Radial micro-channel radiator of manifold structure and radiating system

Abstract

The invention relates to the technical field of heat dissipation packaging of semiconductor devices, and discloses a radial micro-channel radiator of a manifold structure and a heat dissipation system. Comprising a radial microchannel cold plate layer, an annular manifold layer, a first fluid distribution layer, a second fluid distribution layer and a cover plate which are sequentially stacked, the connecting faces of all the layers are sealed, and a cooling medium inlet and a cooling medium outlet are formed in the cover plate; according to the radial micro-channel structure of the manifold, the manifold layer and the fluid distribution layer are additionally arranged on the radial micro-channel, fluid can be more evenly distributed, lower pressure drop can be obtained, meanwhile, the characteristic that the radial micro-channel structure is even in flow distribution in the circumferential direction is reserved, more even temperature distribution and lower pump power consumption are achieved, and the flow distribution efficiency is improved. The heat dissipation performance is improved, and the ever-increasing heat dissipation requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor device heat dissipation packaging, and in particular to a radial microchannel radiator and a heat dissipation system with a manifold structure. Background Art

[0002] With the miniaturization and integration of power electronic devices, the power density and heat flux density of devices and modules are constantly increasing, and traditional cooling solutions cannot meet the growing heat dissipation needs. Since the concept of microchannel liquid cooling was proposed, scholars have optimized the microchannel structure in various ways to obtain better heat dissipation performance and lower pressure drop.

[0003] The most widely used type of microchannel is the straight microchannel, whose structural feature is the parallel distribution of straight microchannels. Another commonly used type of microchannel is the radial microchannel, whose structural feature is that the channels are radially distributed from the center to the outside and have central symmetry. Compared with the straight microchannel, the fluid distribution of the radial microchannel is more uniform, and under the premise of the same cold plate size, the inlet and outlet pressure drop can be reduced by more than half. The common disadvantage of the two microchannel structures is that the pressure loss is large due to the small size of the microchannel structure. In addition, due to the heat exchange between the fluid and the wall during the flow process, the fluid temperature rises, and the downstream heat exchange deteriorates, resulting in uneven temperature.

[0004] Due to the problem of deteriorated downstream heat exchange, the temperature distribution of the radial microchannel is low in the middle and high around. The peripheral area is the high temperature point. The temperature difference between the central area and the peripheral area can reach tens of degrees Celsius, and the temperature uniformity in the radial direction is poor. In addition, the size of the channel determines that the inlet and outlet pressure drop is large, and more pump power is consumed. These shortcomings limit the application of the radial microchannel structure in single-phase liquid cooling and other aspects, and cannot fully exert the advantages of the radial microchannel structure. In the field of semiconductor heat dissipation packaging, the application of radial microchannels is limited to two-phase flow boiling.

[0005] The microchannel structure has a large specific surface area, so the contact area between the coolant and the heat source is large, which can effectively transfer heat. However, the flow path of the microchannel is tiny, the flow resistance of the fluid is large, and the pressure drop is large, which leads to increased energy consumption of the system. In order to solve this problem, the straight microchannel introduces a manifold structure to shorten the fluid flow distance and optimize the fluid distribution to obtain better temperature uniformity and lower pressure drop. Some scholars have proposed a manifold straight microchannel structure. The introduction of the manifold structure shortens the flow distance of the fluid, thereby reducing the pressure drop. In addition, the manifold structure makes the distribution of the fluid more uniform, which is conducive to improving temperature uniformity.

[0006] In radial microchannels, the channels naturally expand gradually. Applying them to two-phase flow boiling can suppress flow instability and backflow. However, since the fluid flow in radial microchannels radiates from the center to the outside, the flow velocity in the central area is higher and the flow velocity in the peripheral area is lower, resulting in a significant temperature difference between the central and peripheral areas. In addition, the large flow resistance is also one of the reasons that limit the application potential of radial microchannels.

[0007] CN111678364A discloses a microchannel heat exchanger, which increases the heat exchange efficiency to a certain extent by providing grooves on the side walls of the guide vanes and using the heat exchange space formed by the grooves to create secondary heat exchange channels. However, in this patent, due to the viscosity of the working fluid in the microchannel, huge friction losses will be generated along the flow direction, and the flow loss is very large, which increases the overall energy consumption and affects the operating stability of the heat dissipation equipment.

[0008] CN118960471A discloses a layered topology microchannel heat sink with a low flow resistance manifold structure, comprising a cover plate layer, a manifold layer, a reflow layer and a heat dissipation layer arranged in sequence; the cooling medium flows into the manifold layer from an inlet on the heat dissipation layer and an inlet flow hole penetrating the reflow layer and the manifold layer, and is evenly divided into two or more paths in the shunt manifold structure of the manifold layer, and enters the heat dissipation structure on the heat dissipation layer through the jet flow hole and the annular through hole on the annular boss structure in the reflow layer at the end of the shunt manifold structure, and performs convection heat exchange in the heat dissipation structure on the heat dissipation layer, and then enters the reflow layer through the reflow groove in the reflow layer at the edge of the heat dissipation structure, and finally flows out through the reflow flow hole penetrating the reflow layer and the outlet of the heat dissipation layer; the present invention has the characteristics of low flow resistance, uniform flow distribution and high heat exchange efficiency, adopts topology optimization technology to realize the optimized design of the shunt manifold structure and the microchannel fin structure, and can effectively realize the heat transport and heat dissipation of high heat flux density electronic equipment.

[0009] In summary, although the existing microchannel heat dissipation equipment has made some progress, it still has many shortcomings. Further research and optimization can effectively solve the uneven distribution of fluids, reduce pressure drop, and have a simple manufacturing process and low cost. Microchannel heat dissipation equipment has important practical significance. Summary of the invention

[0010] In order to solve the shortcomings of large temperature difference between the center and periphery of radial microchannels and large pressure drop at the inlet and outlet, the present invention provides a liquid-cooled radiator structure with an improved design. The heat dissipation device of this structure is conducive to fully utilizing the structural potential of radial microchannels, and its application can be expanded to scenarios such as single-phase liquid cooling and low pump power requirements.

[0011] To achieve the above object, the technical solution adopted by the present invention is: A radial microchannel heat sink with a manifold structure, comprising a microchannel cold plate layer, an annular manifold layer, a first fluid distribution layer, a second fluid distribution layer and a cover plate stacked in sequence, the connection surfaces of each layer are sealed, and a cooling medium inlet and a cooling medium outlet are provided on the cover plate; The second fluid distribution layer is provided with a central radial straight channel; the straight channel is divided into a liquid inlet channel and a liquid outlet channel, the liquid inlet channel is connected to the cooling medium inlet of the cover plate, and the liquid outlet channel is connected to the cooling medium outlet of the cover plate; The first fluid distribution layer is provided with a central radial circular hole channel; the central radial circular hole channel is radially aligned with the central radial straight channel of the second fluid distribution layer and is annularly aligned with the channel of the annular manifold layer; The inlet annular manifold and the outlet annular manifold of the annular manifold layer are arranged alternately; and the channel width of the radial microchannel cold plate layer gradually expands in the radial direction.

[0012] The present invention mainly improves the traditional radial microchannel and proposes a manifold radial microchannel structure. A manifold layer and a fluid distribution layer are added to the radial microchannel, which helps to distribute the fluid more evenly and obtain a lower pressure drop. At the same time, the characteristic of the radial microchannel structure of uniform flow distribution in the circumferential direction is retained, thereby achieving a more uniform temperature distribution and lower pump power consumption, improving the heat dissipation performance, and meeting the growing heat dissipation needs.

[0013] The straight channel ends of the second fluid distribution layer are connected to a circular cavity, which is aligned upward with the cooling medium inlet and outlet of the cover plate layer. This circular cavity can help distribute the fluid from the circular cooling medium inlet and outlet on the cover plate into the second fluid distribution layer.

[0014] In the straight channels of the second fluid distribution layer, liquid inlet channels and liquid outlet channels are arranged alternately, and all liquid inlet channels merge at the center.

[0015] A pin-fin array is provided in the central area of ​​the radial microchannel cold plate layer in the radial microchannel heat sink to enhance the heat dissipation effect of the central area.

[0016] The hole diameter of the circular hole channel of the first fluid distribution layer does not exceed the channel diameter of the annular manifold layer to which the circular hole is aligned, so as to ensure the separate flow of inlet and outlet fluids. The circular hole diameter needs to be reasonably set, the upper limit is the corresponding annular manifold width in the manifold layer, and the lower limit needs to be reasonably set. Too small circular hole diameter may lead to uneven fluid distribution and excessive flow pressure drop.

[0017] The circular hole structure of the first fluid distribution layer is replaced by an annular curved notch, the width of the notch does not exceed the width of the inlet and outlet manifolds in the annular manifold layer, and the spacing between the notches on the same annular ring is larger than the central radial straight channel in the second fluid distribution layer to ensure that the inlet and outlet fluids flow separately. Compared with the circular hole structure, the annular notch can further enhance the uniform distribution of the fluid.

[0018] The structures of the annular manifold layer, the first fluid distribution layer and the second fluid distribution layer are precisely optimized to ensure that the fluids maintain strict discreteness during the flow process, and to avoid the inlet fluid from intersecting or short-circuiting with the outlet fluid before entering the microchannel layer.

[0019] The channels of each layer in the radial microchannel heat sink are prepared by machining, additive manufacturing or micro-nano processing technology.

[0020] The annular manifold layer, the first fluid distribution layer and the second fluid distribution layer can be directly manufactured as a whole by an integrated molding process, such as additive manufacturing or integral milling. The integrated molding technology can reduce assembly steps, reduce interface thermal resistance, and improve mechanical stability and thermal management performance.

[0021] The preparation process includes: cleaning and removing impurities on the surface of the substrate, preparing microchannels through machining, additive manufacturing or micro-nano processing technology according to the designed microchannel structure and size, and then connecting and forming each layer through pressure silver sintering or bonding technology to obtain the radial microchannel heat sink.

[0022] The first feature of this production method is that for heat dissipation structures with a scale below 100 microns, microchannels can be prepared using micro-nano processing technology. Specifically, an etching mask can be obtained through photolithography-sputtering-stripping, and then deep reactive ion etching or wet etching can be performed. For materials with higher hardness, microchannels can also be prepared by laser processing.

[0023] The second feature of this production method is that the pressure silver sintering method has higher thermal conductivity, excellent mechanical properties and thermal stability than the traditional welding method, and low-temperature silver sintering can be completed at a lower temperature, reducing the thermal stress of power devices and avoiding damage caused by high-temperature welding.

[0024] The third feature of this manufacturing method is that for the bonding between semiconductor materials such as silicon, plasma bonding, eutectic bonding, thermal compression bonding, molecular bonding, etc. can be used. Different process methods can be selected according to the structure, material and application scenario of the heat sink.

[0025] The substrates of each layer in the radial microchannel heat sink are made of metal or transparent polymer material, and the channels are made of metal or semiconductor material; the materials of the substrates of each layer are the same or different, and the materials of the channels of each layer are the same or different.

[0026] The metal includes copper, aluminum and other metals, brass and other alloy materials or diamond copper and other metal-based composite materials; the semiconductor includes any one or more of silicon, silicon carbide, gallium nitride, gallium oxide or diamond; the transparent material includes one or more of glass, acrylic, polydimethylsiloxane (PDMS). The use of transparent materials makes it easy to observe the flow of the cooling medium.

[0027] The present invention also provides a radial micro-channel heat dissipation system with a manifold structure, comprising the radial micro-channel heat sink with a manifold structure.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention solves the problems of large temperature difference between the center and the periphery of the radial microchannel radiator and large inlet and outlet pressure drop. Through the structure of the annular manifold layer, the fluid is more evenly distributed, achieving more uniform temperature distribution and lower pump power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic exploded view of the structure of the radial microchannel heat sink with a manifold structure in the embodiment.

[0030] Figure 2 It is a front view of the integrally formed annular manifold layer and fluid distribution layer of the radial microchannel heat sink of the manifold structure in the embodiment.

[0031] Figure 3 It is a schematic diagram of the back side of the annular manifold layer and the fluid distribution layer integrally formed in the radial microchannel heat sink of the manifold structure in the embodiment.

[0032] Figure 4 Schematic diagram of the radial microchannel cold plate layer structure of the radial microchannel heat sink with a manifold structure in the embodiment.

[0033] Figure 5 Schematic diagram of the annular manifold layer structure of the radial microchannel radiator manifold structure in the embodiment.

[0034] Figure 6 Schematic diagram of the structure of the first fluid distribution layer of the radial microchannel radiator with a manifold structure in the embodiment.

[0035] Figure 7 Schematic diagram of the structure of the second fluid distribution layer of the radial microchannel radiator with a manifold structure in the embodiment.

[0036] Figure 8 It is a schematic diagram of the structure of the radial microchannel cold plate layer and the annular manifold layer of the radial microchannel heat sink with a manifold structure in the embodiment after being combined.

[0037] Fig. 9 Schematic diagram of the process flow for preparing the radial microchannel radiator with a manifold structure in the embodiment.

[0038] Fig.10 Schematic diagram of the structure of a traditional radial microchannel radiator in the comparative example.

[0039] Fig.11 This is a comparison chart of the simulated inlet and outlet pressure drops of the radial microchannel radiator with a manifold structure and the traditional radial microchannel radiator in the application example.

[0040] Fig.12 This is a comparison chart of the simulated chip surface temperature difference between the radial microchannel heat sink with a manifold structure and the traditional radial microchannel heat sink in the application example.

[0041] Fig.13 Schematic diagram of the replacement structure of the first fluid distribution layer of the radial microchannel heat sink with a manifold structure in the embodiment. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0043] The raw materials used in the following specific embodiments are all purchased from the market.

[0044] Example like Figure 1-Figure 3 As shown, a radial microchannel heat sink with a manifold structure comprises a radial microchannel cold plate layer 1, an annular manifold layer 2, a first fluid distribution layer 3, a second fluid distribution layer 4 and a cover plate 5 which are stacked in sequence, the connection surfaces of each layer are sealed, and a cooling medium inlet and a cooling medium outlet are provided on the cover plate 5; the microchannel cold plate layer adopts a copper-based cold plate, the microchannel width is 100 microns, the depth is 500 microns, and the total thickness of the cold plate layer is 1 mm.

[0045] like Figure 4-Figure 7 As shown, the second fluid distribution layer 4 has a central radial straight channel, and all the liquid inlet channels converge at the center; the straight channel is divided into a liquid inlet channel and a liquid outlet channel, which are arranged alternately; the liquid inlet channel is connected to the cooling medium inlet of the cover plate 5, and the liquid outlet channel is connected to the cooling medium outlet of the cover plate; the end of the straight channel of the second fluid distribution layer 4 is connected to a circular cavity, and the circular cavity is aligned upward with the cooling medium inlet and outlet of the cover plate layer. This circular cavity can help distribute the fluid from the circular cooling medium inlet and outlet on the cover plate into the second fluid distribution layer 4.

[0046] The first fluid distribution layer 3 has a central radial circular hole channel; the central radial circular hole channel is radially aligned with the central radial straight channel of the second fluid distribution layer, and is annularly aligned with the channel of the annular manifold layer; the hole diameter of the circular hole channel of the first fluid distribution layer does not exceed the channel diameter of the annular manifold layer to which the circular hole is aligned, so as to ensure the separate flow of inlet and outlet fluids.

[0047] The inlet annular manifold and the outlet annular manifold of the annular manifold layer 2 are arranged alternately; the channel width of the radial microchannel cold plate layer 1 gradually expands in the radial direction. Figure 8 As shown, a pin-fin array is provided in the central area of ​​the radial microchannel cold plate layer 1 to improve the heat exchange capacity of the central area.

[0048] according to Fig. 9 The preparation process uses picosecond laser etching to manufacture radial microchannel cold plate layers on copper metal substrates; the composite integrated substrate of annular manifold layer, first fluid distribution layer, and second fluid distribution layer is manufactured by milling machine processing, and the material is copper, collectively referred to as fluid distribution layer; firstly, the central radial straight channel and circular cavity shown in the second fluid distribution layer are processed on the front of the copper sheet, and then the copper sheet is opened at the circular hole or annular notch shown in the first fluid distribution layer. Finally, the annular manifold is processed on the front of the copper sheet at the manifold position corresponding to the annular manifold layer.

[0049] After the fluid distribution layer and the microchannel layer are manufactured, the metal surface of the radial microchannel cold plate layer is polished and pickled to remove impurities. Nano silver paste is printed on the upper surface of the radial microchannel cold plate layer and the bottom surface of the fluid distribution layer. The device is sintered into one piece using low-temperature silver sintering. Finally, a silicone gasket is used to seal the glass cover and the device.

[0050] The present invention mainly improves the traditional radial microchannel, adds a manifold layer and a fluid distribution layer, and after the fluid enters the cooling medium inlet of the cover plate, it passes through the liquid inlet channel of the second fluid distribution layer 4, is distributed into the first fluid distribution layer 3 and distributed into the annular manifold layer 2. The fluid expands in the annular manifold layer 2, enters the radial microchannel cold plate layer 1 downward, and then flows along the radial microchannel, moves to the bottom of the outlet annular manifold layer 2, moves upward to the outlet of the annular manifold layer, passes through the first fluid distribution layer 3 to the second fluid distribution layer 4 for collection, and flows out from the cooling medium outlet of the cover plate 5.

[0051] Comparative Example According to the above preparation process, prepare Fig.10 The radial microchannel cold plate layer cold plate shown is combined with a glass cover plate to obtain a conventional radial microchannel heat sink in the prior art, which is used as a comparative example to compare the heat dissipation effect. The microchannel size of the comparative example is consistent with that in the embodiment, with a microchannel width of 100 microns and a depth of 500 microns.

[0052] Application Examples Finite element simulation software ANSYS FLUENT was used to establish a simulation model for the microchannel radiator prepared according to the embodiment and the comparative example. During the simulation, a heat flux density was applied to the back of the microchannel layer to simulate the actual chip heating. The material property settings of the embodiment and the comparative example were consistent, the simulation model was consistent, the inlet cooling medium mass flow rate was consistent, and the size and heat flux density of the simulated heat source were consistent. The chip surface temperature difference is the difference between the highest temperature and the lowest temperature of the heat source surface. The inlet and outlet pressure drop is the difference between the average pressure of the liquid inlet and the average pressure of the liquid outlet.

[0053] The results are as follows Figure 11-Figure 12 The radial microchannel heat sink with manifold design in the present invention has significantly lower inlet and outlet pressure drop and chip surface temperature difference than the traditional radial microchannel heat sink.

[0054] In the present invention, the second fluid distribution layer can also be replaced by Fig.13 The annular curved slot shown, or other similar structure for distributing fluid.

[0055] Figure 1 The cover plate shown in has four inlets and four outlets, and the cover plate can also be further distributed to merge the four inlets and outlets into one inlet and one outlet or any number of inlets and outlets. An inlet can also be set in the center of the cover plate, which is aligned upward with the position where all the inlets in the second fluid distribution layer converge in the center.

Claims

1. A radial microchannel radiator with a manifold structure, characterized in that: It includes a radial microchannel cold plate layer, an annular manifold layer, a first fluid distribution layer, a second fluid distribution layer and a cover plate which are stacked in sequence, the connection surfaces of each layer are sealed, and a cooling medium inlet and a cooling medium outlet are arranged on the cover plate; The second fluid distribution layer is provided with a central radial straight channel; the straight channel is divided into a liquid inlet channel and a liquid outlet channel, the liquid inlet channel is connected to the cooling medium inlet of the cover plate, and the liquid outlet channel is connected to the cooling medium outlet of the cover plate; The first fluid distribution layer is provided with a central radial circular hole channel; the central radial circular hole channel is radially aligned with the central radial straight channel of the second fluid distribution layer and is annularly aligned with the channel of the annular manifold layer; The inlet annular manifold and the outlet annular manifold of the annular manifold layer are arranged alternately; and the channel width of the radial microchannel cold plate layer gradually expands in the radial direction.

2. The radial microchannel radiator of the manifold structure according to claim 1, characterized in that: The ends of the straight channels of the second fluid distribution layer are connected to the circular cavity, and the cooling medium inlet and outlet of the circular cavity and the cover plate layer are aligned upward.

3. The radial microchannel radiator of the manifold structure according to claim 1, characterized in that: In the straight channels of the second fluid distribution layer, liquid inlet channels and liquid outlet channels are arranged alternately, and all liquid inlet channels merge at the center.

4. The radial microchannel radiator of the manifold structure according to claim 1, characterized in that: A pin-fin array is provided in the central area of ​​the radial microchannel cold plate layer in the radial microchannel heat sink.

5. The radial microchannel radiator of the manifold structure according to claim 1, characterized in that: The hole diameter of the circular hole channel of the first fluid distribution layer does not exceed the channel diameter of the annular manifold layer with which the circular hole is aligned.

6. The radial microchannel heat sink of the manifold structure according to claim 1, characterized in that: The circular hole structure of the first fluid distribution layer is replaced by annular curved slots, the slot width does not exceed the width of the inlet and outlet manifolds in the annular manifold layer, and the spacing between the slots on the same circular ring is larger than the central radial straight channel in the second fluid distribution layer.

7. The radial microchannel radiator of the manifold structure according to claim 1, characterized in that: The channels of each layer in the radial microchannel heat sink are prepared by machining, additive manufacturing or micro-nano processing technology.

8. The radial microchannel heat sink of the manifold structure according to claim 1, characterized in that: The substrates of each layer in the radial microchannel heat sink are made of metal or transparent polymer material, and the channels are made of metal or semiconductor material; the materials of the substrates of each layer are the same or different, and the materials of the channels of each layer are the same or different.

9. The radial microchannel heat sink of the manifold structure according to claim 8, characterized in that: The metal includes a single metal, an alloy material or a metal-based composite material; the semiconductor includes any one or more of silicon, silicon carbide, gallium nitride, gallium oxide or diamond; the transparent material includes one or more of glass, acrylic, and polydimethylsiloxane.

10. A radial microchannel heat dissipation system with a manifold structure, characterized in that: A radial microchannel radiator comprising the manifold structure according to any one of claims 1 to 9.

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