Radiator, circuit board assembly and electronic equipment

Abstract

The invention relates to the technical field of electronic equipment, and discloses a radiator, a circuit board assembly and electronic equipment. The radiator is used for radiating the chip and comprises a body and a driving part, the surface of one side, facing the chip, of the body comprises a heat conduction area, the heat conduction area is used for being in heat conduction connection with the first surface of the chip, and the shape of the heat conduction area in a first temperature interval is matched with the shape of the first surface in the first temperature interval; the driving piece is fixed to the body and used for driving the heat conduction area to deform in the second temperature interval so that the shape of the heat conduction area in the second temperature interval can be matched with the shape of the first surface in the second temperature interval. According to the invention, the shape of the heat conduction area is dynamically adjusted by using the driving part, so that the heat conduction area is dynamically matched with the shape of the first surface, high heat conduction efficiency can be kept between the chip and the radiator in a full-temperature section, and the heat dissipation performance of the radiator is improved.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to a heat sink, circuit board assembly, and electronic equipment. Background Technology

[0002] As the performance of electronic devices improves, chips within these devices are becoming increasingly integrated and power-density. This leads to a continuous increase in chip power consumption, making heat dissipation a growing concern. Electronic devices typically incorporate heat sinks to dissipate heat from the chips. These heat sinks are connected to the chip's surface via a thermally conductive medium, allowing heat generated by the chip to be conducted to the heat sink through the thermal contact area. During operation, temperature variations can cause deformation of the chip's surface. This deformation can increase the gap between the chip's surface and the heat sink, thereby increasing the thermal resistance and impacting the chip's heat dissipation performance. Summary of the Invention

[0003] This application provides a heat sink, a circuit board assembly, and an electronic device to improve the heat dissipation performance of the heat sink, thereby improving the reliability of electronic devices using the chip module.

[0004] In a first aspect, this application provides a heat sink for dissipating heat from a chip. The chip includes a first surface disposed facing the heat sink. The shape of the first surface in a first temperature range differs from its shape in a second temperature range, wherein the maximum temperature value in the first temperature range is less than the minimum temperature value in the second temperature range. The heat sink includes a body and a driving member, the driving member being fixed to the body. The side surface of the body facing the chip includes a heat-conducting region, which is thermally connected to the first surface of the chip so that heat generated during chip operation can be transferred to the body through the heat-conducting region. The shape of the heat-conducting region in the first temperature range is adapted to the shape of the first surface in the first temperature range; the driving member can be used to drive the heat-conducting region to deform in the second temperature range so that the shape of the heat-conducting region in the second temperature range is adapted to the shape of the first surface in the second temperature range.

[0005] In this application, the heat sink can use a driving component to dynamically adjust the shape of the heat conduction area, so that the shape of the heat conduction area can be adapted to the shape of the first surface of the chip in different temperature ranges, thereby realizing dynamic matching of the morphology of the heat conduction area and the first surface. This can better suppress the problem of excessive increase in the gap between the heat sink and the chip under high temperature conditions, so that the chip and the heat sink can maintain high heat conduction efficiency in the entire temperature range, and improve the heat dissipation performance of the heat sink.

[0006] In some implementations, a boss is provided on the surface of the body facing the chip, and the surface of the boss can be formed as a heat conduction area. The boss can improve the rigidity of the body.

[0007] In some implementations, the body includes an inner cavity containing support pillars. The two ends of the support pillars are connected to the inner walls of the body on opposite sides along a first direction, thereby supporting the inner cavity and improving the structural strength of the body. Here, the first direction refers to the thickness direction of the heat sink, which can be understood as the stacking direction of the heat sink and the chip.

[0008] In some implementations, the driving component is a metal sheet with a coefficient of thermal expansion lower than that of the body. The metal sheet can be disposed on the outer wall of a sidewall opposite to the sidewall containing the heat conduction zone, or on the inner wall of the sidewall containing the heat conduction zone. For example, the body can be made of copper, and the metal sheet can be made of Invar alloy.

[0009] When the temperature rises to the second temperature range, the first surface of the chip undergoes a concave deformation. The metal sheet and the body also deform due to the temperature rise. Since the metal sheet is rigidly connected to the body and the metal sheet has a small coefficient of thermal expansion, the metal sheet will deform and bulge towards the chip. The bulge of the metal sheet can drive the body to bulge towards the chip, which means that the heat conduction area deforms towards the direction close to the first surface, so that the shape of the heat conduction area matches the shape of the first surface.

[0010] In some implementations, the driving component is a metal sheet with a coefficient of thermal expansion greater than that of the body. The metal sheet can be disposed on the outer wall of the sidewall containing the heat conduction zone of the body, or on the inner wall of the sidewall opposite to the sidewall containing the heat conduction zone. For example, the body can be made of copper, and the metal sheet can be made of aluminum alloy.

[0011] When the temperature rises to the second temperature range, the first surface of the chip undergoes a concave deformation. The metal sheet and the body also deform due to the temperature rise. Since the metal sheet is rigidly connected to the body and the metal sheet has a large coefficient of thermal expansion, the metal sheet will deform in the direction of the chip and drive the body to deform in the same or similar direction. In this way, not only can the shape of the metal sheet be adapted to the shape of the first surface, but the shape of the heat conduction area can also be adapted to the shape of the first surface.

[0012] In some embodiments, the body includes a first cover plate and a second cover plate, which are fixedly connected and enclose an inner cavity. In one implementation, a metal sheet may be disposed on the first cover plate, and the thickness d0 of the metal sheet and the thickness d1 of the first cover plate satisfy the condition: 0.5 ≤ d0 / d1 ≤ 1.5, to ensure that the deformation of the metal sheet can reliably drive the deformation of the first cover plate. In another implementation, a metal sheet is disposed on the second cover plate, and the thickness d0 of the metal sheet and the thickness d2 of the second cover plate satisfy the condition: 0.5 ≤ d0 / d2 ≤ 1.5, to ensure that the deformation of the metal sheet can reliably drive the deformation of the second cover plate.

[0013] In some implementations, the body is a liquid-cooled heat sink. Heat generated by the chip is transferred from the heat conduction area to the bottom of the body. The liquid cooling medium at the bottom of the body absorbs the heat and evaporates into a gaseous state. The gaseous cooling medium diffuses to the top of the body and transfers heat to the fins through the first cover plate, allowing heat to dissipate to the outside through the fins. Simultaneously, the gaseous cooling medium at the top of the body condenses back into a liquid state through heat exchange with the fins, and then returns to the bottom of the body to evaporate and exchange heat with the chip, thus achieving cyclical heat dissipation for the chip.

[0014] In some implementations, the heat sink can be a solid structure. The driving component is a metal sheet disposed on one side surface of the body where the heat conduction zone is located, and the coefficient of thermal expansion of the metal sheet is greater than that of the body. For example, the body can be made of copper, and the metal sheet can be made of aluminum alloy.

[0015] When the temperature rises to the second temperature range, the first surface of the chip undergoes a concave deformation. The metal sheet and the body also deform due to the temperature rise. Since the metal sheet is rigidly connected to the body and the metal sheet has a large coefficient of thermal expansion, the metal sheet will deform in the direction of the chip and drive the body to deform in the same or similar direction. In this way, not only can the shape of the metal sheet be adapted to the shape of the first surface, but the shape of the heat conduction area can also be adapted to the shape of the first surface.

[0016] In some implementations, the metal sheet can be a rectangular structure, and the orthographic projection of the metal sheet in the first direction covers at least 50% of the orthographic projection of the heat conduction area in the first direction. In this way, when the metal sheet deforms, it will drive at least 50% of the heat conduction area to deform, thereby ensuring the fit between the shape of the heat conduction area and the shape of the first surface.

[0017] In some implementations, the metal sheet can be a ring structure, with its orthographic projection in the first direction surrounding the periphery of the orthographic projection of the heat conduction area in the first direction. When the metal sheet undergoes convex deformation, it drives the annular area covered by the body to convex. Due to the stress inside the body, the portion inside the annular area will also convex and deform in the same direction as the annular area, that is, the heat conduction area will convex and deform towards the chip, thereby enabling the heat conduction area to adapt to the first surface of the chip.

[0018] In some embodiments, the metal sheet is a strip structure comprising a first part, a second part, and a third part. The second part is connected between the first and third parts. The orthographic projection of the second part in a first direction covers at least a portion of the orthographic projection of the heat-conducting region in the first direction. The orthographic projections of the first part and the heat-conducting region in the first direction do not coincide. Similarly, the orthographic projections of the third part and the heat-conducting region in the first direction do not coincide. When the metal sheet undergoes a convex deformation, the deformation of the second part drives at least a portion of the heat-conducting region to deform, thereby ensuring the fit between the shape of the heat-conducting region and the shape of the first surface.

[0019] In some embodiments, the body includes an inner cavity. The driving member includes at least one elastic element, each elastic element disposed within the inner cavity. Both ends of each elastic element are fixedly connected to the inner wall of the body, which is disposed opposite to it along a first direction. At least a portion of the orthographic projection of each elastic element in the first direction coincides with the orthographic projection of the heat-conducting region in the first direction, which is the thickness direction of the heat sink. Within a first temperature range, each elastic element is in a compressed state to adapt the shape of the heat-conducting region to the shape of the first surface of the chip. When the temperature rises to a second temperature range, the first surface of the chip undergoes a concave deformation, weakening the chip's support for the heat-conducting region. Driven by the elastic force of the elastic elements, the cover plate on the side of the body where the heat-conducting region is located bulges and deforms towards the chip until the heat-conducting region re-adheres to the first surface of the chip, thus adapting the shape of the heat-conducting region to the shape of the first surface of the chip.

[0020] In some embodiments, the elastic element is a spring. At least one limiting post may be provided in the inner cavity of the body. Along the first direction, at least one end of each limiting post is connected to the inner wall of the body. At least a portion of the orthographic projection of each limiting post in the first direction coincides with the orthographic projection of the heat conduction area in the first direction. Each limiting post has a degree of freedom of movement in the first direction relative to at least one of the two side walls of the body that are opposite to each other along the first direction. This facilitates the extension and contraction of the spring and enables the limiting post to provide support in the inner cavity of the body.

[0021] In some embodiments, each limiting post includes a first post and a second post, which are respectively fixed to the inner walls of the body on both sides opposite to each other along a first direction. The first post includes a first end face facing the second post, and the second post includes a second end face facing the first post. The first end face and the second end face are opposite to each other. When the heat sink or the electronic device using the heat sink is dropped, if the outer surface of the heat sink is impacted by an external force, the first end face of the first post and the second end face of the second post can abut against each other, thereby forming support within the cavity of the body and reducing the risk of inward deformation of the body.

[0022] In some embodiments, each limiting post includes a first post and a second post, which are respectively fixed to the inner walls of two opposite sides of the body along a first direction. The first post includes a first end face facing the second post, and a first hook is provided on the first end face. The first hook includes a first vertical wall and a first horizontal wall. One end of the first vertical wall is connected to the first end face, and the other end of the first vertical wall is connected to the first horizontal wall. There is a first gap between the first horizontal wall and the first end face. Similarly, the second post includes a second end face facing the first post, and a second hook is provided on the second end face. The second hook includes a second vertical wall and a second horizontal wall. One end of the second vertical wall is connected to the second end face, and the other end of the second vertical wall is connected to the second horizontal wall. There is a second gap between the second horizontal wall and the second end face. The first hook and the second hook are engaged. The first horizontal wall is located between the second end face and the second horizontal wall, and the thickness of the first horizontal wall along the first direction is less than the second gap. The second horizontal wall is located between the first end face and the first horizontal wall, and the thickness of the second horizontal wall along the first direction is less than the first gap.

[0023] This design allows the second column to move up and down relative to the first column along the first direction, while also restricting its movement. In the event of a drop of the heat sink or an electronic device using it, if the outer surface of the heat sink is impacted, the first transverse wall can abut against the second end face, and the second transverse wall can abut against the first end face, thus providing support within the internal cavity and reducing the risk of inward deformation. Furthermore, for the heat sink unit itself, before it is assembled into the circuit board assembly, the first and second transverse walls can abut against each other to prevent the heat conduction area from bulging outwards significantly under the force of the spring, thus affecting the heat sink's appearance.

[0024] In some implementations, the elastic element can be metal rubber. Metal rubber not only drives the deformation of the heat conduction zone, but also possesses a certain degree of stiffness under compression, thus providing support for the inner cavity. This eliminates the need for locating pillars in the space corresponding to the heat conduction zone within the inner cavity, simplifying the overall structure. Furthermore, metal rubber exhibits capillary action; when the body is a liquid-cooled heat sink, it can act as a liquid wick, allowing the liquid cooling medium condensing at the top of the body to flow back to the bottom through the metal rubber.

[0025] In some embodiments, the body includes an inner cavity. The driving component includes at least one connecting post, each connected post disposed within the inner cavity. The two ends of each connecting post are fixedly connected to the inner walls of the body on opposite sides along a first direction, and at least a portion of the orthographic projection of each connecting post in the first direction coincides with the orthographic projection of the heat conduction area in the first direction. The connecting post is made of shape memory alloy, and its length in a second temperature range is greater than its length in the first temperature range. When the temperature rises to the second temperature range, the first surface of the chip undergoes a concave deformation, and the length of the connecting post also elongates due to the temperature increase. Therefore, the connecting post can drive the cover plate on one side of the body containing the heat conduction area to bulge and deform towards the chip, so that the shape of the heat conduction area adapts to the shape of the first surface of the chip.

[0026] Secondly, this application also provides a circuit board assembly, which includes a substrate, a chip, and a heat sink as described in any of the embodiments of the first aspect. The chip is disposed on the surface of the substrate, and the heat sink is disposed on the side of the chip facing away from the substrate. The heat conduction area of ​​the heat sink is thermally connected to the first surface of the chip to dissipate heat from the chip through the heat sink, thereby ensuring that the chip can be kept within a normal temperature range during operation.

[0027] In some implementations, a thermal interface material can be provided between the chip and the heat sink. The thermal interface material can be used to fill the interface gap between the chip and the heat sink, thereby improving the heat conduction efficiency between the chip and the heat sink, and thus improving the heat dissipation effect of the chip.

[0028] Furthermore, since the first surface of the chip and the heat conduction area of ​​the heat sink can be shaped to fit each other across the entire temperature range, the thermal interface material can always maintain good contact with the first surface of the chip and the heat conduction area of ​​the heat sink, thereby further improving the heat conduction efficiency between the chip and the heat sink.

[0029] Thirdly, this application also provides an electronic device, which includes a housing and a circuit board assembly. The circuit board assembly is disposed within the housing to provide protection for the circuit board assembly. This electronic device has excellent heat dissipation performance and high operational reliability. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0031] Figure 2 A side view of a circuit board assembly;

[0032] Figure 3 A side view of a circuit board assembly provided in an embodiment of this application;

[0033] Figure 4a for Figure 3 The side view showing the assembly relationship between the chip and the heat sink within the first temperature range;

[0034] Figure 4b for Figure 3 The side view showing the assembly relationship between the chip and the heat sink in the second temperature range;

[0035] Figure 5 for Figure 3 A top view of the radiator shown;

[0036] Figure 6 for Figure 3 Another top view of the radiator shown;

[0037] Figure 7 for Figure 3 Another top view of the radiator shown;

[0038] Figure 8 A side view of another circuit board assembly provided in an embodiment of this application;

[0039] Figure 9a for Figure 8 The side view showing the assembly relationship between the chip and the heat sink within the first temperature range;

[0040] Figure 9b for Figure 8 The side view showing the assembly relationship between the chip and the heat sink in the second temperature range;

[0041] Figure 10a Side view of the assembly relationship between the chip and another heat sink provided in an embodiment of this application within a first temperature range;

[0042] Figure 10b A side view of the assembly relationship between a chip and another heat sink provided in an embodiment of this application within a second temperature range;

[0043] Figure 11 A side view of another circuit board assembly provided in an embodiment of this application;

[0044] Figure 12a for Figure 11 The side view showing the assembly relationship between the chip and the heat sink within the first temperature range;

[0045] Figure 12b for Figure 11 The side view showing the assembly relationship between the chip and the heat sink in the second temperature range;

[0046] Figure 13A side view of another circuit board assembly provided in an embodiment of this application;

[0047] Figure 14a for Figure 13 The side view showing the assembly relationship between the chip and the heat sink within the first temperature range;

[0048] Figure 14b for Figure 13 The side view showing the assembly relationship between the chip and the heat sink in the second temperature range;

[0049] Figure 15a This is a schematic diagram of the structure of a limiting post provided in an embodiment of this application;

[0050] Figure 15b This is a schematic diagram of the structure of a limiting post provided in an embodiment of this application;

[0051] Figure 16a Side view of the assembly relationship between the chip and another heat sink provided in an embodiment of this application within a first temperature range;

[0052] Figure 16b A side view of the assembly relationship between a chip and another heat sink provided in an embodiment of this application within a second temperature range;

[0053] Figure 17 A side view of another circuit board assembly provided in an embodiment of this application;

[0054] Figure 18a for Figure 17 The side view showing the assembly relationship between the chip and the heat sink within the first temperature range;

[0055] Figure 18b for Figure 17 The side view shows the assembly relationship between the chip and the heat sink in the second temperature range.

[0056] Figure label:

[0057] 1000 - Electronic equipment; 1100 - Housing; 1200 - Circuit board assembly; 1210 - Circuit board; 1220 - Chip packaging module; 100 - Substrate;

[0058] 200 - Chip; 210 - First surface; 300 - Heat sink; 310 - Body; 310a - Heat conduction area; 311 - Boss; 312 - Fin; 313 - Inner cavity;

[0059] 314-Support column; 315-First cover plate; 316-Second cover plate; 317-Limiting column; 3171-First column body; 31711-First end face;

[0060] 3172 - Second column; 31721 - Second end face; 3173 - First hook; 31731 - First vertical wall; 31732 - First horizontal wall;

[0061] 3174 - Second hook; 31741 - Second vertical wall; 31742 - Second horizontal wall; 320 - Driving component; 321 - Metal sheet; 3211 - First part;

[0062] 3212 - Second part; 3213 - Third part; 321a - First metal sheet; 321b - Second metal sheet; 322 - Elastic element; 323 - Connecting post;

[0063] 330 - Spring screw; 400 - Thermal interface material; 500 - Frame. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0065] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0066] Figure 1 This is a schematic diagram of the structure of an electronic device 1000 provided in an embodiment of this application. (Reference) Figure 1 As shown in the embodiments of this application, the electronic device 1000 can be an artificial intelligence device, a cloud computing device, a server, a communication device (e.g., a router), a storage device, an in-vehicle device, a mobile phone, a tablet computer, a computer, or a wearable device, etc. The electronic device 1000 includes a housing 1100 and a circuit board assembly 1200. The circuit board assembly 1200 is disposed within the housing 1100 to provide protection for the circuit board assembly 1200. The circuit board assembly 1200 may include a circuit board 1210 and various electronic components or functional modules disposed on the circuit board to support the electronic device 1000 in performing corresponding functions.

[0067] Figure 2 This is a side view of a circuit board assembly 1200. (Reference) Figure 2 As shown, the circuit board assembly 1200 includes a chip packaging module 1220, which is disposed on the circuit board 1210. The chip packaging module 1220 includes a substrate 100, a chip 200, and a heat sink 300. The chip 200 is disposed on the surface of the substrate 100, and the heat sink 300 is disposed on the side of the chip 200 facing away from the substrate 100. The substrate 100 serves as the packaging carrier for the chip 200, providing electrical connection, protection, support, and assembly functions. The heat sink 300 dissipates heat from the chip 200 to ensure that the chip 200 remains within a normal temperature range during operation, thereby improving the operational reliability of the chip packaging structure 1220.

[0068] For example, chip 200 may be a baseband chip, a graphics processing unit (GPU), a central processing unit (CPU), a system on chip (SoC), or other chips with logic operation capabilities. It may also be other types of application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.

[0069] In one implementation, the substrate 100 can be a rigid circuit board, a flexible circuit board, or a rigid-flex circuit board. In another implementation, the substrate 100 can also be a direct bonding copper (DBC) ceramic substrate. In addition to providing electrical connections for the chip 200, the DBC ceramic substrate has excellent thermal conductivity, which allows it to absorb some of the heat generated by the chip 200, enabling the chip 200 to achieve double-sided heat dissipation through the substrates 100 on the top and bottom sides and the heat sink 300.

[0070] In this embodiment, the chip 200 and the substrate 100 can be connected via flip chip technology. Flip chip technology refers to creating conductive bumps on the surface of the chip 200 corresponding to the I / O contacts, then flipping the chip 200 onto the surface of the substrate 100 using a flipping device, and electrically connecting the conductive bumps to the pads on the substrate 100 via hot pressing or soldering. Flip chip technology has advantages such as high pin count and high signal density, and the conductive bumps on the surface of the chip 200 provide a shorter electrical path for the interconnection between the chip 200 and the substrate 100. Therefore, flip chip technology can also achieve excellent electrical performance with low capacitance, low inductance, and low resistance.

[0071] It should be noted that in the chip packaging module 1220, the main material of chip 200 is silicon, while the main material of substrate 100 is ceramic or organic polymer, etc. Therefore, chip 200 and substrate 100 have different coefficients of thermal expansion (CTE). In other words, there is a CTE mismatch between chip 200 and substrate 100. When flip-chip 200 is flip-chip mounted onto the surface of substrate 100, the adhesive or solder needs to be melted at high temperature. The molten adhesive or solder gradually fixes chip 200 and substrate 100 relative to each other during the cooling process. However, as the temperature gradually cools down to room temperature, a rigid connection is formed between chip 200 and substrate 100. Due to the CTE mismatch between chip 200 and substrate 100, chip 200 and substrate 100 will deform to varying degrees. Specifically, the CTE of substrate 100 is greater than that of chip 200. As the temperature decreases, substrate 100 undergoes relatively large shortening deformation, while chip 200 undergoes relatively small shortening deformation. Based on this difference, chip 200 will bulge in a direction away from substrate 100. Therefore, at room temperature, chip 200 on substrate 100 will exhibit... Figure 2 The image shows an upward-convex "crying face" shape.

[0072] In this embodiment, a thermal interface material (TIM) 400 may be disposed between the chip 200 and the heat sink 300. The TIM 400 can be used to fill the interface gap between the chip 200 and the heat sink 300, thereby improving the heat conduction efficiency between the chip 200 and the heat sink 300. Exemplarily, the TIM 400 includes, but is not limited to, materials with good thermal conductivity such as silicone grease, carbon-based thermal pads, or phase change materials (PCMs).

[0073] In some other embodiments, the thermal interface material 400 may not be provided between the chip 200 and the heat sink 300. For example, the chip 200 and the heat sink 300 may be in direct contact.

[0074] Furthermore, in practical applications, considering factors such as thermal performance, reliability, complexity, and manufacturing cost, the chip packaging module 1220 can adopt either lidded (Lid) packaging or lidless packaging. Lid packaging refers to a cover being placed above the chip 200, enclosing the chip 200 within the space formed by the cover and the substrate 100. In this packaging method, the heat sink 300 is fixed to the side of the cover facing away from the substrate 100, and the chip 200 is thermally connected to the heat sink 300 through the cover. Lidless packaging, on the other hand, does not require a cover within the packaging module; the heat sink 300 is directly located on the side of the chip 200 facing away from the substrate 100. Therefore, compared to lidded packaging, lidless packaging offers better thermal performance and lower manufacturing costs. Figure 2 The illustrated embodiment is a lidless packaging structure. In the lidless package, a frame 500 may be provided on the side surface of the substrate 100 where the chip 200 is located, and the frame 500 surrounds the edge of the substrate 100. The frame 500 can protect the chip 200 on the one hand, and reduce the warping of the substrate 100 at high temperatures on the other hand, thereby improving the structural reliability of the chip packaging module 1220.

[0075] As mentioned earlier, there is a CTE mismatch between chip 200 and substrate 100. Due to this problem, during the operation of chip 200, as the temperature of chip 200 increases, substrate 100 undergoes relatively large elongation deformation, while chip 200 undergoes relatively small elongation deformation. Therefore, chip 200 tends to deform downwards towards substrate 100. Combined with the upward convex shape of chip 200 caused during the packaging process, the degree of convexity of chip 200 at high temperatures will decrease, or it will exhibit a concave shape.

[0076] The surface of chip 200 facing heat sink 300 is defined as first surface 210. Based on the above analysis, the shape of chip 200 differs between normal and high-temperature states; therefore, first surface 210 also exhibits different shapes at these temperatures. Due to this shape change, the gap between chip 200 and heat sink 300 increases accordingly. For the thermal interface material 400 disposed between chip 200 and heat sink 300, poor contact between the thermal interface material 400 and chip 200 or heat sink 300 is likely to occur, leading to reduced heat conduction efficiency and affecting the heat dissipation effect of chip 200. It is easy to understand that if no thermal interface material 400 is disposed between chip 200 and heat sink 300, an excessively large increase in the gap between chip 200 and heat sink 300 will also lead to poor contact and affect the heat dissipation effect of chip 200.

[0077] In view of this, embodiments of this application provide a heat sink 300 that can adapt to the shape characteristics of the chip 200 in different temperature ranges, thereby maintaining high heat conduction efficiency with the chip 200, improving the heat dissipation effect of the chip 200, and thus improving the operational reliability of electronic devices using the heat sink 300. The heat sink 300 provided in the embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0078] Figure 3 This is a side view of a circuit board assembly 1200 provided in an embodiment of this application. Figure 4a for Figure 3 The side view shown illustrates the assembly relationship between chip 200 and heat sink 300 within the first temperature range. Figure 4b for Figure 3 The side view shown depicts the assembly relationship between chip 200 and heat sink 300 within the second temperature range. Figure 4a and Figure 4b Thermal interface materials are omitted.

[0079] In this embodiment, the first temperature range can be a temperature range of room temperature or close to room temperature, and the second temperature range is a temperature range with relatively higher temperatures. The maximum temperature value of the first temperature range is less than the minimum temperature value of the second temperature range. The first and second temperature ranges are related to the operating state of the chip 200. Generally, the temperature of the chip 200 in its non-operating state is within the first temperature range, and the temperature of the chip 200 in its operating state is within the second temperature range. Therefore, the first and second temperature ranges can basically cover the entire temperature range of the chip 200 during its service life. For example, the first temperature range can be in the range of 15℃-40℃, and the second temperature range is greater than or equal to 50℃. It should be noted that the maximum temperature value of the second temperature range is determined by the junction temperature of the chip 200 (the actual maximum allowable temperature of the chip 200 in its operating state). Generally, the junction temperature of the chip 200 does not exceed 105℃. Therefore, the second temperature range can specifically be between 50℃ and 105℃.

[0080] Please refer to the above. Figure 3 , Figure 4a and Figure 4b As shown, in this embodiment, the heat sink 300 includes a body 310 and a driving member 320, with the driving member 320 fixed to the body 310. The body 310 can be connected to the circuit board 1210 via spring screws 330. This allows for the assembly and fixation of the body 310 within the circuit board assembly 1200, and also presses the chip 200 between the body 310 and the circuit board 1210. Furthermore, when the chip 200 deforms under high-temperature conditions, the spring in the spring screw 330 can apply a certain downward pressure to the body 310, causing the body 310 to move closer to the chip 200, which helps improve the heat conduction efficiency between the body 310 and the chip 200. The body 310 and the circuit board 1210 can be connected via multiple spring screws 330 to improve the connection strength. Specifically, the multiple spring screws 330 can be evenly distributed around the periphery of the body 310 to improve the uniformity of force distribution on the body 310.

[0081] The surface of the body 310 facing the chip 200 includes a heat-conducting region 310a, which is thermally connected to the first surface 210 of the chip 200, for example, through a thermal interface material 400. Furthermore, the shape of the heat-conducting region 310a adapts to the shape of the first surface 210 of the chip 200 within a first temperature range. The driving member 320 can be used to drive the heat-conducting region 310a to deform within a second temperature range, so that the shape of the heat-conducting region 310a adapts to the shape of the first surface 210 of the chip 200 within the second temperature range.

[0082] It should be noted that the driving element 320 is inactive within the first temperature range, and therefore has no effect on the shape of the heat conduction area 310a. The shape of the heat conduction area 310a within the first temperature range can be designed according to the shape of the first surface 210 of the chip 200 within the first temperature range to ensure that the shapes of the two are compatible within the first temperature range.

[0083] Here, shape adaptation can be understood as two surfaces being complementary to each other to a certain extent, so that the two surfaces can be in a parallel or nearly parallel state. For example, in Figure 4a and Figure 4b In the embodiment shown, the first surface 210 of the chip 200 is a raised shape in the first temperature range, and the heat conduction area 310a is a recessed shape that complements the raised shape in the first temperature range; the degree of protrusion of the first surface 210 of the chip 200 in the second temperature range becomes smaller, and the degree of recess of the heat conduction area 310a in the second temperature range also becomes smaller accordingly.

[0084] In this embodiment, the heat sink 300 can dynamically adjust the shape of the heat conduction area 310a using the driving component 320, so that the shape of the heat conduction area 310a can be adapted to the shape of the first surface 210 of the chip 200 in different temperature ranges. This achieves dynamic matching of the morphology of the heat conduction area 310a and the first surface 210, which to a certain extent suppresses the problem of excessive increase in the gap between the heat sink 300 and the chip 200 under high temperature conditions. This enables the chip 200 and the heat sink 300 to maintain high heat conduction efficiency in the entire temperature range, thereby improving the heat dissipation effect of the heat sink 300 on the chip 200.

[0085] In this embodiment, the thickness direction of the heat sink 300 is defined as the first direction x, which can also be understood as the stacking direction of the heat sink 300 and the chip 200. The orthographic projection of the heat conduction region 310a in the first direction x covers at least a portion of the orthographic projection of the first surface 210 in the first direction x. In other words, the heat conduction region 310a and at least a portion of the first surface 210 are positioned opposite each other, and the shape of the heat conduction region 310a is adapted to the shape of at least a portion of the first surface 210 in different temperature ranges. In one implementation, the orthographic projection of the heat conduction region 310a in the first direction x completely covers the orthographic projection of the first surface 210 in the first direction x, thereby increasing the area of ​​the shape-adapted region between the heat conduction region 310a and the first surface 210 and improving the heat conduction efficiency between the heat sink 300 and the chip 200.

[0086] In some embodiments, a boss 311 is provided on the surface of the body 310 facing the chip 200, and the surface of the boss 311 can be formed as the aforementioned heat conduction region 310a. The boss can improve the rigidity of the body 310 on the one hand, and reduce the risk of interference between the body 310 and other electronic components (such as capacitors, resistors, etc.) disposed on the surface of the substrate 100 on the other hand, thereby improving the structural reliability of the electronic device.

[0087] In addition, multiple fins 312 can be provided on the surface of the body 310 facing away from the chip 200. The heat absorbed by the body 310 from the chip 200 can be dissipated to the outside through the fins 312. The fins 312 can increase the contact area between the body 310 and the outside, thereby improving the heat exchange efficiency between the body 310 and the air flowing over its surface, and thus improving the heat dissipation performance of the body 310.

[0088] In this embodiment, the body 310 can be a cavity structure. A support column 314 is provided in the inner cavity 313 of the body 310. The two ends of the support column 314 are fixedly connected to the inner walls of the body 310 on both sides, which are arranged opposite each other along the first direction x, to support the inner cavity of the body 310 and improve the structural strength of the body 310. Specifically, the body 310 may include a first cover plate 315 and a second cover plate 316. The first cover plate 315 and the second cover plate 316 are fixedly connected and enclose the inner cavity 313. In this case, the two ends of the support column 314 are fixedly connected to the first cover plate 315 and the second cover plate 316, respectively. The surface of the first cover plate 315 facing away from the second cover plate 316 is the surface where the fins 312 are provided, and the surface of the second cover plate 316 facing away from the first cover plate 315 is the surface where the heat conduction zone 310a is provided. It is easy to understand that when the body 310 includes a boss 311, the boss 311 is specifically disposed on the second cover plate 316. The boss 311 can be regarded as a local area of ​​the second cover plate 316 protruding in a direction away from the first cover plate 315. For example, the first cover plate 315 and the second cover plate 316 can be made of a metal material with good thermal conductivity, such as copper.

[0089] In some embodiments, the body 310 can be a vapor chamber (VC) liquid cooling heat sink. A VC liquid cooling heat sink, also known as a planar heat pipe, vapor chamber, or heat spreader, utilizes the phase change cycle of an internal cooling medium (e.g., water) between liquid and gaseous states for heat dissipation. When the heat generated by the chip 200 is transferred from the heat conduction zone 310a to the bottom of the body 310, the liquid cooling medium at the bottom of the body 310 absorbs the heat and evaporates into a gaseous state. The gaseous cooling medium diffuses to the top of the body 310 and transfers heat to the fins 312 through the first cover plate 315, dissipating heat to the outside through the fins 312. Simultaneously, the gaseous cooling medium at the top of the body 310 condenses into a liquid state through heat exchange with the fins 312, and then returns to the bottom of the body 310 to evaporate and exchange heat with the chip 200, thus achieving cyclic heat dissipation for the chip 200.

[0090] In addition, a liquid wick (not shown in the figure) is provided in the inner cavity 313 of the body 310. The liquid cooling medium condensed at the top of the body 310 can flow back to the bottom of the body 310 by means of the liquid wick, so as to accelerate the circulation process of the cooling medium and improve the heat dissipation performance of the body 310. For example, the liquid wick type includes, but is not limited to, microchannel type, sintered powder type, sintered wire mesh type, etc.

[0091] Continue to refer to Figures 3 to 4b In this embodiment, the drive element 320 can be a metal sheet 321. The CTE of the metal sheet 321 is less than that of the body 310. When the body 310 is made of copper, its CTE is approximately 18 ppm. Therefore, the metal sheet 321 can be selected from metal materials with a CTE of less than 18 ppm. For example, the material of the metal sheet 321 can be Invar alloy, which has a CTE of approximately 1.5 ppm, satisfying the CTE requirement for the metal sheet 321 in this embodiment.

[0092] In one implementation, the metal sheet 321 can be disposed on a side wall of the body 310 opposite to the side wall where the heat conduction zone 310a is located, that is, on the first cover plate 315. Specifically, the metal sheet 321 can be disposed on the surface of the first cover plate 315 facing away from the second cover plate 316. In this case, if fins 312 are disposed on the side surface of the first cover plate 315 facing away from the second cover plate 316, the fins 312 can be disposed in a region that avoids the metal sheet 321. Exemplarily, the metal sheet 321 can be fixedly connected to the first cover plate 315 by welding, bonding, or other methods.

[0093] In another implementation, the metal sheet 321 can also be disposed on the side wall where the heat conduction zone 310a is located in the body 310, that is, on the second cover plate 316. Specifically, the metal sheet 321 can be disposed on the surface of the second cover plate 316 facing the first cover plate 315. Similarly, the metal sheet 321 can be fixedly connected to the second cover plate 316 by welding, bonding or other methods.

[0094] Taking the metal sheet 321 disposed on the first cover plate 315 as an example, during the operation of the chip 200, when the temperature rises to the second temperature range, the first surface 210 of the chip 200 undergoes concave deformation, and the metal sheet 321 and the first cover plate 315 also deform due to the temperature increase. Based on the difference in CTE between the metal sheet 321 and the first cover plate 315, they will produce different deformations during the temperature rise process. Specifically, the deformation of the metal sheet 321, which has a relatively smaller CTE, will be smaller than that of the first cover plate 315, which has a relatively larger CTE. While maintaining a rigid connection between the metal sheet 321 and the first cover plate 315, the side of the metal sheet 321 facing the first cover plate 315 will be stretched due to the relatively large deformation of the first cover plate 315. Therefore, the metal sheet 321 will exhibit a deformation that bulges towards the first cover plate 315. The protrusion of the metal sheet 321 can drive the first cover plate 315 to protrude in the same or similar trend. Since the first cover plate 315 and the second cover plate 316 are rigidly connected by the support column 314, the protrusion of the first cover plate 315 will drive the second cover plate 316 to protrude toward the chip 200 through the support column 314. That is, it drives the heat conduction area 310a to deform toward the direction close to the first surface 210, so that the shape of the heat conduction area 310a is adapted to the shape of the first surface 210.

[0095] In this embodiment, the thickness of the metal sheet 321 can be designed according to specific circumstances, and this application does not limit it, as long as the metal sheet 321 can reliably drive the deformation of the body 310 without affecting the heat dissipation performance of the body 310. In one implementation, the thickness d0 of the metal sheet 321 is close to the thickness d1 of the first cover plate 315, and the thickness d0 of the metal sheet 321 and the thickness d1 of the first cover plate 315 satisfy: 0.5≤d0 / d1≤1.5. In addition, the thickness d1 of the first cover plate 315 is relatively close to the thickness d2 of the second cover plate 316 to ensure that the deformation of the first cover plate 315 can reliably drive the deformation of the second cover plate 316. For example, the thickness d1 of the first cover plate 315 and the thickness d2 of the second cover plate 316 satisfy: 0.5≤d1 / d2≤1.5.

[0096] Figure 5 for Figure 3 A top view of the heat sink 300 shown. (Reference) Figure 5As shown, in this embodiment, the metal sheet 321 can be a rectangular structure. The orthographic projection of the metal sheet 321 in the first direction x covers at least 50% of the orthographic projection of the heat conduction area 310a in the first direction x. The figure shows a case where the orthographic projection of the metal sheet 321 in the first direction x completely covers the orthographic projection of the heat conduction area 310a in the first direction x. Thus, when the metal sheet 321 deforms, it drives the deformation of most of the heat conduction area 310a, thereby ensuring the fit between the shape of the heat conduction area 310a and the shape of the first surface 210.

[0097] Figure 6 for Figure 3 Another top view of the heat sink 300 shown. (Reference) Figure 6 As shown, in this embodiment, the metal sheet 321 can be an annular structure, with its orthographic projection in the first direction x surrounding the periphery of the orthographic projection of the heat conduction area 310a in the first direction x. Exemplarily, the metal sheet 321 can be a rectangular ring, a circular ring, etc. When the metal sheet 321 undergoes a convex deformation, it drives the annular area covered by the first cover plate 315 to convex. Due to the internal stress of the first cover plate 315, the portion inside the annular area also convexes and deforms in the same direction as the annular area. Therefore, the actual deformation area of ​​the first cover plate 315, in its orthographic projection in the first direction x, covers the orthographic projection of the heat conduction area 310a in the first direction x. Thus, the first cover plate 315 can drive the heat conduction area 310a within the second cover plate 316 to convex and deform, making the heat conduction area 310a fit the first surface 210 of the chip 200.

[0098] Figure 7 for Figure 3 Another top view of the heat sink 300 shown. (Reference) Figure 7 As shown, in this embodiment, the metal sheet 321 can be a strip structure, comprising a first portion 3211, a second portion 3212, and a third portion 3213. The second portion 3212 is connected between the first portion 3211 and the third portion 3213. The orthographic projection of the second portion 3212 in the first direction x covers at least a portion of the orthographic projection of the heat conduction region 310a in the first direction x. The orthographic projection of the first portion 3211 in the first direction x does not coincide with the orthographic projection of the heat conduction region 310a in the first direction x, and the orthographic projection of the third portion 3213 in the first direction x does not coincide with the orthographic projection of the heat conduction region 310a in the first direction x. When the metal sheet 321 undergoes a convex deformation, the deformation of the second portion 3212 will drive at least a portion of the heat conduction region 310a to deform, thereby ensuring the fit between the shape of the heat conduction region 310a and the shape of the first surface 210.

[0099] Figure 8 This is a side view of another circuit board assembly 1200 provided in an embodiment of this application. Figure 9a for Figure 8 The side view shown illustrates the assembly relationship between chip 200 and heat sink 300 within the first temperature range. Figure 9b for Figure 8 The side view shown depicts the assembly relationship between chip 200 and heat sink 300 within the second temperature range. Figure 9a and Figure 9b The thermal interface material is omitted here. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0100] Please refer to the above. Figure 8 , Figure 9a and Figure 9b As shown in this embodiment, the heat sink 300 includes a body 310 and a drive member 320. The surface of the body 310 facing the chip 200 includes a heat conduction region 310a, which is thermally connected to the first surface 210 of the chip 200, for example, through a thermal interface material 400. Furthermore, the shape of the heat conduction region 310a within a first temperature range adapts to the shape of the first surface 210 of the chip 200 within the first temperature range. The drive member 320 is fixed to the body 310 and can be used to drive the heat conduction region 310a to deform within a second temperature range, so that the shape of the heat conduction region 310a within the second temperature range adapts to the shape of the first surface 210 of the chip 200 within the second temperature range.

[0101] The body 310 can be a cavity structure similar to or the same as in the previous embodiments, such as a VC liquid cooling heat sink, and the driving component 320 is also a metal sheet 321. Unlike the previous embodiments, the CTE of the metal sheet 321 is greater than that of the body 310 in this embodiment. When the body 310 is made of copper, its CTE is approximately 18 ppm. Therefore, the metal sheet 321 can be selected from metal materials with a CTE greater than 18 ppm. For example, the metal sheet 321 can be made of aluminum alloy, which has a CTE of approximately 23 ppm, meeting the CTE requirement for the metal sheet 321 in this embodiment.

[0102] In one implementation, the metal sheet 321 is disposed on the side wall of the heat conduction zone 310a in the body 310, that is, on the second cover plate 316. Specifically, the metal sheet 321 can be disposed on the surface of the second cover plate 316 facing away from the first cover plate 315, or it can be understood that the metal sheet 321 is disposed on the side surface of the heat conduction zone 310a. Exemplarily, the metal sheet 321 can be fixedly connected to the second cover plate 316 by welding, bonding or other methods.

[0103] In another implementation, the metal sheet 321 can also be disposed on the side wall of the body 310 opposite to the side wall where the heat conduction zone 310a is located, that is, on the first cover plate 315. Specifically, the metal sheet 321 can be disposed on the surface of the first cover plate 315 facing the second cover plate 316. Similarly, the metal sheet 321 can be fixedly connected to the second cover plate 316 by welding, bonding or other methods.

[0104] Taking the metal sheet 321 disposed on the second cover plate 316 as an example, during the operation of the chip 200, when the temperature rises to the second temperature range, the first surface 210 of the chip 200 undergoes concave deformation, and the metal sheet 321 and the second cover plate 316 also deform due to the temperature rise. Based on the CTE difference between the metal sheet 321 and the second cover plate 316, the deformation of the metal sheet 321 will be greater than that of the second cover plate 316. With the metal sheet 321 and the second cover plate 316 maintaining a rigid connection, the side of the metal sheet 321 facing the second cover plate 316 will tend to shrink due to the relatively small deformation of the second cover plate 316. Therefore, the metal sheet 321 will deform in a direction away from the second cover plate 316, or in other words, the metal sheet 321 will deform in a direction close to the first surface 210 of the chip 200, and drive the second cover plate 316 to deform in the same or similar direction. In this way, not only can the shape of the metal sheet 321 be adapted to the shape of the first surface 210, but the shape of the heat conduction area 310a can also be adapted to the shape of the first surface 210.

[0105] In some embodiments, the thickness d0 of the metal sheet 321 is close to the thickness d2 of the second cover plate 316 to ensure that the metal sheet 321 can reliably drive the second cover plate 316 to deform during deformation. In one implementation, the thickness d0 of the metal sheet 321 and the thickness d2 of the second cover plate 316 satisfy: 0.5 ≤ d0 / d2 ≤ 1.5.

[0106] In addition, in the embodiments of this application, the shape of the metal sheet 321 can also be rectangular, ring-shaped, strip-shaped, etc. For specific implementation methods, please refer to the description in the foregoing embodiments, which will not be repeated here.

[0107] Figure 10a This is a side view showing the assembly relationship between the chip 200 and another heat sink 300 within a first temperature range, as provided in an embodiment of this application. Figure 10b This is a side view showing the assembly relationship between the chip 200 and another heat sink 300 provided in an embodiment of this application within a second temperature range. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0108] Please refer to the above. Figure 10a and Figure 10b As shown in the embodiments of this application, the body 310 can be Figure 3 The cavity structure in the illustrated embodiment is, for example, a VC liquid cooling heat sink. The driving component 320 includes two metal sheets: a first metal sheet 321a disposed on the surface of the body 310 opposite to the heat conduction region 310a, and a second metal sheet 321b disposed on the surface of the body where the heat conduction region 310a is located. The CTE of the first metal sheet 321a is less than the CTE of the body 310, and the CTE of the second metal sheet 321b is greater than the CTE of the body 310. For example, if the body 310 is made of copper, the first metal sheet 321a can be made of Invar alloy, and the second metal sheet 321b can be made of aluminum alloy.

[0109] In one implementation, the first metal sheet 321a can be disposed on the surface of the first cover plate 315 facing away from the second cover plate 316; in another implementation, the first metal sheet 321a can also be disposed on the surface of the second cover plate 316 facing towards the first cover plate 315. Similarly, in one implementation, the second metal sheet 321b can be disposed on the surface of the second cover plate 316 facing away from the first cover plate 315; in another implementation, the second metal sheet 321b can also be disposed on the surface of the first cover plate 315 facing towards the second cover plate 316.

[0110] Taking the first metal sheet 321a disposed on the surface of the first cover plate 315 facing away from the second cover plate 316, and the second metal sheet 321b disposed on the surface of the second cover plate 316 facing away from the first cover plate 315 as an example, during the operation of the chip 200, when the temperature rises to the second temperature range, the first surface 210 of the chip 200 undergoes a concave deformation, and the metal sheet 321 and the body 310 (including the first cover plate 315 and the second cover plate 316) also deform due to the temperature rise. Since the first metal sheet 321a is rigidly connected to the first cover plate 315, and the CTE of the first metal sheet 321a is small, the first metal sheet 321a will exhibit a deformation that bulges towards the first cover plate 315. The protrusion of the first metal sheet 321a can drive the first cover plate 315 to protrude in the same or similar direction. Since the first cover plate 315 and the second cover plate 316 are rigidly connected by the support post 314, the protrusion of the first cover plate 315 will also drive the second cover plate 316 to protrude towards the chip 200 via the support post 314. Because the second metal sheet 321b is rigidly connected to the second cover plate 316, and the second metal sheet 321b has a larger CTE, the second metal sheet 321b will deform and protrude towards the chip 200, driving the second cover plate 316 to also protrude towards the chip 200. Thus, under the combined action of the first metal sheet 321a and the second metal sheet 321b, the heat conduction area 310a can deform towards the direction close to the first surface 210, and the shape of the heat conduction area 310a can be adapted to the shape of the first surface 210.

[0111] In this embodiment, the thickness of the first metal sheet 321a and the second metal sheet 321b can be referenced as described above. Figure 3 and Figure 8 The design of the embodiment shown will not be elaborated further here. In addition, the shapes of the first metal sheet 321a and the second metal sheet 321b can also be rectangular, ring-shaped, strip-shaped, etc. For specific implementation methods, please refer to the description in the foregoing embodiment, which will not be repeated here.

[0112] Figure 11 This is a side view of another circuit board assembly 1200 provided in an embodiment of this application. Figure 12a for Figure 11 The side view shown illustrates the assembly relationship between chip 200 and heat sink 300 within the first temperature range. Figure 12b for Figure 11 The side view shown depicts the assembly relationship between chip 200 and heat sink 300 within the second temperature range. Figure 12a and Figure 12b The thermal interface material is omitted here. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0113] Please refer to the above. Figure 11 , Figure 12a and Figure 12b As shown in this embodiment, the heat sink 300 includes a body 310 and a drive member 320. The surface of the body 310 facing the chip 200 includes a heat conduction region 310a, which is thermally connected to the first surface 210 of the chip 200, for example, through a thermal interface material 400. Furthermore, the shape of the heat conduction region 310a within a first temperature range adapts to the shape of the first surface 210 of the chip 200 within the first temperature range. The drive member 320 is fixed to the body 310 and can be used to drive the heat conduction region 310a to deform within a second temperature range, so that the shape of the heat conduction region 310a within the second temperature range adapts to the shape of the first surface 210 of the chip 200 within the second temperature range.

[0114] The body 310 is a solid structure, and its material can be a metal with good thermal conductivity, such as copper. The driving component 320 is a metal sheet 321, which is disposed on the surface of the body 310 where the heat conduction zone 310a is located. In specific implementations, the metal sheet 321 can be fixedly connected to the body 310 by welding, bonding, or other methods. The CTE of the metal sheet 321 is greater than that of the body 310. When the body 310 is made of copper, its CTE is approximately 18 ppm. Therefore, the metal sheet 321 can be selected from metal materials with a CTE greater than 18 ppm. For example, the metal sheet 321 can be made of aluminum alloy, which has a CTE of approximately 23 ppm, meeting the CTE requirement for the metal sheet 321 in this embodiment.

[0115] During operation, when the temperature of chip 200 rises to the second temperature range, the first surface 210 of chip 200 undergoes a concave deformation, and the metal sheet 321 and body 310 also deform due to the increased temperature. Since the metal sheet 321 is rigidly connected to the body 310 and the CTE of the metal sheet 321 is relatively large, the metal sheet 321 will deform in a direction away from the body 310, or in other words, the metal sheet 321 will deform in a direction close to the first surface 210 of chip 200, driving the body 310 to deform in the same or similar direction. In this way, not only can the shape of the metal sheet 321 be adapted to the shape of the first surface 210, but the shape of the heat conduction area 310a can also be adapted to the shape of the first surface 210.

[0116] In addition, in the embodiments of this application, the shape of the metal sheet 321 can also be rectangular, ring-shaped, strip-shaped, etc. For specific implementation methods, please refer to the description in the foregoing embodiments, which will not be repeated here.

[0117] Figure 13 This is a side view of another circuit board assembly 1200 provided in an embodiment of this application. Figure 14a for Figure 13 The side view shown illustrates the assembly relationship between chip 200 and heat sink 300 within the first temperature range. Figure 14b for Figure 13 The side view shown depicts the assembly relationship between chip 200 and heat sink 300 within the second temperature range. Figure 14a and Figure 14b The thermal interface material is omitted here. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0118] Please refer to the above. Figure 13 , Figure 14a and Figure 14bAs shown in this embodiment, the heat sink 300 includes a body 310 and a drive member 320. The surface of the body 310 facing the chip 200 includes a heat conduction region 310a, which is thermally connected to the first surface 210 of the chip 200, for example, through a thermal interface material 400. Furthermore, the shape of the heat conduction region 310a within a first temperature range adapts to the shape of the first surface 210 of the chip 200 within the first temperature range. The drive member 320 is fixed to the body 310 and can be used to drive the heat conduction region 310a to deform within a second temperature range, so that the shape of the heat conduction region 310a within the second temperature range adapts to the shape of the first surface 210 of the chip 200 within the second temperature range.

[0119] Among them, the main body 310 can be Figure 3 The cavity structure in the illustrated embodiment is, for example, a VC liquid cooling heat sink. The drive element 320 may include at least one elastic element 322, such as... Figure 14a and Figure 14b An exemplary example is shown with two elastic members 322. Each elastic member 322 is disposed in the inner cavity 313, and both ends of each elastic member 322 are fixedly connected to the inner walls of the body 310 on both sides arranged opposite each other along the first direction x. That is, both ends of each elastic member 322 abut against the first cover plate 315 and the second cover plate 316, respectively. At least a portion of the orthographic projection of each elastic member 322 in the first direction x coincides with the orthographic projection of the heat conduction area 310a in the first direction x. Within the first temperature range, each elastic member 322 is in a compressed state. Therefore, the elastic member 322 applies a certain downward pressure force to the second cover plate 316, so that the shape of the heat conduction area 310a adapts to the shape of the first surface 210 of the chip 200.

[0120] In this embodiment, the sum of the elastic forces of at least one elastic element 322 is less than the sum of the elastic forces of multiple spring screws 330, so as to prevent the elastic element 322 from overcoming the elastic forces of the spring screws 330 and returning to its natural state, thus losing its driving effect on the heat conduction zone 310a.

[0121] During the operation of chip 200, when the temperature rises to the second temperature range, the first surface 210 of chip 200 undergoes concave deformation, and the supporting effect of chip 200 on heat conduction area 310a weakens. Driven by the elastic force of elastic member 322, second cover plate 316 will bulge and deform towards chip 200 until heat conduction area 310a re-fits the first surface 210 of chip 200. In this way, the shape of heat conduction area 310a can be adapted to the shape of the first surface 210 of chip 200.

[0122] Continue to refer to Figure 14a and Figure 14bIn this embodiment, the elastic element 322 can be a spring. At least one limiting post 317 can be provided in the inner cavity 313 of the body 310. The figure exemplarily shows the case of three limiting posts 317. Each limiting post 317 extends along the first direction x, and at least one end of each limiting post 317 is connected to the inner wall of the body 310. At least a portion of the orthographic projection of each limiting post 317 in the first direction x coincides with the orthographic projection of the heat conduction zone 310a in the first direction x. Each limiting post 317 has a degree of freedom of movement in the first direction x relative to at least one of the two side walls of the body 310 that are opposite each other along the first direction x. That is, each limiting post 317 can move in the first direction relative to at least one of the two side walls of the body 310 (i.e., at least one of the first cover plate 315 and the second cover plate 316). This not only facilitates the extension and retraction of the spring, but also allows the limiting post 317 to provide support within the inner cavity 313 of the body 310.

[0123] It should be noted that in the inner cavity 313 of the body 310, except for the space corresponding to the heat conduction zone 310a, other spaces can still be supported by the support column 314 between the first cover plate 315 and the second cover plate 316 to ensure the rigidity of the body 310.

[0124] Figure 15a A schematic diagram of a limiting post 317 provided in an embodiment of this application is shown. (See also...) Figure 14a , Figure 14b , Figure 15a As shown, in this embodiment, the limiting post 317 includes a first post 3171 and a second post 3172. The first post 3171 and the second post 3172 are respectively fixed to the inner walls of the body 310 on both sides arranged opposite to each other along the first direction x. That is, the first post 3171 is fixed to the first cover plate 315, and the second post 3172 is fixed to the second cover plate 316. In this way, the first post 3171 has a degree of freedom of movement along the first direction x relative to the second cover plate 316, and the second post 3172 has a degree of freedom of movement along the first direction x relative to the first cover plate 315. The first post 3171 includes a first end face 31711 facing the second post 3172, and the second post 3172 includes a second end face 31721 facing the first post 3171. The first end face 31711 and the second end face 31721 are arranged opposite to each other. When the heat sink 300 or the electronic device using the heat sink 300 is dropped, if the outer surfaces of the first cover plate 315 and the second cover plate 316 are impacted by an external force, the first end face 31711 of the first column 3171 and the second end face 31721 of the second column 3172 can abut against each other, thereby forming a support in the inner cavity 313 of the body 310, preventing the heat conduction area 310a or the area of ​​the first cover plate 315 corresponding to the heat conduction area 310a from undergoing concave deformation, and improving the structural reliability of the body 310.

[0125] Figure 15b A schematic diagram of a limiting post 317 provided in an embodiment of this application is shown. (See also...) Figure 14a , Figure 14b , Figure 15b As shown, in this embodiment, the limiting post 317 also includes a first post 3171 and a second post 3172. The first post 3171 is fixed to the first cover plate 315, and the second post 3172 is fixed to the second cover plate 316. Similarly, the first post 3171 has a degree of freedom of movement relative to the second cover plate 316 along the first direction x, and the second post 3172 has a degree of freedom of movement relative to the first cover plate 315 along the first direction x. The first post 3171 includes a first end face 31711 facing the second post 3172, and the first end face 31711 is provided with a first hook 3173. The first hook 3173 includes a first vertical wall 31731 and a first horizontal wall 31732. One end of the first vertical wall 31731 is connected to the first end face 31711, and the other end of the first vertical wall 31731 is connected to the first horizontal wall 31732. There is a first gap between the first horizontal wall 31732 and the first end face 31711. Similarly, the second column 3172 includes a second end face 31721 facing the first column 3171. The second end face 31721 is provided with a second hook 3174. The second hook 3174 includes a second vertical wall 31741 and a second horizontal wall 31742. One end of the second vertical wall 31741 is connected to the second end face 31721, and the other end of the second vertical wall 31741 is connected to the second horizontal wall 31742. There is a second distance between the second horizontal wall 31742 and the second end face 31721.

[0126] The first hook 3173 is engaged with the second hook 3174. The first transverse wall 31732 is located between the second end face 31721 and the second transverse wall 31742, and the thickness of the first transverse wall 31732 along the first direction x is less than the second spacing. The second transverse wall 31742 is located between the first end face 31711 and the first transverse wall 31732, and the thickness of the second transverse wall 31742 along the first direction x is less than the first spacing. With this design, the second column 3172 can move up and down relative to the first column 3171 along the first direction x, while the movement displacement of the second column 3172 can be restricted. When the heat sink 300 or an electronic device using the heat sink 300 is dropped, if the outer surfaces of the first cover plate 315 and the second cover plate 316 are impacted by an external force, the first transverse wall 31732 can abut against the second end face 31721, and the second transverse wall 31742 can abut against the first end face 31711, thereby forming a support in the inner cavity 313 of the body 310. This prevents the heat conduction area 310a or the area of ​​the first cover plate 315 corresponding to the heat conduction area 310a from undergoing concave deformation, thus improving the structural reliability of the body 310. In addition, for the heat sink 300 unit, before the heat sink 300 is assembled into the circuit board assembly, the first transverse wall 31732 and the second transverse wall 31742 can abut against each other to prevent the heat conduction area 310a from bulging outwards significantly under the force of the spring, affecting the appearance of the heat sink 300.

[0127] In some other embodiments, the limiting post 317 can also be an integral structure, with one end of the limiting post 317 connected to the first cover plate 315 and the other end of the limiting post 317 being a free end facing the second cover plate 316. The limiting post 317 has a degree of freedom of movement relative to the second cover plate 316 along the first direction x. When the heat sink 300 or the electronic device using the heat sink 300 is dropped, if the outer surfaces of the first cover plate 315 and the second cover plate 316 are impacted by an external force, the end of the limiting post 317 facing the second cover plate 316 abuts against the second cover plate 316, thereby forming a support in the inner cavity 313 of the body 310, preventing the heat conduction area 310a or the area of ​​the first cover plate 315 corresponding to the heat conduction area 310a from undergoing concave deformation, and improving the structural reliability of the body 310.

[0128] Of course, the limiting post 317 can also be connected to the second cover plate 316. In this case, the end of the limiting post 317 facing the first cover plate 315 is a free end, and the limiting post 317 has a degree of freedom of movement relative to the first cover plate 315 along the first direction x. When the outer surfaces of the first cover plate 315 and the second cover plate 316 are impacted by an external force, the end of the limiting post 317 facing the first cover plate 315 can form a support in the inner cavity of the body 310 by abutting against the first cover plate 315.

[0129] Figure 16aThis is a side view showing the assembly relationship between the chip 200 and another heat sink 300 within a first temperature range, as provided in an embodiment of this application. Figure 16b This is a side view showing the assembly relationship between the chip 200 and another heat sink 300 provided in an embodiment of this application within a second temperature range. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0130] Please refer to the above. Figure 16a and Figure 16b As shown in the embodiments of this application, the body 310 can be Figure 3 The cavity structure in the illustrated embodiment is, for example, a VC liquid cooling heat sink. The driving component 320 may include at least one elastic element 322, and the position and connection method of each elastic element 322 in the cavity can be referred to the foregoing. Figures 13 to 14b The design of the illustrated embodiment will not be repeated here. The difference is that in this embodiment, the elastic element 322 can be metal rubber. Metal rubber not only drives the deformation of the heat conduction zone 310a, but also possesses a certain rigidity under compression, thus providing support for the inner cavity 313. This eliminates the need for the limiting post 317 in the space corresponding to the heat conduction zone 310a within the inner cavity 313, simplifying the structure of the body 310. Furthermore, metal rubber also exhibits capillary action. When the body 310 is a VC liquid cooling heat sink, the metal rubber can act as a liquid wick for the body 310, allowing the liquid cooling medium condensed at the top of the body 310 to flow back to the bottom of the body 310 through the metal rubber.

[0131] It should be noted that, in the inner cavity 313 of the body 310, except for the space corresponding to the heat conduction zone 310a, other spaces can still be supported by the support column 314 between the first cover plate 315 and the second cover plate 316 to ensure the rigidity of the body 310.

[0132] Figure 17 This is a side view of another circuit board assembly 1200 provided in an embodiment of this application. Figure 18a for Figure 17 The side view shown illustrates the assembly relationship between chip 200 and heat sink 300 within the first temperature range. Figure 18b for Figure 17 The side view shown depicts the assembly relationship between chip 200 and heat sink 300 within the second temperature range. Figure 18a and Figure 18b The thermal interface material is omitted here. The ranges of the first and second temperature ranges can be referred to the definitions in the preceding embodiments, and will not be repeated here.

[0133] Please refer to the above. Figure 17 , Figure 18a and Figure 18bAs shown in this embodiment, the heat sink 300 includes a body 310 and a drive member 320. The surface of the body 310 facing the chip 200 includes a heat conduction region 310a, which is thermally connected to the first surface 210 of the chip 200, for example, through a thermal interface material 400. Furthermore, the shape of the heat conduction region 310a within a first temperature range adapts to the shape of the first surface 210 of the chip 200 within the first temperature range. The drive member 320 is fixed to the body 310 and can be used to drive the heat conduction region 310a to deform within a second temperature range, so that the shape of the heat conduction region 310a within the second temperature range adapts to the shape of the first surface 210 of the chip 200 within the second temperature range.

[0134] Among them, the main body 310 can be Figure 3 The cavity structure in the illustrated embodiment is, for example, a VC liquid cooling heat sink. The drive unit 320 includes at least one connecting post 323, such as... Figure 18a and Figure 18b An exemplary configuration of four connecting posts 323 is shown. Each connecting post 323 is disposed in the inner cavity 313, and both ends of each connecting post 323 are fixedly connected to the inner walls of the body 310 on both sides arranged opposite each other along the first direction x. That is, both ends of each connecting post 323 abut against the first cover plate 315 and the second cover plate 316, respectively. At least a portion of the orthographic projection of each connecting post 323 in the first direction x coincides with the orthographic projection of the heat conduction zone 310a in the first direction x.

[0135] In the specific implementation, the connecting post 323 is made of shape memory alloy (SMA). Shape memory alloy is a general term for metals with a shape memory effect. Specifically, below the memory temperature, the shape memory alloy exhibits a certain structural form; above the memory temperature, its internal crystal structure changes, causing deformation, at which point the shape memory alloy can exhibit a structural form. In the specific embodiment of this application, the length of the connecting post 323 in the second temperature range is greater than its length in the first temperature range.

[0136] During the operation of chip 200, when the temperature rises to the second temperature range, the first surface 210 of chip 200 undergoes a concave deformation, and the length of the connecting post 323 also elongates due to the temperature rise. Therefore, the connecting post 323 can drive the second cover plate 316 to bulge and deform in the direction of chip 200, so that the shape of the heat conduction area 310a is adapted to the shape of the first surface 210 of chip 200.

[0137] In addition, in this embodiment, the thickness of the second cover plate 316 can be slightly less than or equal to the thickness of the first cover plate 315. In this way, the stiffness of the second cover plate 316 is also correspondingly less than or equal to the stiffness of the first cover plate 315. This allows the connecting column 323 to reliably drive the deformation of the second cover plate 316 when it elongates, thereby improving the reliability of the radiator 300.

[0138] Table 1 shows the changes in warpage of the chip and heat sink, as well as the distance between them, under temperature conditions of a certain temperature within a first temperature range (e.g., 25°C) and a certain temperature within a second temperature range (e.g., 100°C). In Scheme 1, the heat conduction area of ​​the heat sink is a planar structure; in Scheme 2, the heat conduction area of ​​the heat sink is a curved structure adapted to the shape of the first surface of the chip at room temperature; neither Scheme 1 nor Scheme 2 has a driving component in the heat sink; Scheme 3 is the one described in this application. Figures 3-4b The heat sink in the illustrated embodiment uses a metal plate as the driving element; Scheme 4 is the one described in this application. Figures 16a-16b The heat sink in the illustrated embodiment uses metal rubber as the driving component.

[0139] W1 represents the warpage of the first surface of the chip, and W2 represents the warpage of the heat conduction area of ​​the heat sink. A positive warpage value can be interpreted as the first surface or heat conduction area being convex, while a negative warpage value can be interpreted as the first surface or heat conduction area being concave. The center-to-center spacing represents the distance between the center area of ​​the first surface of the chip and the heat conduction area of ​​the heat sink in the first direction, and the edge spacing represents the distance between the edge area of ​​the chip and the heat conduction area of ​​the heat sink in the first direction.

[0140] As shown in Table 1, compared to the heat sinks without driving components in Schemes 1 and 2, the warpage of the heat conduction zone of the heat sinks in Schemes 3 and 4 changes significantly in the two temperature ranges. This indicates that the driving component of the heat sink can effectively adjust the shape of the heat conduction zone at high temperatures. Furthermore, in Schemes 3 and 4, the changes in the center distance and edge distance between the first surface of the chip and the heat conduction zone of the heat sink are relatively small in the two temperature ranges. This indicates that the deformation direction of the heat conduction zone is roughly the same as the deformation direction of the first surface of the chip. Therefore, the shape of the heat conduction zone in the second temperature range can also be well adapted to the shape of the first surface of the chip in the second temperature range.

[0141] Table 1

[0142]

[0143] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A radiator, characterized in that, The heat sink is used to dissipate heat from the chip, the chip including a first surface disposed toward the heat sink, the shape of the first surface in a first temperature range being different from the shape of the first surface in a second temperature range; The heat sink includes a body and a driving component. The side surface of the body facing the chip includes a heat conduction area. The heat conduction area is used for thermally conductive connection with the first surface. The shape of the heat conduction area in the first temperature range is adapted to the shape of the first surface in the first temperature range. The driving member is fixed to the body, and the driving member is used to drive the heat conduction area to deform within the second temperature range so that the shape of the heat conduction area within the second temperature range adapts to the shape of the first surface within the second temperature range. The maximum temperature value in the first temperature range is less than the minimum temperature value in the second temperature range.

2. The radiator as described in claim 1, characterized in that, The body includes an inner cavity, in which a support column is provided. The two ends of the support column are fixedly connected to the inner walls of the body on both sides, which are arranged opposite to each other along a first direction. The first direction is the thickness direction of the heat sink.

3. The radiator as described in claim 2, characterized in that, The driving component is a metal sheet, and the coefficient of thermal expansion of the metal sheet is less than the coefficient of thermal expansion of the body. The metal sheet is disposed on the outer wall of a side wall opposite to the side wall where the heat conduction zone is located in the main body; or, the metal sheet is disposed on the inner wall of the side wall where the heat conduction zone is located in the main body.

4. The radiator as described in claim 2, characterized in that, The driving component is a metal sheet, and the coefficient of thermal expansion of the metal sheet is greater than that of the body. The metal sheet is disposed on the outer wall of the side wall on the side where the heat conduction area is located in the body; or, the metal sheet is disposed on the inner wall of the side wall on the side opposite to the side wall where the heat conduction area is located in the body.

5. The radiator as described in claim 3 or 4, characterized in that, The body includes a first cover plate and a second cover plate, the first cover plate and the second cover plate being fixedly connected and enclosing to form the inner cavity; The metal sheet is disposed on the first cover plate, and the thickness d0 of the metal sheet and the thickness d1 of the first cover plate satisfy: 0.5 ≤ d0 / d1 ≤ 1.5; or, The metal sheet is disposed on the second cover plate, and the thickness d0 of the metal sheet and the thickness d2 of the second cover plate satisfy: 0.5≤d0 / d2≤1.

5.

6. The radiator as described in claim 1, characterized in that, The heat sink has a solid structure; The driving component is a metal sheet, which is disposed on one side surface of the body where the heat conduction area is located. The coefficient of thermal expansion of the metal sheet is greater than that of the body.

7. The radiator according to any one of claims 3-6, characterized in that, The metal sheet has a rectangular structure, and the orthographic projection of the metal sheet in the first direction covers at least 50% of the orthographic projection of the heat conduction area in the first direction. The first direction is the thickness direction of the heat sink.

8. The radiator according to any one of claims 3-6, characterized in that, The metal sheet has a ring structure, and the orthographic projection of the metal sheet in the first direction surrounds the periphery of the orthographic projection of the heat conduction area in the first direction. The first direction is the thickness direction of the heat sink.

9. The radiator according to any one of claims 3-6, characterized in that, The metal sheet has a strip-shaped structure and includes a first part, a second part, and a third part. The second part is connected between the first part and the third part. The orthographic projection of the second part in the first direction covers at least a portion of the orthographic projection of the heat conduction area in the first direction. The orthographic projection of the first part in the first direction does not coincide with the orthographic projection of the heat conduction area in the first direction. The orthographic projection of the third part in the first direction does not coincide with the orthographic projection of the heat conduction area in the first direction. The first direction is the thickness direction of the heat sink.

10. The radiator as claimed in claim 1, characterized in that, The body includes an inner cavity; The driving component includes at least one elastic element, each elastic element is disposed in the inner cavity, and both ends of each elastic element are fixedly connected to the inner walls of the two sides of the body disposed opposite to each other along the first direction. At least a portion of the orthographic projection of each elastic element in the first direction coincides with the orthographic projection of the heat conduction area in the first direction. Within the first temperature range, each of the elastic elements is in a compressed state; The first direction is the thickness direction of the heat sink.

11. The radiator as claimed in claim 10, characterized in that, The elastic element is a spring; At least one limiting post is provided in the inner cavity. At least one end of each limiting post is connected to the inner wall of the body along the first direction. At least a portion of the orthographic projection of each limiting post in the first direction coincides with the orthographic projection of the heat conduction area in the first direction. Each limiting post has a degree of freedom of movement along the first direction relative to at least one of the two side walls of the body that are disposed opposite to each other along the first direction.

12. The radiator as claimed in claim 11, characterized in that, The limiting post includes a first post and a second post, which are respectively fixed to the inner walls of the two sides of the body that are arranged opposite to each other along the first direction; the first post includes a first end face facing the second post, and the second post includes a second end face facing the first post, with the first end face and the second end face being arranged opposite to each other.

13. The radiator as claimed in claim 11, characterized in that, The limiting post includes a first post and a second post, which are respectively fixed to the inner walls of the two sides of the body that are arranged opposite to each other along the first direction. The first post includes a first end face facing the second post, and the first end face is provided with a first hook. The first hook includes a first vertical wall and a first horizontal wall. One end of the first vertical wall is connected to the first end face, and the other end of the first vertical wall is connected to the first horizontal wall. The first horizontal wall and the first end face have a first distance along the first direction. The second column includes a second end face facing the first column. The second end face is provided with a second hook. The second hook includes a second vertical wall and a second horizontal wall. One end of the second vertical wall is connected to the second end face, and the other end of the second vertical wall is connected to the second horizontal wall. The second horizontal wall and the second end face have a second distance along the first direction. The first hook is attached to the second hook, the first horizontal wall is located between the second end face and the second horizontal wall, and the thickness of the first horizontal wall along the first direction is less than the second spacing; the second horizontal wall is located between the first end face and the first horizontal wall, and the thickness of the second horizontal wall along the first direction is less than the first spacing.

14. The radiator as claimed in claim 10, characterized in that, The elastic element is made of metal rubber.

15. The radiator as claimed in claim 1, characterized in that, The body includes an inner cavity; The driving component includes at least one connecting post, each connecting post being disposed in the inner cavity, and both ends of each connecting post being fixedly connected to the inner walls of the two sides of the body disposed opposite to each other along the first direction. At least a portion of the orthographic projection of each connecting post in the first direction coincides with the orthographic projection of the heat conduction area in the first direction. The connecting post is made of shape memory alloy, and the length of the connecting post in the second temperature range is greater than the length of the connecting post in the first temperature range.

16. A circuit board assembly, characterized in that, The device includes a substrate, a chip, and a heat sink as described in any one of claims 1-15, wherein the chip is disposed on the surface of the substrate, the heat sink is disposed on the side of the chip facing away from the substrate, and the heat conduction area of ​​the heat sink is thermally connected to the first surface of the chip.

17. An electronic device, characterized in that, It includes a housing and a circuit board assembly as described in claim 16, the circuit board assembly being disposed within the housing.

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