Gradient interconnection micro-channel heat dissipation structure and preparation method thereof

Abstract

The invention discloses a gradient interconnection micro-channel heat dissipation structure and a preparation method thereof, and belongs to the technical field of circuit boards, the gradient interconnection micro-channel heat dissipation structure comprises an LTCC substrate, a shunting mechanism is embedded in the LTCC substrate, the shunting mechanism is connected with a gradient interconnection heat dissipation mechanism, and the gradient interconnection heat dissipation mechanism is connected with the LTCC substrate. The gradient micro-channel heat dissipation mechanism comprises a top-layer micro-channel and a bottom-layer micro-channel which are arranged up and down, at least one interconnected micro-channel is arranged between the top-layer micro-channel and the bottom-layer micro-channel, a disturbance part is arranged in the top-layer micro-channel, and a heat conduction mounting layer is arranged above the gradient micro-channel heat dissipation mechanism. Meanwhile, the invention discloses a preparation method of the structure, the top-layer micro-channel and the bottom-layer micro-channel which are arranged up and down and communicated with each other are arranged in the gradient micro-channel heat dissipation mechanism, the heat dissipation efficiency is improved, the requirement for efficient heat dissipation of the T / R assembly is met, a disturbance piece is additionally arranged on the top-layer micro-channel, convective heat transfer can be effectively enhanced, the heat dissipation effect is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and particularly to a gradient interconnected microchannel heat dissipation structure and a preparation method thereof. Background Art

[0002] Microchannel heat dissipation technology is an efficient heat dissipation method based on fluid flow. By designing micron-scale channels in a substrate or heat sink, heat can be quickly removed through the convective heat transfer of the fluid. This technology has the advantages of high heat dissipation efficiency, small size, and light weight, and is suitable for the thermal management of high-power density devices. However, traditional microchannel structures are usually relatively simple and difficult to cope with the problem of uneven heat distribution in T / R components (transmit / receive components).

[0003] When T / R components operate under high-frequency and high-power conditions, a large amount of heat is generated, especially in key components such as power amplifiers and RF switches. The accumulation of heat will cause the device temperature to rise, thereby affecting its performance, reliability, and lifespan. Traditional heat dissipation solutions, such as metal heat sinks and heat pipes, although can alleviate the heat dissipation problem to a certain extent, in high-power density and high-integration T / R components, their heat dissipation capacity has approached the limit.

[0004] Low-temperature co-fired ceramic (LTCC) substrate is a multi-layer substrate material widely used in high-frequency electronic devices, with good thermal conductivity, mechanical strength, and electrical properties. The LTCC substrate can achieve complex circuit layouts through a multi-layer structure and can integrate microchannel structures inside the substrate to achieve efficient heat dissipation. However, traditional LTCC substrate microchannel designs usually adopt simple straight-through channels and are difficult to meet the complex thermal management requirements in T / R components. Summary of the Invention

[0005] The purpose of the present invention is to provide a gradient interconnected microchannel heat dissipation structure and a preparation method thereof to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides a gradient interconnected microchannel heat dissipation structure, including an LTCC substrate. A flow splitting mechanism is embedded in the LTCC substrate, and the flow splitting mechanism is connected to a gradient interconnected heat dissipation mechanism. The gradient microchannel heat dissipation mechanism includes a top microchannel and a bottom microchannel arranged up and down. At least one interconnected microchannel is arranged between the top microchannel and the bottom microchannel. A disturbing member is arranged in the top microchannel, and a heat conduction mounting layer is arranged above the gradient microchannel heat dissipation mechanism.

[0007] Preferably, disturbing members are arranged at both the top and the bottom inside the top microchannel. The disturbing members at the top and the bottom are arranged in a mirror image and staggered manner, and the disturbing member at the lower part is arranged opposite to the heat-generating chip on the heat conduction mounting layer.

[0008] Preferably, the disturbing member is in an inclined cone structure, and the inclination angle of the liquid-facing surface of the inclined cone structure is 15°-60°.

[0009] Preferably, both the top and bottom of the bottom microchannel are wavy.

[0010] Preferably, a heat conduction column group is arranged on the heat conduction installation layer opposite to the heat generating chip. Each heat conduction column group includes at least one heat conduction column, and a heat conduction adhesive is arranged between the heat conduction column and the heat generating chip.

[0011] Preferably, the flow splitting mechanism includes two main channels. A number of groups of sub-channels are arranged on the main channels. Each group of sub-channels includes two sub-channels arranged up and down. The sub-channels arranged up and down are respectively connected to the top microchannel and the bottom microchannel. An inlet and an outlet are respectively arranged on the two main channels.

[0012] Preferably, the flow splitting mechanism is connected with a liquid supply mechanism. The liquid supply mechanism includes a liquid supply pump. The water outlet pipe of the liquid supply pump is connected to the inlet. The outlet is connected to a liquid storage tank through a recovery pipe. The water inlet pipe of the liquid supply pump is connected to the liquid storage tank. The heat dissipation fluid is a gas-liquid two-phase fluid.

[0013] A preparation method of a gradient interconnected microchannel heat dissipation structure based on the above-mentioned one, the specific steps are as follows:

[0014] Step S1: Prepare a green ceramic sheet according to the gradient interconnected microchannel heat dissipation structure, and determine the lamination sequence. Use the green ceramic sheet to laminate and press into an LTCC substrate with a flow splitting mechanism and a gradient interconnected heat dissipation mechanism.

[0015] Step S2: Arrange heat conduction columns in the heat conduction installation layer according to the installation position of the heat generating chip.

[0016] Step S3: Coat a heat conduction adhesive on the upper surface of the heat conduction installation layer at the position opposite to the heat generating chip, and install the heat generating chip on the upper surface of the heat conduction installation layer.

[0017] Therefore, the present invention adopts the above-mentioned gradient interconnected microchannel heat dissipation structure and its preparation method, and the beneficial effects are as follows:

[0018] (1) The present invention uses a heat conduction adhesive, heat conduction columns and a gradient microchannel heat dissipation mechanism for heat dissipation. Among them, the gradient microchannel heat dissipation mechanism is provided with a top microchannel and a bottom microchannel arranged up and down and communicating with each other, which improves the heat dissipation efficiency and meets the requirements of efficient heat dissipation of the T / R component.

[0019] (2) A disturbing member is added to the top microchannel, and the bottom microchannel adopts a wavy structure. The combination of the two structures can effectively enhance the convective heat transfer, improve the Nusselt coefficient of the T / R component, and improve the heat dissipation effect and reduce the cost.

[0020] (3) A thermal conductive adhesive and thermal conductive columns are provided between the gradient microchannel heat dissipation mechanism and the heat - generating chip, avoiding the problem of poor heat transfer performance caused by the low thermal conductivity of LTCC materials and effectively reducing the thermal resistance of the heat dissipation channels.

[0021] (4) The heat - dissipating fluid uses a gas - liquid two - phase fluid. When the heat - dissipating fluid passes under the heat source, the heat - dissipating fluid absorbs heat and heats up. The bubbles in the heat - dissipating fluid expand as the temperature rises, and the bubbles bounce periodically along the wall surface, strengthening the convective heat transfer by disturbing the boundary layer, improving the heat transfer efficiency of the microchannel while maintaining low cost.

[0022] The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a three - dimensional structure schematic diagram of a gradient - interconnected microchannel heat dissipation structure of the present invention;

[0024] Figure 2 It is a top view of a gradient - interconnected microchannel heat dissipation structure of the present invention;

[0025] Figure 3 It is an A - A cross - sectional view of a gradient - interconnected microchannel heat dissipation structure of the present invention;

[0026] Figure 4 It is a B - B cross - sectional view of a gradient - interconnected microchannel heat dissipation structure of the present invention;

[0027] Figure 5 It is Figure 2 a partial schematic diagram;

[0028] Figure 6 It is Figure 3 a partial schematic diagram;

[0029] Figure 7 It is a schematic diagram of the structure when the inclination angle of the liquid - facing surface of the inclined cone structure is 15°;

[0030] Figure 8 It is a schematic diagram of the structure when the inclination angle of the liquid - facing surface of the inclined cone structure is 30°;

[0031] Figure 9 It is a schematic diagram of the structure when the inclination angle of the liquid - facing surface of the inclined cone structure is 45°;

[0032] Figure 10 It is a schematic diagram of the structure when the inclination angle of the liquid - facing surface of the inclined cone structure is 60°;

[0033] Figure 11 It is a liquid - supply principle block diagram;

[0034] Figure 12Fluid simulation diagram when the inclination angle of the liquid-facing surface of the inclined cone structure is 30°;

[0035] Figure 13 Fluid simulation diagram when the inclination angle of the liquid-facing surface of the inclined cone structure is 45°.

[0036] Reference numerals

[0037] 1. LTCC substrate; 2. Shunt mechanism; 201. Main flow channel; 202. Sub-flow channel; 3. Bottom micro-channel; 4. Interconnecting micro-channel; 5. Top micro-channel; 501. Disturbing member; 6. Heat conducting column; 7. Liquid outlet; 9. Thermal conductive adhesive; 10. Heat generating chip; 11. Liquid inlet; 12. Liquid supply pump; 13. Liquid storage tank. Detailed implementation manners

[0038] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0039] The following will describe the implementation manners of the present invention in detail with reference to the drawings.

[0040] As Figure 1 shown, a gradient interconnect micro-channel 4 heat dissipation structure includes an LTCC substrate 1. As Figures 2 - 6 shown, a shunt mechanism 2 is embedded in the LTCC substrate 1. The shunt mechanism 2 is connected to a gradient interconnect heat dissipation mechanism. The gradient micro-channel heat dissipation mechanism includes a top micro-channel 5 and a bottom micro-channel 3 arranged up and down.

[0041] The shunt mechanism 2 includes two main flow channels 201. There are 8 groups of sub-flow channels 202 arranged on the main flow channels 201. Each group of sub-flow channels 202 includes two sub-flow channels 202 arranged up and down. The sub-flow channels 202 arranged up and down are respectively connected to the top micro-channel 5 and the bottom micro-channel 3. Liquid inlets 11 and liquid outlets 7 are respectively arranged on the two main flow channels 201. The shunt mechanism 2 is connected to a liquid supply mechanism. As Figure 11As shown in the figure, the liquid supply mechanism includes a liquid supply pump 12. The water outlet pipe of the liquid supply pump 12 is connected to the liquid inlet 11 through a liquid cooling connector. The liquid outlet 7 is connected to a liquid storage tank 13 through a recovery pipe. The water inlet pipe of the liquid supply pump 12 is connected to the liquid storage tank 13. The heat dissipation fluid is a gas-liquid two-phase fluid (multi-bubble liquid). The liquid supply pump 12 is started to perform forced heat dissipation on the heat dissipation fluid. The heat dissipation fluid flows in a gradient between the top microchannel 5 and the bottom microchannel 3 and flows out from the liquid outlet 7 and returns to the liquid storage tank 13. In order to realize the multi-bubble characteristics of the heat dissipation fluid, a bubble increasing device can also be added, such as a stirring or gas injection device, etc.

[0042] There are three interconnected microchannels 4 arranged between the top microchannel 5 and the bottom microchannel 3 to strengthen the fluid temperature transfer between layers, so that heat can be more evenly distributed throughout the substrate, strengthening the mixing of the fluid and making heat transfer more efficient. There are disturbing members 501 arranged in the top microchannel 5. There are disturbing members 501 arranged at both the top and the bottom in the top microchannel 5. The disturbing members 501 are of an inclined cone structure. The inclination angle of the liquid-facing surface of the inclined cone structure is 15°-60°. The disturbing members 501 at the top and the bottom are arranged in a mirror-image staggered manner. The disturbing member 501 at the lower part is arranged opposite to the heat-generating chip 10 on the heat-conducting installation layer, forming a serrated channel structure similar to a sawtooth. When the heat dissipation fluid passes through the disturbing member 501, the flow of the heat dissipation fluid will be disturbed along with the sawtooth structure, and the fluid velocity will have a discontinuous point to generate tiny turbulences, lengthening the residence heat transfer time of the heat dissipation fluid and improving the heat dissipation efficiency. The heat dissipation fluid adopts a multi-bubble fluid, and the bubbles in the heat dissipation fluid will continuously collide with the serrated wall surface, making the near-wall heat boundary layer in a continuous disturbed state, thereby strengthening the convective heat transfer. There is a heat-conducting installation layer above the gradient microchannel heat dissipation mechanism. In the technical solution of this embodiment, there are 8×8 heat-generating chips 10. There are 6 groups of heat-conducting columns arranged on the heat-conducting installation layer opposite to the heat-generating chips 10. Each group of 6 heat-conducting columns includes four heat-conducting columns 6 distributed in a matrix. The heat-conducting columns 6 can effectively reduce the substrate thermal resistance and improve the heat transfer efficiency. There is a heat-conducting adhesive 9 between the heat-conducting column 6 and the heat-generating chip 10. The heat-generating chip 10 generates heat as a heat source, and the heat is transferred downward to the heat-conducting adhesive 9. The heat-conducting adhesive 9 vertically transfers the heat downward through the heat-conducting column 6 into the top microchannel 5 for heat dissipation.

[0043] Both the top and the bottom in the bottom microchannel 3 are wavy. The wavy shape causes the heat dissipation fluid to generate rotation and eddies during the flow process, thereby dispersing the velocity of the heat dissipation fluid, reducing the fluid resistance, and further reducing the energy consumption. When the heat dissipation fluid passes through, it can significantly increase the surface area of the fluid in contact with the wall surface, thereby improving the heat transfer efficiency.

[0044] As Figures 7 - 10As shown in the figure, in this embodiment, in order to verify the heat transfer characteristics caused by different sawtooth structures in the sawtooth structure microchannel, four frustum cones with inclination angles of 15°, 30°, 45°, and 60° are selected to analyze the bubble bouncing motion of the multi-bubble fluid and the fluid flow trajectory. In the top microchannel with a periodic sawtooth structure, the multi-bubble fluid is used as the fluid medium, and the inertial limited flow passes over the surface of the sawtooth microstructure, generating periodic bubble bouncing motion to disturb the thermal boundary layer in the near-wall region. According to the inclination angle of the sawtooth structure. By performing numerical simulation, the fluid motion trajectory corresponding to the inclination angle is recorded. As Figures 12 - 13 shown, the simulation results are carried out for inclination angles of 30° and 45°. Different colors of the arrows in the figure represent different flow velocities, and the color represents the magnitude of the velocity. The distribution of the flow velocity from high to low can be reflected through the color scale range. At the same time, the size of the arrow also characterizes the magnitude of the flow velocity. The longer the arrow, the greater the flow velocity. By comparing the influence of the flow trajectory of the heat dissipation fluid and the bubble bouncing on heat dissipation in the sawtooth structures with different inclination angles, the backflow generated by the heat dissipation fluid with a 30° sawtooth inclination angle is more obvious, the number of collisions between the bubbles and the sawtooth wall surface is more, and its heat transfer efficiency is higher.

[0045] A preparation method for a heat dissipation structure of a gradient interconnected microchannel 4 is as follows:

[0046] Step S1: Use green ceramic sheets to laminate and press to form an LTCC substrate 1 with a flow splitting mechanism 2 and a gradient interconnected heat dissipation mechanism. Place the green ceramic sheets with printed circuit patterns and pre-drilled microchannel holes in a tight lamination mold in the preset number of layers and order. The mold is designed with alignment posts consistent with the alignment holes of the green ceramic sheets to ensure the alignment accuracy. Adopt the low-temperature co-fired ceramic process to tightly bond the laminated green ceramic sheets at the set temperature and pressure to form a complete multi-layer substrate blank. Make the lamination pressure evenly distributed on the green ceramic body through isostatic pressing to ensure consistent sintering shrinkage of the substrate and form an LTCC structure substrate that meets the requirements.

[0047] Step S2: Set heat conduction columns 6 in the heat conduction installation layer according to the installation position of the heat generating chip 10.

[0048] Step S3: Coat heat conduction glue 9 on the upper surface of the heat conduction installation layer at the position relative to the heat generating chip 10, and install the heat generating chip 10 on the upper surface of the heat conduction installation layer.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A gradient interconnected microchannel heat dissipation structure, including an LTCC substrate, characterized in that: The LTCC substrate is internally provided with a flow splitting mechanism, and the flow splitting mechanism is connected with a gradient interconnected heat dissipation mechanism. The gradient microchannel heat dissipation mechanism includes a top microchannel and a bottom microchannel arranged up and down. At least one interconnected microchannel is arranged between the top microchannel and the bottom microchannel. A disturbing member is arranged in the top microchannel, and a heat conduction mounting layer is arranged above the gradient microchannel heat dissipation mechanism.

2. The gradient interconnected microchannel heat dissipation structure according to claim 1, wherein: Disturbing members are arranged at both the top and the bottom in the top microchannel. The disturbing members at the top and the bottom are arranged in a mirror-image staggered manner, and the disturbing member at the lower part is arranged opposite to the heat-generating chip on the heat conduction mounting layer.

3. The gradient interconnected microchannel heat dissipation structure according to claim 2, characterized in that: The disturbing member is of an inclined cone structure, and the inclination angle of the liquid-facing surface of the inclined cone structure is 15°-60°.

4. The gradient interconnected microchannel heat dissipation structure according to claim 1, wherein: Both the top and the bottom in the bottom microchannel are wavy.

5. The gradient interconnected microchannel heat dissipation structure according to claim 1, wherein: Heat conduction columns are arranged on the heat conduction mounting layer opposite to the heat-generating chip. Each group of heat conduction columns includes at least one heat conduction column distributed in a matrix. A heat conduction adhesive is arranged between the heat conduction column and the heat-generating chip.

6. The gradient interconnected microchannel heat dissipation structure according to claim 1, characterized in that: The flow splitting mechanism includes two main channels. A number of groups of sub-channels are arranged on the main channels. Each group of sub-channels includes two sub-channels arranged up and down. The sub-channels arranged up and down are respectively connected with the top microchannel and the bottom microchannel. An inlet and an outlet are respectively arranged on the two main channels.

7. The gradient interconnected microchannel heat dissipation structure according to claim 1, characterized in that: The flow splitting mechanism is connected with a liquid supply mechanism. The liquid supply mechanism includes a liquid supply pump. The outlet pipe of the liquid supply pump is connected with the inlet. The outlet is connected with a liquid storage tank through a recovery pipe. The inlet pipe of the liquid supply pump is connected with the liquid storage tank. The heat dissipation fluid is a gas-liquid two-phase fluid.

8. A preparation method of a gradient interconnected microchannel heat dissipation structure according to any one of claims 1-7, characterized in that, The specific steps are as follows: Step S1: Prepare a green ceramic sheet according to the gradient interconnected microchannel heat dissipation structure, and determine the lamination sequence. The green ceramic sheet is laminated and pressed into an LTCC substrate with a flow splitting mechanism and a gradient interconnected heat dissipation mechanism. Step S2: Arrange heat conduction columns in the heat conduction mounting layer according to the installation position of the heat-generating chip. Step S3: Coat a heat conduction adhesive on the upper surface of the heat conduction mounting layer at the position opposite to the heat-generating chip, and install the heat-generating chip on the upper surface of the heat conduction mounting layer.

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