Power module packaging structure and preparation method and application thereof

Abstract

The invention provides a power module packaging structure and a preparation method and application thereof, and belongs to the technical field of power module packaging. The power module packaging structure comprises a chip, a substrate and an aluminum-diamond composite bottom plate, the chip is fixedly connected to the substrate, and the substrate is fixedly connected to the aluminum-diamond composite bottom plate; the aluminum-diamond composite bottom plate comprises an aluminum-diamond composite body and a heat dissipation micro-channel structure arranged in the aluminum-diamond composite body. The heat dissipation micro-channel structure comprises parallel heat dissipation micro-channel units, and the heat dissipation micro-channel units are used for circulation of a cooling working medium. According to the power module packaging structure, a cooling network formed by arranging the heat dissipation micro-channel structure in the aluminum-diamond composite bottom plate of the power module packaging structure can significantly reduce the junction temperature of a device, and meanwhile, the matching of thermal expansion coefficients is considered.

Description

Technical Field

[0001] This application relates to the field of power module packaging technology, and in particular to a power module packaging structure, its preparation method and application. Background Technology

[0002] With the increasing demand for high-efficiency power conversion in fields such as new energy vehicles, photovoltaic inverters, and industrial drives, wide-bandgap semiconductor devices, represented by SiC devices, have advantages such as high voltage, high frequency, and high temperature performance, and are widely used in power module design. However, fully leveraging the advantages of wide-bandgap semiconductor devices presents new challenges for packaging technology. The junction temperature of wide-bandgap power devices often exceeds 250°C under high power density conditions. Traditional power module packaging structures have long heat dissipation paths and multi-layer structures, leading to significant thermal resistance accumulation, making it difficult to effectively control the device junction temperature and affecting switching performance and lifespan.

[0003] To improve heat dissipation performance, microchannel liquid cooling technology has been introduced. However, existing microchannel solutions are mostly based on aluminum or copper substrates, which are difficult to fully match high thermal conductivity chips and meet the requirements of higher heat flux densities. At the same time, traditional interface materials between the chip and the substrate still have the problem of increased thermal boundary impedance (TBR) due to interface mismatch, making it difficult to meet the needs of next-generation high power density applications. Summary of the Invention

[0004] Based on this, the main objective of this application is to provide a power module packaging structure, its fabrication method, and its application, so as to improve the junction temperature and temperature gradient of the device and enhance the interface matching of the power module packaging structure.

[0005] The first aspect of this application provides a power module packaging structure, including a chip, a substrate, and an aluminum-diamond composite base plate;

[0006] The chip is fixedly connected to the substrate, and the substrate is fixedly connected to the aluminum-diamond composite substrate;

[0007] The aluminum-diamond composite base plate includes an aluminum-diamond composite body and a heat dissipation microchannel structure disposed inside the aluminum-diamond composite body.

[0008] The heat dissipation microchannel structure includes parallel heat dissipation microchannel units, which are used to circulate cooling fluid.

[0009] In some embodiments, the aluminum-diamond composite bulk comprises the following components by volume fraction:

[0010] 60%-80% aluminum matrix and 20%-40% diamond particles.

[0011] In some embodiments, the particle size of the aluminum matrix is ​​5-80 μm.

[0012] In some embodiments, the diamond particles have a particle size of 20-150 μm.

[0013] In some embodiments, the internal dimensions of the heat dissipation microchannel unit are: a width of 0.2-2 mm and a depth of 2-5 mm.

[0014] In some embodiments, the shape of the heat dissipation microchannel structure includes: straight, U-shaped, serpentine, rectangular corrugated, Z-shaped, gradient, fishbone-shaped, or spiral.

[0015] In some embodiments, the cross-section of the heat dissipation microchannel structure includes a rectangle, a circle, an ellipse, a triangle, a sector, or a pentagon.

[0016] In some embodiments, the flow direction of the cooling medium in the heat dissipation microchannel unit is parallel to that of the chip.

[0017] In some embodiments, the power module packaging structure further includes an aluminum nitride layer, which is fixedly connected between the substrate and the aluminum-diamond composite base plate.

[0018] In some embodiments, the aluminum nitride layer is fixedly attached to the aluminum-diamond composite substrate by deposition.

[0019] In some embodiments, the power module packaging structure further includes a transition layer fixedly connected between the aluminum nitride layer and the aluminum-diamond composite substrate.

[0020] In some embodiments, the transition layer includes at least one of nickel and copper.

[0021] In some embodiments, the power module packaging structure further includes a wetting layer, which is fixedly connected between the aluminum nitride layer and the aluminum-diamond composite substrate.

[0022] In some embodiments, the wetting layer comprises at least one of silicon carbide and boron nitride.

[0023] In some embodiments, the aluminum-diamond composite substrate is prepared by the following method:

[0024] An aluminum-diamond composite substrate with a heat dissipation microchannel structure was prepared using additive manufacturing technology.

[0025] Alternatively, by using a die casting or injection molding process, the slurry of the aluminum-diamond composite body is filled into a mold with a heat dissipation microchannel structure, and then demolded to prepare an aluminum-diamond composite base plate with a heat dissipation microchannel structure.

[0026] Alternatively, a pre-formed layer is prepared using a slurry of the aluminum-diamond composite matrix, and then the interior of the pre-formed layer is etched using a laser etching method to form a heat dissipation microchannel structure, thereby preparing an aluminum-diamond composite substrate with a heat dissipation microchannel structure.

[0027] In some embodiments, the mold material for the load heat dissipation microchannel structure includes steel, silicone, or resin.

[0028] In some embodiments, the thermal conductivity of the aluminum-diamond composite substrate is 600-800 W / m·K.

[0029] In some embodiments, the substrate includes at least one of a direct copper-clad ceramic substrate, a polyimide plate, a molybdenum sheet, and a silver sheet.

[0030] In some embodiments, the power module packaging structure further includes an insulating housing and electrode terminals.

[0031] In some embodiments, the insulating housing comprises at least one of ceramic and poly(terephthalamide) sulfide.

[0032] In some embodiments, the cooling medium includes deionized water, an aqueous ethylene glycol solution, or a nanofluid coolant.

[0033] In some embodiments, the chip is fixedly attached to the substrate by at least one of solder and silver-based sintering agent.

[0034] In some implementations, the chip is electrically interconnected to the substrate via bonding wires.

[0035] In some embodiments, the conditions for fixing the connection include: fixing the connection by means of a bonding agent or direct contact, wherein the bonding agent includes at least one of solder and silver-based sintering agent; wherein the solder includes at least one of lead-free tin solder, gold-tin alloy solder, silver solder and copper solder.

[0036] A second aspect of this application provides a method for fabricating the power module packaging structure described in the first aspect, comprising the following steps:

[0037] Prepare a heat-dissipating aluminum-diamond composite substrate with a heat dissipation microchannel structure;

[0038] After the chip is fixedly connected to the substrate, the substrate is fixedly connected to the aluminum-diamond composite substrate to prepare the power module packaging structure.

[0039] In some implementations, the methods for securing the connection include welding, sintering, or pressing.

[0040] In some embodiments, the soldering conditions include: soldering with solder, said solder including at least one of lead-free tin solder, gold-tin alloy solder, silver solder, and copper solder.

[0041] The third aspect of this application provides the application of the power module packaging structure described in the first aspect or the power module packaging structure prepared by the preparation method described in the second aspect in an IGBT module.

[0042] Compared with traditional technologies, this application has at least the following beneficial effects:

[0043] This application utilizes a microscale fluid cooling network composed of heat dissipation microchannels within the aluminum-diamond composite substrate of the power module packaging structure. This constructs a rapid and efficient three-dimensional heat dissipation path, significantly reducing device junction temperature and temperature gradient, suppressing the generation of local hot spots, and improving the temperature uniformity and thermal stress resistance of the power module under thermal cycling conditions. This surpasses traditional external forced air cooling or simple water cooling methods, and is particularly suitable for the application requirements of wide-bandgap power devices in high heat flux density scenarios. Furthermore, using a high thermal conductivity aluminum-diamond composite substrate as the base of the power module packaging structure maintains low thermal resistance while also achieving low density and matching thermal expansion coefficients. This not only provides an efficient and stable heat dissipation channel for high-power device operation but also offers a reliable packaging solution for extreme operating conditions such as rail transit, grid converters, and large-scale new energy conversion. Attached Figure Description

[0044] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0045] Figure 1 This is a schematic diagram of the power module packaging structure in Example 1. Detailed Implementation

[0046] The present application will be further described in detail below with reference to the embodiments and examples. These embodiments and examples are for illustrative purposes only and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to enable a more thorough and comprehensive understanding of the disclosure of the present application. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0048] To address the issues of high junction temperatures and interface mismatches inherent in traditional power module packaging structures, this application employs a microscale fluid cooling network within the aluminum-diamond composite substrate of the power module packaging structure. This constructs a rapid and efficient three-dimensional heat dissipation path, significantly reducing device junction temperature and temperature gradients, suppressing the generation of localized hot spots, and improving the temperature uniformity and thermal stress tolerance of the power module under thermal cycling conditions. This surpasses traditional external forced air cooling or simple water cooling methods, and is particularly suitable for the application requirements of wide-bandgap power devices in high heat flux density scenarios. Furthermore, using a highly thermally conductive aluminum-diamond composite substrate as the base of the power module packaging structure maintains low thermal resistance while also ensuring low density and matching thermal expansion coefficients, providing an efficient and stable heat dissipation channel for high-power device operation.

[0049] The first aspect of this application provides a power module packaging structure, including a chip, a substrate, and an aluminum-diamond composite base plate;

[0050] The chip is fixedly connected to the substrate, and the substrate is fixedly connected to the aluminum-diamond composite substrate;

[0051] The aluminum-diamond composite base plate includes an aluminum-diamond composite body and a heat dissipation microchannel structure disposed inside the aluminum-diamond composite body.

[0052] The heat dissipation microchannel structure includes parallel heat dissipation microchannel units, which are used to circulate cooling fluid.

[0053] This application employs an aluminum-diamond composite substrate, which improves the thermal conductivity and interface compatibility of the power module packaging structure. Furthermore, compared to traditional heat dissipation structures, the microchannel structure within the aluminum-diamond composite substrate significantly shortens the heat dissipation path between the chip and the cooling medium, thereby reducing thermal resistance and improving heat conduction efficiency. This significantly enhances the heat dissipation performance of the packaging structure and lowers the device junction temperature. Simultaneously, it simplifies the assembly process of the power module packaging structure while maintaining structural stability and reliability.

[0054] In some embodiments, the aluminum-diamond composite bulk comprises the following components by volume fraction:

[0055] 60%-80% aluminum matrix and 20%-40% diamond particles.

[0056] In some embodiments, the particle size of the aluminum matrix is ​​5-80 μm.

[0057] In some embodiments, the diamond particles have a particle size of 20-150 μm.

[0058] In some embodiments, the preparation method of the aluminum-diamond composite body includes: powder metallurgy or vacuum hot pressing.

[0059] In some embodiments, the thickness of the aluminum-diamond composite substrate is 1-8mm, which can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm.

[0060] In some embodiments, the chip includes a silicon carbide chip.

[0061] In some embodiments, the chip is a SiC MOSFET chip. The SiC MOSFET chip is a metal-oxide-semiconductor field-effect transistor chip made of silicon carbide (SiC).

[0062] In some embodiments, the coefficient of thermal expansion of the chip is 2.5-3.5 ppm / K, which can be 2.5 ppm / K, 3 ppm / K or 3.5 ppm / K.

[0063] In some embodiments, the coefficient of thermal expansion of the substrate is 7-8 ppm / K, which can be 7 ppm / K, 7.5 ppm / K or 8 ppm / K.

[0064] In some embodiments, the coefficient of thermal expansion of the aluminum-diamond composite substrate is 4-7 ppm / K, which can be 4 ppm / K, 5 ppm / K, 6 ppm / K or 7 ppm / K.

[0065] In some embodiments, the thermal conductivity of the aluminum-diamond composite substrate is 600-800 W / m·K.

[0066] In some embodiments, the coefficient of thermal expansion of the aluminum nitride layer is 4.5-5.3 ppm / K, which can be 4.5 ppm / K, 4.8 ppm / K, 5 ppm / K or 5.3 ppm / K.

[0067] The aluminum-diamond composite substrate used in this application has a thermal conductivity of 600-800 W / m·K, and its coefficient of thermal expansion is highly matched with that of the chip. By using a high thermal conductivity aluminum-diamond composite substrate as the substrate for the power module packaging structure, and optimizing particle size distribution, interfacial bonding strength, and the microstructure of the metal matrix, a thermal conductivity >500 W / m·K is achieved. This substrate also features low density, high rigidity, and a controllable coefficient of thermal expansion, significantly improving the heat dissipation capacity and structural stability of the power module, and meeting the operational requirements of high-voltage, high-power IGBT (Insulated Gate Bipolar Transistor) devices under harsh thermal load conditions.

[0068] In some embodiments, the internal dimensions of the heat dissipation microchannel unit are: a width of 0.2-2 mm and a depth of 2-5 mm. Integrating micron-scale cooling microchannels directly into the aluminum-diamond composite substrate reduces the heat conduction path between the cooling medium and the heat source.

[0069] In some embodiments, the shape of the heat dissipation microchannel structure includes: straight, U-shaped, serpentine, rectangular corrugated, Z-shaped, gradient, fishbone-shaped, or spiral.

[0070] In some embodiments, the cross-section of the heat dissipation microchannel structure includes a rectangle, a circle, an ellipse, a triangle, a sector, or a pentagon.

[0071] In some embodiments, the flow direction of the cooling medium in the heat dissipation microchannel unit is parallel to that of the chip.

[0072] In some embodiments, the heat dissipation microchannel structure includes 10-20 heat dissipation microchannel units.

[0073] In some embodiments, the heat dissipation microchannel units in the heat dissipation microchannel structure are parallel to each other.

[0074] In some embodiments, the cooling medium includes deionized water, an aqueous ethylene glycol solution, or a nanofluid coolant.

[0075] In some embodiments, the nanofluid coolant includes at least one nanoparticle selected from Al2O3, SiC, and CNT particles.

[0076] In some embodiments, the flow conditions of the cooling working fluid include a pressure of 1-10 bar and a flow rate of 0.3-3 m / s, which can achieve good heat exchange performance.

[0077] In some embodiments, the inner wall of the heat dissipation microchannel unit is treated with sandblasting or chemical etching.

[0078] After sandblasting or chemical etching, the inner wall of the heat dissipation microchannel unit forms a micro-nano roughened texture, which can enhance the turbulence effect of the cooling medium and improve the heat exchange efficiency.

[0079] In some implementations, the inner wall of the heat dissipation microchannel unit is reserved with an interface for an embedded micro temperature sensor, pressure sensor, flow sensor or power plant sensor, and the data is transmitted in real time through a microconduct or optical fiber. This enables real-time acquisition and early warning feedback of key parameters inside the device, and provides intelligent operation and fault identification capabilities, making it suitable for reliable operation and status assessment of high-end power equipment.

[0080] This application constructs a heat dissipation microchannel unit with a circulating cooling medium inside the aluminum-diamond composite base plate, so that the cooling medium is in close contact with the bottom surface of the device, which can achieve rapid three-dimensional heat diffusion, significantly reduce the junction temperature of the device, reduce the uneven heat flow and additional thermal resistance caused by planar diffusion, and suppress the risk of local overheating. It is superior to traditional unidirectional water cooling or air cooling methods, and is particularly suitable for high heat flux density packaging of wide bandgap devices.

[0081] In some implementations, the power module package structure includes an IGBT (Insulated Gate Bipolar Transistor).

[0082] In some embodiments, the power module packaging structure further includes an aluminum nitride layer, which is fixedly connected between the substrate and the aluminum-diamond composite base plate.

[0083] In some embodiments, the aluminum nitride layer is fixedly attached to the aluminum-diamond composite substrate by deposition.

[0084] In some embodiments, the thickness of the aluminum nitride layer is 5-50 nm.

[0085] This application fixes a nanostructured aluminum nitride layer between the contact surface of the substrate and the aluminum-diamond composite base plate to significantly reduce the interfacial thermal resistance and enhance the interfacial bonding strength, relieve stress, enhance the interfacial bonding strength, effectively prevent failure behaviors such as microcracks, voids or interfacial peeling caused by thermal cycling, and significantly improve the electro-thermal-mechanical coupling reliability of the packaging structure.

[0086] In some embodiments, the power module packaging structure further includes a transition layer fixedly connected between the aluminum nitride layer and the aluminum-diamond composite substrate.

[0087] In some embodiments, the transition layer includes at least one of nickel and copper.

[0088] In some embodiments, the thickness of the transition layer is 5-20 μm.

[0089] By introducing a transition layer between the aluminum nitride layer and the aluminum-diamond composite substrate, the adhesion and corrosion resistance of the aluminum-diamond composite substrate can be improved.

[0090] In some embodiments, the power module packaging structure further includes a wetting layer, which is fixedly connected between the aluminum nitride layer and the aluminum-diamond composite substrate.

[0091] In some embodiments, the wetting layer comprises at least one of silicon carbide and boron nitride.

[0092] In some embodiments, the aluminum-diamond composite substrate is prepared by the following method:

[0093] An aluminum-diamond composite substrate with a heat dissipation microchannel structure was prepared using additive manufacturing technology.

[0094] Alternatively, by using a die casting or injection molding process, the slurry of the aluminum-diamond composite body is filled into a mold with a heat dissipation microchannel structure, and then demolded to prepare an aluminum-diamond composite base plate with a heat dissipation microchannel structure.

[0095] Alternatively, a pre-formed layer is prepared using a slurry of the aluminum-diamond composite matrix, and then the interior of the pre-formed layer is etched using a laser etching method to form a heat dissipation microchannel structure, thereby preparing an aluminum-diamond composite substrate with a heat dissipation microchannel structure.

[0096] In some embodiments, the steps of fabricating an aluminum-diamond composite substrate with a heat dissipation microchannel structure using additive manufacturing technology specifically include:

[0097] An aluminum-diamond composite powder was prepared by combining an aluminum matrix and diamond particles. Selective laser melting (SLM) was then used to melt the aluminum-diamond composite powder layer by layer under an argon or nitrogen protective atmosphere using a high-precision laser beam. A heat dissipation microchannel structure was programmed using computer-aided design software to fabricate an aluminum-diamond composite substrate with an internal heat dissipation microchannel structure. The geometric dimensions and shape layout of the microchannel structure were precisely programmed using computer-aided design software to match the fluid dynamics requirements of the cooling medium.

[0098] In some embodiments, after the slurry of the aluminum-diamond composite body is filled into the mold of the load heat dissipation microchannel structure, the step of curing the slurry is also included.

[0099] In some embodiments, the curing conditions include a temperature of 150-300°C.

[0100] In some embodiments, a prefabricated layer is prepared using a slurry of an aluminum-diamond composite matrix. Then, laser etching is used to etch the interior of the prefabricated layer to form a heat dissipation microchannel structure, thus preparing an aluminum-diamond composite substrate with a heat dissipation microchannel structure. The rapid prototyping of the heat dissipation microchannel structure is achieved by adjusting the laser parameters of the laser etching method.

[0101] In some implementations, the laser etching conditions include using a UV laser with a wavelength of 355 nm.

[0102] In some embodiments, after laser etching is used to etch the interior of the prefabricated layer to form a heat dissipation microchannel structure, the method further includes a step of sandblasting or chemical etching the inner wall of the heat dissipation microchannel structure. By sandblasting or chemically etching the inner wall of the heat dissipation microchannel structure, a micro-nano-scale rough texture is formed on the inner wall, thereby enhancing the cooling heat transfer efficiency of the heat dissipation microchannel structure.

[0103] In some implementations, chemical etching is performed using a hydrofluoric acid solution.

[0104] In some embodiments, the mold material of the load heat dissipation microchannel structure includes steel, silicone, or high-temperature resin.

[0105] In some embodiments, the thermal conductivity of the aluminum-diamond composite substrate is 600-800 W / m·K.

[0106] In some embodiments, the substrate includes at least one of a direct copper-clad ceramic substrate (DBC ceramic substrate), a polyimide sheet, a molybdenum sheet, and a silver sheet.

[0107] In some embodiments, the thickness of the substrate is 0.3-3 mm, and can be 0.3 mm, 0.5 mm, 0.75 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm.

[0108] In some embodiments, the power module packaging structure further includes an insulating housing and electrode terminals. The insulating housing is used to encapsulate the overall module, and the electrode terminals are used for electrical conductivity.

[0109] In some embodiments, the insulating housing comprises at least one of ceramic and poly(phenylene terephthalamide) sulfide for encapsulating the integral module.

[0110] In some embodiments, the power module packaging structure includes a creepage distance enhancement structure inside the insulating shell.

[0111] In some embodiments, the connectors between the heat dissipation microchannel unit and the inlet of the cooling medium, and the connectors between the heat dissipation microchannel unit and the outlet of the cooling medium, are covered with polyvinylidene fluoride or fluoride anti-corrosion and anti-scaling coatings, which can meet the reliable operation requirements of extreme environments such as oceans, salt spray, and high altitudes and low pressures.

[0112] In some embodiments, the power module package structure further includes power terminals and signal terminals. The power terminals and signal terminals are led out via high-temperature sealing rings, compatible with bolted or crimp-mounted mounting mechanisms.

[0113] In some embodiments, the chip is connected to the substrate by at least one of solder and silver-based sintering agent.

[0114] In some embodiments, the solder includes at least one of lead-free tin solder, gold-tin alloy solder, silver solder, and copper solder to meet high current requirements.

[0115] In some embodiments, the solder forms solder joints with a thickness of 50-150 nm to ensure excellent thermal conductivity and mechanical bonding performance.

[0116] In some implementations, the chip is electrically interconnected to the substrate via bonding wires.

[0117] In some embodiments, the conditions for fixing the connection include: fixing the connection by means of a bonding agent or direct contact, wherein the bonding agent includes at least one of solder and silver-based sintering agent; wherein the solder includes at least one of lead-free tin solder, gold-tin alloy solder, silver solder and copper solder.

[0118] In some embodiments, the bonding wire comprises bonding aluminum wire.

[0119] A second aspect of this application provides a method for fabricating the power module packaging structure described in the first aspect, comprising the following steps:

[0120] Prepare a heat-dissipating aluminum-diamond composite substrate with a heat dissipation microchannel structure;

[0121] After the chip is fixedly connected to the substrate, the substrate is fixedly connected to the aluminum-diamond composite substrate to prepare the power module packaging structure.

[0122] In some implementations, the methods for securing the connection include welding, sintering, or pressing.

[0123] In some embodiments, the soldering conditions include: soldering with solder, said solder including at least one of lead-free tin solder, gold-tin alloy solder, silver solder, and copper solder.

[0124] In some embodiments, the lead-free solder includes lead-free solder of type SAC305.

[0125] In some embodiments, the mass ratio of gold to tin in the gold-tin alloy solder is 80:20.

[0126] In some embodiments, the silver solder comprises nano-silver solder paste.

[0127] In some embodiments, the power module packaging structure further includes an aluminum nitride layer, which is fixedly connected between the substrate and the aluminum-diamond composite base plate.

[0128] In some embodiments, the method for preparing the aluminum nitride layer includes: in-situ deposition between the substrate and the aluminum-diamond composite substrate to prepare the aluminum nitride layer.

[0129] In some embodiments, the in-situ deposition is performed using ALD (atomic layer deposition) or PECVD (plasma-enhanced chemical vapor deposition).

[0130] In some embodiments, the thickness of the aluminum nitride layer is 5-50 nm, which can be 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm or 50 nm.

[0131] In some embodiments, the power module packaging structure includes a chip, a substrate, an aluminum nitride layer, and an aluminum-diamond composite substrate; the method for fabricating the power module packaging structure includes the following steps:

[0132] An aluminum nitride layer is prepared by in-situ deposition on the aluminum-diamond composite substrate;

[0133] The aluminum nitride layer and the substrate are welded, sintered, or pressed together; the chip is welded, sintered, or pressed onto the side of the substrate away from the base plate to prepare the power module packaging structure. Each structural module is fixedly connected using processes such as reflow soldering, pressure sintering, or pressureless sintering to achieve a reliable connection with high strength and low resistance in the power module packaging structure, ensuring the mechanical robustness and electrical continuity of the overall structure.

[0134] This application demonstrates the in-situ deposition of a nanostructured aluminum nitride layer on an aluminum-diamond composite substrate, which can significantly reduce interfacial thermal resistance and enhance interfacial bonding strength, thereby achieving synergistic minimization of the structure's thermal resistance.

[0135] In some embodiments, the power module packaging structure includes a chip, a substrate, an aluminum nitride layer, a transition layer, and an aluminum-diamond composite substrate; the fabrication method of the power module packaging structure includes the following steps:

[0136] A transition layer is prepared by electroplating copper or nickel onto the aluminum-diamond composite substrate.

[0137] An aluminum nitride layer is prepared by in-situ deposition on the transition layer;

[0138] The aluminum nitride layer and the substrate are welded, sintered, or pressed together, and then the chip is welded, sintered, or pressed together on the side of the substrate away from the base plate to prepare the power module packaging structure.

[0139] An aluminum-diamond composite substrate was electroplated with an aluminum nitride layer to improve its adhesion and corrosion resistance. The aluminum nitride layer was then deposited in situ. This coating fills the fine voids between the diamond particles and the aluminum matrix, reducing thermal boundary resistance.

[0140] In some embodiments, to further optimize interface performance, a wetting layer with a thickness of <10 nm can be added between the aluminum nitride layer and the aluminum-diamond composite substrate, wherein the wetting layer comprises silicon carbide (SiC) or boron nitride (h-BN).

[0141] In some embodiments, a functional gradient region with a thickness of 0.1-1 mm is designed between the near-chip region and the far-chip region of the aluminum-diamond composite substrate. By adjusting the diamond content or grain size in the aluminum-diamond composite substrate, thermal cycling stress can be precisely controlled.

[0142] The third aspect of this application provides the application of the power module packaging structure described in the first aspect or the power module packaging structure prepared by the preparation method described in the second aspect in an IGBT module.

[0143] In some implementations, IGBT modules are packaged using multiple power modules connected in parallel or series, which allows for rapid cascading of fluid and electrical components via dedicated quick-connect couplings, greatly improving the maintainability and scalability of the system.

[0144] The embodiments of this application will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0145] Example 1

[0146] Power module packaging structure as follows Figure 1As shown, the module comprises: a chip (SiC MOSFET chip, with a coefficient of thermal expansion of 2.5 ppm / K), a substrate (DBC ceramic substrate, 0.75 mm thick, with a coefficient of thermal expansion of 7.5 ppm / K), an aluminum nitride layer (25 nm thick), and an aluminum-diamond composite substrate (3 mm thick); as well as an insulating shell, electrode terminals (copper-based conductive material), and bonding wires (aluminum bonding wires). The aluminum nitride layer is deposited on the aluminum-diamond composite substrate using ALD. The substrate is fixed to the aluminum nitride layer using solder (lead-free solder Sn-Ag-Cu, model SAC305). The chip is fixedly connected to the substrate using a sintered silver layer. The insulating shell encapsulates the entire module. The electrode terminals conduct electricity. The aluminum bonding wires electrically interconnect the chip and the substrate.

[0147] The aluminum-diamond composite substrate comprises an aluminum-diamond composite body and a heat dissipation microchannel structure disposed within the aluminum-diamond composite body. The heat dissipation microchannel structure consists of 10 parallel heat dissipation microchannel units. The aluminum-diamond composite substrate is prepared by using a flow channel design with an internal width of 1mm and a depth of 2mm in the heat dissipation microchannel units (e.g.,...). Figure 1 As shown, an aluminum-diamond composite substrate was prepared using additive manufacturing (SLM) technology. Specifically, 70% by mass of aluminum matrix (particle size 5-80 μm) and 30% by mass of diamond particles (particle size 20-150 μm) were uniformly mixed to prepare aluminum-diamond composite powder. Under argon protection, selective laser melting (SLM) was used to melt the aluminum-diamond composite powder layer by layer. Using a CAD model, 10 flow lines 1 mm wide and 2 mm deep were formed inside the aluminum-diamond composite substrate. A heat dissipation microchannel unit is used to fabricate an aluminum-diamond composite base plate. The inner wall surface of the channel is anodized to improve the heat exchange area and corrosion resistance. Specifically, the process is carried out in a 5% sulfuric acid solution to form a dense aluminum oxide layer on the inner wall. Then, chemical etching is performed using an HF solution to form a micro-nano rough texture, which improves the heat exchange effect. One end of the heat dissipation microchannel unit is connected to the inlet of the cooling medium (deionized water), and the other end is connected to the outlet of the cooling medium. The cooling medium is discharged from the outlet after forced convection heat exchange through the heat dissipation microchannel.

[0148] The thermal conductivity of the aluminum-diamond composite base plate is 800 W / m·K.

[0149] The insulating shell is made of insulating material (PPS), and the internal cavity (i.e. the encapsulation area) is made of silicone gel to provide sufficient dielectric protection, environmental sealing and stress buffering, and to prevent damage caused by moisture intrusion and physical impact.

[0150] The fabrication method of the power module packaging structure is as follows:

[0151] The chip is fixedly connected to the DBC ceramic substrate by a sintered silver layer, and the bonding of the bonding wires is completed by ultrasonic welding.

[0152] An aluminum nitride layer is deposited on top of an aluminum-diamond composite substrate to improve thermal conductivity. Then, the bottom of the DBC ceramic substrate is metallurgically bonded to the aluminum nitride layer using solder (lead-free solder Sn-Ag-Cu, model SAC305).

[0153] This embodiment optimizes thermal management through the following measures: 1) shortening the heat conduction path between the heat dissipation microchannel structure through which the cooling working fluid flows and the chip heat source; 2) the thermal expansion coefficient (CTE=7ppm / K) of the aluminum-diamond composite substrate is highly matched with the thermal expansion coefficient (CTE=7.5ppm / K) of the DBC ceramic substrate, the thermal expansion coefficient (CTE=4.5ppm / K) of the aluminum nitride layer, and the thermal expansion coefficient (CTE=2.5ppm / K) of the chip, thereby reducing thermal stress.

[0154] Example 2

[0155] The difference between the power module packaging structure of Example 2 and Example 1 is that: no aluminum nitride layer is set, and the power module packaging structure is prepared according to the method of Example 1, wherein the bottom of the DBC ceramic substrate is metallurgically bonded to the aluminum-diamond composite base plate by solder (lead-free solder Sn-Ag-Cu, model SAC305).

[0156] This embodiment optimizes thermal management through the following measures: 1) shortening the heat conduction path between the heat dissipation microchannel structure through which the cooling working fluid flows and the chip heat source; 2) the thermal expansion coefficient (CTE=7ppm / K) of the aluminum-diamond composite substrate is highly matched with that of the DBC ceramic substrate (CTE=7.5ppm / K), thus reducing thermal stress.

[0157] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0158] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A power module packaging structure, characterized in that, Includes chips, substrates, and aluminum-diamond composite base plates; The chip is fixedly connected to the substrate, and the substrate is fixedly connected to the aluminum-diamond composite substrate; The aluminum-diamond composite base plate includes an aluminum-diamond composite body and a heat dissipation microchannel structure disposed inside the aluminum-diamond composite body. The heat dissipation microchannel structure includes parallel heat dissipation microchannel units, which are used to circulate cooling fluid.

2. The power module packaging structure according to claim 1, characterized in that, The aluminum-diamond composite bulk comprises the following components by volume fraction: 60%-80% aluminum matrix and 20%-40% diamond particles; Optionally, the particle size of the aluminum matrix is ​​5-80 μm; Optionally, the diamond particles have a particle size of 20-150 μm.

3. The power module packaging structure according to claim 1, characterized in that, It meets at least one of the following characteristics: (1) The internal dimensions of the heat dissipation microchannel unit are: width 0.2-2mm, depth 2-5mm; (2) The shape of the heat dissipation microchannel structure includes: straight, U-shaped, serpentine, rectangular corrugated, Z-shaped, gradient, fishbone-shaped or spiral; (3) The cross-section of the heat dissipation microchannel structure includes rectangle, circle, ellipse, triangle, sector or pentagon; (4) The flow direction of the cooling working fluid in the heat dissipation microchannel unit is parallel to that of the chip.

4. The power module packaging structure according to claim 1, characterized in that, The power module packaging structure also includes an aluminum nitride layer, which is fixedly connected between the substrate and the aluminum-diamond composite base plate; Optionally, the aluminum nitride layer is fixedly bonded to the aluminum-diamond composite substrate by deposition; Optionally, the power module packaging structure further includes a transition layer, which is fixedly connected between the aluminum nitride layer and the aluminum-diamond composite base plate; Optionally, the transition layer includes at least one of nickel and copper; Optionally, the power module packaging structure further includes a wetting layer, which is fixedly connected between the aluminum nitride layer and the aluminum-diamond composite base plate; Optionally, the wetting layer includes at least one of silicon carbide and boron nitride.

5. The power module packaging structure according to claim 1, characterized in that, The aluminum-diamond composite base plate is prepared by the following method: An aluminum-diamond composite substrate with a heat dissipation microchannel structure was prepared using additive manufacturing technology. Alternatively, by using a die casting or injection molding process, the slurry of the aluminum-diamond composite body is filled into a mold with a heat dissipation microchannel structure, and then demolded to prepare an aluminum-diamond composite base plate with a heat dissipation microchannel structure. Alternatively, a pre-formed layer is prepared using a slurry of the aluminum-diamond composite matrix, and then the interior of the pre-formed layer is etched using a laser etching method to form a heat dissipation microchannel structure, thereby preparing an aluminum-diamond composite substrate with a heat dissipation microchannel structure.

6. The power module packaging structure according to claim 5, characterized in that, In the mold of the load heat dissipation microchannel structure, the mold material includes steel, silicone or resin.

7. The power module packaging structure according to claim 1, characterized in that, It meets at least one of the following characteristics: (1) The thermal conductivity of the aluminum-diamond composite base plate is 600-800 W / m·K; (2) The substrate includes at least one of direct copper-clad ceramic substrate, polyimide plate, molybdenum sheet and silver sheet; (3) The power module packaging structure also includes an insulating shell and electrode terminals; Optionally, the insulating housing comprises at least one of ceramic and poly(phenylene terephthalamide) sulfide; (4) The cooling medium includes deionized water, ethylene glycol aqueous solution or nanofluid coolant; (5) The chip is fixedly connected to the substrate by at least one of solder and silver-based sintering agent; (6) The chip is electrically interconnected with the substrate via bonding wires; (7) The conditions for fixed connection include: fixed connection by means of a bonding agent or direct contact, wherein the bonding agent includes at least one of solder and silver-based sintering agent; wherein the solder includes at least one of lead-free tin solder, gold-tin alloy solder, silver solder and copper solder.

8. The method for preparing the power module packaging structure according to any one of claims 1-7, characterized in that, Includes the following steps: Prepare a heat-dissipating aluminum-diamond composite substrate with a heat dissipation microchannel structure; After the chip is fixedly attached to the substrate, the substrate is fixedly attached to the aluminum-diamond composite substrate to prepare the power module packaging structure.

9. The preparation method according to claim 8, characterized in that, Methods of fixing connections include: welding, sintering, or pressing; Optionally, the welding conditions include: welding with solder, said solder including at least one of lead-free tin solder, gold-tin alloy solder, silver solder and copper solder.

10. The application of the power module packaging structure as described in any one of claims 1-7 or the power module packaging structure prepared by the preparation method described in claims 8-9 in an IGBT module.

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