Liquid-cooled ceramic substrate with embedded micro-nano structure and manufacturing method of liquid-cooled ceramic substrate

Abstract

The invention provides a liquid-cooled ceramic substrate with an embedded micro-nano structure and a manufacturing method thereof, and belongs to the field of semiconductor device packaging, and the manufacturing method comprises the following steps: processing a micro-groove on one side of a metal plate, and electroplating a first copper micro-nano structure film on the inner wall of the micro-groove; electroplating a second copper micro-nano structure film on the first metal layer of the ceramic substrate at a position corresponding to the micro groove; the shape of the second copper micro-nano structure film is matched with the shape of the opening side of the micro groove at the corresponding position; a first metal layer and a second metal layer are respectively arranged on two opposite sides of the ceramic substrate; the second copper micro-nano structure film is aligned and attached to the opening side of the micro groove, and the first metal layer and the metal plate are welded into a whole; and performing electrical interconnection and encapsulation process treatment on the power chip and the second metal layer. A traditional thermal interface material and a metal bottom plate are not needed, the process is simple, and a heat transfer path is shortened; the copper micro-nano structure on the inner wall of the micro-channel can increase the heat exchange coefficient of a solid-liquid interface and improve the overall heat dissipation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device packaging technology, and more specifically, relates to a liquid-cooled ceramic substrate with embedded micro-nano structures and its manufacturing method. Background Technology

[0002] Traditional heat dissipation technologies for semiconductor power chips mainly include air cooling and water cooling. Air cooling, with its core fin-fan combination, relies on forced convection to remove heat from the power chip surface. It is simple in structure and low in cost, and has been widely used in consumer electronics, low-voltage power chips, and early electric vehicle inverters. Microchannel liquid cooling technology has been applied in high-performance computing, laser diodes, RF power amplifiers, and electric vehicle power chips. Microchannel liquid cooling primarily involves fabricating millimeter-to-submillimeter scale flow channels within a traditional metal substrate to form a liquid cooler. A thermal interface material is then used to connect the liquid cooler to the heat source of the power chip, leveraging the high surface area-to-volume ratio at a small scale and the forced convection mechanism to achieve rapid heat removal.

[0003] Existing liquid coolers mostly focus on designing and optimizing the configuration of microchannels, such as developing various configurations like single serpentine, double serpentine, stepped cavity, and biomimetic fractal. However, they do not fully consider the influence of the heat transfer coefficient and contact area between the fluid and the channel wall in the microchannel, resulting in the heat dissipation capacity of existing liquid coolers still needing improvement.

[0004] In addition, existing liquid coolers and power chips are usually manufactured separately, and then the liquid cooler and power chip are packaged and integrated using thermal interface materials. This results in a long heat transfer path from the power chip to the liquid cooler, and the thermal interface material has low thermal conductivity, which leads to low overall heat dissipation efficiency. This makes it difficult to meet the heat dissipation requirements of high heat flux density and seriously affects heat dissipation efficiency and chip junction temperature. Summary of the Invention

[0005] The purpose of this invention is to provide a liquid-cooled ceramic substrate with embedded micro / nano structures and its manufacturing method. This allows for efficient heat dissipation through near-hot spots, while simultaneously increasing the solid-liquid interface heat transfer coefficient by electroplating a copper micro / nano structure thin film layer on the inner wall of the microchannels, thereby improving heat transfer capacity and achieving efficient thermal management of power chips. This addresses the technical problems of long heat transfer paths and low overall heat dissipation efficiency in existing liquid-cooled power chips. The liquid-cooled ceramic substrate with embedded micro / nano structures of this invention has the advantages of high heat dissipation efficiency and high integration.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures, comprising the following steps:

[0007] Microgrooves are fabricated on one side of a metal plate, and a first copper micro / nano structure film is electroplated on the inner wall of the microgrooves.

[0008] A second copper micro / nano structure film is electroplated on the first metal layer of the ceramic substrate at a position corresponding to the micro trench; the shape of the second copper micro / nano structure film matches the shape of the open side of the micro trench at the corresponding position; the first metal layer and the second metal layer are respectively provided on opposite sides of the ceramic substrate.

[0009] The second copper micro / nano structure film is aligned and bonded to the open side of the micro trench, and the first metal layer is welded to the metal plate to form a liquid-cooled ceramic substrate.

[0010] The power chip is electrically interconnected with the second metal layer and encapsulated to complete the power module packaging.

[0011] Furthermore, the ceramic substrate includes, but is not limited to, DBC ceramic substrate, AMB ceramic substrate, direct electroplated copper ceramic substrate, and metal-ceramic diffusion soldering ceramic substrate; the thickness of the first metal layer and the second metal layer is 100-500 μm.

[0012] Furthermore, the electroplating conditions for the first copper micro / nanostructure film and the second copper micro / nanostructure film are as follows: the electrolyte is 0.2-0.6 M CuSO4 and 0.5-1.0 M H2SO4, the distance between electrodes is 2-10 cm, and an electrode plating temperature of 1-3 A / cm is applied at room temperature. 2 A constant current density was maintained, and the deposition time was 10-60 s.

[0013] Furthermore, the types of microgrooves include, but are not limited to, straight-through, serpentine, branched, or arrayed types. The microgrooves include interconnected inlet channels, multiple spaced-apart branch channels, and outlet channels. The depth of the microgrooves is 2-10 mm, the width of each branch channel is 0.5-5 mm, and the spacing between adjacent branch channels is 0.5-2 mm.

[0014] Furthermore, the distance from the inlet of the inlet channel to the branch channel is greater than the distance from the outlet of the outlet channel to the branch channel.

[0015] Furthermore, the method includes the following steps: before electroplating the first copper micro / nano structure film and the second copper micro / nano structure film, the surfaces of the micro trenches and the first metal layer are ultrasonically cleaned and activated, and then washed with water and dried.

[0016] Furthermore, the ultrasonic cleaning and activation step is as follows: first ultrasonic cleaning with acetone, followed by ultrasonic cleaning with 0.05-0.2 M HCl solution.

[0017] Furthermore, the method also includes the following steps: machining through holes at both ends of the metal plate, wherein the through holes are connected to the microgrooves.

[0018] Furthermore, the microgroove processing methods include, but are not limited to, micromilling, photolithography, laser ablation, and wet etching.

[0019] Furthermore, the electrical interconnection includes the following steps: printing solder onto the second metal layer, then mounting the power chip onto the solder printing location, and holding it at a temperature of 180-300℃ and a pressure of 0-20 MPa for 5-60 minutes to complete the electrical connection.

[0020] A second aspect of the present invention provides a liquid-cooled ceramic substrate with embedded micro / nano structures obtained by the manufacturing method described above, comprising:

[0021] A metal plate with microgrooves on one side, the inner wall of which is electroplated with a first copper micro / nano structure film;

[0022] A ceramic substrate is sealed onto the microtrench; a first metal layer and a second metal layer are provided on opposite sides of the ceramic substrate; a second copper micro / nano structure film is electroplated on the first metal layer at a position corresponding to the microtrench; the shape of the second copper micro / nano structure film matches the shape of the open side of the microtrench at its corresponding position; the second copper micro / nano structure film is aligned and bonded to the open side of the microtrench; and...

[0023] The power chip is electrically connected to the second metal layer and encapsulated.

[0024] Compared with the prior art, the present invention has the following technical effects:

[0025] The present invention discloses a method for manufacturing a liquid-cooled ceramic substrate with embedded micro-nano structures. This method uses only the ceramic substrate as an intermediary connecting the metal plate and the power chip, achieving integrated manufacturing of the liquid cooler and the power chip. The heat generated by the power chip is directly transferred to the liquid-cooled channels within the metal plate through the ceramic substrate for efficient solid-liquid heat exchange. This eliminates the need for traditional thermal interface materials and metal base plates, simplifying the process and shortening the heat transfer path, thus enabling rapid heat dissipation near hot spots. Simultaneously, the first copper micro-nano structure film on the inner wall of the micro-groove and the second copper micro-nano structure film on the ceramic substrate together form the inner wall of the microchannel. The copper micro-nano structure effectively expands the contact area between the fluid and the inner wall of the microchannel and triggers local turbulence, increasing the solid-liquid interface heat transfer coefficient and thereby improving overall heat dissipation efficiency, achieving efficient heat dissipation of the power chip.

[0026] The present invention discloses a liquid-cooled ceramic substrate with embedded micro-nano structures in which the metal plate and the power chip share a single ceramic substrate. The first metal layer of the ceramic substrate forms one sidewall of the microfluidic channel. The ceramic substrate and the metal plate are integrated as a single unit. The heat generated by the power chip can directly reach the coolant in the metal plate without passing through traditional low thermal conductivity interface materials, achieving efficient heat dissipation near the hot spot. At the same time, a copper micro-nano structure thin film layer is electroplated on the inner wall of the microfluidic channel, which effectively expands the contact area between the fluid in the microfluidic channel and the inner wall of the microfluidic channel and triggers local turbulence, increasing the heat transfer coefficient at the solid-liquid interface and achieving efficient heat dissipation of the power chip. It has the advantages of high heat dissipation efficiency and high integration. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall cross-sectional structure of a liquid-cooled ceramic substrate with embedded micro / nano structures provided in an embodiment of the present invention.

[0029] Figure 2 for Figure 1 A magnified schematic diagram of a single branch flow channel in the middle;

[0030] Figure 3 for Figure 1 Schematic diagram of the structure of the metal plate in the middle;

[0031] Figure 4 for Figure 3 A top-view structural diagram.

[0032] In the figure, the attached figures are labeled as follows:

[0033] 1. Power chip, 2. Solder, 3. Ceramic substrate, 4. Branch channel, 5. First copper micro / nano structure film, 6. Metal plate, 7. Second copper micro / nano structure film, 8. Inlet channel, 9. Outlet channel, 10. Through hole. Detailed Implementation

[0034] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0035] In this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0036] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] The terms "first" and "second" are used for descriptive purposes only to distinguish objects from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of the present invention, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0038] This invention provides a liquid-cooled ceramic substrate with embedded micro / nano structures and a method for manufacturing the same. The structure of the liquid-cooled ceramic substrate with embedded micro / nano structures is as follows: Figure 1-4 As shown, the method for manufacturing this liquid-cooled ceramic substrate with embedded micro / nano structures includes the following steps:

[0039] S1. Microgrooves are processed on one side of the metal plate 6, and a first copper micro-nano structure film 5 is electroplated on the inner wall of the microgrooves.

[0040] S2. A second copper micro / nano structure film 7 is electroplated on the first metal layer of the ceramic substrate 3 at the position corresponding to the micro trench. The shape of the second copper micro / nano structure film 7 matches the shape of the open side of the micro trench at the corresponding position, so that the second copper micro / nano structure film 7 can be sealed and covered on the open side of the micro trench. The ceramic substrate 3 has a first metal layer and a second metal layer on opposite sides respectively.

[0041] S3. Align and attach the second copper micro-nano structure film 7 on the first metal layer of the ceramic substrate 3 with the open side of the micro-groove of the metal plate 6, and weld the first metal layer of the ceramic substrate 3 and the metal plate 6 together to form a liquid-cooled ceramic substrate.

[0042] S4. Electrically interconnect and potting process the power chip 1 and the second metal layer of the ceramic substrate 3 to complete the power module packaging.

[0043] In step S1 above, the metal plate 6 can be made of copper alloy, and the microgrooves are used as the main channels for coolant flow. The processing method can be any one of micromilling, photolithography, laser ablation, or wet etching.

[0044] The types of microchannels include, but are not limited to, straight-through, serpentine, branched, or arrayed types. Preferably, the microchannel is a straight-through type, comprising an interconnected inlet channel 8, multiple spaced-apart branch channels 4, and an outlet channel 9; the depth of the microchannel is 2-10 mm, the width of each branch channel 4 is 0.5-5 mm, and the spacing between adjacent branch channels 4 is 0.5-2 mm. Straight-through microchannels have advantages such as simple processing, low fluid resistance, and uniform coolant flow. Furthermore, straight-through channels have lower pressure drop and shorter coolant residence time at the bottom of the power chip 1, effectively preventing localized overheating.

[0045] More preferably, the distance from the inlet of the inlet channel 8 to the branch channel 4 is greater than the distance from the outlet of the outlet channel 9 to the branch channel 4, such as... Figure 4 As shown, this facilitates the flow of coolant into multiple branch channels 4 after it enters the inlet channel 8.

[0046] In step S2 above, the ceramic substrate 3 includes a ceramic base plate and metal layers (a first metal layer and a second metal layer) connected to the upper and lower sides of the ceramic base plate. Preferably, a DBC (Direct Bonded Copper) ceramic substrate is used as the ceramic substrate 3. Alternatively, an AMB (Active Metal Brazing) ceramic substrate, a direct electroplated copper ceramic substrate, or a metal-ceramic diffusion bonding (TLP bonding) ceramic substrate can be selected. The metal-ceramic diffusion bonding ceramic substrate achieves dense bonding between the metal layer and the ceramic through interdiffusion systems such as Cu / Sn / Cu, Ag / Sn, and Ag / In at 250-350℃. The diffusion bonding ceramic substrate is compatible with various metal layers (such as Cu, Ag, Cu-Ni alloys, Cu-Mo, etc.) and can achieve higher mechanical strength and heat dissipation capacity by thickening the metal layers. Generally, the thickness of the first and second metal layers on the upper and lower sides of the ceramic substrate 3 is 100-500 μm, which provides sufficient mechanical strength and meets good heat dissipation requirements.

[0047] In steps S1 and S2 above, the electroplating conditions for the first copper micro / nanostructure film 5 and the second copper micro / nanostructure film 7 are as follows: the electrolyte is 0.2-0.6 M CuSO4 and 0.5-1.0 M H2SO4, the distance between electrodes is 2-10 cm, and an application rate of 1-3 A / cm is applied at room temperature. 2A constant current density was applied, and the deposition time was 10-60 s. After electroplating, the cathode was removed, rinsed with deionized water, and dried with nitrogen.

[0048] In this embodiment of the invention, electrolyte concentration, current density, and deposition time are key factors affecting the microstructure. If the CuSO4 concentration in the electrolyte is too low, insufficient copper ion supply may lead to discontinuous and fragile structures; if the CuSO4 concentration is too high, deposition may be too rapid, forming an overly dense deposition layer rather than a micro / nano structure. If the H2SO4 concentration is too low, the solution conductivity is poor, thereby inhibiting electroplating and preventing the formation of micro / nano structures; if the H2SO4 concentration is too high, it may exacerbate the chemical dissolution of the substrate and deposition layer (especially when the power is off), and may alter the electrocrystallization kinetics. Excessively high or low H2SO4 concentrations will either excessively exacerbate or inhibit electroplating, preventing the formation of ideal micro / nano structures. Regarding current density, if the current density is too low (e.g., <1 A / cm²), the electroplating chemical reaction rate is slow, the hydrogen evolution rate is too slow, the number of bubbles generated is small and the size is large, making it impossible to form dense, fine bubble templates and thus failing to form good micro / nano structures, potentially resulting in a near-dense, nodular copper layer. If the current density is too high (e.g., >3 A / cm²), the deposit may be loose and have poor adhesion. Simultaneously, vigorous hydrogen evolution may cause the formation of micro / nano structures to be disrupted by the gas flow, making it difficult to form a complete and continuous micro / nano structure film. Regarding deposition time, if the deposition time is too short, the deposited micro / nano structure layer will be too thin, and the structure may be incomplete and discontinuous. If the deposition time is too long, the micro / nano structure will become sparse due to overgrowth, significantly reducing the capillary pressure driving the rapid spread of the liquid. Furthermore, the electrode spacing also affects the electroplating of micro / nano structures. Too close a distance may lead to uneven electric field distribution and enhanced edge effects, resulting in uneven thickness of the deposited micro / nano structure, or even short circuits caused by the micro / nano structure touching the anode during growth. Too far a distance increases solution resistance and energy loss, requiring a higher voltage to maintain the same current density.

[0049] Preferably, the manufacturing method of this embodiment further includes the following step S5: before electroplating the first copper micro / nano structure film 5 and the second copper micro / nano structure film 7, the surfaces of the microgrooves on the metal plate 6 and the first metal layer on the ceramic substrate 3 are ultrasonically cleaned and activated, then washed with water and dried. Ultrasonic cleaning removes surface contaminants, and surface activation facilitates subsequent electroplating and growth of the copper micro / nano structure film. In one embodiment, the ultrasonic cleaning and activation step is as follows: first ultrasonic cleaning with acetone, then ultrasonic cleaning with a 0.05-0.2 M HCl solution.

[0050] Preferably, the manufacturing method of this embodiment further includes the following step S6: Through holes 10 are machined at both ends of the metal plate 6, and the through holes 10 communicate with the microgrooves within the metal plate 6. External coolant is introduced into / out of the metal plate 6 through the through holes 10 at both ends. This step S6 can be performed simultaneously with the machining of the microgrooves in step S1, or it can be performed after step S4, i.e., after assembling the power chip 1 and the ceramic substrate 3, and then machining the through holes 10 at both ends of the metal plate 6.

[0051] In step S3 above, the welding of the first metal layer of the ceramic substrate 3 to the metal plate 6 can be performed by laser welding.

[0052] In step S4 above, the electrical interconnection includes the following steps: printing solder 2 onto the second metal layer, then mounting the power chip 1 onto the solder printing position, and holding it at a temperature of 180-300℃ and a pressure of 0-20 MPa for 5-60 minutes to complete the electrical connection.

[0053] Using the above manufacturing method, this embodiment of the invention yields a liquid-cooled ceramic substrate with an embedded micro / nano structure, comprising: a metal plate 6, a ceramic substrate 3, and a power chip 1. The metal plate 6 has a microgroove on one side, and the inner wall of the microgroove is electroplated with a first copper micro / nano structure film 5. The ceramic substrate 3 is sealed onto the microgroove. A first metal layer and a second metal layer are provided on opposite sides of the ceramic substrate 3. A second copper micro / nano structure film 7 is electroplated on the first metal layer of the ceramic substrate 3 at a position corresponding to the microgroove. The shape of the second copper micro / nano structure film 7 matches the shape of the open side of the microgroove at its corresponding position. The second copper micro / nano structure film 7 is aligned and bonded to the open side of the microgroove. The power chip 1 is electrically connected to and encapsulated on the second metal layer of the ceramic substrate 3. Conventional connection settings are sufficient for the connection leads between the components, and they are not shown in the figure.

[0054] Specifically, the power chip 1 and the ceramic substrate 3 can be soldered together by solder 2. The micro trench is a through type, and the micro trench includes an interconnected inlet channel 8, multiple spaced branch channels 4 and an outlet channel 9. The depth of the micro trench is 2-10 mm, the width of each branch channel 4 is 0.5-5 mm, and the spacing between adjacent branch channels 4 is 0.5-2 mm.

[0055] The manufacturing method of a liquid-cooled ceramic substrate with embedded micro-nano structures according to an embodiment of the present invention uses only the ceramic substrate 3 as an intermediary connecting the metal plate 6 and the power chip 1, realizing the integrated manufacturing of the liquid cooler and the power chip. The heat generated by the power chip 1 is transferred to the liquid-cooled flow channel in the metal plate 6 through the ceramic substrate 3 for efficient solid-liquid heat exchange. There is no need for traditional thermal interface materials and metal base plates. The process is simple and the heat transfer path is shortened, realizing rapid heat dissipation near the hot spot. At the same time, the first copper micro-nano structure film 5 on the inner wall of the micro-groove and the second copper micro-nano structure film 7 on the ceramic substrate 3 together form the inner wall of the micro-flow channel. The copper micro-nano structure can effectively expand the contact area between the fluid in the micro-flow channel and the inner wall of the micro-flow channel and trigger local turbulence, increase the solid-liquid interface heat transfer coefficient, thereby improving the overall heat dissipation efficiency and realizing efficient heat dissipation of the power chip.

[0056] In this embodiment of the invention, a metal plate 6 embedded with a micro / nano structure in a liquid-cooled ceramic substrate shares a ceramic substrate 3 with a power chip 1. The first metal layer of the ceramic substrate 3 forms one sidewall of the microfluidic channel. The ceramic substrate 3 and the metal plate 6 are integrated. The heat generated by the power chip 1 can directly reach the coolant in the metal plate 6 without passing through traditional low thermal conductivity interface materials, so that the heat is carried away vertically before it diffuses laterally, achieving efficient heat dissipation near the hot spot. At the same time, a copper micro / nano structure thin film layer is electroplated on the inner wall of the microfluidic channel, which effectively expands the contact area between the fluid in the microfluidic channel and the inner wall of the microfluidic channel and triggers local turbulence, increases the heat transfer coefficient of the solid-liquid interface, and achieves efficient heat dissipation of the power chip. It has the advantages of high heat dissipation efficiency and high integration.

[0057] The following specific embodiment illustrates a liquid-cooled ceramic substrate with embedded micro / nano structures and its manufacturing method according to an embodiment of the present invention.

[0058] Example

[0059] Step 1: Substrate Preparation

[0060] A DBC ceramic substrate (Al2O3 as the ceramic substrate) with a thickness of 0.4 mm was selected, and the thickness of the metal layers on the top and bottom sides was 0.3 mm. The DBC ceramic substrate serves as both the mounting substrate for the power chip and the sealing cover for the microfluidic cavity below.

[0061] Step 2: Microgroove Machining

[0062] The metal plate is made of copper alloy (80×60×8 mm). A 1064 nm fiber laser is used for precision ablation with high power (100W), short pulses (100 ns), and high-speed scanning (600 mm / s) to process more than twenty straight-through, equally spaced array of branch channels, along with their inlet and outlet channels on both sides, in a single operation. The microgrooves are 4 mm deep, each branch channel is 2 mm wide, the spacing between adjacent branch channels is 2 mm, the distance between the inlet of the inlet channel and the branch channel is 15 mm, and the distance between the outlet of the outlet channel and the branch channel is 5 mm.

[0063] Step 3: Post-processing

[0064] The DBC ceramic substrate and metal plate were first ultrasonically cleaned in acetone, and then ultrasonically cleaned in 0.10 M HCl to ensure the cleanliness of the deposited surface. They were then rinsed with ultrapure water and dried with nitrogen.

[0065] Step 4: Electroplating to grow copper micro / nano structure films

[0066] A 25-50 µm dry film (to block electroplating) was hot-pressed onto the surfaces of the DBC ceramic substrate and metal plate, excluding the inner walls of the microchannels. The DBC ceramic substrate and metal plate were used sequentially as cathodes (working electrodes), and pure copper was used as anode. Both electrodes were immersed in an electrolyte of 0.2 M CuSO4 and 1.0 M H2SO4, with an electrode spacing of approximately 2 cm. An A / cm² electrolyte was applied at room temperature. 2 A constant current density is maintained, and the deposition time is controlled to 30 s. This process forms copper micro / nano structures on the cathode surface. After electroplating, the cathode is removed, rinsed with deionized water, and dried with nitrogen gas.

[0067] Step 5: Sealing and welding of the microchannel cavity

[0068] The open side of the microgrooves on the processed metal plate was aligned and bonded to the copper micro / nanostructure film on the lower copper layer of the DBC ceramic substrate. A 515 nm continuous laser was used to perform penetration welding along the perimeter at high power (800 W) and a specific scanning speed (1.2 m / min). The laser energy was sufficient to locally melt and fuse the two 0.20 mm thick copper layers, forming a 0.20 mm deep sealed weld.

[0069] Step 6: Low-temperature sintering interconnection between power chip and DBC ceramic substrate

[0070] 1. Solder paste printing: Using a stainless steel stencil, the solder is precisely printed onto the upper copper layer of the DBC ceramic substrate.

[0071] 2. Power Chip Mounting and Sintering: The power chip (50 mm × 50 mm) is mounted onto the solder printing position. In a vacuum sintering furnace, a nitrogen atmosphere is introduced for additional protection. The temperature is slowly increased to 200°C at a rate of 3°C / min, while a high pressure of 10 MPa is applied and held at that temperature for 20 minutes. During this process, the solder densifies under heat and pressure.

[0072] 3. Encapsulation Process: First, contaminants on the bonding and bonding wire surfaces are removed through plasma cleaning and drying. Next, the surface is preheated in a vacuum environment of 50-60°C. Using a encapsulation machine, epoxy resin encapsulant is slowly injected into the housing, using negative pressure to completely immerse the chip and bonding wires, ensuring no air bubbles remain. Then, it is heated and cured to form a solid insulating protective layer, achieving electrical insulation, mechanical protection, and environmental sealing of the module.

[0073] Step 7: Fluid Port Fabrication

[0074] A 532 nm picosecond laser was used to drill rectangular through-holes at both ends of a metal plate, penetrating the plate and connecting the rectangular through-holes to microgrooves on the metal plate. After laser processing, the hole walls were cleaned with oxygen plasma. Finally, a rectangular copper tube was inserted and vacuum brazed at 820°C using Ag-28Cu welding rings to form a strong, sealed coolant inlet and outlet.

[0075] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures, characterized in that, Includes the following steps: Microgrooves are fabricated on one side of a metal plate, and a first copper micro / nano structure film is electroplated on the inner wall of the microgrooves. A second copper micro / nano structure film is electroplated on the first metal layer of the ceramic substrate at the position corresponding to the micro trench. The shape of the second copper micro / nano structure film matches the shape of the open side of the microgroove at its corresponding position; the first metal layer and the second metal layer are respectively provided on opposite sides of the ceramic substrate; The second copper micro / nano structure film is aligned and bonded to the open side of the micro trench, and the first metal layer is welded to the metal plate to form a liquid-cooled ceramic substrate. The power chip is electrically interconnected with the second metal layer and encapsulated to complete the power chip packaging.

2. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 1, characterized in that, The ceramic substrate includes, but is not limited to, DBC ceramic substrate, AMB ceramic substrate, direct electroplated copper ceramic substrate, and metal-ceramic diffusion soldering ceramic substrate; the thickness of the first metal layer and the second metal layer is 100-500 μm.

3. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 1, characterized in that, The electroplating conditions for the first and second copper micro / nanostructure films are as follows: the electrolyte is 0.2-0.6 M CuSO4 and 0.5-1.0 M H2SO4, the electrode distance is 2-10 cm, and an electrode pressure of 1-3 A / cm is applied at room temperature. 2 A constant current density was maintained, and the deposition time was 10-60 s.

4. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 1, characterized in that, The types of microgrooves include, but are not limited to, straight-through, serpentine, branched, or arrayed types. Each microgroove includes an interconnected inlet channel, multiple spaced-apart branch channels, and an outlet channel. The depth of each microgroove is 2-10 mm, the width of each branch channel is 0.5-5 mm, and the spacing between adjacent branch channels is 0.5-2 mm.

5. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 4, characterized in that, The distance from the inlet of the inlet channel to the branch channel is greater than the distance from the outlet of the outlet channel to the branch channel.

6. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 1, characterized in that, It also includes the following steps: Before electroplating the first copper micro-nano structure film and the second copper micro-nano structure film, the surfaces of the micro trenches and the first metal layer are ultrasonically cleaned and activated, then washed with water and dried.

7. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 6, characterized in that, The ultrasonic cleaning and activation steps are as follows: first, ultrasonic cleaning with acetone, followed by ultrasonic cleaning with 0.05-0.2 M HCl solution.

8. The method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in claim 1, characterized in that, It also includes the following steps: Through holes are machined at both ends of the metal plate, and the through holes are connected to the microgrooves.

9. A method for manufacturing a liquid-cooled ceramic substrate with embedded micro / nano structures as described in any one of claims 1-8, characterized in that, The microgroove fabrication methods include, but are not limited to, micromilling, photolithography, laser ablation, wet etching; and / or, The electrical interconnection includes the following steps: soldering is printed onto the second metal layer, then the power chip is mounted onto the solder printing position, and the circuit is kept at a temperature of 180-300℃ and a pressure of 0-20 MPa for 5-60 minutes to complete the electrical connection.

10. A liquid-cooled ceramic substrate with embedded micro / nano structures obtained by the manufacturing method according to any one of claims 1-9, characterized in that, include: A metal plate with microgrooves on one side, the inner wall of which is electroplated with a first copper micro / nano structure film; A ceramic substrate, with a sealing cap disposed on the microgroove; The ceramic substrate has a first metal layer and a second metal layer on opposite sides; a second copper micro / nano structure film is electroplated on the first metal layer at the position corresponding to the micro trench. The shape of the second copper micro / nano structure film matches the shape of the open side of the microgroove at its corresponding position; The second copper micro / nano structure film is aligned and bonded to the open side of the microtrench; as well as The power chip is electrically connected to the second metal layer and encapsulated.

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