solder balls 21 when the chip module 20 is operating and transfers the absorbed heat to the outside of the chip module 20.

[0132] Along the thickness direction of the circuit board 10, one end of the heat-conducting component 50 is thermally connected to the second heat-conducting part 42, and the other end of the heat-conducting component 50 is thermally connected to the heat sink 30. That is, when the chip module 20 is working, the heat absorbed by the solder balls 21 by the first heat-conducting part 41 can be absorbed by the heat-conducting component 50 after being transferred to the second heat-conducting part 42, and then transferred to the heat sink 30, and then dissipated outward by the heat sink 30, thereby achieving heat dissipation for the chip module 20.

[0133] In existing technologies, the chip module's casing and heat sink are thermally connected. The heat generated during chip module operation is transferred to the heat sink through the chip module's casing. However, due to the low thermal conductivity of the chip module's casing, the thermal resistance between the chip module and the heat sink is relatively high, resulting in poor heat dissipation efficiency. In this application, the circuit board assembly 100 achieves a thermally conductive connection between the chip module 20 and the heat sink 30 through the contact between the solder balls 21 and the thermally conductive adhesive 40, and the contact between the thermally conductive adhesive 40 and the heat-conducting component 50. This allows the heat generated during chip module 20 operation to be transferred sequentially to the heat sink 30 via the solder balls 21, the thermally conductive adhesive 40, and the heat-conducting component 50. This achieves the heat dissipation function of the circuit board assembly 100.

[0134] Compared to existing technologies that use a heatsink to thermally connect the chip module's casing, this application's circuit board assembly 100 reduces the thermal resistance between the chip module 20 and the heatsink 30 by utilizing the thermally conductive adhesive 40 and the heatsink 50. This increases the heat transfer efficiency between the chip module 20 and the heatsink 30, thereby improving the overall heat dissipation efficiency of the circuit board assembly 100.

[0135] In one embodiment, the heat-conducting element 50 is made of a colloid and is also used to adhere to the sidewall 22 of the chip module 20.

[0136] Please refer to Figure 4 for a cross-sectional view of the circuit board assembly 100 provided in this embodiment of the application.

[0137] Specifically, as shown in Figure 4, along the planar direction of the circuit board 10, the heat-conducting component 50 is attached to the sidewall 22 of the chip module 20, so that the heat transferred to the outer casing of the chip module 20 during operation can be transferred from the sidewall 22 to the heat-conducting component 50, and then from the heat-conducting component 50 to the heat sink 30. That is, the attachment of the heat-conducting component 50 to the sidewall 22 of the chip module 20 increases the heat transfer path between the heat sink 30 and the chip module 20. On the other hand, with the first thermally conductive portion 41 of the thermally conductive adhesive 40 filling the space between the chip module 20 and the circuit board 10, the contact between the heat-conducting component 50 and the sidewall 22 of the chip module 20 increases the heat exchange area between the chip module 20 and the heat-conducting component 50 and the thermally conductive adhesive 40. This further improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0138] In one embodiment, the heat-conducting component 50 is made of colloid, and the heat sink 30 extends out of the chip module 20 along the plane of the circuit board 10. The heat-conducting component 50 is thermally connected to the heat sink 30 by adhering to the surface of the heat sink 30 facing the circuit board 10.

[0139] Specifically, as shown in Figure 4, the heat sink 30 extends out of the chip module 20 along the plane of the circuit board 10. Along the thickness direction of the circuit board 10, the projection of the heat sink 30 onto the circuit board 10 covers both the chip module 20 and the heat conductor 50. The heat conductor 50 and the heat sink 30 are in contact with the surfaces of the circuit board 10 facing each other, ensuring that heat transferred from the chip module 20 to the heat conductor 50 can be transferred to the heat sink 30. This ensures the heat dissipation function of the heat sink 30 for the chip module 20.

[0140] In one embodiment, the heat-conducting element 50 is made of colloid, and the heat-conducting element 50 is thermally connected to the heat sink 30 by adhering to the sidewall of the heat sink 30.

[0141] Specifically, along the thickness direction of the circuit board 10, the projection of the heat sink 30 onto the circuit board 10 covers the chip module 20. The heat conductor 50 contacts the sidewall of the heat sink 30 to ensure that the heat transferred from the chip module 20 to the heat conductor 50 can be transferred to the heat sink 30. This ensures the heat dissipation function of the heat sink 30 for the chip module 20.

[0142] In one embodiment, along the thickness direction of the circuit board 10, the projection of the heat sink 30 onto the circuit board 10 covers the chip module 20 and partially covers the heat conductor 50. The heat conductor 50 is attached to the surface of the heat sink 30 facing the circuit board 10. In another embodiment, along the thickness direction of the circuit board 10, the projection of the heat sink 30 onto the circuit board 10 covers the chip module 20 and partially covers the heat conductor 50. The heat conductor 50 is attached to both the surface of the heat sink 30 facing the circuit board 10 and the sidewall of the heat sink 30.

[0143] In one embodiment, the first heat-conducting part 41 is made of the same material as the second heat-conducting part 42, while the heat-conducting component 50 is made of a different material than the second heat-conducting part 42. As shown in FIG. 4, a portion of the thermally conductive adhesive 40 is filled between the chip module 20 and the circuit board 10, and another portion of the thermally conductive adhesive 40 overflows from between the chip module 20 and the circuit board 10 to facilitate contact with the heat-conducting component 50. During the fabrication process of the circuit board assembly 100 of this application, thermally conductive adhesive 40 of the same material can be first filled between the chip module 20 and the circuit board 10, allowing a portion of the thermally conductive adhesive 40 to overflow outside the chip module 20. At this time, the thermally conductive adhesive 40 located between the chip module 20 and the circuit board 10 is the first heat-conducting part 41, and the thermally conductive adhesive 40 overflowing outside the chip module 20 is the second heat-conducting part 42. Then, an adhesive of the same material as the heat-conducting component 50 is coated on the second heat-conducting part 42 until the adhesive contacts the heat sink 30. This forms the heat-conducting component 50.

[0144] In one embodiment, the materials of the first heat-conducting part 41 and the second heat-conducting part 42 are different, while the material of the heat-conducting component 50 is the same as that of the second heat-conducting part 42.

[0145] Please refer to Figure 5 for a schematic diagram of the structure of the circuit board assembly 100 provided in one embodiment of this application.

[0146] Specifically, as shown in Figure 5, the heat-conducting component 50 and the second heat-conducting part 42 are integrally formed. The first heat-conducting part 41 is filled between the chip module 20 and the circuit board 10. Along the plane of the circuit board 10, the first heat-conducting part 41 is flush with the sidewall 22 of the chip module 20 to facilitate contact with the second heat-conducting part 42. In the process of manufacturing the circuit board assembly 100 of this application, an adhesive of the same material as the first heat-conducting part 41 can be filled between the chip module 20 and the circuit board 10 first, and then the overflowing adhesive can be treated to ensure that the adhesive is flush with the sidewall of the chip module 20. This forms the first heat-conducting part 41. Then, an adhesive of the same material as the heat-conducting component 50 is coated on the outside of the chip module 20, and the adhesive is made to contact the first heat-conducting part 41 until the adhesive contacts the heat sink 30. This forms the second heat-conducting part 42 and the heat-conducting component 50.

[0147] In one embodiment, the material of the heat-conducting component 50 is the same as the material of the second heat-conducting part 42, and the material of the first heat-conducting part 41 includes a variety of adhesives, and at least one of the adhesives is made of the same material as the heat-conducting component 50.

[0148] Please refer to Figure 6 for a schematic diagram of the structure of the circuit board assembly 100 provided in another embodiment of this application.

[0149] Specifically, as shown in Figure 6, the heat-conducting component 50 and the second heat-conducting part 42 are integrally formed. Along the thickness direction of the circuit board 10, the first heat-conducting part 41 fills the space between the chip module 20 and the circuit board 10, and a portion of the heat-conducting component 50 fills the space between the chip module 20 and the circuit board 10, and contacts the first heat-conducting part 41. In the process of manufacturing the circuit board assembly 100 of this application, an adhesive of the same material as the first heat-conducting part 41 can be first filled between the chip module 20 and the circuit board 10, ensuring that the adhesive does not overflow from the space between the chip module 20 and the circuit board 10. Then, an adhesive of the same material as the heat-conducting component 50 is coated on the outside of the chip module 20. This adhesive can flow into the space between the chip module 20 and the circuit board 10 and contact the adhesive set in the previous step. This forms the first heat-conducting part 41. When the adhesive contacts the heat sink 30, the adhesive located outside the chip module 20 forms the second heat-conducting part 42 and the heat-conducting component 50.

[0150] In one embodiment, the material of the thermally conductive element 50 is the same as the material of the thermally conductive adhesive 40. During the fabrication of the circuit board assembly 100 of this application, an adhesive of the same material as the thermally conductive element 50 can be directly filled between the circuit board 10 and the heat sink 30, thereby filling the gap between the chip module 20 and the circuit board 10. This forms both the thermally conductive element 50 and the thermally conductive adhesive 40.

[0151] In one embodiment, along the thickness direction of the circuit board 10, one end of the heat-conducting element 50 extends into the second heat-conducting portion 42, and the other end of the heat-conducting element 50 extends toward the heat sink 30. The other end of the heat-conducting element 50 contacts the sidewall of the heat sink 30 to conduct heat and connect to the heat sink 30. Alternatively, the other end of the heat-conducting element 50 contacts the bottom surface of the heat sink 30 extending out of the chip module 20 to conduct heat and connect to the heat sink 30.

[0152] Please refer to Figure 7 for another structural schematic diagram of the circuit board assembly 100 provided in this embodiment of the application.

[0153] As shown in Figure 7, the heat-conducting component 50 is made of a solid material. The end of the heat-conducting component 50 near the circuit board 10 extends into the second heat-conducting portion 42 to achieve a thermally conductive connection with the thermally conductive adhesive 40. When the chip module 20 is operating, the heat absorbed and transferred outside the chip module 20 by the thermally conductive adhesive 40 can be transferred to the heat sink 30 through the heat-conducting component 50. This achieves a thermally conductive connection between the chip module 20 and the heat sink 30, and improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0154] In one embodiment, the heat-conducting element 50 is made of a solid material and is in contact with the sidewall 22 of the chip module 20 along the plane of the circuit board 10. When the chip module 20 is working, the heat generated by the chip module 20 can be transferred from the sidewall 22 of the chip module 20 to the heat-conducting element 50, and then from the heat-conducting element 50 to the heat sink 30, thereby increasing the heat transfer path between the chip module 20 and the heat sink 30 and improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0155] In one embodiment, the chip module 20 includes a first surface 23 and a plurality of sidewalls 22. The first surface 23 has protruding solder balls 21, and each sidewall 22 is connected to the first surface 23. The plurality of sidewalls 22 includes a first sidewall 221, which is located between a first heat-conducting part 41 and a second heat-conducting part 42 along the plane of the circuit board 10. The second heat-conducting part 42 is located on one side of the first sidewall 221 of the chip module 20. A plurality of heat-conducting elements 50 are located on one side of the first sidewall 221 of the chip module 20.

[0156] Please refer to Figure 8 for a top cross-sectional view of the circuit board assembly 100 provided in one embodiment of this application. Figure 8 is a top cross-sectional view of the circuit board 10 obtained by cutting along the first top line L1 after omitting the heat sink 30, and looking towards the circuit board 10 from Figure 4.

[0157] As shown in Figures 4 and 8, during the fabrication of the circuit board assembly 100 of this application, thermally conductive adhesive 40 extends from the first sidewall 221 of the chip module 20 to the outside of the chip module 20 along the planar direction of the circuit board 10 to form a second thermally conductive portion 42. In the schematic diagram shown in Figure 8, there is one first sidewall 221. A plurality of thermally conductive elements 50 are located on the same side of the first sidewall 221 of the chip module 20 and are in contact with the second thermally conductive portion 42.

[0158] In one embodiment, there are multiple first sidewalls 221. There are also multiple heat-conducting elements 50, with multiple heat-conducting elements 50 arranged on one side of each first sidewall 221 of the chip module 20.

[0159] Please refer to Figures 9 and 10 for reference. Figure 9 is a cross-sectional view of the circuit board assembly 100 provided in an embodiment of this application, and Figure 10 is a top cross-sectional view of the circuit board assembly 100 provided in another embodiment of this application. Figure 10 is a top cross-sectional view of the circuit board 10 obtained by cutting along the second top line L2 after omitting the heat sink 30 in Figure 9.

[0160] As shown in Figures 9 and 10, during the fabrication of the circuit board assembly 100 of this application, thermally conductive adhesive 40 extends from each of the first sidewalls 221 in different directions to the outside of the chip module 20 along the planar direction of the circuit board 10 to form a second thermally conductive portion 42. In the schematic diagram shown in Figure 10, there are two first sidewalls 221, which are two opposite sidewalls 22 of the chip module 20 along the planar direction of the circuit board 10. Multiple thermally conductive elements 50 are arranged on one side corresponding to each first sidewall 221 of the chip module 20, and each thermally conductive element 50 is in contact with the corresponding second thermally conductive portion 42.

[0161] In one embodiment, a second heat-conducting portion 42 surrounds the chip module 20. A heat-conducting element 50 is used to surround the chip module 20.

[0162] Please refer to Figure 11 for a top cross-sectional view of the circuit board 10 provided in another embodiment of this application. Figure 11 is a top cross-sectional view of the circuit board 10 obtained by cutting along the second top line L2 after omitting the heat sink 30, and looking towards the circuit board 10.

[0163] As shown in Figure 11, there are multiple heat-conducting components 50, which are spaced around the chip module 20 and contact the second heat-conducting portion 42 respectively. The number of first sidewalls 221 is the same as the number of sidewalls 22 connecting the chip module 20 to the first surface 23. That is, during the fabrication of the circuit board assembly 100 in this application, along the planar direction of the circuit board 10, the thermally conductive adhesive 40, while filling the gap between the chip module 20 and the circuit board 10, extends outwards from the chip module 20 to form the second heat-conducting portion 42.

[0164] In one embodiment, the heat-conducting element 50 is annular, surrounds the chip module 20, and contacts the second heat-conducting part 42. This achieves a thermally conductive connection between the chip module 20 and the heat sink 30.

[0165] Please refer to Figure 12 for a top cross-sectional view of the circuit board assembly 100 provided in another embodiment of this application. Figure 12 corresponds to Figure 9, which is a top cross-sectional view obtained by cutting along the second top line L2 after omitting the heat sink 30 and looking towards the circuit board 10.

[0166] The number of first sidewalls 221 is the same as the number of sidewalls 22 connecting the chip module 20 to the first surface 23. That is, during the fabrication of the circuit board assembly 100 in this application, along the planar direction of the circuit board 10, the thermally conductive adhesive 40 extends outward from the chip module 20 to form the second thermally conductive portion 42, while filling the gap between the chip module 20 and the circuit board 10.

[0167] In the four embodiments described above, the number and arrangement of the heat-conducting elements 50 are matched to the position of the second heat-conducting portion 42 to ensure that the thermally conductive adhesive 40 extending beyond the chip module 20 in each direction can contact the heat-conducting elements 50. Furthermore, the arrangement of multiple heat-conducting elements 50 increases the contact area between the second heat-conducting portion 42 and the heat-conducting elements 50, thereby increasing the heat exchange area between the chip module 20 and the heat sink 30. This further reduces the thermal resistance between the chip module 20 and the heat sink 30, improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0168] For ease of description, in subsequent embodiments of this application, the second heat-conducting part 42 surrounds the chip module 20, the heat-conducting element 50 is made of colloid, and the heat-conducting element 50 is annular and surrounds the chip module 20. It is worth noting that, to facilitate the fabrication of the heat-conducting element 50, when the material of the heat-conducting element 50 is colloid, the heat-conducting element 50 can be set in an annular shape. When the material of the heat-conducting element 50 is a solid material, multiple heat-conducting elements 50 can be used to surround the chip module 20 at intervals.

[0169] In one embodiment, the thermal conductivity of the thermally conductive adhesive 40 is greater than that of air, and the thermal conductivity of the thermally conductive adhesive 40 is greater than that of the circuit board 10. In this embodiment, the circuit board assembly 100 fills the space between the chip module 20 and the circuit board 10 with the thermally conductive adhesive 40, thereby expelling the air between the chip module 20 and the circuit board 10, thus enhancing the heat transfer efficiency of the circuit board assembly 100 for the heat released by the solder balls 21 during the operation of the chip module 20.

[0170] Since the circuit board 10 is in contact with the solder balls 21, the heat released by the solder balls 21 will also be released outward through the circuit board 10 during the operation of the chip module 20. In this embodiment, the thermal conductivity of the thermally conductive adhesive 40 is set to be greater than that of the circuit board 10, so that more of the heat released by the solder balls 21 can be absorbed by the thermally conductive adhesive 40, thereby reducing the amount of heat released by the solder balls 21 that is released outward through the circuit board 10. This improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0171] In one embodiment, the thermal conductivity of the thermally conductive adhesive 40 is greater than or equal to 0.5 W / (m·K). In another embodiment, the thermal conductivity of the thermally conductive adhesive 40 is equal to 1.3 W / (m·K). In yet another embodiment, the thermal conductivity of the thermally conductive adhesive 40 is equal to 2 W / (m·K).

[0172] In one embodiment, the thermally conductive adhesive 40 comprises an epoxy resin and a filler material, wherein the filler material of the thermally conductive adhesive 40 comprises alumina and / or silicon oxide. During the preparation of the thermally conductive adhesive 40, an epoxy resin is used as the base material, and alumina and / or silicon oxide are filled into the base material. This forms the thermally conductive adhesive 40 required for preparing the circuit board assembly 100 of this application.

[0173] In one embodiment, the ratio of the mass of the filler material in the thermally conductive adhesive 40 to the sum of the masses of the filler material and the matrix material in the thermally conductive adhesive 40 is greater than or equal to 10%. In another embodiment, the ratio of the mass of the filler material in the thermally conductive adhesive 40 to the sum of the masses of the filler material and the matrix material in the thermally conductive adhesive 40 is greater than or equal to 10%. For example, in one embodiment, the filler material of the thermally conductive adhesive 40 is silicon oxide, the epoxy resin content in the thermally conductive adhesive 40 is 90%, and the silicon oxide content is 10%, corresponding to a thermal conductivity of 0.5 W / (m·K). In another embodiment, the filler material of the thermally conductive adhesive 40 is alumina, the epoxy resin content in the thermally conductive adhesive 40 is 30%, and the alumina content is 70%, corresponding to a thermal conductivity of 1.4 W / (m·K).

[0174] In one embodiment, the filler material of the thermally conductive adhesive 40 is in the shape of a sheet.

[0175] In one embodiment, the thermal conductivity of the heat-conducting element 50 is greater than that of air, and also greater than that of the circuit board 10. In this embodiment, the circuit board assembly 100 utilizes the heat-conducting element 50, whose thermal conductivity is greater than that of air, to ensure that a greater portion of the heat transferred to the thermally conductive adhesive 40 is transferred to the heat sink 30. This ensures that the heat-conducting element 50 improves the heat dissipation efficiency of the circuit board assembly 100.

[0176] Since the circuit board 10 contacts the heat-conducting component 50 through the second heat-conducting part 42, the heat absorbed by the thermally conductive adhesive 40 will also be released to the outside through the circuit board 10 during the operation of the chip module 20. In this embodiment, the thermal conductivity of the heat-conducting component 50 is set to be greater than that of the circuit board 10, so that more of the heat absorbed by the thermally conductive adhesive 40 can be absorbed by the heat-conducting component 50, thereby reducing the release of the heat absorbed by the thermally conductive adhesive 40 to the outside through the circuit board 10. This improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0177] In one embodiment, the thermal conductivity of the heat-conducting element 50 is greater than or equal to 6 W / (m·K). In another embodiment, the thermal conductivity of the heat-conducting element 50 is equal to 8 W / (m·K). In yet another embodiment, the thermal conductivity of the heat-conducting element 50 is equal to 10 W / (m·K).

[0178] In one embodiment, the material of the thermally conductive element 50 includes epoxy resin and a filler material, wherein the filler material of the thermally conductive element 50 includes alumina and / or aluminum nitride. During the fabrication of the thermally conductive element 50, epoxy resin is used as the matrix material, and alumina and / or aluminum nitride are filled into the matrix material. This forms the colloid required for fabricating the thermally conductive element 50 in the circuit board assembly 100 of this application. In one embodiment, the filler material of the thermally conductive element 50 includes alumina and aluminum nitride. Exemplarily, in one embodiment, the proportion of epoxy resin in the thermally conductive element 50 is 20%, the proportion of alumina is 40%, and the proportion of aluminum nitride is 40%, corresponding to a thermal conductivity of 6 W / (m·K).

[0179] In this embodiment, when the filler material of the thermal conductive element 50 includes aluminum nitride, the thermal conductivity of aluminum oxide is 35 W / (m·K), while that of aluminum nitride is 250 W / (m·K). By employing a thermal conductive element 50 with aluminum nitride, the circuit board assembly 100 of this application improves the thermal conductivity of the thermal conductive element 50, thereby enhancing the heat transfer efficiency between the heat sink 30 and the thermally conductive adhesive 40, and ultimately improving the heat dissipation efficiency of the circuit board assembly 100.

[0180] Therefore, based on the limitations of the above embodiments, the circuit board assembly 100 of this application achieves thermally conductive connection between the chip module 20 and the heat sink 30 through the contact between the solder ball 21 and the thermally conductive adhesive 40, and the contact between the thermally conductive adhesive 40 and the thermally conductive component 50. The thermal resistance between the chip module 20 and the heat sink 30 is reduced by relying on the thermally conductive component 50 and the thermally conductive adhesive 40, thereby improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0181] Based on the circuit board assembly 100 of this application, thermal conductive elements 50 and thermal conductive adhesive 40 are used to achieve thermally conductive connection between the heat sink 30 and the solder balls 21 of the chip module 20, and to reduce the thermal resistance between the heat sink 30 and the chip module 20, thereby improving heat dissipation efficiency. When the circuit board assembly 100 of this application is applied to an electronic device, the electronic device can realize the display function of the electronic device through the battery 203 in conjunction with the circuit board assembly 100 and the screen 202. The improved heat dissipation efficiency of the circuit board assembly 100 also improves the heat dissipation efficiency of the electronic device, ensuring the reliability of the electronic device of this application.

[0182] The circuit board assembly 100 of this application can also be applied to other usage scenarios where power signals are received and processed. For example, the structure of the circuit board assembly 100 is applied to electronic devices such as tablets, computers, mobile phones, and wearable devices. This application does not impose any particular limitations on this. Because the circuit board assembly 100 of this application includes a thermally conductive component 50 and a thermally conductive adhesive 40, the thermally conductive component 50 and the thermally conductive adhesive 40 can reduce the thermal resistance between the chip module 20 and the heat sink 30, thereby improving the heat dissipation efficiency of the circuit board assembly 100. In other usage scenarios, electronic devices using the circuit board assembly 100 of this application have higher heat dissipation efficiency and better reliability.

[0183] In one embodiment, the circuit board assembly 100 of this application includes a second heat-conducting element 60. The material of the second heat-conducting element 60 is a colloid. Along the thickness direction of the circuit board 10, the second heat-conducting element 60 is used to fill the mounting gap between the heat sink 30 and the chip module 20.

[0184] Referring back to Figure 9, along the thickness direction of the circuit board 10, the surface of the chip module 20 facing away from the circuit board 10 is thermally connected to the heat sink 30 via the second thermal conductive element 60. When the chip module 20 is operating, the heat generated by the chip module 20 is transferred from the surface of the chip module 20 facing away from the circuit board 10 to the second thermal conductive element 60, and then from the second thermal conductive element 60 to the heat sink 30. This further reduces the thermal resistance between the chip module 20 and the heat sink 30, further improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0185] On the other hand, based on the installation gap between the heat sink 30 and the chip module 20, the setting of the second heat conductor 60 can also exhaust the air between the heat sink 30 and the chip module 20, thereby reducing the thermal resistance between the chip module 20 and the heat sink 30 and improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0186] In one embodiment, the material of the second heat-conducting element 60 is the same as that of the heat-conducting element 50.

[0187] In one embodiment, the chip module 20 includes two stacked chips 24, which are connected by a second solder ball 25. The space between the two chips 24 is filled with a second thermally conductive adhesive 26, which is used to thermally connect to the second solder ball 25 and the thermally conductive component 50, respectively.

[0188] In the schematic diagram shown in Figure 9, when the two chips 24 are operating, the heat-generating units inside the two chips 24 generate heat. This heat dissipates outwards, causing the temperature of the casings of each chip 24 and the second solder ball 25 to rise. Since the casings of each chip 24 are typically made of plastic, while the second solder ball 25 is typically made of metal to achieve conductivity between the two chips 24, the thermal conductivity of the plastic is lower than that of the metal. Therefore, the heat generated when the two chips 24 are operating is mainly transferred outwards through the second solder ball 25. In other words, the second solder ball 25 is the main heat source exposed to the outside between the two chips 24.

[0189] In this embodiment, the second thermally conductive adhesive 26 is filled between the two chips 24 and contacts the second solder ball 25. The second thermally conductive adhesive 26 is used to absorb the heat transferred to the second solder ball 25 when the two chips 24 are working, and transfer the heat to the thermally conductive component 50, and then from the thermally conductive component 50 to the heat sink 30. This achieves heat dissipation for the second solder ball 25.

[0190] In existing technology, a chip module comprises two stacked chips. One of the chips is thermally connected to a heat sink, while the other chip is located near a circuit board. The two chips are connected by a second solder ball. When both chips are operating, they generate heat. If the chip closer to the circuit board generates excessive heat, this heat will be transferred through the solder ball to the casing of the other chip, and then from the casing to the heat sink. However, because the thermal conductivity of the chip casing is relatively low, the thermal resistance between the chip module and the heat sink is relatively high, resulting in poor heat dissipation efficiency of the chip module.

[0191] The circuit board assembly 100 of this application achieves a thermally conductive connection between the chip module 20 and the heat sink 30 through the contact between the second solder ball 25 and the second thermally conductive adhesive 26, and the contact between the second thermally conductive adhesive 26 and the thermally conductive component 50. This allows the heat generated when the two chips 24 are working to be transferred to the heat sink 30 in sequence through the second solder ball 25, the second thermally conductive adhesive 26 and the thermally conductive component 50.

[0192] Because the second thermally conductive adhesive 26 has a high thermal conductivity, the circuit board assembly 100 of this application, in conjunction with the thermally conductive adhesive 40, further reduces the thermal resistance between the chip module 20 and the heat sink 30, thereby increasing the heat transfer efficiency between the chip module 20 and the heat sink 30. This further improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0193] On the other hand, compared with the prior art where two chips are spaced apart, the circuit board assembly 100 of this application stacks two chips 24, which reduces the space occupied by the chip module 20 on the circuit board 10, making the structure of the circuit board assembly 100 of this application compact.

[0194] In one embodiment, each chip 24 includes a thermally conductive surface 241. The two thermally conductive surfaces 241 of the two chips 24 face each other along the thickness direction of the circuit board 10. The areas of the two thermally conductive surfaces 241 of the two chips 24 are equal. Along the plane direction of the circuit board 10, the second thermally conductive adhesive 26 is flush with the sidewalls of the two chips 24 and contacts the thermally conductive component 50.

[0195] Please refer to Figure 13 for a cross-sectional view of the circuit board assembly 100 provided in one embodiment of this application.

[0196] As shown in Figure 13, the sidewalls of the two chips 24 are flush. The heat-conducting component 50 contacts the sidewalls of the two chips 24 and also contacts the second thermally conductive adhesive 26, ensuring that the heat released by the two chips 24 through the second solder ball 25 during operation can be transferred to the heat-conducting component 50 via the second thermally conductive adhesive 26. This ensures the heat dissipation function of the circuit board assembly 100 for the two chips 24.

[0197] In one embodiment, the two chips 24 include a first chip 24a and a second chip 24b. The area of ​​the thermally conductive surface 241 of the first chip 24a is larger than the area of ​​the thermally conductive surface 241 of the second chip 24b. A portion of the second thermally conductive adhesive 26 is located between the first chip 24a and the second chip 24b, and another portion of the second thermally conductive adhesive 26 is located outside the second chip and in contact with the thermally conductive component 50.

[0198] For ease of description, a portion of the second thermally conductive adhesive 26 is defined as the third thermally conductive part 261, and the other portion of the second thermally conductive adhesive 26 is defined as the fourth thermally conductive part 262.

[0199] Referring back to Figure 9, along the thickness direction of the circuit board 10, the projection of the second chip 24b onto the first chip 24a is housed on the first chip 24a. A third heat-conducting part 261 fills the gap between the first chip 24a and the second chip 24b and contacts the second solder ball 25. A fourth heat-conducting part 262 is located outside the second chip 24b. That is, when both chips 24 are operating, the third heat-conducting part 261 absorbs the heat released by the second solder ball 25 through contact with it, and the fourth heat-conducting part 262 absorbs the heat absorbed by the third heat-conducting part 261 to transfer the heat from the second solder ball 25 to the outside of the second chip 24b. The heat-conducting component 50 contacts the fourth heat-conducting part 262 to absorb the heat transferred from the second solder ball 25 by the fourth heat-conducting part 262 and transfers the heat to the heat sink 30.

[0200] In the schematic diagram shown in Figure 9, along the thickness direction of the circuit board 10, the first chip 24a is closer to the circuit board 10 than the second chip 24b, and the first chip 24a is electrically connected to the circuit board 10 via solder balls 21. In another embodiment, along the thickness direction of the circuit board 10, the first chip 24a is farther from the circuit board 10 than the second chip 24b, and the second chip 24b is electrically connected to the circuit board 10 via solder balls 21. In other embodiments, the chip module 20 includes multiple chips 24, and the number of chips 24 is greater than two, where the first chip 24a and the second chip 24b are any two stacked chips 24.

[0201] In one embodiment, the chip module 20 includes a chip 24, which is connected to the circuit board 10 via solder balls 21, wherein the chip 24 is thermally connected to the heat sink 30 away from the surface of the circuit board 10 along the thickness direction of the circuit board 10.

[0202] Please refer to Figure 14 for another structural schematic diagram of the circuit board assembly 100 provided in this embodiment of the application.

[0203] As shown in Figure 14, the heat-conducting component 50 is in contact with the sidewall of the chip 24. When the chip 24 is operating, the heat generated by the chip 24 is transferred sequentially to the thermally conductive adhesive 40 and the heat-conducting component 50 through the solder balls 21. The heat generated by the chip 24 can also be transferred from the sidewall of the chip 24 through the casing to the heat-conducting component 50. The heat transferred to the heat-conducting component 50 is then transferred to the heat sink 30. On the other hand, the heat generated by the chip 24 can also be transferred from the surface of the chip 24 away from the circuit board 10 through the casing to the heat sink 30. This achieves a thermally conductive connection between the chip 24 and the heat sink 30, and reduces the thermal resistance between the chip 24 and the heat sink 30 by relying on the heat-conducting component 50 and the thermally conductive adhesive 40, thereby improving the thermal conductivity of the circuit board assembly 100 of this application.

[0204] In this embodiment, chip 24 is a system on chip (SOC).

[0205] For ease of description, the illustrations of the embodiments of this application and subsequent embodiments all show that the chip module 20 includes two chips 24. Along the thickness direction of the circuit board 10, the first chip 24a is closer to the circuit board 10 than the second chip 24b. The first chip 24a is connected to the circuit board 10 through solder balls 21.

[0206] In one embodiment, the first chip 24a is a system-on-chip (SOC). As shown in FIG. 15, the solder balls 21 of the first chip 24a are arranged in a full array on the surface of the first chip 24a facing the circuit board 10. During the fabrication of the circuit board assembly 100 of this application, when filling the space between the first chip 24a and the circuit board 10 with thermally conductive adhesive 40, the adhesive can be dispensed along the outer edge of any two connected sidewalls of the first chip 24a. In one embodiment, as shown in FIG. 15, when filling the space between the first chip 24a and the circuit board 10 with thermally conductive adhesive 40, the adhesive can be dispensed in the direction indicated by the arrow in FIG. 15. In another embodiment, when filling the space between the first chip 24a and the circuit board 10 with thermally conductive adhesive 40, the adhesive can also be dispensed in other ways to ensure that the thermally conductive adhesive 40 fills the gap between the first chip 24a and the circuit board 10.

[0207] In one embodiment, the second chip 24b is a double-data-rate synchronous dynamic random access memory (DDR). As shown in FIG16, the second solder balls 25 of the second chip 24b are arranged in a non-full array on the surface of the second chip 24b facing the first chip 24a. In the schematic diagram shown in FIG16, each of the second solder balls 25 is arranged in an array around the central region of the surface of the second chip 24b facing the first chip 24a. During the fabrication of the circuit board assembly 100 of this application, when filling the space between the second chip 24b and the first chip 24a with the second thermally conductive adhesive 26, the adhesive can be dispensed along the outer edge of any three connected sidewalls of the second chip 24b. In one embodiment, as shown in FIG16, when filling the space between the second chip 24b and the first chip 24a with the second thermally conductive adhesive 26, the adhesive can be dispensed in the direction indicated by the arrow in FIG16. In another embodiment, when filling the space between the second thermally conductive adhesive 26 and the first chip 24a, the adhesive can be applied in other ways to ensure that the second thermally conductive adhesive 26 fills the gap between the first chip 24a and the second chip 24b.

[0208] In one embodiment, the material of the third thermally conductive part 261 is the same as that of the fourth thermally conductive part 262, while the material of the thermally conductive element 50 is different from that of the fourth thermally conductive part 262. As shown in FIG9, a portion of the second thermally conductive adhesive 26 is filled between the first chip 24a and the second chip 24b, and another portion of the second thermally conductive adhesive 26 overflows from between the first chip 24a and the second chip 24b to facilitate contact with the thermally conductive element 50. During the fabrication process of the circuit board assembly 100 of this application, the second thermally conductive adhesive 26 of the same material can be first filled between the first chip 24a and the second chip 24b, and a portion of the second thermally conductive adhesive 26 can overflow outside the second chip 24b. This forms the third thermally conductive part 261 and the fourth thermally conductive part 262 respectively. Then, an adhesive of the same material as the thermally conductive element 50 is coated on the second thermally conductive part 42, and the adhesive is brought into contact with the fourth thermally conductive part 262 until the adhesive comes into contact with the heat sink 30. This forms the thermally conductive element 50.

[0209] In one embodiment, the material of the third heat-conducting part 261 is different from that of the fourth heat-conducting part 262, while the material of the heat-conducting component 50 is the same as that of the fourth heat-conducting part 262.

[0210] Please refer to Figure 17 for a cross-sectional view of the circuit board assembly 100 provided in another embodiment of this application.

[0211] Specifically, as shown in Figure 17, the heat-conducting component 50 and the fourth heat-conducting part 262 are integrally formed. The third heat-conducting part 261 is filled between the first chip 24a and the second chip 24b. Along the plane of the circuit board 10, the third heat-conducting part 261 is flush with the sidewall of the second chip 24b to facilitate contact with the fourth heat-conducting part 262. In the process of manufacturing the circuit board assembly 100 of this application, an adhesive of the same material as the third heat-conducting part 261 can be filled between the first chip 24a and the second chip 24b first, and then the overflowing adhesive can be treated to ensure that the adhesive is flush with the sidewall of the second chip 24b. This forms the third heat-conducting part 261. Then, an adhesive of the same material as the heat-conducting component 50 is coated on the second heat-conducting part 42, and the adhesive is brought into contact with the third heat-conducting part 261 until the adhesive comes into contact with the heat sink 30. This forms the fourth heat-conducting part 262 and the heat-conducting component 50.

[0212] In one embodiment, the material of the heat-conducting component 50 is the same as the material of the fourth heat-conducting part 262, and the material of the third heat-conducting part 261 includes a variety of second adhesive materials, and at least one of the multiple second adhesive materials is made of the same material as the heat-conducting component 50.

[0213] Please refer to Figure 18 for a cross-sectional view of the circuit board assembly 100 provided in another embodiment of this application.

[0214] Specifically, as shown in Figure 18, the heat-conducting component 50 and the fourth heat-conducting part 262 are integrally formed. Along the thickness direction of the circuit board 10, the third heat-conducting part 261 fills between the first chip 24a and the second chip 24b, and part of the heat-conducting component 50 fills between the first chip 24a and the second chip 24b and contacts the third heat-conducting part 261. In the process of manufacturing the circuit board assembly 100 of this application, an adhesive of the same material as the third heat-conducting part 261 can be first filled between the first chip 24a and the second chip 24b, ensuring that the adhesive does not overflow from between the first chip 24a and the second chip 24b. Then, an adhesive of the same material as the heat-conducting component 50 is coated on the second heat-conducting part 42, wherein the adhesive can flow into the space between the first chip 24a and the second chip 24b and contact the adhesive set in the previous step. This forms the third heat-conducting part 261. When the adhesive contacts the heat sink 30, the adhesive located outside the chip module 20 forms the fourth heat-conducting part 262 and the heat-conducting component 50.

[0215] In one embodiment, the thermal conductivity of the second thermally conductive adhesive 26 is greater than that of air.

[0216] In one embodiment, the material of the third heat-conducting part 261 is the same as the material of the first heat-conducting part 41.

[0217] In one embodiment, the material of the fourth heat-conducting part 262 is the same as the material of the second heat-conducting part 42.

[0218] In one embodiment, the first heat-conducting part 41 is made of the same material as the second heat-conducting part 42, and the third heat-conducting part 261 and the fourth heat-conducting part 262 are made of the same material. The thermally conductive adhesive 40 is made of the same material as the second thermally conductive adhesive 26.

[0219] In one embodiment, each chip 24 includes a thermally conductive surface 241, and the two thermally conductive surfaces 241 of the two chips 24 are opposite each other along the thickness direction of the circuit board 10. At least one thermally conductive surface 241 includes a heat dissipation pad 242, which is used to extend into the interior of the chip 24 and thermally connect with the heat-generating unit 243 of the chip 24. The second thermally conductive adhesive 26 or the thermally conductive component 50 is also used to thermally connect the heat dissipation pad 242.

[0220] Please refer to Figures 19-21 for details. Figure 19 is a cross-sectional view of the internal structure of the chip 24 in the circuit board assembly 100 provided in this embodiment of the application. Figure 20 is another cross-sectional view of the internal structure of the chip 24 in the circuit board assembly 100 provided in this embodiment of the application. Figure 21 is a top view of the chip module 20 in the circuit board assembly 100 provided in this embodiment of the application. To better illustrate the relative position of the heat dissipation pads 242, the second thermally conductive adhesive 26 is omitted in the top view shown in Figure 21.

[0221] As shown in Figures 19-21, the chip 24 includes a housing 244 and a heating unit 243, with the heating unit 243 housed within the housing 244. For the chip 24 with a heat dissipation pad 242 on the heat-conducting surface 241, one end of the heat dissipation pad 242 is housed within the housing 244 and thermally connected to the heating unit 243 along the thickness direction of the circuit board 10, while the other end of the heat dissipation pad 242 protrudes from the heat-conducting surface 241 of the chip 24 to facilitate thermal connection with the second thermally conductive adhesive 26 or the thermally conductive component 50.

[0222] For the chip 24 with heat dissipation pads 242 on the thermally conductive surface 241, the heat generated during the operation of the chip 24 is transferred to the heat sink 30 in sequence through the second solder ball 25, the second thermally conductive adhesive 26, and the thermally conductive component 50, and can also be transferred to the heat sink 30 through the heat dissipation pads 242. That is, the setting of the heat dissipation pads 242 increases the heat transfer path between the chip 24 and the heat sink 30. This further reduces the thermal resistance between the chip module 20 and the heat sink 30, and further improves the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0223] In one embodiment, there are multiple heat dissipation pads 242 to increase the heat exchange area between the heat-generating unit 243 of the chip 24 and the second thermally conductive adhesive 26 or the thermally conductive component 50, thereby further improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0224] In one embodiment, the area of ​​the heat-conducting surface 241 of the first chip 24a is larger than the area of ​​the heat-conducting surface 241 of the second chip 24b. The heat dissipation pad 242 is located on the heat-conducting surface 241 of the first chip 24a along the thickness direction of the circuit board 10. The projection of the second chip 24b on the heat-conducting surface 241 of the first chip 24a does not cover the heat dissipation pad 242.

[0225] In one embodiment, as shown in FIG19, along the planar direction of the circuit board 10, the heat dissipation pad 242 is located outside the second chip 24b and contacts the fourth heat-conducting part 262 of the second thermally conductive adhesive 26. When the chip 24 with the heat dissipation pad 242 is working, the heat generated by the heat-generating unit 243 of the chip 24 is sequentially transferred through the heat dissipation pad 242 to the fourth heat-conducting part 262 and the heat-conducting component 50, and then transferred by the heat-conducting component 50 to the heat sink 30. This achieves a thermally conductive connection between the chip module 20 and the heat sink 30.

[0226] In one embodiment, as shown in FIG20, along the planar direction of the circuit board 10, the heat dissipation pad 242 is located outside the second chip 24b and spaced apart from the fourth thermally conductive portion 262 of the second thermally conductive adhesive 26. The heat dissipation pad 242 is in contact with the thermally conductive component 50. When the chip 24 with the heat dissipation pad 242 is working, the heat generated by the heat-generating unit 243 of the chip 24 is transferred to the thermally conductive component 50 through the heat dissipation pad 242, and then transferred from the thermally conductive component 50 to the heat sink 30. This achieves a thermally conductive connection between the chip module 20 and the heat sink 30.

[0227] In both embodiments described above, as shown in Figures 19-21, the heat dissipation pad 242 is disposed on the heat-conducting surface 241 of the first chip 24a. In another embodiment, the heat dissipation pad 242 may also be disposed on the heat-conducting surface 241 of the second chip 24b.

[0228] In one embodiment, along the planar direction of the circuit board 10, the heat dissipation pad 242 is located outside the second chip 24b and contacts the fourth thermally conductive portion 262 of the second thermally conductive adhesive 26 and the thermally conductive element 50, respectively.

[0229] In one embodiment, a heat dissipation pad 242 is located between two chips 24 and spaced apart from second solder balls 25. The heat dissipation pad 242 contacts a second thermally conductive adhesive 26 to conduct heat and connect the second thermally conductive adhesive 26.

[0230] Please refer to Figure 22 for another cross-sectional view of the internal structure of the chip 24 of the circuit board assembly 100 provided in this embodiment of the application.

[0231] As shown in Figure 22, along the thickness direction of the circuit board 10, the second solder ball 25 is located on the thermally conductive surface 241 of the first chip 24a, and the projection of the second chip 24b on the first chip 24a covers the heat dissipation pad 242. The second thermally conductive adhesive 26 is used to fill the gap between the first chip 24a and the second chip 24b, and contacts the second solder ball 25 and the heat dissipation pad 242 respectively. When the first chip 24a is working, the heat generated by the heat-generating unit 243 of the first chip 24a can be transferred to the second thermally conductive adhesive 26 through the heat dissipation pad 242, and then transferred to the heat sink 30 through the thermally conductive component 50. This achieves a thermally conductive connection between the chip module 20 and the heat sink 30.

[0232] In one embodiment, the chip module 20 includes a first chip 24a and a second chip 24b. The first chip 24a and the second chip 24b are connected by a second solder ball 25. The area of ​​the heat-conducting surface 241 of the first chip 24a is larger than the area of ​​the heat-conducting surface 241 of the second chip 24b. The heat-dissipating pad 242 is located on the heat-conducting surface 241 of the first chip 24a and is spaced apart from the second chip 24b. The heat-dissipating pad 242 is in contact with the heat-conducting component 50.

[0233] Please refer to Figure 23 for another cross-sectional view of the internal structure of the chip 24 of the circuit board assembly 100 provided in this embodiment of the application.

[0234] As shown in Figure 23, when the first chip 24a is working, the heat generated by the heat-generating unit 243 of the first chip 24a can be transferred to the heat-conducting component 50 via the heat dissipation pad 242, and then to the heat sink 30 via the heat dissipation component 50. This achieves a thermally conductive connection between the first chip 24a and the heat sink 30, and reduces the thermal resistance between the first chip 24a and the heat sink 30 by relying on the heat dissipation pad 242, thereby improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0235] In one embodiment, the heat dissipation pad 242 is made of copper.

[0236] In one embodiment, the chip module 20 includes a first chip 24a and a second chip 24b, which are connected by a second solder ball 25. Along the thickness direction of the circuit board 10, the first chip 24a is closer to the circuit board 10 than the second chip 24b. The second chip 24b is thermally connected to the heat sink 30, and the material of the surface of the second chip 24b facing the heat sink 30 includes metal.

[0237] When the circuit board assembly 100 of this application is in operation, part of the heat in the second chip 24b comes from the heat generated by the heating unit 243 inside the second chip 24b, and another part comes from the heat transferred from the first chip 24a to the second chip 24b through the second solder ball 25. At this time, the heat in the second chip 24b can be transferred to the heat sink 30 through the surface of the second chip 24b toward the heat sink 30.

[0238] In this embodiment, since the thermal conductivity of metal is greater than that of the molding compound, setting the material of the surface of the second chip 24b facing the heat sink 30 as metal can reduce the thermal resistance between the second chip 24b and the heat sink 30, thereby improving the heat dissipation efficiency of the circuit board assembly 100. In one embodiment, during the fabrication of the circuit board assembly 100, a metal plating layer can be deposited on the surface of the second chip 24b facing the heat sink 30 through a vapor deposition process.

[0239] In one embodiment, along the thickness direction of the circuit board 10, the surface of the circuit board 10 facing the chip module 20 includes a second heat dissipation pad 11. One end of the second heat dissipation pad 11 extends into the interior of the circuit board 10, and the other end of the second heat dissipation pad 11 protrudes from the surface of the circuit board 10 facing the chip module 20. The other end of the second heat dissipation pad 11 is spaced from the solder ball 21 along the planar direction of the circuit board 10 and is thermally connected to the thermally conductive adhesive 40.

[0240] Please refer to Figure 24 for a schematic diagram of the internal structure of the circuit board 10 of the circuit board assembly 100 provided in this embodiment of the application.

[0241] As shown in Figure 24, since the solder ball 21 is in contact with the circuit board 10, the heat generated by the chip module 20 during operation will also be transferred to the circuit board 10 through the solder ball 21. The circuit board 10 also generates heat during operation. In this embodiment, the second heat dissipation pad 11 is used to absorb the heat from the circuit board 10 and transfer the heat to the heat-conducting component 50 through the thermally conductive adhesive 40, and then from the heat-conducting component 50 to the heat sink 30. This achieves a thermally conductive connection between the circuit board 10 and the heat sink 30.

[0242] In one embodiment, one end of the second heat dissipation pad 11 extends into the interior of the circuit board 10, and the other end of the second heat dissipation pad 11 protrudes from the surface of the circuit board 10 facing the chip module 20. The other end of the second heat dissipation pad 11 is thermally connected to the heat conductor 50.

[0243] Please refer to Figure 25 for another structural schematic diagram of the internal structure of the circuit board 10 of the circuit board assembly 100 provided in this embodiment of the application.

[0244] As shown in Figure 25, the second heat dissipation pad 11 is used to absorb the heat of the circuit board 10 and transfer the heat to the heat sink 30 through the heat conductor 50. This achieves a thermally conductive connection between the circuit board 10 and the heat sink 30.

[0245] In both embodiments described above, the provision of the second heat dissipation pad 11 reduces the impact of the heat from the circuit board 10 on the operation of the chip module 20. On the other hand, since part of the heat from the circuit board 10 originates from the heat released by the solder balls 21 during the operation of the chip module 20, the provision of the second heat dissipation pad 11 increases the heat transfer path between the solder balls 21 and the heat sink 30, further improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0246] In one embodiment, the heat sink 30 includes a heat sink 31 and a shield 32. Along the thickness direction of the circuit board 10, the shield 32 is attached to the surface of the heat sink 31 facing the chip module 20. The projection of the shield 32 covers the chip module 20, the thermally conductive adhesive 40, and the thermally conductive component 50. The outer edge of the shield 32 includes a protrusion 321. The protrusion 321 extends toward the circuit board 10 and is fixedly connected to the circuit board 10. The protrusion 321 at least surrounds the chip module 20 and the thermally conductive component 50.

[0247] As shown in Figure 9, the protrusion 321 of the shielding cover 32, away from the heat sink 31, contacts the circuit board 10. The protrusion 321 surrounds the chip module 20 to shield the propagation of electromagnetic waves and prevent electromagnetic waves from affecting the operation of the chip module 20. This ensures the stable operation of the circuit board assembly 100 of this application. During the operation of the chip module 20, the heat released by the solder balls 21 of the chip module 20 is transferred to the shielding cover 32 through the thermally conductive adhesive 40 and the thermally conductive component 50, and then transferred by the shielding cover 32 to the heat sink 31, whereby the heat sink 31 dissipates the heat.

[0248] In this embodiment, the end of the protrusion 321 away from the heat sink 31 is in contact with the circuit board 10. In other embodiments, the end of the protrusion 321 away from the heat sink 31 may also have a gap with the circuit board 10.

[0249] In one embodiment, the heat sink 30 includes a heat sink 31. Along the thickness direction of the circuit board 10, the heat sink 31 is located on the side of the chip module 20 away from the circuit board 10 and is thermally connected to the chip module 20 and the heat conductor 50.

[0250] Please refer to Figure 26 for another structural schematic diagram of the circuit board assembly 100 provided in this embodiment of the application.

[0251] As shown in Figure 26, along the thickness direction of the circuit board 10, the projection of the heat sink 31 covers the chip module 20 and the heat conductor 50, so as to facilitate the heat conductor 50 and the chip module 20 to be thermally connected to the heat sink 31.

[0252] In one embodiment, the heat sink 31 is made of graphite.

[0253] In one embodiment, the circuit board assembly 100 of this application further includes a baffle 70, which is fixed to the circuit board 10 and extends toward the heat sink 30. Along the plane of the circuit board 10, the baffle 70 and the chip module 20 are spaced apart from each other, and the second heat-conducting part 42 and the heat-conducting part 50 are located between the chip module 20 and the baffle 70.

[0254] Please refer to Figure 27 for a schematic diagram of the retaining wall 70 of the circuit board assembly 100 provided in this embodiment of the application.

[0255] As shown in Figure 27, along the plane of the circuit board 10, the baffle 70 is used to limit the flow range of the thermally conductive adhesive 40, so as to avoid the installation of other components 1001 mounted on the circuit board 10 being affected by the excessive flow range of the thermally conductive adhesive 40 during the preparation of the circuit board assembly 100 of this application.

[0256] In this embodiment, the material of the heat-conducting component 50 is a colloid, and the baffle 70 is also used to limit the flow range of the heat-conducting component 50, so as to facilitate the heat-conducting component 50 to fill to contact the heat sink 30 during the fabrication of the circuit board assembly 100. That is, the baffle 70 is used to ensure the filling height of the heat-conducting component 50, ensuring that the heat-conducting component 50 can contact the heat sink 30 and the thermally conductive adhesive 40 respectively. On the other hand, the baffle 70 can also prevent the installation of other components 1001 mounted on the circuit board 10 from being affected by the excessive flow range of the heat-conducting component 50 during the fabrication of the circuit board assembly 100.

[0257] In one embodiment, a second thermally conductive portion 42 surrounds the chip module 20 along the planar direction of the circuit board 10. Multiple baffles 70 are provided to surround the thermally conductive adhesive 40.

[0258] Please refer to Figures 28 and 29 for further details. Figure 28 is a schematic diagram of another structure of the retaining wall 70 of the circuit board assembly 100 provided in this embodiment of the application, and Figure 29 is a partial top view of the circuit board assembly 100 provided in this embodiment of the application. In particular, Figure 29 is a partial top view of Figure 28 after omitting the heat sink 30 and taking a top view along the third top line L3 towards the circuit board 10.

[0259] As shown in Figures 28 and 29, multiple baffles 70 are spaced around the thermally conductive adhesive 40 to further restrict the flow range of the thermally conductive adhesive 40. In this embodiment, the material of the thermally conductive component 50 is a gel. Along the planar direction of the circuit board 10, the surface of each baffle 70 facing the chip module 20 contacts the thermally conductive component 50 to further restrict the flow range of the thermally conductive component 50, facilitating the fabrication of the thermally conductive component 50 in contact with the heat sink 30 and the thermally conductive adhesive 40.

[0260] In one embodiment, a second thermally conductive portion 42 surrounds the chip module 20 along the planar direction of the circuit board 10. A ring-shaped baffle 70 surrounds the thermally conductive adhesive 40.

[0261] Please refer to Figure 30 for another partial top view of the circuit board assembly 100 provided in this embodiment of the application. Figure 30 is another partial top view of the circuit board 10 obtained by cutting along the third top line L3 after omitting the heat sink 30 in Figure 28.

[0262] As shown in Figure 30, the annular baffle 70 is used to further restrict the flow range of the thermally conductive adhesive 40. In this embodiment, the material of the thermally conductive component 50 is a colloid. Along the planar direction of the circuit board 10, the inner surface of the annular baffle 70 contacts the thermally conductive component 50 to further restrict the flow range of the thermally conductive component 50, facilitating the fabrication of the thermally conductive component 50 that contacts the heat sink 30 and the thermally conductive adhesive 40.

[0263] In one embodiment, the height of the baffle 70 along the thickness direction of the circuit board 10 is greater than or equal to the height of the chip module 20. When the material of the thermal conductive element 50 is a gel, the thermal conductive element 50 contacts the sidewall 22 of the chip module 20. In this embodiment, the baffle 70 with a height greater than or equal to the height of the chip module 20 is provided to facilitate ensuring the contact relationship between the thermal conductive element 50 and the sidewall 22 of the chip module 20 during the fabrication of the thermal conductive element 50. On the other hand, providing the baffle 70 with a height greater than or equal to the height of the chip module 20 also facilitates the fabrication of the thermal conductive element 50 that contacts the heat sink 30 and the thermally conductive adhesive 40.

[0264] In one embodiment, the height of the retaining wall 70 along the thickness direction of the circuit board 10 is less than or equal to the spacing between the heat sink 30 and the circuit board 10.

[0265] Please refer to Figure 31 for another structural schematic diagram of the retaining wall 70 of the circuit board assembly 100 provided in this embodiment of the application.

[0266] As shown in Figure 31, along the thickness direction of the circuit board 10, the end of the baffle 70 away from the circuit board 10 contacts the heat sink 30. In the schematic diagram shown in Figure 31, the heat sink 30 extends from the chip module 20 along the plane of the circuit board 10, and the end of the baffle 70 away from the circuit board 10 contacts the surface of the heat sink 30 facing the circuit board 10. This allows the heat released by the chip module 20 through the solder balls 21 during operation to be transferred to the heat conductor 50 and the thermally conductive adhesive 40, and then to the baffle 70, and finally to the heat sink 30. In this embodiment, the contact between the baffle 70 and the heat sink 30 further increases the heat transfer path between the chip module 20 and the heat sink 30, further reduces the thermal resistance between them, and thus further improves the heat dissipation efficiency of the circuit board assembly 100.

[0267] In the schematic diagram shown in Figure 31, the height of the retaining wall 70 along the thickness direction of the circuit board 10 is equal to the distance between the heat sink 30 and the circuit board 10.

[0268] In another embodiment, the height of the baffle 70 along the thickness direction of the circuit board 10 is less than the distance between the heat sink 30 and the circuit board 10. Correspondingly, the end of the baffle 70 away from the circuit board 10 is thermally connected to the surface of the heat sink 30 facing the circuit board 10.

[0269] Specifically, in one embodiment, the circuit board assembly further includes a third heat-conducting component 80. Along the thickness direction of the circuit board 10, the third heat-conducting component 80 is used to fill the installation gap between the baffle 70 and the heat sink 30 to achieve a thermally conductive connection between the baffle 70 and the heat sink 30.

[0270] Please refer to Figure 32 for another structural schematic diagram of the retaining wall 70 of the circuit board assembly 100 provided in this embodiment of the application.

[0271] As shown in Figure 33, the baffle 70 is thermally connected to the heat sink 30 via the third thermally conductive component 80. When the chip module 20 is operating, the heat generated by the chip module 20 is released through the solder balls 21 and transferred to the baffle 70 via the thermally conductive component 50 and thermally conductive adhesive 40, and then transferred from the baffle 70 to the heat sink 30. This achieves the thermally conductive connection between the heat sink 30 and the chip module 20.

[0272] In one embodiment, the material of the third heat conductor 80 is the same as that of the second heat conductor 60.

[0273] In one embodiment, there are multiple baffles 70. At least some of the baffles 70 are thermally connected to the heat sink 30 and a heat transfer line 12 in the circuit board 10 along the thickness direction of the circuit board 10. Each heat transfer line 12 extends along the plane direction of the circuit board 10 and is connected to a heat-generating unit 243 in the chip module 20 through solder balls 21.

[0274] Please refer to Figure 33 for another structural schematic diagram of the internal structure of the circuit board 10 of the circuit board assembly 100 provided in this application embodiment.

[0275] As shown in Figure 33, the chip 24 in the chip module 20, which is connected to the circuit board 10, contains multiple heat-generating units 243. Each heat-generating unit 243 is connected to a heat transfer line 12 via solder balls 21. When the chip module 20 is working, the heat generated by the heat-generating units 243 is transferred to the heat transfer line 12 via the solder balls 21. The circuit board assembly 100 of this application thermally connects a portion of the baffle 70 to the heat transfer line 12 connected to the heat-generating units 243, so that the heat generated when the chip module 20 is working can be transferred sequentially to the baffle 70 via the solder balls 21 and the heat transfer line 12, and then transferred from the baffle 70 to the heat sink 30.

[0276] In this embodiment, the thermally conductive connection between part of the baffle 70 and the heat transfer line 12 further increases the heat transfer path between the chip module 20 and the heat sink 30, further reduces the thermal resistance between the chip module 20 and the heat sink 30, thereby further improving the heat dissipation efficiency of the circuit board assembly 100 of this application.

[0277] In one embodiment, the retaining wall 70 is made of metal. In another embodiment, the retaining wall 70 is made of copper.

[0278] In one embodiment, the circuit board assembly 100 further includes a component 1001, which is mounted on the surface of the circuit board 10 on which the chip module 20 is mounted. The heat-conducting element 50 and the second heat-conducting part 42 are located between the chip module 20 and the component 1001, and the component 1001 is formed as a barrier 70.

[0279] Based on the descriptions of the two embodiments above, it can be understood that when fabricating the baffle 70 of the circuit board assembly 100 of this application, the baffle 70 can be formed by setting copper pillars on the surface of the circuit board 10 on which the chip module 20 is mounted. Correspondingly, the copper pillars should be thermally connected to the heat sink 30. Alternatively, other components 1001 on the surface of the circuit board 10 on which the chip module 20 is mounted can be used to form the baffle 70. Specifically, when the circuit board assembly 100 of this application is in operation, the heat generated by the chip module 20 can be transferred to the baffle 70 formed by the copper pillars, and then transferred by the baffle 70 to the heat sink 30. It can also be transferred to the baffle 70 formed by the components 1001, and absorbed by the components 1001.

[0280] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of protection of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A circuit board assembly, characterized in that, The circuit board assembly includes a circuit board, a chip module, and a heat sink. The chip module and the heat sink are stacked on the circuit board. The chip module and the circuit board are connected by solder balls. The heat sink is thermally connected to the chip module. The circuit board assembly further includes thermally conductive adhesive and a thermally conductive component. Along the planar direction of the circuit board, a portion of the thermally conductive adhesive fills the gap between the chip module and the circuit board and contacts the solder balls. Another portion of the thermally conductive adhesive is located outside the chip module. The thermally conductive component extends along the thickness direction of the circuit board and is used for thermally conductive connection with the heat sink and another portion of the thermally conductive adhesive, respectively.

2. The circuit board assembly according to claim 1, characterized in that, The thermal conductive element is made of a colloid and is also used to adhere to the sidewall of the chip module, wherein: The heat sink extends out of the chip module along the plane of the circuit board, and the thermal conductive component is thermally connected to the heat sink by attaching to the surface of the heat sink facing the circuit board; or, the thermal conductive component is thermally connected to the heat sink by attaching to the sidewall of the heat sink.

3. The circuit board assembly according to claim 2, characterized in that, The material of the thermal conductive component includes epoxy resin and filler material, wherein the filler material of the thermal conductive component includes aluminum oxide and / or aluminum nitride.

4. The circuit board assembly according to any one of claims 1-3, characterized in that, The thermally conductive adhesive is made of epoxy resin and filler material, wherein the filler material comprises alumina and / or silicon oxide.

5. The circuit board assembly according to any one of claims 1-4, characterized in that, The chip module comprises two stacked chips, which are connected by a second solder ball, wherein: A second thermally conductive adhesive is filled between the two chips, and the second thermally conductive adhesive is used to thermally connect with the second solder ball and the thermally conductive component, respectively.

6. The circuit board assembly according to claim 5, characterized in that, Each of the chips includes a thermally conductive surface, and the two thermally conductive surfaces of the two chips are opposite each other along the thickness direction of the circuit board. At least one of the thermally conductive surfaces includes a heat dissipation pad, which is used to extend into the interior of the chip and thermally connect with the heat-generating unit of the chip. The second thermally conductive adhesive or the thermally conductive component is also used to thermally connect the heat dissipation pad.

7. The circuit board assembly according to claim 6, characterized in that, The two chips include a first chip and a second chip. The area of ​​the heat-conducting surface of the first chip is larger than the area of ​​the heat-conducting surface of the second chip. The heat dissipation pad is located on the heat-conducting surface of the first chip. Along the thickness direction of the circuit board, the projection of the first chip onto the heat-conducting surface of the second chip does not cover the heat dissipation pad.

8. The circuit board assembly according to any one of claims 1-7, characterized in that, The heat dissipation component includes a heat sink and a shield. Along the thickness direction of the circuit board, the shield is attached to the surface of the heat sink facing the chip module. The projection of the shield covers the chip module, the thermally conductive adhesive, and the thermally conductive component. The outer edge of the shield includes a protrusion that extends toward the circuit board and is fixedly connected to the circuit board. The protrusion at least surrounds the chip module and the thermally conductive component.

9. The circuit board assembly according to any one of claims 1-8, characterized in that, The circuit board assembly also includes a baffle wall, which is fixed to the circuit board and extends toward the heat sink. Along the plane of the circuit board, the baffle wall and the chip module are spaced apart from each other. Another part of the thermally conductive adhesive and the thermally conductive component are both located between the chip module and the baffle wall.

10. The circuit board assembly according to claim 9, characterized in that, Another portion of the thermally conductive adhesive surrounds the chip module along the planar direction of the circuit board; The number of the baffles is multiple, and the multiple baffles are used to surround the thermally conductive adhesive at intervals; or, the baffles are annular, and the baffles are used to surround the thermally conductive adhesive.

11. The circuit board assembly according to claim 10, characterized in that, The height of the retaining wall along the thickness direction of the circuit board is less than or equal to the distance between the heat sink and the circuit board.

12. The circuit board assembly according to claim 10, characterized in that, The number of the baffles is multiple, and at least a portion of the baffles are thermally connected to the heat sink and a heat transfer line in the circuit board along the thickness direction of the circuit board. Each heat transfer line extends along the plane of the circuit board and is connected to the heat-generating unit in the chip module through the solder ball.

13. The circuit board assembly according to claim 12, characterized in that, The barrier is made of metal; and / or, the circuit board assembly further includes components mounted on the surface of the circuit board on which the chip module is mounted, and another portion of the thermal conductive element and the thermally conductive adhesive is located between the chip module and the components, the components forming the barrier.

14. An electronic device, characterized in that, The electronic device includes a housing and a circuit board assembly as described in any one of claims 1-13, the circuit board assembly being housed within the housing.

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