Packaging heat dissipation structure for high power density device

Abstract

The invention discloses a packaging heat dissipation structure for a high-power-density device, and relates to the technical field of electronic equipment heat dissipation, the packaging heat dissipation structure comprises a packaging shell connected with the high-power-density device, the packaging shell is provided with a micro-channel for circulation of a cooling working medium, and the micro-channel corresponds to the high-power-density device. After the micro-channel is combined with the packaging structure of the high-power-density device, the interval between the high-power-density device and the micro-channel is reduced, the thermal resistance of the high-power-density device is reduced, the packaging structure does not affect the design of an electronic layer of the high-power-density device, and the practicability is high; the equivalent size of the micro-channel is gradually reduced, the specific surface area of the micro-channel is increased, the pressure drop is reduced, the heat exchange performance is enhanced, the temperature uniformity of the surface of a high-power-density device is further improved, and the situation that the packaging reliability is reduced due to thermal stress generated by a large temperature gradient is avoided. The technical problem that stable operation of a high-power-density device is affected due to the fact that an existing heat dissipation structure has a large temperature gradient is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation of electronic equipment, and in particular to a packaging heat dissipation structure for high power density devices. Background Art

[0002] The country is vigorously building high-end electronic information technologies such as 5G, data centers, artificial intelligence, and industrial Internet. With the rapid development of miniaturization and integration of electronic devices, their power density is getting higher and higher, and the heating problem of electronic devices is becoming more and more serious. At present, the power consumption of high-performance single chips represented by GPU / CPU exceeds 1000W, and the heat flux density will exceed 200W / cm 2 If effective heat dissipation methods are not adopted to solve the heat dissipation problem, the temperature of electronic equipment will rise, greatly reducing its reliability and even causing damage to the electronic equipment. The heat dissipation problem has become one of the bottlenecks in the development of high-power electronic equipment technology.

[0003] The existing heat dissipation problems mainly focus on the following two aspects: On the one hand, high-end electronic information technology such as data centers currently generally adopts traditional liquid cooling and heat dissipation methods, and only remotely cools the outer shell of the packaged chip. In the traditional liquid cooling and heat dissipation method, the packaged chip and the liquid cooling plate are two independent components. The chip packaging structure usually includes a sealed package shell and a package substrate. The package shell and the package substrate form a cavity for fixing the chip. The top of the chip is connected to the package shell through the chip substrate material and TIM1, and the bottom of the chip is connected to the package substrate through the package solder ball and the filling glue; the liquid cooling plate usually includes a cover plate and a bottom plate that fit together. The bottom plate is provided with a microchannel for liquid cooling and heat dissipation, and the cover plate is provided with an inlet and an outlet connected to the microchannel; the package shell and the liquid cooling plate are connected through TIM2, and TIM1 and TIM2 are both thermal interface materials. When a liquid cooling plate is used to cool the chip, the heat generated by the chip needs to pass through the thermal resistance of six intermediate links, namely the substrate material, TIM1, package shell, TIM2, the bottom plate and cover plate of the liquid cooling plate, before it can be dissipated to the environment. Due to the large amount of thermal resistance in the intermediate links, the temperature gradient between the substrate material and the liquid cooling plate is large, which in turn causes the chip temperature to be too high.

[0004] On the other hand, the traditional liquid cooling method uses conventional microchannels, but the flow resistance of conventional microchannels is large, and the temperature of the cooling medium will gradually increase during the flow process along the conventional microchannel, and the cooling effect will gradually weaken, resulting in a large temperature gradient upstream and downstream of the microchannel, resulting in poor temperature uniformity upstream and downstream of the microchannel, and then leading to uneven thermal stress distribution, which may cause chip deformation, warping and reduced reliability of the packaging structure.

[0005] Packaging structures with microchannels have appeared in the prior art, such as the silicon-based three-dimensional packaging structure with embedded microchannels and its manufacturing method disclosed in the Chinese invention patent with an application publication date of 2022.08.30 and application publication number CN 114975312 A, which includes an upper and a bottom embedded silicon-based TSV adapter board; the upper embedded silicon-based TSV adapter board includes a sealing cover layer, a conductive connector and an upper microfluidic heat dissipation functional layer, and the sealing cover layer includes a silicon-based substrate cover, a cover TSV array and a fluid inlet and outlet; the upper microfluidic heat dissipation functional layer includes a silicon-based substrate, a substrate TSV array, a substrate groove body, an adhesive body, a functional chip, a redistribution layer, fluid through holes, array bumps and gaskets; the bottom embedded silicon-based TSV adapter board includes a sealing cover layer, a conductive connector and a bottom microfluidic heat dissipation functional layer; the bottom microfluidic heat dissipation functional layer has fewer fluid through holes and gaskets than the upper microfluidic heat dissipation functional layer. By setting up an upper microfluidic heat dissipation functional layer and a bottom microfluidic heat dissipation functional layer, the heat dissipation capacity is effectively enhanced and the thermal resistance is reduced. However, the microfluidic channels are arranged in upper and lower layers, the temperature gradient upstream and downstream of the microchannel is still large, the packaging structure has many components, and the packaging process is also very complicated. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned background technology, the present invention proposes a packaging heat dissipation structure for high power density devices, which solves the technical problem that the existing heat dissipation structure has a large temperature gradient and affects the stable operation of the high power density devices.

[0007] The technical solution of this application is: A packaging heat dissipation structure for a high power density device comprises a packaging shell and a packaging substrate, wherein the packaging shell and the packaging substrate form a sealed cavity, wherein the high power density device is arranged in the sealed cavity, and a microchannel for cooling medium to flow is arranged on the packaging shell, wherein the position of the microchannel corresponds to the high power density device.

[0008] Preferably, the specific surface area of ​​the microchannel gradually increases from the upstream to the downstream of the microchannel.

[0009] Preferably, the microchannel is composed of a plurality of spaced-apart micro-ribs, and the rib width of the micro-ribs gradually decreases along the flow direction of the cooling medium.

[0010] Preferably, the micro-ribs are at least one of parallelogram micro-ribs, trapezoidal micro-ribs, triangular micro-ribs and semicircular micro-ribs.

[0011] Preferably, the packaging shell comprises an outer heat-conducting plate and an inner high thermal conductivity composite material, the microchannel is arranged between the heat-conducting plate and the high thermal conductivity composite material, and the high power density device is arranged on one side of the high thermal conductivity composite material.

[0012] Preferably, the high thermal conductivity composite material is bonded to the high power density device via a liquid metal interface material, or is welded to the high power density device via a eutectic bonding process, or is welded to the high power density device via a soft soldering process.

[0013] Preferably, the high thermal conductivity composite material is a material with high thermal conductivity and low expansion coefficient, and the expansion coefficient of the side of the high thermal conductivity composite material facing the high power density device is close to the expansion coefficient of the semiconductor.

[0014] Preferably, the high thermal conductivity composite material is any one of a composite material of silicon wafer and copper, a composite material of diamond and copper, and a composite material of diamond and aluminum.

[0015] Preferably, the packaging shell is formed by integrally processing a heat conducting plate and a high thermal conductivity composite material.

[0016] Preferably, the liquid inlet and the liquid outlet of the microchannel are both arranged perpendicular to the heat conducting plate, the liquid inlet is communicated with the upstream of the microchannel, and the liquid outlet is communicated with the downstream of the microchannel.

[0017] Compared with the prior art, the technical solution disclosed in the present invention has the following beneficial effects: 1. The present invention sets a microchannel for liquid cooling on the packaging shell. After combining the microchannel with the packaging structure of the high power density device, the distance between the high power density device and the microchannel is reduced, and the thermal resistance of the intermediate link of the high power density device heat dissipation is reduced, thereby achieving efficient heat exchange between the high power density device and the cooling medium. At the same time, the packaging structure does not affect the electronic layer design of the high power density device, and has strong engineering practicality.

[0018] 2. From the upstream to the downstream of the microchannel, the equivalent size of the microchannel structure gradually decreases. This size gradient structure increases the specific surface area of ​​the microchannel, reduces the pressure drop, improves the convection heat transfer coefficient of the microchannel, and enhances the heat transfer performance, thereby improving the temperature uniformity on the surface of the high power density device, avoiding the thermal stress caused by the large temperature gradient, and reducing the risk of reduced reliability of the packaging structure due to thermal stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0020] Figure 1 is a cross-sectional view of the package heat dissipation structure of the present invention; Figure 2 yes Figure 1Structural schematic diagram of an embodiment of a microchannel; Figure 3 is Figure 1 Structural schematic diagram of another embodiment of a microchannel.

[0021] Explanation of reference numerals in the drawings: 1 Encapsulation housing, 101 Heat conducting plate, 102 High thermal conductivity composite material, 2 Liquid metal interface material, 3 High power density device, 4 Structural adhesive, 5 Underfill, 6 Encapsulation solder ball, 7 Encapsulation substrate, 8 Microchannel, 801 Liquid inlet, 802 Liquid outlet, 803 Rectangular micro rib, 804 Square micro rib. Specific implementation manner

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the core concept of the present invention and the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment 1, a packaging heat dissipation structure for high power density devices, as Figure 1 shown, includes an encapsulation housing 1 and an encapsulation substrate 7. The encapsulation housing 1 and the encapsulation substrate 7 form a sealed cavity. The high power density device 3 is arranged in the sealed cavity. The encapsulation housing 1 is provided with a microchannel 8 for the circulation of a cooling working medium. The position of the microchannel 8 corresponds to that of the high power density device 3.

[0024] Preferably, the high power density device 3 is a high power chip, the cooling working medium is water, the material of the encapsulation housing 1 is copper, the microchannel 8 is arranged on the encapsulation housing 1 by etching, and the substrate material of the high power density device 3 is Si or SiC or diamond. The high power density device 3 can also be other high power density devices, and the cooling working medium can be a gas or other liquid with high thermal conductivity.

[0025] Specifically, as Figure 1 shown, the encapsulation housing 1 is in a "U" shape. The microchannel 8 is etched on the upper surface of the encapsulation housing 1. The microchannel 8 is located in the middle of the "U". The left and right sides of the "U" are respectively bonded to the encapsulation substrate 7 by the structural adhesive 4. The cavity surrounded by the "U" and the encapsulation substrate 7 is the sealed cavity. The top surface of the high power density device 3 is connected to the encapsulation housing 1 through the substrate material and TIM1. The bottom surface and side surfaces of the high power density device 3 are connected to the encapsulation substrate 7 by the underfill 5. There is also an encapsulation solder ball 6 connected between the bottom surface of the high power density device 3 and the encapsulation substrate 7. The packaging-level heat dissipation structure of the present invention does not affect the design of the electronic layer of the high power density device 3 and has high engineering application value.

[0026] Furthermore, the packaging shell 1 is used to package the high power density device 3, and the microchannel 8 is used to circulate the cooling medium to perform liquid cooling on the high power density device 3, and the microchannel 8 is located directly above the high power density device 3. During heat dissipation, the cooling medium continuously flows from the inlet end of the microchannel 8 to the outlet end, and re-flows through the circulation device. The inlet end and the outlet end of the microchannel 8 can be directly arranged on the side of the "J"-shaped packaging shell 1 for easy processing.

[0027] Furthermore, after combining the microchannel 8 with the packaging structure of the high-power density device 3, the interval between the high-power density device 3 and the microchannel 8 is reduced, and the high-power density device 3 is heat-dissipated by bonding with the packaging shell 1 through the thermal interface material. The heat generated by the high-power density device 3 can be dissipated into the environment through the substrate material, TIM1, and the packaging shell 1. Compared with the prior art of heat dissipation using a liquid cooling plate, the thermal resistance of the two intermediate links of TIM2 and the liquid cooling plate is reduced, the thermal resistance of the intermediate link of the heat dissipation of the high-power density device 3 is reduced, the temperature gradient between the high-power density device 3 and the microchannel 8 is reduced, and the temperature of the high-power density device 3 during operation is reduced, thereby achieving efficient heat exchange between the high-power density device 3 and the cooling medium. At the same time, the packaging structure does not affect the electronic layer design of the cooling component 3, and has strong engineering practicality.

[0028] Embodiment 2, based on embodiment 1, a packaging heat dissipation structure for high power density devices, such as Figure 2 and Figure 3 As shown, the specific surface area of ​​the microchannel 8 gradually increases from the upstream to the downstream of the microchannel 8. Specifically, since the temperature of the cooling medium of the conventional microchannel gradually increases along the flow process of the microchannel 8, the cooling effect of the cooling medium will gradually weaken, resulting in a large temperature gradient between the upstream wall and the downstream wall of the microchannel 8. The present invention gradually increases the specific surface area of ​​the microchannel 8 from the upstream to the downstream of the microchannel 8 by gradually reducing the equivalent size of the microchannel 8 structure, thereby increasing the area of ​​the downstream wall of the microchannel 8, thereby enhancing the heat exchange effect downstream of the microchannel 8, and thereby improving the convective heat transfer coefficient downstream of the microchannel 8. Compared with the conventional microchannel 8, the temperature uniformity of the surface of the high power density device 3 is improved.

[0029] Furthermore, the microchannel 8 of the present invention can be a straight channel type or a micro-fin type. The straight channel type microchannel 8 can reduce the flow resistance of the cooling medium downstream of the microchannel 8 by reducing the downstream material, thereby increasing the specific surface area downstream of the microchannel 8; the micro-fin type microchannel 8 can reduce the arrangement density of the micro-fins downstream of the microchannel 8 to reduce the flow resistance of the cooling medium downstream of the microchannel 8, thereby increasing the specific surface area downstream of the microchannel 8, or reduce the material of the micro-fins downstream of the microchannel 8 to reduce the flow resistance of the cooling medium downstream of the microchannel 8, thereby increasing the specific surface area downstream of the microchannel 8; the width of the microchannel of the present invention is 0.01mm~5mm.

[0030] Embodiment 3, based on Embodiment 2, a package heat dissipation structure for high power density devices, wherein the microchannel 8 is composed of a plurality of spaced micro-ribs, and the rib width of the micro-ribs gradually decreases along the flow direction of the cooling medium. Specifically, the micro-ribs are staggered or aligned along the flow direction of the cooling medium, and the rib width of the micro-ribs decreases step by step along the flow direction of the cooling medium. The micro-ribs can be formed by etching on the package shell 1, and the shape of the micro-ribs can be changed arbitrarily. The rib width of the micro-ribs is between 0.01 mm and 5 mm, the rib height is between 0.01 mm and 5 mm, and the projection length of the micro-ribs on the high thermal conductivity composite material 102 is between 0.01 mm and 20 mm.

[0031] When implementing, Figure 1 As shown, when the micro-rib shape is rectangular, the rectangular micro-ribs 803 are aligned and distributed along the flow direction of the cooling medium. After the package heat dissipation structure is cut open along the rectangular micro-ribs 803, along the flow direction of the cooling medium, the rib height of the rectangular micro-ribs 803 remains unchanged, the rib length of the rectangular micro-ribs 803 remains unchanged and is arranged at equal intervals, and the rib width of the rectangular micro-ribs 803 is gradually reduced. A total of 7 types of rectangular micro-ribs 803 with equal rib lengths and gradually reduced rib widths are arranged from the inlet end to the outlet end of the microchannel 8. The reduction in rib width helps to reduce the flow resistance of the cooling medium, enhance the heat exchange effect downstream of the microchannel 8, and thus improve the convective heat transfer coefficient downstream of the microchannel 8. Compared with the conventional microchannel 8, the temperature uniformity on the surface of the high power density device 3 is improved.

[0032] In practice, when the micro-rib is rectangular, Figure 2As shown, the rectangular micro-ribs 803 are staggered along the flow direction of the cooling medium. Along the flow direction of the cooling medium, the rib length of the rectangular micro-ribs 803 remains unchanged and is arranged at equal intervals, and the rib width of the rectangular micro-ribs 803 gradually decreases. Along the flow direction of the cooling medium, there are three kinds of rectangular micro-ribs 803 with different rib widths. The rectangular micro-ribs 803 with three kinds of rib widths are respectively distributed from the inlet end of the microchannel 8 to one-third, from one-third to two-thirds, and from two-thirds to the end, that is, the microchannel 8 is divided into three gradients in the longitudinal direction. The rib length, rib width and rib height of the rectangular micro-ribs 803 of each gradient are equal. The rectangular micro-ribs 803 located in the first gradient are evenly spaced along the transverse direction of the microchannel 8, the rectangular micro-ribs 803 located in the second gradient are evenly spaced along the transverse direction of the microchannel 8, the rectangular micro-ribs 803 located in the third gradient are evenly spaced along the transverse direction of the microchannel 8, and the rectangular micro-ribs 803 located in the latter gradient are staggered with the rectangular micro-ribs 803 located in the former gradient. Preferably, the rib length of the rectangular micro-rib 803 is 5 mm, the rib width gradually decreases from 1 mm to 0.08 mm and 0.06 mm, and the rib height is 2 mm.

[0033] Furthermore, the height of the rectangular micro-ribs 803 gradually decreases, which helps to further reduce the flow resistance of the cooling medium, enhance the heat exchange effect downstream of the microchannel 8, and thus improve the convective heat transfer coefficient downstream of the microchannel 8, thereby improving the temperature uniformity on the surface of the high power density device 3 compared to the conventional microchannel 8. Along the flow direction of the cooling medium, a microchannel 8 undergoes multi-stage diversion, and the cross-sectional area of ​​the next-stage channel is 1 / 2 of the cross-sectional area of ​​the previous-stage channel, until the liquid outlet 802 at the end of the microchannel 8.

[0034] Embodiment 4, based on embodiment 3, provides a packaging heat dissipation structure for high power density devices, wherein the micro-ribs are at least one of parallelogram micro-ribs, triangular micro-ribs and semi-elliptical micro-ribs.

[0035] During implementation, the diamond micro-ribs are used as a special parallelogram micro-rib. The diamond micro-ribs are staggered along the flow direction of the cooling medium, with the flow direction of the cooling medium as the longitudinal direction and the direction perpendicular to the flow direction of the cooling medium as the transverse direction. Along the flow direction of the cooling medium, the rib length of the diamond micro-ribs gradually decreases, the rib width of the diamond micro-ribs gradually decreases, and the rib height of the diamond micro-ribs remains unchanged. Along the transverse direction, the rib length of the diamond micro-ribs remains unchanged, the rib width of the diamond micro-ribs remains unchanged, and the rib height of the diamond micro-ribs remains unchanged. Along the flow direction of the cooling medium, there are a total of 4 diamond micro-ribs with rib widths, and 4 diamond micro-ribs with rib widths. They are respectively distributed from the entrance end to one quarter, one quarter to two quarters, two quarters to three quarters, and three quarters to the end of the microchannel 8, that is, the microchannel 8 is divided into four gradients in the longitudinal direction, and the rib length, rib width and rib height of the diamond-shaped micro-ribs of each gradient are equal. The diamond-shaped micro-ribs located in the first gradient are evenly spaced along the transverse direction of the microchannel 8, the diamond-shaped micro-ribs located in the second gradient are evenly spaced along the transverse direction of the microchannel 8, and the diamond-shaped micro-ribs located in the third gradient are evenly spaced along the transverse direction of the microchannel 8. The diamond-shaped micro-ribs located in the latter gradient are staggered with the diamond-shaped micro-ribs located in the former gradient. Preferably, the rib width of the diamond-shaped micro-ribs is gradually reduced from 1.2 mm to 1 mm, 0.07 mm and 0.04 mm, the side length of the diamond is 5 mm, and the height of the diamond is 3 mm.

[0036] Furthermore, the height of the diamond-shaped micro-ribs can also be gradually reduced, which helps to further reduce the flow resistance of the cooling medium, enhance the heat exchange effect downstream of the microchannel 8, and thus improve the convective heat transfer coefficient downstream of the microchannel 8, thereby improving the temperature uniformity of the surface of the high power density device 3 compared to the conventional microchannel 8. Along the flow direction of the cooling medium, the microchannel 8 undergoes multi-stage diversion, and the cross-sectional area of ​​the next-stage channel is 1 / 2 of the cross-sectional area of ​​the previous-stage channel, until the liquid outlet 802 at the end of the microchannel 8.

[0037] like Figure 3 As shown, the square micro-rib 804 is a special parallelogram micro-rib. Along the flow direction of the cooling medium, the rib width of the square micro-rib 804 gradually decreases along the flow direction of the cooling medium, and the rib length of the square micro-rib 804 also gradually decreases along the flow direction of the cooling medium. There are four sizes of square micro-ribs 804 arranged along the flow direction of the cooling medium. The four sizes of square micro-ribs 804 are respectively arranged from the inlet end of the microchannel 8 to one-quarter, one-quarter to one-half, one-half to three-quarters, and three-quarters to the end. The four sizes of square micro-ribs 804 are arranged alternately in sequence, and the heat exchange effect of the cooling medium is enhanced based on the turbulence effect, thereby improving the heat dissipation efficiency.

[0038] Furthermore, the rib width of the square micro-rib 804 gradually decreases along the flow direction of the cooling medium, the rib length of the square micro-rib 804 also gradually decreases along the flow direction of the cooling medium, and the rib height of the square micro-rib 804 remains unchanged or decreases. When the rib height of the square micro-rib 804 gradually decreases, it helps to further reduce the flow resistance of the cooling medium, enhance the heat exchange effect downstream of the microchannel 8, and then improve the convective heat transfer coefficient downstream of the microchannel 8. Compared with the conventional microchannel 8, the temperature uniformity on the surface of the high power density device 3 is improved.

[0039] The shape of the micro-ribs in this embodiment can also be a right-angled trapezoid, which is composed of a triangle and a rectangle. The right-angled trapezoidal micro-ribs are staggered along the flow direction of the cooling medium. Along the flow direction of the cooling medium, the rib length of the right-angled trapezoidal micro-ribs remains unchanged and is arranged at equal intervals. The rib width of the right-angled trapezoidal micro-ribs gradually decreases. Along the flow direction of the cooling medium, there are three right-angled trapezoidal micro-ribs with different rib widths. The three right-angled trapezoidal micro-ribs with different rib widths are respectively distributed from the inlet end of the microchannel 8 to one-third, one-third to two-thirds. The microchannel 8 is divided into three gradients along the longitudinal direction, the rib length, rib width and rib height of the right-angled trapezoidal micro-ribs of each gradient are equal, the right-angled trapezoidal micro-ribs at the first gradient are equally spaced along the transverse direction of the microchannel 8, the right-angled trapezoidal micro-ribs at the second gradient are equally spaced along the transverse direction of the microchannel 8, the right-angled trapezoidal micro-ribs at the third gradient are equally spaced along the transverse direction of the microchannel 8, and the right-angled trapezoidal micro-ribs at the latter gradient are staggered with the right-angled trapezoidal micro-ribs at the previous gradient. Preferably, the cross-section of the right-angled trapezoidal micro-ribs is a right-angled trapezoid, the upper base of the right-angled trapezoid is 4mm, the lower base is 8mm, the height is 2mm, and the rib width of the right-angled trapezoidal micro-ribs is gradually reduced from 1mm to 0.07mm and 0.05mm.

[0040] Furthermore, the height of the right-angled trapezoidal micro-ribs gradually decreases, which helps to further reduce the flow resistance of the cooling medium, enhance the heat exchange effect downstream of the microchannel 8, and thus improve the convective heat transfer coefficient downstream of the microchannel 8, thereby improving the temperature uniformity on the surface of the high power density device 3 compared to the conventional microchannel 8. Along the flow direction of the cooling medium, the microchannel 8 undergoes multi-stage diversion, and the cross-sectional area of ​​the next-stage channel is 1 / 2 of the cross-sectional area of ​​the previous-stage channel, until the liquid outlet 802 at the end of the microchannel 8.

[0041] Embodiment 5, based on any one of embodiments 1-4, a packaging heat dissipation structure for a high power density device, such as Figure 1 As shown, the packaging shell 1 includes an outer heat-conducting plate 101 and an inner high thermal conductivity composite material 102 , the microchannel 8 is arranged between the heat-conducting plate 101 and the high thermal conductivity composite material 102 , and the high power density device 3 is arranged on one side of the high thermal conductivity composite material 102 .

[0042] Preferably, the heat conducting plate 101 and the high thermal conductivity composite material 102 are connected up and down, the microchannel 8 is arranged at the bottom of the heat conducting plate 101, the heat conducting plate 101 is in the shape of a "J", and the high thermal conductivity composite material 102 is attached to the bottom of the middle position of the "J" shape, so that a microchannel 8 is formed between the heat conducting plate 101 and the high thermal conductivity composite material 102, the high power density device 3 is connected to the bottom of the high thermal conductivity composite material 102, and the high power density device 3 is arranged directly below the microchannel 8, so that the heat exchange efficiency between the cooling medium and the high power density device in the microchannel 8 is the highest, thereby achieving the highest efficiency of liquid cooling. Further, the microchannel 8 should be larger than the area of ​​the high power density device 3 or the area of ​​the heating area of ​​the high power density device 3. Preferably, the material of the heat conducting plate 101 is copper, and the high thermal conductivity composite material 102 should have high thermal conductivity, so that the heat generated by the high power density device 3 can quickly exchange heat with the cooling medium to achieve rapid cooling of the high power density device 3.

[0043] Embodiment 6, based on Embodiment 5, a packaging heat dissipation structure for high power density devices, wherein the high thermal conductivity composite material 102 is bonded to the high power density device 3 through a liquid metal interface material 2, or is welded to the high power density device 3 through a eutectic bonding process, or is welded to the high power density device 3 through a soft soldering process. In short, the high thermal conductivity composite material 102 is fixedly connected to the high power density device 3. Specifically, the use of liquid metal interface material 2 to bond the high power density device 3 can reduce the thermal stress of the connection between the high thermal conductivity composite material 102 and the high power density device 3, improve the heat dissipation effect and the reliability of the packaging structure. Liquid metal interface material 2, eutectic bonding process welding and soft soldering process welding can all achieve low thermal resistance connection between the packaging shell 1 and the high power density device 3, so as to reduce the thermal resistance of the intermediate link and enhance the heat dissipation effect.

[0044] Embodiment 7, based on Embodiment 6, a packaging heat dissipation structure for high power density devices, wherein the high thermal conductivity composite material 102 is a material with high thermal conductivity and low expansion coefficient, and the expansion coefficient of the high thermal conductivity composite material 102 facing the high power density device 3 is close to the expansion coefficient of the semiconductor. In addition to high thermal conductivity, the high thermal conductivity composite material 102 should also have a low expansion coefficient, and the low expansion coefficient material has an expansion coefficient close to that of the semiconductor material, and the low expansion coefficient material should face the side of the high power density device 3, so as to reduce the thermal stress of the device connected to the high power density device 3 during the reflow process, avoid the large size difference caused by thermal expansion and contraction due to the large difference in expansion coefficient, and thus reduce the connection reliability between the high thermal conductivity composite material 102 and the high power density device 3, affecting the heat dissipation effect and the reliability of the packaging structure.

[0045] Embodiment 8, based on Embodiment 7, a packaging heat dissipation structure for high power density devices, wherein the high thermal conductivity composite material 102 is any one of a composite material of silicon wafer and copper, a composite material of diamond and copper, and a composite material of diamond and aluminum. The material of the high thermal conductivity composite material 102 should have high thermal conductivity and low expansion coefficient, so that after the high thermal conductivity composite material 102 is connected to the substrate material of the high power density device 3, it has low thermal resistance and high heat exchange efficiency, avoiding thermal expansion and contraction with changes in the external ambient temperature, causing connection stress between the high thermal conductivity composite material 102 and the high power density device 3, and thus reducing the connection reliability between the high thermal conductivity composite material 102 and the high power density device 3.

[0046] Specifically, when connecting the high thermal conductivity composite material 102 and the substrate material of the high power density device 3, when the high thermal conductivity composite material 102 is a composite material of silicon wafer and copper, the silicon wafer is connected to the substrate material of the high power density device 3, and the copper is connected to the thermal conductive plate 101; when the high thermal conductivity composite material 102 is a composite material of diamond and copper, the diamond is connected to the substrate material of the high power density device 3, and the copper is connected to the thermal conductive plate 101; when the high thermal conductivity composite material 102 is a composite material of diamond and aluminum, the diamond is connected to the substrate material of the high power density device 3, and the aluminum is connected to the thermal conductive plate 101.

[0047] Embodiment 9, based on Embodiment 8, a package heat dissipation structure for a high power density device, wherein the package shell 1 is formed by integrally processing a heat conducting plate 101 and a high thermal conductivity composite material 102. The heat conducting plate 101 and the high thermal conductivity composite material 102 are integrally processed to enhance the reliability of the connection and avoid the situation where the microchannel 8 between the heat conducting plate 101 and the high thermal conductivity composite material 102 is not tightly sealed. When the package shell 1 is connected to the high power density device 3, only the low expansion material of the high thermal conductivity composite material 102 is connected to the substrate material of the high power density device 3, thereby simplifying the package structure and the production process of the package.

[0048] Embodiment 10, based on embodiment 9, a packaging heat dissipation structure for a high power density device, such as Figure 1 As shown, the liquid inlet 801 and the liquid outlet 802 of the microchannel 8 are both arranged vertically to the heat conducting plate 101 , the liquid inlet 801 is connected to the upstream of the microchannel 8 , and the liquid outlet 802 is connected to the downstream of the microchannel 8 .

[0049] The liquid inlet 801 of this embodiment is used to introduce the cooling medium, and the liquid outlet 802 is used to lead out the cooling medium. After the cooling medium enters the microchannel from the liquid inlet 801, it continuously exchanges heat with the high power density device 3 to take away the heat generated by the high power density device 3, thereby cooling the high power density device 3.

[0050] Furthermore, the liquid inlet 801 and the liquid outlet 802 of the microchannel 8 are both arranged vertically with the heat conducting plate 101, so as to facilitate the introduction of the cooling medium. When dissipating heat, the cooling medium continuously flows from the inlet end of the microchannel 8 to the outlet end, and re-flows through the circulation device. The inlet end and the outlet end of the microchannel 8 can be directly arranged on the top surface of the "J"-shaped packaging shell 1, so as to facilitate the connection of the circulation device.

[0051] The details not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0052] The above content shows and describes the basic principles, main features and beneficial effects of the present invention. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A packaging heat dissipation structure for high power density devices, characterized in that: The invention comprises a packaging shell (1) and a packaging substrate (7), wherein the packaging shell (1) and the packaging substrate (7) form a sealed cavity, wherein the high power density device (3) is arranged in the sealed cavity, and the packaging shell (1) is provided with a microchannel (8) for circulating a cooling medium, wherein the position of the microchannel (8) corresponds to the high power density device (3).

2. The packaging heat dissipation structure for high power density devices according to claim 1, characterized in that: The specific surface area of ​​the microchannel (8) gradually increases from the upstream to the downstream of the microchannel (8).

3. The packaging heat dissipation structure for high power density devices according to claim 2, characterized in that: The microchannel (8) is composed of a plurality of spaced-apart micro-ribs, and the rib width of the micro-ribs gradually decreases along the flow direction of the cooling medium.

4. The packaging heat dissipation structure for high power density devices according to claim 3, characterized in that: The micro-ribs are at least one of parallelogram micro-ribs, trapezoidal micro-ribs, triangular micro-ribs and semicircular micro-ribs.

5. The packaging heat dissipation structure for high power density devices according to any one of claims 1 to 4, characterized in that: The packaging shell (1) comprises an outer heat-conducting plate (101) and an inner high-thermal-conductivity composite material (102); the microchannel (8) is arranged between the heat-conducting plate (101) and the high-thermal-conductivity composite material (102); and the high-power-density device (3) is arranged on one side of the high-thermal-conductivity composite material (102).

6. The packaging heat dissipation structure for high power density devices according to claim 5, characterized in that: The high thermal conductivity composite material (102) is bonded to the high power density device (3) via a liquid metal interface material (2), or is welded to the high power density device (3) via a eutectic bonding process, or is welded to the high power density device (3) via a soft soldering process.

7. The packaging heat dissipation structure for high power density devices according to claim 6, characterized in that: The high thermal conductivity composite material (102) is a material with high thermal conductivity and low expansion coefficient, and the expansion coefficient of the side of the high thermal conductivity composite material (102) facing the high power density device (3) is close to the expansion coefficient of the semiconductor.

8. The packaging heat dissipation structure for high power density devices according to claim 7, characterized in that: The high thermal conductivity composite material (102) is any one of a composite material of silicon wafer and copper, a composite material of diamond and copper, and a composite material of diamond and aluminum.

9. The packaging heat dissipation structure for high power density devices according to claim 8, characterized in that: The packaging shell (1) is formed by integrally processing a heat conducting plate (101) and a high heat conducting composite material (102).

10. The packaging heat dissipation structure for high power density devices according to claim 9, characterized in that: The liquid inlet (801) and the liquid outlet (802) of the microchannel (8) are both arranged vertically to the heat conducting plate (101); the liquid inlet (801) is connected to the upstream of the microchannel (8), and the liquid outlet (802) is connected to the downstream of the microchannel (8).

Images