Composite radiator with microstructure and preparation method thereof
By incorporating microstructures and needle-fin composites inside the heat sink, and utilizing laser-assisted electrodeposition technology and ultrasonic transducer array modules, the problem of low convective heat transfer efficiency at the bottom of the heat sink substrate was solved, achieving a more efficient heat dissipation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUANGSHAN GUANGJIE SURFACE TREATMENT TECH CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-01
AI Technical Summary
In existing liquid cooling technologies for power modules, the convective heat transfer efficiency at the bottom of the heat dissipation substrate is low, making it difficult to effectively improve heat dissipation efficiency to cope with the thermal stress problem of highly integrated, high-power-density chips.
Microstructures and needle-fin composites are set inside the heat sink. By arranging teardrop-shaped and wave-shaped microstructures in the gaps between the needle fins, combined with laser-assisted electrodeposition technology and ultrasonic transducer array modules, high-precision molding and uniform deposition of microstructures are achieved, thereby enhancing fluid convection heat transfer.
It significantly improves the heat dissipation capacity of the radiator, increases the heat dissipation area and fluid turbulence, ensures that the heat of high power density modules is quickly dispersed, and improves the overall heat dissipation performance of the radiator.
Smart Images
Figure CN121969149A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a composite heat sink with microstructures and its preparation method, belonging to the field of power semiconductor packaging technology. Background Technology
[0002] As power semiconductors develop towards higher integration and higher power density, the temperature of the chips continues to rise during operation. The increase in thermal stress seriously affects the performance stability and service life of the chips. Therefore, it is urgent to improve heat dissipation efficiency to ensure the stable operation of power modules.
[0003] Existing liquid cooling technologies for power modules primarily utilize internal finned structures within the heatsink to increase the contact area with the cooling medium, dispersing and transferring heat from the chips on the substrate into the cooling medium for heat exchange. However, while a single finned structure can increase the heat transfer area, the low convective heat transfer efficiency at the bottom of the substrate remains a problem. Therefore, designing a composite heatsink combining microstructures and fins, with microstructures inside the heatsink to enhance fluid flow at the bottom of the substrate and improve convective heat transfer, is an effective solution to improve heat dissipation. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite heat sink with microstructure and its preparation method to achieve better heat dissipation effect.
[0005] This invention first provides a composite heat sink with microstructures, including a substrate and a cover plate. One side of the substrate has pin fins, and densely arranged microstructures are present in the gaps between the pin fins. The microstructures include teardrop-shaped microstructures and wave-shaped microstructures. The teardrop-shaped microstructures are the upper half of a rotating ellipsoid, and the minor radius of the rotating ellipsoid is perpendicular to the pin fin surface of the substrate. The cross-section of the wave-shaped microstructures is a wave pattern with pointed ends and equal width in the middle. The heat sink formed by connecting the cover plate and the substrate is a hollow closed structure. The pin fins and microstructures are located inside the closed structure. The cover plate has liquid inlets and liquid outlets at both ends.
[0006] Specifically, the cross-section of the needle wing can be circular, elliptical, rhomboid, or square.
[0007] Specifically, the microstructure has a height of 10-30 μm, the long radius of the teardrop-shaped microstructure is 30-90 μm, and the length of the wavy microstructure along the flow direction is 1-2 mm, and the width is 60-120 μm; the teardrop-shaped microstructure is distributed in the gap between the needle fins and the wavy microstructure.
[0008] The distance between the microstructure and the needle fin is 100-200 μm, and the distance between the microstructures is 80-160 μm.
[0009] The shape of the centerline of the cross-section of the wave-shaped microstructure can be a sine curve y=0.5sin(x).
[0010] The microstructure material can be Ni or a P-Ni alloy with a P content of 0-12%.
[0011] This invention also provides a method for preparing a composite heat sink with microstructures, comprising the following steps: Step 1: Draw the laser scanning motion path layer by layer based on the three-dimensional information of the microstructure to be formed. The laser scanning path of each layer of the microstructure is to first scan the interior in an "S" shape and then scan the boundary. Step 2: Cold forging a needle-fin structure on one side of the substrate, followed by pretreatment, including sandblasting, degreasing, and pickling activation; Step 3: Connect the positive terminal of the DC pulse power supply to the anode and the negative terminal to the substrate. Immerse the anode in the deposition solution. Fix the substrate with the pin fin side facing up on the worktable. Lower the worktable so that the bottom surface of the pin fins of the substrate is immersed in the deposition solution and 2-3 mm away from the liquid surface. Step 4: Turn on the DC pulse power supply and set the electrochemical parameters; Step 5: Turn on the transmitting transducer array module embedded in the worktable. The ultrasound is concentrated on the substrate to generate normal resonance, so that the composition of the thin layer of deposited liquid on the needle fin side of the substrate is uniform. Step Six: Turn off the transmitting transducer array module, turn on the laser, set the laser scanning parameters and scanning path, so that the laser beam emitted by the laser is reflected and focused and scans along the planned path. Utilize the local thermal effect of the laser to form microstructures layer by layer on the needle fin surface of the substrate. After each layer is processed, proceed to Step Five to use ultrasonic action to homogenize the composition of the deposition liquid. Steps Five and Six are performed alternately. Step 7: After the microstructure processing is completed, turn off the laser, lower the worktable until the entire substrate is completely immersed, adjust the electrochemical parameters, and perform overall electroplating on the substrate. During the electroplating process, turn on the emission transducer array module and intermittently perform ultrasonic treatment. Step 8: Post-process the substrate prepared in Step 7, including washing and drying; Step 9: Attach the cover plate and the base plate together to form a hollow composite heat sink structure.
[0012] Specifically, the laser is a pulsed laser with a wavelength of 1064 nm, a laser spot diameter of 5-10 μm, a laser power of 5-20 W, a scanning speed of 200-2000 mm / s, and a pulse frequency of 1-3 MHz.
[0013] Specifically, during the electroplating process in step seven, the transmitting transducer array module undergoes ultrasonic treatment once per minute for 1 second.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention increases the heat dissipation surface area by combining the microstructure on the heat dissipation substrate surface with the pin fin composite heat dissipation, ensuring that the heat sink can handle more heat in the same volume, and dispersing the heat of high power density modules into the cooling medium more quickly.
[0015] 2. The microstructures of the present invention are distributed in the gaps of the needle-fin array. The teardrop-shaped microstructures and wave-shaped microstructures enhance the fluid disorder on the surface of the heat dissipation substrate with a small flow resistance, thereby further improving the overall heat dissipation capacity of the heat sink.
[0016] 3. This invention utilizes the local thermal effect of laser to induce directional deposition to prepare microstructures, and employs transducer array ultrasound to ensure uniform composition within the processed thin layer region. By adjusting the electrochemical and laser parameters, and in conjunction with the worktable, precise control of local electrodeposition can be achieved. Attached Figure Description
[0017] Figure 1 Schematic diagram of the cover plate and cooling fluid inlet / outlet; Figure 2 This is a partial schematic diagram of the internal space of the radiator; Figure 3 Top view, front view and enlarged view of microstructure and needle fin distribution; Figure 4 Top view and front view of the teardrop-shaped microstructure; Figure 5 Top view and front view of the wavy microstructure; Figure 6 A schematic diagram illustrating the principle of laser-assisted electrodeposition for fabricating microstructures; Figure 7 A schematic diagram of the working state of the overall electroplating process of the substrate; Figure 8 This is a schematic diagram of the laser scanning path; Figure 9 This is a schematic diagram of the distribution of the transmitting transducer array.
[0018] Reference numerals: 1. Cover plate; 2. Substrate; 3. Inner channel; 4. Laser; 5. Anode; 6. Worktable; 7. Transmitter array module; 8. Transmitter; 9. Worktable lifting device; 11. Liquid inlet; 12. Liquid outlet; 21. Needle fin; 22. Teardrop-shaped microstructure; 23. Wave-shaped microstructure. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0020] In a typical embodiment of the present invention, such as Figure 1-5As shown, a heat sink combining microstructures and pin fins is proposed, comprising a cover plate 1 and a substrate 2. The heat sink formed by connecting the cover plate 1 and the substrate 2 is a hollow, closed structure. The cover plate 1 has an inlet 11 and an outlet 12 at both ends. Teardrop-shaped microstructures 22 and wave-shaped microstructures 23 are mixed with pin fins 21 and distributed on the upper surface of the substrate 2. The pin fins 21 are arranged vertically and alternately on the substrate, and the microstructures are densely arranged in the gaps between the pin fins 21.
[0021] The cross-section of the needle fin 21 can be circular, elliptical, rhomboid, or square. The teardrop-shaped microstructure 22 is the upper half of a rotating ellipsoid, with the minor radius of the rotating ellipsoid perpendicular to the needle fin surface of the substrate, such as... Figure 4 As shown. The cross-section of the wavy microstructure 23 is a wavy pattern with pointed ends and equal width in the middle, as illustrated. Figure 5 As shown. In this embodiment, all teardrop-shaped microstructures 22 are the same size, and the shape of the center line of the cross-section of the wavy microstructure 23 adopts a sine curve y=0.5sin(x). The needle fins 21 are formed by forging, while the teardrop-shaped microstructures 22 and the wavy microstructures 23 are formed by laser-assisted electrodeposition technology. The material of the microstructures is Ni or a P-Ni alloy with a P content of 0-12%.
[0022] In this embodiment, the needle fin 21 has a height of 4-8 mm, and its cross-section is elliptical with a major axis of 2 mm and a minor axis of 1 mm. The gap between the needle fins is 2 mm along the major axis and 1 mm along the minor axis. The heights of the two microstructures are 10-30 μm. The teardrop-shaped microstructure 22 has a major radius r of 30-90 μm, and the wavy microstructure 23 has a length of 1-2 mm and a width of 60-120 μm along the flow direction. Figure 3 As shown, teardrop-shaped microstructures 22 are distributed in the gap between the needle fins 21 and the wave-shaped microstructures 23. The distance between the microstructures and the needle fins 21 is 100-200 μm, and the distance between the microstructures is 80-160 μm.
[0023] The working principle of the composite heat sink structure applied to the power module described above is as follows: Reference Figure 1-2 The heat sink, which is formed by connecting the cover plate 1 and the substrate 2, is a hollow, closed structure. The liquid inlet 11 and the liquid outlet 12 are circular and symmetrically arranged on both sides of the cover plate 1. The upper surface of the substrate 2 is provided with needle fins 21, teardrop-shaped microstructures 22 and wave-shaped microstructures 23. The cooling fluid enters the heat sink through the liquid inlet 11, undergoes heat exchange in the inner channel 3 with needle fins 21 and microstructures, and then flows out through the liquid outlet 12. The heat generated by the chip soldered to the back of the substrate 2 is discharged through the flowing cooling medium.
[0024] First, the needle fins 21, in conjunction with the microstructures, increase the contact area between the fluid and the heat dissipation substrate 2, dispersing the heat from the chip on the substrate 2 into the fluid more quickly. On the other hand, when the fluid flows through the needle fins 21, it encounters resistance, separating from both sides of the needle fins and creating disturbance at the rear end, enhancing the convection effect of the fluid within the channel. The fluid separated on both sides of the needle fins and the chaotic fluid at the rear end further change their flow direction upon encountering the microstructures, increasing the turbulence of the fluid on the substrate 2 surface, resulting in stronger heat exchange and improved heat dissipation. Since the teardrop-shaped microstructures 22 and the wave-shaped microstructures 23 are located on the surface of the substrate 2, closer to the heat source, the microstructures further enhance the heat dissipation performance of the substrate surface. Moreover, the teardrop and wave-shaped designs have lower flow resistance, which is beneficial for balancing the temperature and velocity fields of the fluid within the channel.
[0025] This invention also provides a method for fabricating the microstructure of the aforementioned composite heat sink. Since laser radiation causes a localized temperature increase, accelerates the diffusion of solution particles, and improves the electrodeposition rate, the higher the laser power and the smaller the spot diameter, the higher the temperature rise, which is beneficial for achieving high-precision directional deposition. Based on this principle, as... Figure 6 , 7 As shown, the specific steps of the preparation method used in this invention are as follows: 1. Based on the three-dimensional information of the microstructure to be formed, the laser scanning motion path is drawn layer by layer. The laser scanning path for each layer of the microstructure is an S-shaped internal scan followed by a boundary scan, such as... Figure 8 As shown.
[0026] 2. The needle-fin structure is cold-forged on the substrate. The cold-forged substrate 2 with needle fins is pre-treated, including sandblasting, degreasing and pickling activation.
[0027] 3. For example Figure 6 As shown, the anode 5 is immersed in the deposition solution. The positive terminal of the DC pulse power supply is connected to the anode 5, and the negative terminal is connected to the substrate 2. The substrate 2 is fixed on the worktable 6 with the pin fins facing upward. The worktable 6 is lowered so that the bottom surface of the pin fins of the substrate is immersed and the distance from the liquid surface is 2-3 mm. 4. Turn on the DC pulse power supply and set the electrochemical parameters, such as voltage and current density.
[0028] 5. Turn on the transmitting transducer array module 7 embedded in the worktable 6. The transmitting transducer array module 7 is embedded on the side of the worktable near the substrate 2. It is similar in size to the substrate 2. The length and width of the transmitting transducer array module 7 are no more than 2mm different from the substrate 2 in the same direction. The substrate 2 is fixed to the transmitting transducer array module 7. The ultrasonic waves are concentrated on the substrate 2 to generate normal resonance, so that the composition of the thin layer of deposited liquid near the needle fin side of the substrate is uniform.
[0029] 6. Turn off the transmitting transducer array module 7, turn on the laser 4, and set the laser scanning parameters, including laser power, spot diameter, scanning speed, scanning path, pulse frequency, etc., so that the laser beam emitted by the laser 4 is reflected and focused and scans along the planned path. The local thermal effect of the laser is used to form microstructures layer by layer on the needle fin surface of the substrate. After each layer is processed, there is a 1-second interval before entering step five, where ultrasonic action is used to homogenize the composition of the deposition liquid. In this way, step six laser processing and step five ultrasonic action are performed alternately.
[0030] In this embodiment, the laser is a pulsed laser with a wavelength of 1064 nm, a spot diameter of 5-10 μm, a power of 5-20 W, a scanning speed of 200-2000 mm / s, and a pulse frequency of 1-3 MHz.
[0031] 7. After the teardrop-shaped microstructure 22 and the wave-shaped microstructure 23 are processed, the laser 4 is turned off, and the worktable is lowered until the entire substrate is completely immersed. Figure 7 As shown, the electrochemical parameters were adjusted to perform overall electroplating on the substrate 2. In this embodiment, the transmitting transducer array module 7 was subjected to ultrasonic treatment once per minute during the electroplating process, with a treatment duration of 1 second.
[0032] 8. Post-process the prepared substrate 2, including washing and drying.
[0033] 9. Fasten and install the cover plate 1 and the base plate 2 to form a hollow composite heat sink structure.
[0034] like Figure 9 As shown, in the transmitter transducer array module 7 used in the embodiment, there are 5-13 transmitter transducers 8, which are uniformly distributed in an X-shape. The frequency of a single transducer is 1-35 KHz and the power is 10-30W.
[0035] This invention achieves directional high-precision microstructure molding through laser-assisted electrodeposition, and uses a transducer array to generate normal resonance to achieve deposition and homogenize the composition. The heat transfer area is increased by setting surface microstructures and pin fins. At the same time, when the cooling fluid flows through the microstructure, the convective heat transfer effect of the fluid near the substrate is enhanced. The synergistic effect with the pin fin turbulence changes the flow state of the fluid and improves the heat dissipation capacity of the heat sink.
[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A composite heat sink with microstructures, comprising a substrate and a cover plate, characterized in that: One side of the substrate has needle-like fins, and densely arranged microstructures are present in the gaps between the needle-like fins. The microstructures include teardrop-shaped microstructures and wave-shaped microstructures. The teardrop-shaped microstructure is the upper half of a rotating ellipsoid, and the short radius of the rotating ellipsoid is perpendicular to the needle-like fin surface of the substrate. The cross-section of the wave-shaped microstructure is a wave pattern with pointed ends and equal width in the middle. The heat sink, which is composed of a cover plate and a base plate, is a hollow, closed structure. The needle fins and microstructures are located inside the closed structure, and the cover plate has an inlet and an outlet at both ends.
2. The composite heat sink with microstructure according to claim 1, characterized in that: The cross-section of the needle fin is circular, elliptical, rhomboid, or square.
3. The composite heat sink with microstructure according to claim 1, characterized in that: The microstructure has a height of 10-30 μm, the long radius of the teardrop-shaped microstructure is 30-90 μm, and the length of the wavy microstructure along the flow direction is 1-2 mm and the width is 60-120 μm; the teardrop-shaped microstructure is distributed in the gap between the needle fin and the wavy microstructure.
4. The composite heat sink with microstructure according to claim 1, characterized in that: The distance between the microstructure and the needle fin is 100-200 μm, and the distance between the microstructures is 80-160 μm.
5. The composite heat sink with microstructure according to claim 1, characterized in that: The shape of the centerline of the cross-section of the wave-shaped microstructure is a sine curve y=0.5sin(x).
6. The composite heat sink with microstructure according to claim 1, characterized in that: The microstructure material is Ni or a P-Ni alloy with a P content of 0-12%.
7. The method for preparing a composite heat sink with microstructures as described in claim 1, characterized in that, Includes the following steps: Step 1: Draw the laser scanning motion path layer by layer based on the three-dimensional information of the microstructure to be formed. The laser scanning path of each layer of the microstructure is to first scan the interior in an "S" shape and then scan the boundary. Step 2: Cold forging a needle-fin structure on one side of the substrate, followed by pretreatment, including sandblasting, degreasing, and pickling activation; Step 3: Connect the positive terminal of the DC pulse power supply to the anode and the negative terminal to the substrate. Immerse the anode in the deposition solution. Fix the substrate with the pin fin side facing up on the worktable. Lower the worktable so that the bottom surface of the pin fins of the substrate is immersed in the deposition solution and 2-3 mm away from the liquid surface. Step 4: Turn on the DC pulse power supply and set the electrochemical parameters; Step 5: Turn on the transmitting transducer array module embedded in the worktable. The concentrated ultrasonic waves act on the substrate to generate normal resonance, making the composition of the thin layer of deposited liquid on the needle-fin side of the substrate uniform. Step Six: Turn off the transmitting transducer array module, turn on the laser, set the laser scanning parameters and scanning path, so that the laser beam emitted by the laser is reflected and focused and scans along the planned path. Utilize the local thermal effect of the laser to form microstructures layer by layer on the needle fin surface of the substrate. After each layer is processed, proceed to Step Five to use ultrasonic action to homogenize the composition of the deposition liquid. Steps Five and Six are performed alternately. Step 7: After the microstructure processing is completed, turn off the laser, lower the worktable until the entire substrate is completely immersed, adjust the electrochemical parameters, and perform overall electroplating on the substrate. During the electroplating process, turn on the emission transducer array module and intermittently perform ultrasonic treatment. Step 8: Post-process the substrate prepared in Step 7, including washing and drying; Step 9: Attach the cover plate and the base plate together to form a hollow composite heat sink structure.
8. The method for preparing a composite heat sink with microstructures as described in claim 7, characterized in that, The laser is a pulsed laser with a wavelength of 1064 nm, a laser spot diameter of 5-10 μm, a laser power of 5-20 W, a scanning speed of 200-2000 mm / s, and a pulse frequency of 1-3 MHz.
9. The method for preparing a composite heat sink with microstructures as described in claim 7, characterized in that, During the electroplating process in step seven, the transmitting transducer array module undergoes ultrasonic treatment once per minute for 1 second.