A power module, power supply circuit and chip

Abstract

The application discloses a power module, a power supply circuit and a chip. The power module comprises a first metal-clad substrate and a second metal-clad substrate arranged oppositely, a chip and an interconnecting column located between the first metal-clad substrate and the second metal-clad substrate. The chip and the first metal-clad substrate are electrically connected by pressure sintering of a sintering material, so that the bonding reliability can be improved, and the chip is electrically connected with the second metal-clad substrate through the interconnecting column. Since the chip is arranged on both sides of the substrate, the heat generated in the power module can be discharged from the two substrates, so that the heat dissipation performance of the power module is improved. In addition, the sintering material formed by silver paste, copper paste or silver film has the advantages of low sintering temperature, high melting point and high thermal conductivity, so that the heat dissipation performance of the power module can be further improved, and the power density of the power module is improved.

Description

[0001] This application is a divisional application. The original application has the application number 202110908858.8 and the original application date is August 9, 2021. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of semiconductor packaging technology, and in particular to a power module, power supply circuit and chip. Background Technology

[0003] With the development of power electronics technology, power modules have attracted increasing attention. At the same time, the demand for energy saving and low cost urgently requires power modules to be lighter and smaller. However, this demand presents a significant challenge to the development of power modules, because weight reduction and miniaturization lead to an increase in module current density, which in turn generates higher heat inside the module, causing a rise in junction temperature. If the generated heat cannot be dissipated in time, the high junction temperature will affect the overall thermomechanical performance and reliability of the power module. Summary of the Invention

[0004] This application provides a power module, a power supply circuit, and a chip, which are used to provide a power module with high heat dissipation performance, power density, and reliability.

[0005] Firstly, this application provides a power module comprising a first metal-clad substrate and a second metal-clad substrate disposed opposite to each other, a chip and interconnect pillars located between the first and second metal-clad substrates; wherein a sintering material is further disposed between the chip and the first metal-clad substrate, and the chip and the first metal-clad substrate are electrically connected by pressure sintering using the sintering material, which may include at least one of silver paste, copper paste, or silver film; the interconnect pillars are located between the chip and the second metal-clad substrate, and the chip is electrically connected to the second metal-clad substrate through the interconnect pillars. Since substrates are disposed on both sides of the chip, heat generated inside the power module can be discharged from the direction of the first metal-clad substrate and the direction of the second metal-clad substrate, improving the heat dissipation performance of the power module. Furthermore, the sintering material has low stress, and the pressure sintering method for electrically connecting the chip and the first metal-clad substrate can improve the bonding reliability. In addition, the sintering material in this application has the advantages of low sintering temperature, high melting point, and high thermal conductivity; therefore, it can not only further improve the heat dissipation performance of the power module, but also increase the operating ambient temperature and service life of the power module, thereby increasing the power density of the power module.

[0006] In specific implementations, the first and second metal-clad substrates can be copper-clad ceramic substrates (Direct Bond Copper, DBC), active metal brazed copper (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB), or insulated metal substrates (IMS), etc., and are not limited here.

[0007] For example, in order to further improve power density, the first metal-clad substrate and the second metal-clad substrate may be formed using AlN-DBC, Si3N4-AMB or AlN-AMB with high thermal conductivity, and there is no limitation herein.

[0008] For example, the sintering material can be formed from silver paste, copper paste, or silver film.

[0009] In practice, silver paste can include at least one of micrometer silver particle paste and nanometer silver particle paste. Micrometer silver particle paste refers to silver paste made using micrometer-sized silver particles and organic solvents; it is low-cost and safe. It is typically sintered under pressure, resulting in highly dense sintered materials, strong interfacial bonding, and high bonding reliability. Nanometer silver particle paste, on the other hand, is made using nanometer-sized silver particles and organic solvents; it is more expensive and carries the safety risks associated with handling nanoparticles.

[0010] Optionally, in order to improve the reliability of sintering bonding and reduce costs, the sintering material of this application may be formed using micrometer silver particle paste.

[0011] To further improve the reliability of sintered bonding, the elastic modulus, coefficient of thermal expansion (CTE), etc., of the sintered material can be adjusted by adding materials to the sintered material. For example, the sintered material includes a host material and a filler filled within the host material; wherein the host material includes at least one of silver paste, copper paste, or silver film, and the filler is formed of a material with good adhesion to the host material, and the filler's coefficient of thermal expansion is less than that of the host material, thereby improving the reliability of the sintered bonding.

[0012] Taking micron-sized silver paste as the main material as an example, fillers are added to the micron-sized silver paste to reduce its coefficient of thermal expansion and bonding stress, thereby improving the bonding reliability of silver sintering. For example, the fillers may include at least one of nickel (Ni), Ni alloys, copper (Cu), nickel-plated copper, titanium (Ti), Ti alloys, iron (Fe), Fe alloys, Kovar alloy (4J29), and SiC powder, etc., without limitation.

[0013] In this application, the metal layer covering the surfaces of the first and second metal-clad substrates is generally copper. When the sintering material is silver paste or silver film, to improve the bonding performance between the sintering material and the first metal-clad substrate, the first metal-clad substrate can be silver-plated at the sintering point; that is, the first metal-clad substrate is covered with a silver-plated layer in the area corresponding to the sintering material. For example, the thickness of the silver-plated layer can be controlled between 0.1 μm and 30 μm. Of course, if the bonding performance between the sintering material and the first metal-clad substrate is good, silver plating may not be necessary. For example, when the sintering material is copper paste, silver plating is not required at the sintering point of the first metal-clad substrate.

[0014] For example, pressure sintering may include the following steps: Step (1) When the sintering material is copper paste or silver paste, the copper paste or silver paste can be printed onto the sintering area corresponding to the first metal-clad substrate using stencil printing or screen printing. Then, the copper paste or silver paste printed on the first metal-clad substrate can be pre-dried at a temperature of 100°C to 180°C for 5 min to 40 min under an N2 atmosphere. Afterward, the chip is fixed onto the dried copper paste or silver paste by vacuum adsorption, and a pressure of 0.1 MPa to 10 MPa is applied to the chip mounted on the first metal-clad substrate at a temperature of 100°C to 180°C for at least 10 ms. When the sintering material is silver film, the chip can be adsorbed by a metal suction nozzle at a temperature of 80°C to 200°C. Then, the chip is pressed onto a large piece of silver film, and a pressure of 0.1 MPa to 5 MPa is applied for a time of 1 ms to 10000 ms. In this way, the silver film under the chip is compressed and semi-sintered, adhering to the chip. Then, the chip with the silver film attached is fixed onto the first metal-clad substrate by vacuum adsorption. A pressure of 0.1MPa to 10MPa is applied to the chip mounted on the first metal-clad substrate at a temperature of 100℃ to 180℃ for at least 10ms. Step (2): A pressure head can be used to perform pressure sintering on the chip mounted on the first metal-clad substrate. Taking a pressure head area of ​​50mm*50mm as an example, the parallelism of the pressure head can be set to ≤5μm, thereby reducing product warpage after sintering. For example, the sintering conditions for pressure sintering can be: sintering temperature controlled at 200℃ to 300℃, applied pressure controlled at 5MPa to 30MPa, and sintering time controlled at 1min to 10min. To prevent damage to the chip from the pressure head during sintering, a removable stress-relieving film can be placed between the chip and the pressure head during pressure sintering of the chip mounted on the first metal-clad substrate. Therefore, during pressure sintering, the stress-relieving film can prevent direct contact between the pressure head and the chip, and reduce damage caused by stress concentration on the chip. After pressure sintering is complete, the stress-relieving film can be removed. For example, the stress-relieving film can be an organic film such as a Teflon film, and this is not limited to this.

[0015] Furthermore, in order to control the warpage of the product after sintering, the first metal-clad substrate and the chip after sintering can be cooled under pressure. For example, the cooling conditions can be: the applied pressure is controlled between 5 MPa and 20 MPa, and the cooling time is controlled between 1 min and 10 min.

[0016] Optionally, after pressure sintering the chip mounted on the first metal-clad substrate, the first metal-clad substrate with the chip mounted can be cleaned to remove residual organic matter. For example, plasma treatment or organic solvent cleaning processes can be used to remove residual organic matter from the first metal-clad substrate, increasing the interfacial adhesion of the subsequent molding compound, preventing delamination of the molding compound, and further improving the reliability of the power module.

[0017] Optionally, in order to relieve the stress generated on the chip during soldering or sintering and improve the reliability of the power module, the chip has surface electrodes on both the side facing the first metal-clad substrate and the side of the chip away from the first metal-clad substrate. The surface electrodes include soldered or sintered metal layers. The surface electrode on the side of the chip facing the first metal-clad substrate further includes a stress-buffered metal layer on the side of the soldered or sintered metal layer away from the first metal-clad substrate. And / or, the surface electrode on the side of the chip away from the first metal-clad substrate further includes a stress-buffered metal layer on the side of the soldered or sintered metal layer facing the first metal-clad substrate.

[0018] For example, the stress-relief metal layer can be made of a soft metal with a hardness less than HV60, such as aluminum, aluminum alloys, copper, magnesium alloys, zinc, zinc alloys, silver, silver alloys, gold, or gold alloys. The flexibility of the soft metal is utilized to release stress at the joint.

[0019] In practical implementation, when the stress buffer metal layer is made of a non-weldable metal, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be placed below the welded or sintered metal layer.

[0020] For example, the welded or sintered metal layer may include: Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, Ni(P) / Au or Ni(P) / Ag, etc.

[0021] In practice, the first solder can be used to connect the interconnect pillars to the side of the chip away from the first metal-clad substrate by welding; the second solder can be used to connect the interconnect pillars to the second metal-clad substrate on the side away from the chip by welding.

[0022] In practical implementation, the solder thickness has a significant impact on solder joint reliability. To ensure controllable and uniform solder thickness, at least one first support pillar is provided between the interconnect pillar and the chip. This at least one first support pillar can be formed on the side of the interconnect pillar facing the chip, i.e., on the interconnect pillar; or it can be formed on the side of the chip facing the interconnect pillar, i.e., on the chip. And / or, at least one second support pillar is provided between the interconnect pillar and the second metal-clad substrate. This at least one second support pillar can be formed on the side of the interconnect pillar facing the second metal-clad substrate, i.e., on the interconnect pillar; or it can be formed on the side of the second metal-clad substrate facing the interconnect pillar, i.e., on the second metal-clad substrate.

[0023] In the power module of this application, in addition to the chip and interconnect pillars, electronic components may also be included on the side of the first metal-clad substrate facing the second metal-clad substrate. The electronic components are connected to the first metal-clad substrate by a third solder.

[0024] In this application, the first solder, the second solder, and the third solder can be formed using solder paste or solder sheet, and no limitation is made herein.

[0025] Optionally, all solders in this application can be made of the same material. For example, the first solder, the second solder, and the third solder can be formed using the same solder. In this way, the soldering of the chip to the interconnect pillar, the soldering of the interconnect pillar to the second metal-clad substrate, and the soldering of the electronic components to the first metal-clad substrate can be completed in one reflow soldering, thereby simplifying the process steps and saving costs.

[0026] Of course, in specific implementations, the first, second, and third solders can be different solders, and this is not limited here. For example, the first and third solders can be high-temperature solders, such as high-lead solders, Au-based solders, etc., and the second solder can be a medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0027] For example, the electronic components in this application include any electronic components, such as signal terminals, power terminals, thermistors, etc., which are soldered onto the first metal-clad substrate.

[0028] To improve the bonding reliability between the electronic components and the first metal-clad substrate, at least one third support post is provided between the electronic components and the first metal-clad substrate. The at least one third support post can be formed on the side of the electronic components facing the first metal-clad substrate or on the side of the first metal-clad substrate facing the electronic components, and there is no limitation on this.

[0029] Optionally, the support pillar is made of a conductive material. For example, the support pillar may be formed of at least one of Al, Al alloy, Au, Au alloy, Cu, Cu alloy, Ni, Ni alloy, aluminum-coated copper, Cu-Sn high-melting-point alloy, or high-temperature solder.

[0030] Furthermore, this application also includes a molding compound that fills the space between the first metal-clad substrate and the second metal-clad substrate and encapsulates the first metal-clad substrate and the second metal-clad substrate. To prevent delamination between the molding compound and the molding interface and to improve the reliability of the power module, a low-modulus molding compound is used. For example, the molding compound can be formed from a material with an elastic modulus between 0.5 GPa and 20 GPa, such as epoxy molding compound, etc., and is not limited thereto.

[0031] The power module of this application may further include a first heat sink located on the side of the first metal-clad substrate away from the second metal-clad substrate and a second heat sink located on the side of the second metal-clad substrate away from the first metal-clad substrate, thereby cooling the module from both sides and improving the power density and reliability of the power module.

[0032] Optionally, in order to improve heat dissipation, the first heat sink can be connected to the first metal-clad substrate by welding or sintering; and / or, the second heat sink can be connected to the second metal-clad substrate by welding or sintering.

[0033] Furthermore, a first support component is provided between the first heat sink and the first metal-clad substrate, and the first support component may be formed by a plurality of fourth support pillars, metal wires or metal mesh; and / or, a second support component is provided between the second heat sink and the second metal-clad substrate, and the second support component may be formed by a plurality of fifth support pillars or metal wires, thereby using the first support component and the second support component to control the solder thickness and ensure the reliability of the soldering.

[0034] In practice, the metal wire can be bonded and fixed to the mating surface of the heat sink or the heat dissipation surface of the power module to prevent the metal wire from flowing with the liquid metal during reflow.

[0035] Secondly, embodiments of this application also provide a power supply circuit, including a circuit board and a power module as described in the first aspect or various embodiments of the first aspect, wherein the power module is electrically connected to the circuit board, and the circuit board provides signals to the power module.

[0036] The technical effects that can be achieved in the second aspect mentioned above can be described with reference to the technical effects that can be achieved by any possible design in the first aspect mentioned above, and will not be repeated here.

[0037] Thirdly, this application also provides a chip whose surface electrode includes a stress-buffered metal layer and a welded or sintered metal layer stacked together. The stress-buffered metal layer can be made of a soft metal with a hardness less than HV60, which utilizes the flexibility of the soft metal to release the stress at the joint.

[0038] For example, soft metals may include at least one of aluminum, aluminum alloys, copper, magnesium alloys, zinc, zinc alloys, silver, silver alloys, gold, and gold alloys, etc., without limitation.

[0039] In practical implementation, when the stress buffer metal layer is made of a non-weldable metal, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be placed below the welded or sintered metal layer.

[0040] For example, the welded or sintered metal layer may include: Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, Ni(P) / Au or Ni(P) / Ag, without limitation herein. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of a power module provided in an embodiment of this application;

[0042] Figure 2 A schematic flowchart illustrating a method for fabricating a power module according to an embodiment of this application;

[0043] Figure 3 This is a schematic cross-sectional view of a sintered material filled with filler provided in an embodiment of this application;

[0044] Figure 4 A schematic flowchart illustrating another method for fabricating a power module provided in this application embodiment;

[0045] Figure 5 This application provides a schematic diagram of the fabrication process of a power module.

[0046] Figure 6 A schematic flowchart illustrating another method for fabricating a power module provided in this application embodiment;

[0047] Figure 7 A schematic diagram illustrating the fabrication process of another power module provided in this application embodiment;

[0048] Figure 8 This is a schematic diagram of another power module provided in an embodiment of this application;

[0049] Figure 9This is a schematic diagram of the chip structure provided in an embodiment of this application;

[0050] Figure 10 This is an ultrasonic scanning photograph of the sintered layer in one embodiment of this application;

[0051] Figure 11 This is a schematic diagram of a structure in an embodiment of this application where a support column is provided between two joined bodies welded together by solder.

[0052] Figure 12 This is a schematic diagram of the interconnecting pillar structure provided in an embodiment of this application;

[0053] Figure 13 This is a schematic diagram of another power module provided in an embodiment of this application;

[0054] Figure 14 A schematic diagram illustrating the fabrication process of another power module provided in this application embodiment;

[0055] Figure 15 This is a schematic diagram of another power module provided in an embodiment of this application;

[0056] Figure 16 This is a schematic diagram of another power module provided in an embodiment of this application. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0058] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0059] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms expressing position and direction described in this application are all illustrated with the accompanying drawings as examples, but changes can be made as needed, and all changes are included within the scope of protection of this invention. The accompanying drawings of this application are only used to illustrate relative positional relationships and do not represent actual proportions. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0060] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0061] To facilitate understanding of the power module provided in this application embodiment, its application scenario will be explained first. This power module is widely used in power supply circuits. The power module is a semiconductor device that transforms the voltage, current, and frequency of a power supply, and is the core device for power conversion in a power supply circuit. For example, this power supply circuit can serve as the core device for DC-to-AC conversion in the motor control unit (MCU) of an electric vehicle, outputting DC power from the electric vehicle's battery, or converting DC power into AC power required for vehicle operation.

[0062] Driven by the need for energy conservation and low cost, there is an urgent demand for power modules to be lighter and smaller. However, this demand presents a significant challenge to the development of power modules, as weight reduction and miniaturization lead to an increase in module current density, resulting in higher heat generation inside the module and consequently, an increase in junction temperature. If the generated heat cannot be dissipated in time, the higher junction temperature will affect the overall thermomechanical performance and reliability of the module.

[0063] Based on this, this application provides a power module with high heat dissipation performance, power density, and reliability. To facilitate understanding of the technical solution of this application, the power module provided by this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] See Figure 1 , Figure 1This is a schematic diagram of a power module provided in an embodiment of this application. The power module 1 includes: a first metal-clad substrate 10 and a second metal-clad substrate 20 disposed opposite to each other, a chip 11 and interconnect pillars 12 located between the first metal-clad substrate 10 and the second metal-clad substrate 20; wherein, a sintering material 13 is further disposed between the chip 11 and the first metal-clad substrate 10, and the chip 11 and the first metal-clad substrate 10 are electrically connected by pressure sintering using the sintering material 13, which may include at least one of silver paste, copper paste, or silver film; the interconnect pillars 12 are located between the chip 11 and the second metal-clad substrate 20, and the chip 11 is electrically connected to the second metal-clad substrate 20 through the interconnect pillars 12. Since substrates are disposed on both sides of the chip 11, the heat generated inside the power module can be discharged from the direction of the first metal-clad substrate 10 and the direction of the second metal-clad substrate 20, improving the heat dissipation performance of the power module. Furthermore, the sintering material has low stress, and the pressure sintering method for electrically connecting the chip 11 and the first metal-clad substrate 10 can improve the bonding reliability. In addition, the sintering material 13 in this application has the advantages of low sintering temperature, high melting point and high thermal conductivity. Therefore, it can not only further improve the heat dissipation performance of the power module, but also improve the operating temperature and service life of the power module, thereby increasing the power density of the power module.

[0065] See Figure 2 , Figure 2 This is a schematic flowchart illustrating a method for fabricating a power module according to an embodiment of this application. The fabrication method may include the following steps:

[0066] S101, Provide a first metal-clad substrate and a second metal-clad substrate.

[0067] In specific implementations, the first and second metal-clad substrates can be copper-clad ceramic substrates (Direct Bond Copper, DBC), active metal brazed copper (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB), or insulated metal substrates (IMS), etc., and are not limited here.

[0068] For example, in order to further improve power density, the first metal-clad substrate and the second metal-clad substrate may be formed using AlN-DBC, Si3N4-AMB or AlN-AMB with high thermal conductivity, and there is no limitation herein.

[0069] S102. The chip is mounted on the first metal-clad substrate, and there is a sintering material between the chip and the first metal-clad substrate.

[0070] For example, the sintering material can be formed from silver paste, copper paste, or silver film.

[0071] In practice, silver paste can include at least one of micrometer silver particle paste and nanometer silver particle paste. Micrometer silver particle paste refers to silver paste made using micrometer-sized silver particles and organic solvents; it is low-cost and safe. It is typically sintered under pressure, resulting in highly dense sintered materials, strong interfacial bonding, and high bonding reliability. Nanometer silver particle paste, on the other hand, is made using nanometer-sized silver particles and organic solvents; it is more expensive and carries the safety risks associated with handling nanoparticles.

[0072] Optionally, in order to improve the reliability of sintering bonding and reduce costs, the sintering material of this application may be formed using micrometer silver particle paste.

[0073] To further improve the reliability of sintered bonding, the elastic modulus, coefficient of thermal expansion (CTE), etc., of the sintered material can be adjusted by adding materials to the sintered material. For example, the sintered material includes a host material and a filler filled within the host material; wherein the host material includes at least one of silver paste, copper paste, or silver film, and the filler is formed of a material with good adhesion to the host material, and the filler's coefficient of thermal expansion is less than that of the host material, thereby improving the reliability of the sintered bonding.

[0074] Taking micron-sized silver paste as the main material as an example, fillers are added to the micron-sized silver paste to reduce its coefficient of thermal expansion and bonding stress, thereby improving the bonding reliability of silver sintering. For example, the fillers may include at least one of nickel (Ni), Ni alloys, copper (Cu), nickel-plated copper, titanium (Ti), Ti alloys, iron (Fe), Fe alloys, Kovar alloy (4J29), and SiC powder, etc., without limitation.

[0075] This application does not limit the shape of the packing material; for example, such as... Figure 3 As shown, the length L1 of the packing 131 can be controlled between 20 μm and 100 μm, and the dimension W1 of the packing 131 in the vertical length direction can be controlled between 20 μm and 30 μm. The cross-section along the length direction can be circular, elliptical, polygonal, etc.

[0076] In this application, the metal layer covering the surfaces of the first and second metal-clad substrates is generally copper. When the sintering material is silver paste or silver film, to improve the bonding performance between the sintering material and the first metal-clad substrate, the first metal-clad substrate can be silver-plated at the sintering point; that is, the first metal-clad substrate is covered with a silver-plated layer in the area corresponding to the sintering material. For example, the thickness of the silver-plated layer can be controlled between 0.1 μm and 30 μm. Of course, if the bonding performance between the sintering material and the first metal-clad substrate is good, silver plating may not be necessary. For example, when the sintering material is copper paste, silver plating is not required at the sintering point of the first metal-clad substrate.

[0077] For example, when the sintering material is copper paste or silver paste, see [reference needed]. Figure 4 and Figure 5 The chip can be mounted on the first metal-clad substrate using the following steps:

[0078] Step S1021a: Print the sintering material onto the first metal-clad substrate.

[0079] In specific implementation, such as Figure 5 As shown in (a) and (b), the sintering material 13 (copper paste or silver paste) can be printed on the sintering area corresponding to the first metal-clad substrate 10 using either stencil printing or screen printing. Since stencil printing is less expensive and simpler to manufacture than screen printing, this application optionally uses stencil printing to print the copper paste or silver paste on the sintering area corresponding to the first metal-clad substrate.

[0080] For example, the thickness of the printed copper or silver paste can be controlled between 30μm and 160μm. The specific thickness can be designed according to the actual product and is not limited here.

[0081] Optionally, the area of ​​the printed copper or silver paste can be set to be larger than the area of ​​the corresponding sintering region on the chip to absorb alignment errors between the chip and the sintering material. The boundary of the copper or silver paste can extend outward by 20μm to 300μm beyond the target boundary (ideally the boundary of the sintering region of the chip).

[0082] Step S1022a: Pre-dry the printed sintered material.

[0083] In practice, pre-drying the printed copper or silver paste is to prevent the sintered material from collapsing during pressure sintering.

[0084] For example, such as Figure 5 As shown in (c), the sintering material 13 (copper paste or silver paste) printed on the first metallized substrate 10 can be pre-dried for 5 min to 40 min at a temperature of 100℃ to 180℃ under N2 atmosphere.

[0085] Step S1023a: Pressurize the chip onto the sintering material of the first metal-clad substrate.

[0086] In specific implementation, such as Figure 5 As shown in (d), the chip 11 can be picked up by vacuum adsorption first, and then the sintering material 13 (copper paste or silver paste) can be aligned by the image recognition system. After that, the chip 11 is fixed on the dried sintering material 13 (copper paste or silver paste) and pressure is applied.

[0087] For example, the chip mounting conditions can be: temperature controlled at 100℃~180℃, pressure controlled at 0.1MPa~10MPa, and time controlled at 10ms~999ms. That is, a pressure of 0.1MPa~10MPa is applied to the chip 11 mounted on the first metal-clad substrate 10 at an environment with a temperature of 100℃~180℃ for at least 10ms.

[0088] For example, when the sintering material is a silver film, see [reference needed]. Figure 6 and Figure 7 The chip can be mounted on the first metal-clad substrate using the following steps:

[0089] Step S1021b: Adhere sintering material to the side of the chip facing the first metal-coated substrate.

[0090] In specific implementation, such as Figure 7 As shown in (a), the chip 11 can be adsorbed using a metal suction nozzle with a temperature of 80°C to 200°C. The chip 11 is then pressed onto a large silver film, with a pressure of 0.1 MPa to 5 MPa applied for 1 ms to 10000 ms. In this way, the sintering material 13 (silver film) beneath the chip is compressed and partially sintered, adhering to the chip 11.

[0091] Step S1022b: The chip with the sintering material adhered to it is mounted on the first metal-clad substrate and pressure is applied.

[0092] In specific implementation, such as Figure 7 As shown in (b), the chip 11 can be picked up by vacuum adsorption first, and then the first metal-coated substrate 10 can be aligned by image recognition system. After that, the chip 11 with sintered material 13 (silver film) is fixed on the first metal-coated substrate 10 and pressure is applied.

[0093] For example, the chip mounting conditions can be: temperature controlled at 100℃~180℃, pressure controlled at 0.1MPa~10MPa, and time controlled at 10ms~999ms. That is, a pressure of 0.1MPa~10MPa is applied to the chip mounted on the first metal-clad substrate at an environment with a temperature of 100℃~180℃ for at least 10ms.

[0094] Step S103 is executed after the chip mounting is completed.

[0095] Step S103: Perform pressure sintering on the chip mounted on the first metal-coated substrate.

[0096] Pressure sintering refers to applying pressure to the materials being joined at high temperatures, thereby increasing the density of the sintered material, promoting atomic diffusion between particles of the sintered material and at the interface between the sintered material and the joined material, and enhancing the bonding strength and reliability. This application does not limit the pressure sintering process used and any known method may be employed.

[0097] In specific implementation, such as Figure 5 (e) and Figure 7 As shown in (c), a pressure head can be used to perform pressure sintering on the chip 11 mounted on the first metal-clad substrate 10. Taking a pressure head area of ​​50mm*50mm as an example, the parallelism of the pressure head can be set to ≤5μm to reduce product warping after sintering.

[0098] For example, the sintering conditions for pressure sintering are as follows: the sintering temperature is controlled at 200℃~300℃, the applied pressure is controlled at 5MPa~30MPa, and the sintering time is controlled at 1min~10min.

[0099] In practice, the pressure sintering process can be carried out in an air environment. To prevent product oxidation, the chip mounted on the first metal-coated substrate is pressure-sintered in a protective atmosphere or vacuum environment. The protective atmosphere can be a reducing atmosphere or an inert atmosphere. For example, the protective atmosphere can be N2, a mixture of N2 and H2, Ar or He, etc., without limitation.

[0100] To prevent damage to the chip from the pressure head during the sintering process, such as Figure 5 (e) and Figure 7 As shown in (c), during pressure sintering of the chip mounted on the first metal-clad substrate, a removable stress-relieving film 30 can be placed between the chip 11 and the pressure head. This prevents direct contact between the pressure head and the chip 11 during pressure sintering and reduces damage caused by stress concentration on the chip 11. The stress-relieving film can be removed after pressure sintering is complete.

[0101] Optionally, the thickness of the stress-relieving membrane can be set to 50μm to 90μm, and is not limited here.

[0102] For example, the stress-relieving membrane can be an organic membrane such as a Teflon membrane, and there is no limitation herein.

[0103] Furthermore, in order to control the warpage of the sintered product, such as Figure 5 (f) and Figure 5 As shown in (d), the first metal-coated substrate 10 and the chip 11, after sintering, are cooled under pressure.

[0104] For example, if the pressure sintering process is carried out in a protective atmosphere or vacuum environment, the cooling process is also carried out in a protective atmosphere or vacuum environment.

[0105] For example, the cooling conditions can be: the applied pressure is controlled between 5 MPa and 20 MPa, and the cooling time is controlled between 1 min and 10 min.

[0106] Optionally, to enhance cooling, water cooling or forced nitrogen cooling can be used; no specific restrictions are imposed here.

[0107] Optionally, after pressure sintering the chip mounted on the first metal-clad substrate, the first metal-clad substrate with the chip mounted can be cleaned to remove residual organic matter. For example, plasma treatment or organic solvent cleaning processes can be used to remove residual organic matter from the first metal-clad substrate, increasing the interfacial adhesion of the subsequent molding compound, preventing delamination of the molding compound, and further improving the reliability of the power module.

[0108] Plasma treatment refers to the purification of an object's surface through the bombardment effect of plasma particles and the reaction of plasma ions with organic matter.

[0109] Step S104: Using interconnect pillars, the chip is connected to the second metal-coated substrate on the side away from the first metal-coated substrate.

[0110] In practice, the interconnect pillars can be formed of metal, alloy or composite material, and are used to connect the side of the chip away from the first metal-coated substrate to the second metal-coated substrate.

[0111] For example, the interconnecting pillars can be made of Cu, Ni, Mo, W, tungsten alloys, Cu-Mo alloys, AlSiC, and nickel alloys, or they can be Mo plated with Ni, Ni(P), or Cu; W plated with Ni, Ni(P), or Cu; Cu-Mo alloy plated with Ni, Ni(P), or Cu; or AlSiC composite material plated with Ni, Ni(P), or Cu after surface sensitization treatment. Of course, Ag or Au can also be further plated on the surface of the Ni, Ni(P), or Cu plating.

[0112] In this application, Ni(P) refers to a Ni coating containing phosphorus (P) manufactured through a chemical plating process. During chemical plating, P and Ni precipitate simultaneously from the solution and deposit on the substrate; P is an unavoidable byproduct.

[0113] This application does not limit the type and number of chips in the power module; any number of chips of any type can be used in the power module. For example, such as... Figure 8 As shown, chip 11 can be an insulated gate bipolar transistor (IGBT) or a fast recovery diode (FRD). Both IGBT chip 11 and FRD chip 11 are electrically connected to the first metal-clad substrate 10 through sintering material 13.

[0114] For specific implementation, please refer to [link / reference]. Figure 8 The gate of the IGBT chip 11 can be electrically connected to the first metal-clad substrate 10 via the Al line 104.

[0115] In a specific implementation, the chip has surface electrodes on both the side facing the first metal-clad substrate and the side of the chip away from the first metal-clad substrate. The surface electrodes include a welded or sintered metal layer for welding or sintering with other electrical devices.

[0116] For example, the welded or sintered metal layer may include: Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, Ni(P) / Au or Ni(P) / Ag, etc.

[0117] In this application, NiV refers to an alloy of Ni and V. The coating is produced using a NiV target and a sputtering process during the fabrication of the chip surface electrode.

[0118] Optionally, to relieve stress generated on the chip during soldering or sintering and improve the reliability of the power module, a stress-relief metal layer can be added to the surface electrodes. The stress-relief metal layer can be made of a soft metal with a hardness less than HV60, such as aluminum, aluminum alloys, copper, magnesium alloys, zinc, zinc alloys, silver, silver alloys, gold, or gold alloys. The flexibility of the soft metal is utilized to relieve stress at the joint.

[0119] In practical implementation, when the stress buffer metal layer is made of a non-weldable metal, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be placed below the welded or sintered metal layer.

[0120] For example, a stress-buffered metal layer may be provided only in the surface electrode on the side of the chip facing the first metal-coated substrate, or only in the surface electrode on the side of the chip facing the interconnect pillar, or stress-buffered metal layers may be provided in the surface electrodes on both sides of the chip; no limitation is made here.

[0121] For example, taking aluminum or aluminum alloy as the material of the stress-relief metal layer, such as... Figure 9 As shown, the chip 11 may include a semiconductor body 110, with surface electrodes 111 disposed on the surface of the semiconductor body 110. A stress-relief metal layer 1111 is disposed in the surface electrode 111 facing the first metal-clad substrate. The stress-relief metal layer 1111 is located on the side of the solder or sintered metal layer 1112 away from the first metal-clad substrate, i.e., the stress-relief metal layer 1111 is located between the solder or sintered metal layer 1112 and the semiconductor body 110. And / or, a stress-relief metal layer 1111 is disposed in the surface electrode 111 facing the interconnect pillars, with the stress-relief metal layer 1111 located on the side of the solder or sintered metal layer 1112 away from the interconnect pillars, i.e., the stress-relief metal layer 1111 is located between the solder or sintered metal layer 1112 and the semiconductor body 110. Figure 9 The following is an example of a chip 11 with stress-buffered metal layers 1111 disposed in the surface electrodes 111 on both sides of the chip 11.

[0122] In practical implementation, when forming the surface electrodes of the chip, an Al film or Al alloy layer can first be formed using physical vapor deposition (PVD) or other methods. This is because a protective oxide film easily forms on the Al surface, making it non-solderable. To achieve solderability or sinterability on non-solderable Al, a solderable metal and a surface wettable metal can be chemically plated onto a stress-buffered metal layer to form a solderable or sinterable metal layer. Alternatively, a solderable or sintered metal layer can be fabricated on the surface using methods such as plasma PVD.

[0123] In one feasible implementation, when forming the surface electrode of the chip, an Al film can first be formed using PVD or other methods. Then, the aluminum oxide film is replaced with Zn by zincate treatment, followed by chemical plating of Ni(P) to replace the Zn. Alternatively, gold (Au) or silver (Ag) can be chemically plated onto the Ni(P) layer. That is, the surface electrode comprises a stress-reducing metal layer Al and a welded or sintered metal layer Ni(P) / Au or Ni(P) / Ag. The phosphorus content in Ni(P) is typically 5 wt.% to 12 wt.%. Alternatively, a Ti / Ni / Ag layer can be formed using PVD after forming an Al film, meaning the surface electrode also comprises a stress-reducing metal layer Al and a welded or sintered metal layer Ti / Ni / Ag.

[0124] Of course, when forming surface electrodes, stress buffer metal layers can be skipped, and instead, PVD can be used to directly form welded or sintered metal layers, such as Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, etc.

[0125] This application does not limit the thickness of the surface electrode of the chip, but sets it according to the actual product. For example, the thickness of the surface electrode can be controlled between 2μm and 10μm.

[0126] For example, a chip with a stress-reducing metal layer was sintered onto a metal-coated ceramic substrate using a filler-filled micron-sized silver paste. The ultrasonic (SAT) scan image of the sintered layer after 1000 temperature shocks (-40°C to 125°C) in a harsh, unencapsulated state is shown below. Figure 10 As shown, by Figure 10 As can be seen, no peeling occurred in the sintered layer. This demonstrates that sintering a chip with a stress-buffered metal layer together with silver paste that reduces the elastic modulus and coefficient of thermal expansion can achieve a highly reliable bond.

[0127] In this application, after the chip and the first metal-clad substrate are connected by pressure sintering, as... Figure 1 and Figure 8 As shown, the chip can be connected to the interconnect pillar 12 via the first solder 14, and the interconnect pillar 12 can be connected to the second metal-clad substrate 20 via the second solder 15. In a specific implementation, the first solder can be used to connect the interconnect pillar to the side of the chip away from the first metal-clad substrate by soldering; the second solder can be used to connect the interconnect pillar to the second metal-clad substrate on the side away from the chip by soldering.

[0128] For example, the first solder and the second solder can be formed using solder paste or solder sheet. The first solder can be a high-temperature solder, such as high-lead solder, Au-based solder, etc., and the second solder can be a medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0129] In practical implementation, the thickness of the solder has a significant impact on the reliability of the solder joint. To ensure controllable and uniform solder thickness, such as... Figure 11 As shown, a support post 03 can be provided between two bonded bodies 01 and 02 (two objects welded together by solder, such as a chip and an interconnect post, or an interconnect post and a second metallized substrate), thereby controlling the thickness and uniformity of the solder 04 between the two bonded bodies 01 and 02. The support post 03 can be formed on either of the two bonded bodies 01 and 02.

[0130] For example, in this application, such as Figure 8 As shown, at least one first support post 16 is provided between the interconnect post 12 and the chip 11. The at least one first support post 16 can be formed on the side of the interconnect post 12 facing the chip 11, that is, formed on the interconnect post 12; the at least one first support post 16 can also be formed on the side of the chip 11 facing the interconnect post 12, that is, formed on the chip 11.

[0131] For example, in this application, such as Figure 8 As shown, at least one second support post 17 is provided between the interconnect post 12 and the second metal-clad substrate 20. The at least one second support post 17 can be formed on the side of the interconnect post 12 facing the second metal-clad substrate 20, that is, formed on the interconnect post 12; the at least one second support post 17 can also be formed on the side of the second metal-clad substrate 20 facing the interconnect post 12, that is, formed on the second metal-clad substrate 20.

[0132] This application does not limit the number of the first support column and the second support column, but determines the number of support columns based on the area of ​​the welding area. The larger the area of ​​the welding area, the more support columns are required.

[0133] In this application, the size of the support column can be set to the micrometer level, mainly used to support the jointed bodies located on both sides of the support column, so as to control the thickness of the solder and ensure the uniformity of the solder thickness.

[0134] Optionally, the first and second support pillars are made of conductive materials. For example, the first and second support pillars may be formed from at least one of Al, Al alloys, Au, Au alloys, Cu, Cu alloys, Ni, Ni alloys, aluminum-coated copper, Cu-Sn high-melting-point alloys, or high-temperature solder.

[0135] In practice, the height of the support column is determined by the target thickness of the solder. For example, the thickness of the support column can be controlled between 0.02mm and 10mm.

[0136] For example, ultrasonic technology can be used to implant micron-sized support pillars into the substrates to be joined. The small size of the support pillars has no impact on the soldering process or solder reliability. The implanted support pillars can initially be spherical or cylindrical, and then they are flattened to achieve adjustable and controllable height. This allows for controllable control of solder thickness and warpage during the soldering process.

[0137] For example, such as Figure 12 As shown, taking the implantation of support pillars on both sides of interconnect pillar 12 as an example, micron-sized metal balls are implanted on the chip-facing side of interconnect pillar 12 using ultrasonic technology. The implanted metal balls are then leveled to form the first support pillar 16. The interconnect pillar 12 with the first support pillar 16 implanted facing down is then placed in a fixture, allowing the implanted first support pillar 16 to enter the cavity of the fixture. Using the fixture for positioning, metal balls are implanted on the second metal-clad substrate side of interconnect pillar 12 using the same method. The implanted metal balls are then leveled to form the second support pillar 17. This results in symmetrically positioned support pillars on both sides of interconnect pillar 12, facilitating recognition and gripping during automated mounting.

[0138] One method of flattening the metal balls is to apply pressure to flatten them, so that the height of the implanted metal balls is consistent and meets the design requirements for solder thickness, thereby controlling the uniformity of solder thickness.

[0139] In the power module of this application, such as Figure 13 As shown, in addition to the chip 11 and interconnect pillars 12, it may also include electronic components 101 located on the side of the first metal-clad substrate 10 facing the second metal-clad substrate 20. The electronic components 101 are connected to the first metal-clad substrate 10 via a third solder 102.

[0140] For example, the third solder can be a high-temperature solder, such as a high-lead solder, an Au-based solder, etc.

[0141] For example, such as Figure 13 As shown, the electronic components in this application include any electronic components soldered onto the first metal-clad substrate 10, such as... Figure 13 Signal terminals in Figure 13 Power terminals, thermistors, etc.

[0142] To improve the bonding reliability between electronic components and the first metal-clad substrate, such as Figure 13As shown, at least one third support post 103 is provided between the electronic component 01 and the first metal-clad substrate 10. The at least one third support post 103 may be formed on the side of the electronic component 101 facing the first metal-clad substrate 10, or on the side of the first metal-clad substrate 10 facing the electronic component 101, and is not limited here.

[0143] In practice, the implementation of the third support column can refer to the implementation of the first and second support columns mentioned above, and will not be repeated here.

[0144] In this application, the first solder, the second solder, and the third solder can be formed using solder paste or solder sheet, and no limitation is made herein.

[0145] Optionally, all solders in this application can be made of the same material. For example, the first solder, the second solder, and the third solder can be formed using the same solder. In this way, the soldering of the chip to the interconnect pillar, the soldering of the interconnect pillar to the second metal-clad substrate, and the soldering of the electronic components to the first metal-clad substrate can be completed in one reflow soldering, thereby simplifying the process steps and saving costs.

[0146] Of course, in specific implementations, the first, second, and third solders can be different solders, and this is not limited here. For example, the first and third solders can be high-temperature solders, such as high-lead solders, Au-based solders, etc., and the second solder can be a medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0147] For example, with Figure 13 Taking the power module shown as an example, combined with Figure 14 After the chip 11 and the first metal-clad substrate 10 are pressure-bonded, the gate of the IGBT chip 11 is bonded to the first metal-clad substrate 10 via Al lines 104. Then, a first support pillar 16 and a second support pillar 17 are formed on both sides of the interconnect pillar 12. Next, a third support pillar 103 is implanted on the surface of the first metal-clad substrate 10 using ultrasonic technology. Then, a first solder 14 is formed between the chip 11 and the interconnect pillar 12, a second solder 15 is formed between the interconnect pillar 12 and the second metal-clad substrate 20, and a third solder 102 is formed between the electronic components 101 (power terminals and signal terminals) and the first metal-clad substrate 10. The solder can be a solder sheet or solder paste. Solder sheets can be formed by mounting, and solder paste can be formed by printing processes. The solder sheet or solder paste can be a high-temperature solder, such as a high-lead solder or an Au-based solder.

[0148] Then, vacuum reflow is performed to solder chip 11 to interconnect pillar 12, interconnect pillar 12 to the second metal-clad substrate 20, and electronic components 101 (power terminals and signal terminals) to the first metal-clad substrate 10. In this way, the various components of the power module are joined together. Since support pillars are embedded in the solder of each joined component, the thickness and warpage of the solder can be controlled.

[0149] After completing the internal interconnection of the power module, it needs to be encapsulated. In specific implementation, such as... Figure 15 As shown, molding compound 40 is filled between the first metal-clad substrate 10 and the second metal-clad substrate 20, and molds the first metal-clad substrate 10 and the second metal-clad substrate 20.

[0150] To prevent delamination between the molding compound and the molding interface and thus improve the reliability of the power module, a low-modulus molding compound is used. For example, the molding compound can be formed from a material with an elastic modulus between 0.5 GPa and 20 GPa, such as epoxy molding compound, etc., without limitation.

[0151] In practice, after molding, the top and bottom surfaces of the power module can be ground to make the two sides of the power module parallel. Of course, grinding can also be omitted depending on the requirements.

[0152] For example, after molding, the exposed terminals (such as signal terminals and power terminals) can be tin-plated to prevent terminal oxidation and increase the solderability of the terminals.

[0153] In the power module of this application, such as Figure 16 As shown, it may also include a first heat sink 50 located on the side of the first metal-clad substrate 10 away from the second metal-clad substrate 20 and a second heat sink 60 located on the side of the second metal-clad substrate 20 away from the first metal-clad substrate 10, thereby cooling the module from both sides and improving the power density and reliability of the power module.

[0154] For example, the first radiator and the second radiator can be water-cooled radiators, which are not limited here.

[0155] In specific implementation, the first metal-coated substrate and the first heat sink can be bonded together with thermally conductive silicone grease, and the second metal-coated substrate and the second heat sink can be bonded together with thermally conductive silicone grease.

[0156] Optionally, in order to improve heat dissipation, the first heat sink can be connected to the first metal-clad substrate by welding or sintering; and / or, the second heat sink can be connected to the second metal-clad substrate by welding or sintering.

[0157] For example, the first heat sink can be connected to the first metal-clad substrate by welding; the second heat sink can be connected to the second metal-clad substrate by welding.

[0158] Furthermore, such as Figure 16 As shown, a first support member is provided between the first heat sink 50 and the first metal-clad substrate 10. The first support member may be formed by a plurality of fourth support pillars 51 or metal wires; and / or, a second support member is provided between the second heat sink 60 and the second metal-clad substrate 20. The second support member may be formed by a plurality of fifth support pillars 61 or metal wires, thereby using the first support member and the second support member to control the solder thickness and ensure the reliability of the soldering.

[0159] In practice, the metal wire can be bonded and fixed to the mating surface of the heat sink or the heat dissipation surface of the power module to prevent the metal wire from flowing with the liquid metal during reflow.

[0160] In specific implementations, when the first supporting component is formed by multiple fourth supporting pillars, the fourth supporting pillars can be formed on the first heat sink or on the first metal-clad substrate, without limitation. In specific implementations, the implementation of the fourth supporting pillars can refer to the implementations of the first and second supporting pillars described above, and will not be repeated here.

[0161] In specific implementations, when the second support component is formed by multiple fifth support pillars, the fifth support pillars can be formed on the second heat sink or on the second metal-clad substrate; no limitation is made here. In specific implementations, the implementation of the fifth support pillars can refer to the implementations of the first and second support pillars described above, and will not be repeated here.

[0162] Accordingly, this application also provides a power supply circuit, including a circuit board and any of the power modules provided in this application. The power module is electrically connected to the circuit board, and the circuit board provides signals to the power module. Since the principle by which this power supply circuit solves the problem is similar to that of the aforementioned power module, the implementation of this power supply circuit can refer to the implementation of the aforementioned power module, and repeated details will not be described again.

[0163] Accordingly, this application also provides a chip, see [link to relevant documentation]. Figure 9 The surface electrode 111 of the chip 11 includes a stress buffer metal layer 1111 and a welded or sintered metal layer 1112 stacked together. The stress buffer metal layer 1111 can be made of a soft metal with a hardness of less than HV60, which utilizes the softness of the soft metal to release the stress at the joint.

[0164] For example, soft metals may include at least one of aluminum, aluminum alloys, copper, magnesium alloys, zinc, zinc alloys, silver, silver alloys, gold, and gold alloys, etc., without limitation.

[0165] In practical implementation, when the stress buffer metal layer is made of a non-weldable metal, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be placed below the welded or sintered metal layer.

[0166] For example, the welded or sintered metal layer may include: Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, and is not limited herein.

[0167] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A power module, characterized by The power module comprises: a first metal-clad substrate and a chip located on the first metal-clad substrate; a sintering material is arranged between the chip and the first metal-clad substrate, the chip and the first metal-clad substrate are electrically connected through the sintering material, and the sintering material comprises at least one of silver paste, copper paste and silver film; the sintering material comprises a main material and a filler filled in the main material; the main material comprises at least one of silver paste, copper paste or silver film; wherein the silver paste comprises at least one of micron silver paste and nano silver paste; the thermal expansion coefficient of the filler is less than the thermal expansion coefficient of the main material; the filler comprises at least one of nickel, nickel alloy, copper, nickel-plated copper, titanium, titanium alloy, iron, iron alloy, Kovar alloy and SiC powder.

2. The power module of claim 1, wherein, the chip has surface electrodes on the side facing the first metal-clad substrate and the side away from the first metal-clad substrate, and the surface electrodes comprise a soldered or sintered metal layer; the surface electrodes on the side of the chip facing the first metal-clad substrate further comprise a stress buffer metal layer on the side of the soldered or sintered metal layer away from the first metal-clad substrate; and / or, the surface electrodes on the side of the chip away from the first metal-clad substrate further comprise a stress buffer metal layer on the side of the soldered or sintered metal layer facing the first metal-clad substrate; the material of the stress buffer metal layer is a soft metal, and the hardness of the soft metal is less than HV60.

3. The power module of claim 2, wherein, the soft metal comprises at least one of aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold and gold alloy.

4. The power module of claim 3, wherein, the soldered or sintered metal layer comprises Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, Ni(P) / Au or Ni(P) / Ag.

5. The power module of any one of claims 1-4, wherein, The power module further comprises a second metal-clad substrate and electronic components, the first metal-clad substrate and the second metal-clad substrate are arranged oppositely, and the electronic components are located on the side of the first metal-clad substrate facing the second metal-clad substrate; the electronic components are connected to the first metal-clad substrate through a third solder.

6. The power module of claim 5, wherein, at least one third support column is further arranged between the electronic components and the first metal-clad substrate; the at least one third support column is arranged on the side of the electronic components facing the first metal-clad substrate or on the side of the first metal-clad substrate facing the electronic components.

7. The power module of any one of claims 1-4, wherein, The power module further comprises a second metal-clad substrate and plastic encapsulant, the first metal-clad substrate and the second metal-clad substrate are arranged oppositely, the plastic encapsulant is filled between the first metal-clad substrate and the second metal-clad substrate and encapsulates the first metal-clad substrate and the second metal-clad substrate, and the elastic modulus of the plastic encapsulant is 0.5 GPa-20 GPa.

8. The power module of claim 7, wherein, the material of the plastic encapsulant comprises epoxy plastic encapsulant.

9. The power module of any one of claims 1-4, wherein, The power module further comprises a second metal-clad substrate, a first heat sink and a second heat sink, the first metal-clad substrate is arranged opposite to the second metal-clad substrate, the first heat sink is located on the side of the first metal-clad substrate away from the second metal-clad substrate; the second heat sink is located on the side of the second metal-clad substrate away from the first metal-clad substrate.

10. The power module of claim 9, wherein, The first heat sink is connected with the first metal-clad substrate by welding or sintering; And / or, the second heat sink is connected with the second metal-clad substrate by welding or sintering.

11. The power module of claim 10, wherein, The first heat sink and the first metal-clad substrate have a first supporting component therebetween, the first supporting component comprises a plurality of fourth supporting columns or wires; And / or, the second heat sink and the second metal-clad substrate have a second supporting component therebetween, the second supporting component comprises a plurality of fifth supporting columns or wires.

Images