Power module, power supply circuit and chip

Abstract

The invention 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 which are oppositely arranged, and the chip and an interconnection column which are 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 adopting sintering materials through pressure sintering, the joint reliability can be improved, and the chip is electrically connected with the second metal-clad substrate through the interconnection columns. As the substrates are arranged on the two sides of the chip, heat generated in the power module can be discharged from the two substrates, and the heat dissipation performance of the power module is improved. Besides, the sintering material formed by the silver paste, the copper paste or the 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 application number of the original application is 202110908858.8, and the original application date is August 9, 2021. The entire content of the original application is incorporated herein by reference. Technical Field

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

[0003] With the development of power electronics technology, power modules have attracted more and more attention. At the same time, the requirements for energy conservation and low cost also urgently demand that power modules be more lightweight and miniaturized. However, this requirement poses a huge challenge to the development of power modules because lightweight and miniaturization will lead to an increase in the module current density, which will cause higher heat to be generated inside the module, thereby causing an increase in the junction temperature. If the generated heat cannot be discharged in time, the higher junction temperature will affect the overall thermo-mechanical 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, aiming to provide a power module with high heat dissipation performance, power density, and reliability.

[0005] In a first aspect, a power module provided by this application includes a first metal-clad substrate and a second metal-clad substrate that are oppositely arranged, a chip and an interconnection post located between the first metal-clad substrate and the second metal-clad substrate; wherein, a sintering material is further provided between the chip and the first metal-clad substrate, and the chip and the first metal-clad substrate are electrically connected through pressure sintering using the sintering material. The sintering material may include at least one of silver paste, copper paste, or silver film; the interconnection post is located between the chip and the second metal-clad substrate, and the chip is electrically connected to the second metal-clad substrate through the interconnection post. Since substrates are provided on both sides of the chip, the 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. Moreover, the sintering material has low stress, and the chip and the first metal-clad substrate are electrically connected by pressure sintering, which 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 improving the power density of the power module.

[0006] In specific implementation, the first metal-clad substrate and the second metal-clad substrate can be direct bond copper (DBC) substrates, active metal brazed copper (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) substrates, insulated metal substrate (IMS), etc., which are not limited herein.

[0007] Exemplarily, in order to further improve the power density, the first metal-clad substrate and the second metal-clad substrate can be formed of high thermal conductivity AlN-DBC, Si3N4-AMB or AlN-AMB, which are not limited herein.

[0008] Exemplarily, the sintering material can be formed of silver paste, copper paste or silver film.

[0009] In specific implementation, the silver paste can include at least one of micrometer silver particle paste and nanometer silver particle paste. Among them, the micrometer silver paste refers to the silver paste made of micrometer silver particles and organic solvents, which has low cost and is safe. Generally, it is sintered under pressure, the sintering material has high density, the interface of the bonded body is firmly bonded, and the bonding reliability is high. The nanometer silver paste is the silver paste made of nanometer silver particles and organic solvents, which has high cost and has the operation safety risk of nanometer particles.

[0010] Optionally, in order to improve the reliability of sintering bonding and reduce the cost, the sintering material of the present application can be formed of micrometer silver particle paste.

[0011] In order to further improve the reliability of sintering bonding, the elastic modulus, coefficient of thermal expansion (CTE), etc. of the sintering material can be adjusted by adding materials to the sintering material. Exemplarily, the sintering material includes a main material and a filler filled in the main material; wherein the main material includes at least one of silver paste, copper paste or silver film, the filler is formed of a material with good bonding property with the main material, and the coefficient of thermal expansion of the filler is less than that of the main material, thereby improving the bonding reliability of sintering.

[0012] Taking the main body material as micron silver paste as an example, fillers are added to the micron silver paste to reduce the thermal expansion coefficient of the micron silver paste and reduce the bonding stress, thereby improving the bonding reliability of silver soldering. Exemplarily, the filler may include at least one of nickel (Ni), Ni alloy, copper (Cu), nickel-plated copper, titanium (Ti), Ti alloy, iron (Fe), Fe alloy, Kovar (iron-nickel-cobalt alloy 4J29), and SiC powder, etc., which is not limited herein.

[0013] In this application, the metal layer coated on the surfaces of the first metal-coated layer substrate and the second metal-coated layer substrate is generally copper. When the sintering material is silver paste or silver film, in order to improve the bonding performance between the sintering material and the first metal-coated layer substrate, the first metal-coated layer substrate can be silver-plated at the sintering position, that is, the first metal-coated layer substrate is covered with a silver-plated layer in the area corresponding to the sintering material. Exemplarily, 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 itself and the first metal-coated layer substrate is relatively good, silver plating may not be required. For example, when the sintering material is copper paste, the first metal-coated layer substrate does not need to be silver-plated at the sintering position.

[0014] Exemplarily, 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 may be printed on the corresponding sintering area of the first metal-clad substrate by means of a stencil printing process or a screen printing process. Then, in an N2 atmosphere, the copper paste or silver paste printed on the first metal-clad substrate may be pre-dried at a temperature of 100°C to 180°C for 5 min to 40 min. Thereafter, the chip is fixed on 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 for at least 10 ms in an environment with a temperature of 100°C to 180°C. When the sintering material is a silver film, the chip may be adsorbed by a metal nozzle, and the temperature of the metal nozzle is 80°C to 200°C. Then the chip is pressed on a large piece of silver film, a pressure of 0.1 MPa to 5 MPa is applied, and the pressurization time is 1 ms to 10,000 ms. In this way, the silver film under the chip is compressed and semi-sintered and adheres to the chip. Then, through vacuum adsorption, the chip with the adhered silver film is fixed on the first metal-clad substrate, and a pressure of 0.1 MPa to 10 MPa is applied to the chip mounted on the first metal-clad substrate for at least 10 ms in an environment with a temperature of 100°C to 180°C. Step (2), pressure sintering may be performed on the chip mounted on the first metal-clad substrate by means of a pressure head. Taking the area of the pressure head as 50 mm * 50 mm as an example, the parallelism of the pressure head may be set to ≤ 5 μm, so as to reduce the warping of the sintered product. Exemplarily, the sintering conditions for pressure sintering may be: the sintering temperature is controlled at 200°C to 300°C, the applied pressure is controlled at 5 MPa to 30 MPa, and the sintering time is controlled at 1 min to 10 min. To prevent damage to the chip by the pressure head during the sintering process, when performing pressure sintering on the chip mounted on the first metal-clad substrate, a removable stress relief film may also be placed between the chip and the pressure head. Thus, during pressure sintering, the stress relief film can prevent direct contact between the pressure head and the chip and reduce the damage caused by stress concentration of the pressure head to the chip. When the pressure sintering is completed, the stress relief film may be removed. Exemplarily, the stress relief film may be an organic film such as a Teflon film, which is not limited herein.

[0015] Further, in order to control the warping degree of the sintered product, the first metal-clad substrate and the chip after sintering may be cooled under a pressurized state. Exemplarily, the cooling conditions may be: the applied pressure is controlled at 5 MPa to 20 MPa, and the cooling time is controlled at 1 min to 10 min.

[0016] Optionally, after the chip mounted on the first metal-clad substrate is subjected to pressure sintering, the first metal-clad substrate with the chip mounted thereon can also be subjected to a cleaning process to remove residual organic matter. For example, the plasma treatment process or the organic solvent cleaning process is used to remove the residual organic matter on the first metal-clad substrate and other places, increase the interfacial bonding property of the subsequent encapsulant, prevent the encapsulant from delaminating, and further improve the reliability of the power module.

[0017] Optionally, in order to release the stress generated on the chip during welding or sintering to improve the reliability of the power module, the surface electrodes are provided on both the side of the chip facing the first metal-clad substrate and the side of the chip away from the first metal-clad substrate, and the surface electrodes include a welding or sintering metal layer; the surface electrode on the side of the chip facing the first metal-clad substrate further includes a stress buffer metal layer located on the side of the welding or sintering 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 buffer metal layer located on the side of the welding or sintering metal layer facing the first metal-clad substrate.

[0018] Exemplarily, the material of the stress buffer metal layer can be a soft metal with a hardness less than HV60, such as aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold or gold alloy. The softness of the soft metal is utilized to release the stress at the joint.

[0019] In specific implementation, when the material of the stress buffer metal layer is a metal without weldability, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be provided below the welding or sintering metal layer.

[0020] Exemplarily, the welding or sintering metal layer can 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 specific implementation, the first solder can be used to connect the interconnection posts on the side of the chip away from the first metal-clad substrate by welding; the second solder can be used to connect the side of the interconnection posts away from the chip to the second metal-clad substrate by welding.

[0022] In specific implementation, the thickness of the solder has an important impact on solder joint reliability and the like. To ensure the controllability and uniformity of the solder thickness, at least one first support pillar is provided between the interconnecting pillar and the chip. The at least one first support pillar can be formed on the side of the interconnecting pillar facing the chip, that is, formed on the interconnecting pillar; the at least one first support pillar can also be formed on the side of the chip facing the interconnecting pillar, that is, formed on the chip. And / or, at least one second support pillar is provided between the interconnecting pillar and the second metal-clad substrate. The at least one second support pillar can be formed on the side of the interconnecting pillar facing the second metal-clad substrate, that is, formed on the interconnecting pillar; the at least one second support pillar can also be formed on the side of the second metal-clad substrate facing the interconnecting pillar, that is, formed on the second metal-clad substrate.

[0023] In the power module of the present application, in addition to the chip and the interconnecting pillar, it may further include electronic components located on the side of the first metal-clad substrate facing the second metal-clad substrate, and the electronic components are connected to the first metal-clad substrate through a third solder.

[0024] In the present application, the first solder, the second solder, and the third solder can be formed by solder paste or solder sheet, which is not limited herein.

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

[0026] Of course, in specific implementation, the first solder, the second solder, and the third solder can also be different solders, which is not limited herein. Exemplarily, the first solder and the third solder can be high-temperature solders, such as high-lead solder, Au-based solder, etc., and the second solder can be medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0027] Exemplarily, the electronic components in the present application include any electronic components soldered to the first metal-clad substrate through solder, such as signal terminals, power terminals, thermistors, etc.

[0028] To improve the joint reliability between the electronic components and the first metal-clad substrate, at least one third support pillar is further provided between the electronic components and the first metal-clad substrate. The at least one third support pillar can be formed on the side of the electronic components facing the first metal-clad substrate, or can be formed on the side of the first metal-clad substrate facing the electronic components, which is not limited herein.

[0029] Optionally, the material of the support column is a conductive material. Exemplarily, the support column can be formed of at least one of Al, Al alloy, Au, Au alloy, Cu, Cu alloy, Ni, Ni alloy, copper clad with aluminum, Cu-Sn high melting point alloy, or high temperature solder.

[0030] Furthermore, the present application also includes a molding compound filled between the first metal-clad substrate and the second metal-clad substrate and molding the first metal-clad substrate and the second metal-clad substrate. In order to prevent delamination of the molding compound and the molding interface and improve the reliability of the power module, a low modulus molding compound is used. Exemplarily, the molding compound can be formed of a material with an elastic modulus between 0.5 GPa and 20 GPa, such as an epoxy molding compound, etc., which is not limited herein.

[0031] In the power module of the present application, a first heat sink can also be included on the side of the first metal-clad substrate away from the second metal-clad substrate, and a second heat sink can be included on the side of the second metal-clad substrate away from the first metal-clad substrate, so as to cool the module from both sides and improve the power density and module reliability of the power module.

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

[0033] Furthermore, a first support member is provided between the first heat sink and the first metal-clad substrate, and the first support member can be formed by a plurality of fourth support columns, metal wires or metal meshes; and / or, a second support member is provided between the second heat sink and the second metal-clad substrate, and the second support member can be formed by a plurality of fifth support columns or metal wires, so as to control the solder thickness by using the first support member and the second support member and ensure the reliability of welding.

[0034] In specific implementation, the metal wire can be bonded and fixed on the bonding 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] In a second aspect, an embodiment of the present application also provides a power supply circuit, including a circuit board and a power module as described in the first aspect or various implementation manners of the first aspect. The power module is electrically connected to the circuit board, and the circuit board provides signals for the power module.

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

[0037] In a third aspect, an embodiment of the present application further provides a chip. The surface electrodes of the chip include a stress buffer metal layer and a welding or sintering metal layer arranged in a stacked manner. Among them, the material of the stress buffer metal layer can be a soft metal with a hardness less than HV60, and the flexibility of the soft metal is utilized to release the stress at the joint.

[0038] Exemplarily, the soft metal may include at least one of aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold, and gold alloy, etc., which is not limited herein.

[0039] In specific implementation, when the material of the stress buffer metal layer is a metal without weldability, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be arranged below the welding or sintering metal layer.

[0040] Exemplarily, the welding or sintering 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, which is not limited herein. Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of a power module provided by an embodiment of the present application;

[0042] Figure 2 It is a schematic flow diagram of a method for preparing a power module provided by an embodiment of the present application;

[0043] Figure 3 It is a schematic cross-sectional diagram of a sintered material filled with a filler provided by an embodiment of the present application;

[0044] Figure 4 It is a schematic flow diagram of another method for preparing a power module provided by an embodiment of the present application;

[0045] Figure 5 It is a schematic structural diagram of a process for preparing a power module provided by an embodiment of the present application;

[0046] Figure 6 It is a schematic flow diagram of another method for preparing a power module provided by an embodiment of the present application;

[0047] Figure 7 It is a schematic structural diagram of another process for preparing a power module provided by an embodiment of the present application;

[0048] Figure 8 It is a schematic structural diagram of another power module provided by an embodiment of the present application;

[0049] Figure 9Schematic diagram of the structure of the chip provided by the embodiment of the present application;

[0050] Figure 10 Ultrasonic scanning photo of the sintered layer in an embodiment of the present application;

[0051] Figure 11 Schematic diagram of the structure with support columns arranged between two joined bodies welded by solder in the embodiment of the present application;

[0052] Figure 12 Schematic diagram of the structure of the interconnection column provided by the embodiment of the present application;

[0053] Figure 13 Schematic diagram of the structure of another power module provided by the embodiment of the present application;

[0054] Figure 14 Schematic diagram of the structure of the manufacturing process of another power module provided by the embodiment of the present application;

[0055] Figure 15 Schematic diagram of the structure of another power module provided by the embodiment of the present application;

[0056] Figure 16 Schematic diagram of the structure of another power module provided by the embodiment of the present application. Detailed implementation manners

[0057] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

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

[0059] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "inside", "above", "below", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. The words expressing position and direction described in the present application are all illustrated with the drawings as examples, but can be changed according to needs, and all changes made are included in the protection scope of the present invention. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true proportion. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0060] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0061] To facilitate the understanding of the power module provided by the embodiments of the present application, its application scenario will be described first. The power module is widely used in power supply circuits. Among them, the power module is a semiconductor device that converts the voltage, current, frequency, etc. of the power supply, and is the core device for power conversion in the power supply circuit. For example, the power supply circuit can be used as the core device for converting direct current to alternating current in the motor control part (MCU) of an electric vehicle, output direct current from the battery of the electric vehicle, or convert direct current into alternating current required for vehicle operation, etc.

[0062] Due to the requirements of energy conservation and low cost, there is an urgent need for the power module to be more lightweight and miniaturized. However, this requirement poses a huge challenge to the development of the power module because lightweight and miniaturization will lead to an increase in the module current density, resulting in higher heat generation inside the module, which in turn causes an increase in the junction temperature. If the generated heat cannot be dissipated in time, the high junction temperature will affect the overall thermo-mechanical performance and reliability of the module.

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

[0064] See Figure 1 , Figure 1Schematic diagram of the structure of a power module provided by an embodiment of the present application. The power module 1 includes: a first metal-clad substrate 10 and a second metal-clad substrate 20 which are oppositely arranged, a chip 11 and an interconnect post 12 located between the first metal-clad substrate 10 and the second metal-clad substrate 20; wherein, a sintering material 13 is further arranged 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. The sintering material 13 may include at least one of silver paste, copper paste or silver film; the interconnect post 12 is 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 post 12. Since substrates are arranged 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. Moreover, the sintering material has low stress, and the chip 11 is electrically connected to the first metal-clad substrate 10 by pressure sintering, which can improve the bonding reliability. In addition, the sintering material 13 in the present application has the advantages of low sintering temperature, high melting point and high thermal conductivity. Therefore, not only can the heat dissipation performance of the power module be further improved, but also the operating ambient temperature and service life of the power module can be improved, thereby increasing the power density of the power module.

[0065] See Figure 2 , Figure 2 Schematic diagram of the process of a method for manufacturing a power module provided by an embodiment of the present application. The manufacturing method may include the following steps:

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

[0067] In a specific implementation, the first metal-clad substrate and the second metal-clad substrate may be a direct bond copper (DBC) substrate, an active metal brazed copper (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) substrate, or an insulated metal substrate (IMS), etc., which are not limited herein.

[0068] Exemplarily, in order to further increase the power density, the first metal-clad substrate and the second metal-clad substrate may be formed of high thermal conductivity AlN-DBC, Si3N4-AMB or AlN-AMB, which are not limited herein.

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

[0070] Exemplarily, the sintered material can be formed from silver paste, copper paste, or silver film.

[0071] In specific implementation, the silver paste can include at least one of micrometer silver particle paste and nanometer silver particle paste. Among them, the micrometer silver paste refers to the silver paste made of micrometer silver particles and organic solvents, which has low cost and is safe. Generally, it is sintered under pressure, the sintered material has high density, the bonding at the interface of the bonded body is firm, and the bonding reliability is high. The nanometer silver paste is the silver paste made of nanometer silver particles and organic solvents, which has high cost and the occupational safety risk of nanometer particles.

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

[0073] In order to further improve the reliability of sintering bonding, the elastic modulus, coefficient of thermal expansion (CTE), etc. of the sintered material can be adjusted by adding materials to the sintered material. Exemplarily, the sintered material includes a main material and a filler filled in the main material; where the main material includes at least one of silver paste, copper paste, or silver film, the filler is formed of a material with good bonding property to the main material, and the coefficient of thermal expansion of the filler is less than that of the main material, thereby improving the bonding reliability of sintering.

[0074] Taking the main material as micrometer silver paste as an example, adding a filler to the micrometer silver paste reduces the coefficient of thermal expansion of the micrometer silver paste and reduces the bonding stress, thereby improving the bonding reliability of silver soldering. Exemplarily, the filler can include at least one of nickel (Ni), Ni alloy, copper (Cu), nickel-plated copper, titanium (Ti), Ti alloy, iron (Fe), Fe alloy, Kovar (iron-nickel-cobalt alloy 4J29), and SiC powder, etc., which is not limited herein.

[0075] The present application does not limit the shape of the filler. Exemplarily, as Figure 3 shown, the length L1 of the filler 131 can be controlled between 20 μm and 100 μm, and the dimension W1 of the filler 131 in the direction perpendicular to the length direction can be controlled between 20 nm and 30 μm. The cross-section along the length direction can be circular, elliptical, polygonal, etc.

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

[0077] Exemplarily, when the sintering material is copper paste or silver paste, referring to Figure 4 and Figure 5 , the chip can be mounted on the first metal-coated substrate through the following steps:

[0078] Step S1021a: Print the sintering material on the first metal-coated substrate.

[0079] In specific implementation, as shown in (a) and (b) of Figure 5 , the steel mesh printing process or the screen printing process can be used to print the sintering material 13 (copper paste or silver paste) on the corresponding sintering area of the first metal-coated substrate 10. Since the steel mesh printing process has lower cost and is simpler to manufacture than the screen printing process. Therefore, optionally, the steel mesh printing process is adopted in this application to print the copper paste or silver paste on the corresponding sintering area of the first metal-coated substrate.

[0080] Exemplarily, the thickness of the printed copper paste or silver paste can be controlled between 30 μm and 160 μm, and can be specifically designed according to the actual product, which is not limited herein.

[0081] Optionally, the area of the printed copper paste or silver paste can be set to be larger than the area of the corresponding sintering area on the chip to absorb the alignment error between the chip and the sintering material. The boundary of the copper paste or silver paste can extend 20 μm to 300 μm outward from the target boundary (the boundary of the sintering area of the chip in the ideal state).

[0082] Step S1022a: Perform pre-drying treatment on the printed sintering material.

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

[0084] Exemplarily, as shown in (c) of Figure 5 , in an N2 atmosphere, the sintering material 13 (copper paste or silver paste) printed on the first metal-coated substrate 10 can be pre-dried at a temperature of 100 °C to 180 °C for 5 min to 40 min.

[0085] Step S1023a: Mount the chip on the sintered material of the first metal-clad substrate and apply pressure.

[0086] In specific implementation, as Figure 5 shown in (d), the chip 11 can be lifted by vacuum adsorption first, then the sintered material 13 (copper paste or silver paste) can be aligned through an image recognition system, and then the chip 11 can be fixed on the dried sintered material 13 (copper paste or silver paste) and pressure is applied.

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

[0088] Exemplarily, when the sintered material is a silver film, referring to Figure 6 and Figure 7 , the chip can be mounted on the first metal-clad substrate through the following steps:

[0089] Step S1021b: Adhere the sintered material on the side of the chip facing the first metal-clad substrate.

[0090] In specific implementation, as Figure 7 shown in (a), the chip 11 can be adsorbed by a metal nozzle, and the temperature of the metal nozzle is 80°C to 200°C. Then the chip 11 is pressed on a large silver film, a pressure of 0.1 MPa to 5 MPa is applied, and the pressurization time is 1 ms to 10,000 ms. In this way, the sintered material 13 (silver film) under the chip is compressed and semi-sintered and adheres to the chip 11.

[0091] Step S1022b: Mount the chip with the adhered sintered material on the first metal-clad substrate and apply pressure.

[0092] In specific implementation, as Figure 7 shown in (b), the chip 11 can be lifted by vacuum adsorption first, then the first metal-clad substrate 10 can be aligned through an image recognition system, and then the chip 11 with the adhered sintered material 13 (silver film) is fixed on the first metal-clad substrate 10 and pressure is applied.

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

[0094] After the chip mounting is completed, step S103 is executed.

[0095] Step S103: Press sinter the chip mounted on the first metal-clad substrate.

[0096] Press sintering means applying pressure to the joined body at high temperature to increase the density of the sintered body, promote atomic diffusion between the sintered material particles and at the interface between the sintered material and the joined body, and enhance the bonding strength and joint reliability. The present application does not limit the process of the press sintering adopted, and any well-known method can be used.

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

[0098] Exemplarily, the sintering conditions for press sintering are: the sintering temperature is controlled at 200°C to 300°C, the applied pressure is controlled at 5 MPa to 30 MPa, and the sintering time is controlled at 1 min to 10 min.

[0099] In specific implementation, the press sintering process can be carried out in an air environment. To prevent product oxidation, the chip mounted on the first metal-clad substrate is press sintered in a protective atmosphere or a vacuum environment. The protective atmosphere can be a reducing atmosphere or an inert atmosphere. Exemplarily, the protective atmosphere can be N2, a mixed gas of N2 and H2, Ar, He, etc., which is not limited herein.

[0100] To prevent damage to the chip by the pressure head during the sintering process, as Figure 5 shown in (e) and Figure 7 shown in (c), when press sintering the chip mounted on the first metal-clad substrate, a removable stress relief film 30 can also be placed between the chip 11 and the pressure head. Thus, during the press sintering, the stress relief film 30 can prevent direct contact between the pressure head and the chip 11 and reduce the damage caused by stress concentration of the pressure head to the chip 11. When the press sintering is completed, the stress relief film can be removed.

[0101] Optionally, the thickness of the stress relaxation film can be set to 50 μm to 90 μm, which is not limited herein.

[0102] Exemplarily, the stress relaxation film can be an organic film such as a Teflon film, which is not limited herein.

[0103] Furthermore, in order to control the warpage of the product after sintering, as Figure 5 shown in (f) and Figure 5 shown in (d), the first metal-clad substrate 10 and the chip 11 after sintering are cooled under a pressurized state.

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

[0105] Exemplarily, the cooling conditions can be: the applied pressure is controlled at 5 MPa to 20 MPa, and the cooling time is controlled at 1 min to 10 min.

[0106] Optionally, for enhanced cooling, water cooling can be used, or forced nitrogen cooling can be used, which is not limited herein.

[0107] Optionally, after pressure sintering the chip mounted on the first metal-clad substrate, the first metal-clad substrate with the mounted chip can also be subjected to a cleaning process to remove residual organic substances. For example, the plasma treatment process or the organic solvent cleaning process is used to remove the residual organic substances on the first metal-clad substrate and other places, increase the interfacial bonding property of the subsequent encapsulant, prevent the encapsulant from delaminating, and further improve the reliability of the power module.

[0108] Among them, plasma treatment refers to the cleaning treatment of the surface of an object by the bombardment effect of plasma particles and the reaction of plasma ions with organic substances in the plasma.

[0109] Step S104: Use an interconnect post to connect the side of the chip away from the first metal-clad substrate to the second metal-clad substrate.

[0110] In specific implementation, the interconnect post can be formed of metal, alloy or composite material and is used to connect the side of the chip away from the first metal-clad substrate to the second metal-clad substrate.

[0111] Exemplarily, the material of the interconnecting posts can be Cu, Ni, Mo, W, tungsten alloy, Cu-Mo alloy, AlSiC, nickel alloy, etc., or it can also 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, and Ni, Ni(P) or Cu plated on the surface of the AlSiC composite material after sensitization treatment. Of course, Ag or Au can also be plated on the surface of the Ni, Ni(P) or Cu coating.

[0112] In this application, Ni(P) refers to a Ni coating containing phosphorus (P) manufactured by an electroless plating process. During electroless plating, P and Ni are simultaneously precipitated from the solution and deposited on the substrate, and P is an inevitable accompanying substance.

[0113] This application does not limit the type and number of chips in the power module, and can be any number and any type of chips applied to the power module. Exemplarily, as Figure 8 shown, the chip 11 can be an Insulated Gate Bipolar Transistor (IGBT) and a Fast Recovery Diode (FRD). Both the IGBT chip 11 and the FRD chip 11 are electrically connected to the first metal-clad layer substrate 10 through the sintering material 13.

[0114] In specific implementation, continue to refer to Figure 8 , the gate of the IGBT chip 11 can be electrically connected to the first metal-clad layer substrate 10 through the Al wire 104.

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

[0116] Exemplarily, the welded or sintered metal layer can 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. When manufacturing the surface electrode of the chip, a NiV target is used and the coating is manufactured by a sputtering process.

[0118] Optionally, in order to release the stress generated on the chip during soldering or sintering and improve the reliability of the power module, a stress buffer metal layer can be added to the surface electrode. The material of the stress buffer metal layer can be a soft metal with a hardness less than HV60, such as aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold, or gold alloy, etc. The softness of the soft metal is utilized to release the stress at the joint.

[0119] In specific implementation, when the material of the stress buffer metal layer is a metal without solderability, such as aluminum, aluminum alloy, or magnesium alloy, the stress buffer metal layer can be disposed below the soldering or sintering metal layer.

[0120] Exemplarily, the stress buffer metal layer can be disposed only in the surface electrode on the side of the chip facing the first metal-clad substrate, or only in the surface electrode on the side of the chip facing the interconnect post, or the stress buffer metal layer can be disposed in the surface electrodes on both sides of the chip. There is no limitation here.

[0121] Exemplarily, taking the material of the stress buffer metal layer as aluminum or aluminum alloy as an example, as Figure 9 shown, the chip 11 can include a semiconductor body 110, and a surface electrode 111 is disposed on the surface of the semiconductor body 110. Among them, a stress buffer metal layer 1111 is disposed in the surface electrode 111 on the side of the chip 11 facing the first metal-clad substrate. The stress buffer metal layer 1111 is located on the side of the soldering or sintering metal layer 1112 away from the first metal-clad substrate, that is, the stress buffer metal layer 1111 is located between the soldering or sintering metal layer 1112 and the semiconductor body 110. And / or, a stress buffer metal layer 1111 is disposed in the surface electrode 111 on the side of the chip 11 facing the interconnect post. The stress buffer metal layer 1111 is located on the side of the soldering or sintering metal layer 1112 away from the interconnect post, that is, the stress buffer metal layer 1111 is located between the soldering or sintering metal layer 1112 and the semiconductor body 110. Among them, Figure 9 Taking the example that the stress buffer metal layers 1111 are disposed in the surface electrodes 111 on both sides of the chip 11 for illustration.

[0122] In specific implementation, when forming the surface electrode of the chip, a layer of Al film or Al alloy layer can be formed first by physical vapor deposition (PVD) method or other methods. Because a protective oxide film is easily formed on the surface of Al and it has no solderability. In order to have solderability or sinterability on non-solderable Al, a weldable metal and a surface wetting metal can be electrolessly plated on the stress buffer metal layer to form a soldering or sintering metal layer. Or, the soldering or sintering metal layer can also be fabricated by methods such as plasma PVD method on the surface.

[0123] In a feasible implementation, when forming the surface electrode of the chip, a layer of Al film can be first formed by PVD method or other methods. Then, through Zincate treatment, Zn is used to replace the aluminum oxide film, and then electroless plating Ni(P) is used to replace Zn. It is also possible to electroless plate gold (Au) or silver (Ag) on the Ni(P) layer. That is, the surface electrode includes a stress buffer metal layer Al and a welding or sintering metal layer Ni(P) / Au or Ni(P) / Ag. The phosphorus content in Ni(P) is generally 5wt.% - 12wt.%. Alternatively, after forming a layer of Al film, Ti / Ni / Ag can be formed by PVD method, that is, the surface electrode includes a stress buffer metal layer Al and a welding or sintering metal layer Ti / Ni / Ag.

[0124] Of course, when forming the surface electrode, it is also possible not to form a stress buffer metal layer, but directly form a welding or sintering metal layer by PVD method, such as Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, etc.

[0125] In the present application, the thickness of the surface electrode of the chip is not limited and is set according to the actual product. Exemplarily, the thickness of the surface electrode can be controlled between 2μm and 10μm.

[0126] Exemplarily, a chip with a stress buffer metal layer is sintered to a metalized ceramic substrate with micron silver paste filled with fillers. Under the harsh unencapsulated state, the ultrasonic (SAT) scan photo of the sintered layer after 1000 times of temperature shock (-40°C to 125°C) is as Figure 10 shown, and it can be seen from Figure 10 that no peeling occurs in the sintered layer. It can be seen that sintering the chip with a stress buffer metal layer in combination with silver paste that reduces the elastic modulus and coefficient of thermal expansion can achieve high-reliability bonding.

[0127] In the present application, after the chip is connected to the first metalized layer substrate by pressure sintering, as Figure 1 and Figure 8 shown, the chip can be connected to the interconnection pillar 12 through the first solder 14, and the interconnection pillar 12 is connected to the second metalized layer substrate 20 through the second solder 15. In specific implementation, the first solder can be used to connect the interconnection pillar on the side of the chip away from the first metalized layer substrate by welding; the second solder can be used to connect the side of the interconnection pillar away from the chip to the second metalized layer substrate by welding.

[0128] Exemplarily, the first solder and the second solder can be formed by solder paste or solder sheet. Among them, the first solder can be a high-temperature solder, such as a high-lead solder, an Au-based solder, etc., and the second solder can be a medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0129] In specific implementation, the thickness of the solder has an important impact on solder joint reliability, etc. To ensure the controllability and uniformity of the solder thickness, as Figure 11 shown, support pillars 03 can be provided between two objects to be joined 01 and 02 (two objects welded by solder, such as a chip and an interconnect post, an interconnect post and a second metal-clad substrate), so as to control the thickness and uniformity of the solder 04 between the two objects to be joined 01 and 02 by using the support pillars 03. Among them, the support pillars 03 can be formed on any one of the two objects to be joined 01 and 02.

[0130] Exemplarily, in the present application, as Figure 8 shown, at least one first support pillar 16 is provided between the interconnect post 12 and the chip 11. The at least one first support pillar 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 pillar 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] Exemplarily, in the present application, as Figure 8 shown, at least one second support pillar 17 is provided between the interconnect post 12 and the second metal-clad substrate 20. The at least one second support pillar 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 pillar 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] The present application does not limit the number of the first support pillar and the second support pillar, which is specifically determined according to the area of the welding area. The larger the area of the welding area, the more the number of support pillars.

[0133] In the present application, the size of the support pillar can be set to a micron-level size, which is mainly used to support the objects to be joined on both sides of the support pillar to control the thickness of the solder and ensure the uniformity of the solder thickness.

[0134] Optionally, the materials of the first support pillar and the second support pillar are conductive materials. Exemplarily, the first support pillar and the second support pillar can be formed by at least one of Al, Al alloy, Au, Au alloy, Cu, Cu alloy, Ni, Ni alloy, copper coated with aluminum, Cu-Sn high melting point alloy, or high-temperature solder.

[0135] In specific implementation, the height of the support column is determined according to the target thickness of the solder. Exemplarily, the thickness of the support column can be controlled between 0.02 mm and 10 mm.

[0136] Exemplarily, ultrasonic technology can be used to implant support columns with micron-sized dimensions on the object to be joined. The small-sized support columns have no impact on the soldering process and solder reliability of the solder. The implanted support columns can be spherical or cylindrical initially, and then the implanted support columns are flattened to achieve adjustable and controllable height of the implanted support columns. Thus, the thickness and warpage of the solder during the soldering process can be controlled.

[0137] Exemplarily, as Figure 12 shown, taking the implantation of support columns on both sides of the interconnect post 12 as an example, ultrasonic technology is used to implant metal balls with micron-sized dimensions on the side of the interconnect post 12 facing the chip. The implanted metal balls are flattened (Leveling) to form the first support column 16. Then, the side of the interconnect post 12 with the first support column 16 implanted is placed face down in the fixture, so that the implanted first support column 16 enters the cavity of the fixture. Through the positioning of the fixture, metal balls are implanted on the side of the interconnect post 12 facing the second metal-clad substrate in the same way, and the implanted metal balls are flattened to form the second support column 17, so as to symmetrically arrange support columns on both sides of the interconnect post 12, which is convenient for recognition and grasping during automatic mounting.

[0138] Among them, the flattening process of the metal balls can be achieved by pressing the metal balls flat, making the heights of the implanted metal balls consistent and meeting the requirements of the designed solder thickness, so that the thickness of the solder can be controlled to be uniform.

[0139] In the power module of the present application, as Figure 13 shown, in addition to the chip 11 and the interconnect post 12, it may further 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 through the third solder 102.

[0140] Exemplarily, the third solder can use high-temperature solder, such as high-lead solder, Au-based solder, etc.

[0141] Exemplarily, as Figure 13 shown, the electronic components in the present application include any electronic components soldered on the first metal-clad substrate 10 through solder, such as Figure 13 the signal terminals in Figure 13 the power terminals in

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

[0143] In specific implementation, for the implementation of the third support pillar, reference may be made to the implementation of the above-mentioned first support pillar and second support pillar, which will not be elaborated herein.

[0144] In this application, the first solder, the second solder, and the third solder may be formed by solder paste or solder sheet, which is not limited herein.

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

[0146] Of course, in specific implementation, the first solder, the second solder, and the third solder may also use different solders, which is not limited herein. Exemplarily, the first solder and the third solder may use high-temperature solders, such as high-lead solders, Au-based solders, etc., and the second solder may use medium-temperature solders, such as SAC305, Sn-Sb solders, etc.

[0147] Exemplarily, taking Figure 13 the power module shown as an example, in combination with Figure 14 , after pressure sintering the chip 11 and the first metal-clad substrate 10, the gate of the IGBT chip 11 and the first metal-clad substrate 10 are bonded by an Al wire 104. Then, the first support pillar 16 and the second support pillar 17 are formed on both sides of the interconnecting pillar 12. Then, the third support pillar 103 is implanted on the surface of the first metal-clad substrate 10 by ultrasonic technology. Then, the first solder 14 is formed between the chip 11 and the interconnecting pillar 12, the second solder 15 is formed between the interconnecting pillar 12 and the second metal-clad substrate 20, and the third solder 102 is formed between the electronic component 101 (power terminal and signal terminal) and the first metal-clad substrate 10. Among them, the solder may be a solder sheet or solder paste. The solder sheet may be formed by mounting, and the solder paste may be formed by a printing process. Among them, the solder sheet or solder paste may be a high-temperature solder, such as a high-lead solder, an Au-based solder, etc.

[0148] Then, vacuum reflow is carried out to weld the chip 11 to the interconnecting posts 12, the interconnecting posts 12 to the second metal-clad substrate 20, and the 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 posts are implanted in the solder of each joined body, the thickness and warpage of the solder can be controlled.

[0149] After the internal interconnection of the power module is completed, potting is required. In a specific implementation, as Figure 15 shown, the potting compound 40 is filled between the first metal-clad substrate 10 and the second metal-clad substrate 10, and the first metal-clad substrate 10 and the second metal-clad substrate 20 are potted.

[0150] To prevent delamination at the potting compound and potting interface and improve the reliability of the power module, a potting compound with a low modulus is used. Exemplarily, the potting compound can be formed of a material with an elastic modulus between 0.5 GPa and 20 GPa, such as an epoxy potting compound, etc., which is not limited herein.

[0151] In a specific implementation, after potting, the upper and lower surfaces of the power module can be ground to make the two surfaces of the power module parallel. Of course, grinding may not be required according to the needs.

[0152] Exemplarily, after potting, the exposed terminals (such as signal terminals and power terminals) can also be tinned to prevent terminal oxidation and increase the solderability of the terminals.

[0153] In the power module of the present application, as Figure 16 shown, it may further 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, so as to cool the module from both sides and improve the power density and module reliability of the power module.

[0154] Exemplarily, the first heat sink and the second heat sink can be water-cooled heat sinks, which are not limited herein.

[0155] In a specific implementation, the first metal-clad substrate and the first heat sink can be joined by thermal conductive grease, and the second metal-clad substrate and the second heat sink can be joined by thermal conductive grease.

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

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

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

[0159] In specific implementation, the metal wire can be bonded and fixed on the bonding 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 implementation, when the first support member is formed by a plurality of fourth support posts, the fourth support posts can be formed on the first heat sink or on the first metal-clad substrate, which is not limited herein. In specific implementation, the implementation of the fourth support posts can refer to the implementation of the first support posts and the second support posts above, and will not be elaborated herein.

[0161] In specific implementation, when the second support member is formed by a plurality of fifth support posts, the fifth support posts can be formed on the second heat sink or on the second metal-clad substrate, which is not limited herein. In specific implementation, the implementation of the fifth support posts can refer to the implementation of the first support posts and the second support posts above, and will not be elaborated herein.

[0162] Correspondingly, the embodiment of the present application also provides a power supply circuit, including a circuit board and any one of the power modules provided in the above embodiments of the present application. The power module is electrically connected to the circuit board, and the circuit board provides signals for the power module. Since the principle of solving problems of this power supply circuit is similar to that of the foregoing power module, the implementation of this power supply circuit can refer to the implementation of the foregoing power module, and the repeated parts will not be elaborated.

[0163] Correspondingly, the embodiment of the present application also provides a chip. Refer to Figure 9 , the surface electrode 111 of the chip 11 includes a stress buffer metal layer 1111 and a welding or sintering metal layer 1112 which are stacked. Among them, the material of the stress buffer metal layer 1111 can be a soft metal with a hardness less than HV60, and the stress at the joint is released by using the softness characteristics of the soft metal.

[0164] Exemplarily, the soft metal can include at least one of aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold, and gold alloy, etc., which is not limited herein.

[0165] In specific implementation, when the material of the stress buffer metal layer is a metal without weldability, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be disposed below the welding or sintering metal layer.

[0166] Exemplarily, the welding or sintering metal layer can include: Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, which is not limited herein.

[0167] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. A power module, characterized in that, Comprising: A first metal-clad substrate and a chip located on the first metal-clad substrate; A sintering material is provided between the chip and the first metal-clad substrate, and the chip and the first metal-clad substrate are electrically connected through the sintering material. The sintering material includes at least one of silver paste, copper paste, and silver film; The sintering material includes a main material and fillers filled in the main material; the main material includes at least one of silver paste, copper paste, or silver film; wherein, the silver paste includes at least one of micron silver paste and nano silver paste; The thermal expansion coefficient of the filler is less than that of the main material; The filler includes 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 according to claim 1, characterized in that Both the side of the chip facing the first metal-clad substrate and the side of the chip away from the first metal-clad substrate have surface electrodes, and the surface electrodes include a welded or sintered metal layer; The surface electrode located on the side of the chip facing the first metal-clad substrate further includes a stress buffer metal layer located on the side of the welded or sintered metal layer away from the first metal-clad substrate; And / or, the surface electrode located on the side of the chip away from the first metal-clad substrate further includes a stress buffer metal layer located on the side of the welded 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 according to claim 2, wherein The soft metal includes at least one of aluminum, aluminum alloy, copper, magnesium alloy, zinc, zinc alloy, silver, silver alloy, gold, and gold alloy.

4. The power module according to claim 3, characterized in that, The welded or sintered metal layer includes: 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 according to any one of claims 1-4, characterized in that, The power module further includes a second metal-clad substrate and an interconnection post; the first metal-clad substrate and the second metal-clad substrate are disposed opposite to each other, the interconnection post is located between the chip and the second metal-clad substrate, and the chip is connected to the second metal-clad substrate through the interconnection post; The chip is connected to the interconnection post through a first solder, and the interconnection post is connected to the second metal-clad substrate through a second solder.

6. The power module according to claim 5, characterized in that, Further comprising: At least one first support post located between the interconnection post and the chip, and the at least one first support post is formed on the side of the interconnection post facing the chip or on the side of the chip facing the interconnection post; And / or, at least one second support post located between the interconnection post and the second metal-clad substrate, and the at least one second support post is formed on the side of the interconnection post facing the second metal-clad substrate or on the side of the second metal-clad substrate facing the interconnection post.

7. The power module according to any one of claims 1-4, characterized in that, Further comprising electronic components 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.

8. The power module according to claim 7, wherein It further includes at least one third support pillar located between the electronic component and the first metal-clad layer substrate; The at least one third support pillar is disposed on the side of the electronic component facing the first metal-clad layer substrate or on the side of the first metal-clad layer substrate facing the electronic component.

9. The power module according to claim 6 or 8, characterized in that, The material of the support pillar is a conductive material.

10. The power module according to claim 9, wherein The material of the support pillar includes at least one of aluminum, aluminum alloy, gold, gold alloy, copper, copper alloy, nickel, nickel alloy, copper clad with aluminum, copper-tin high melting point alloy, and high-temperature solder.

11. The power module according to any one of claims 1-4, characterized in that, It further includes a molding compound filled between the first metal-clad layer substrate and the second metal-clad layer substrate and molding the first metal-clad layer substrate and the second metal-clad layer substrate, and the elastic modulus of the molding compound is 0.5 GPa to 20 GPa.

12. The power module according to claim 11, wherein The material of the molding compound includes an epoxy molding compound.

13. The power module according to any one of claims 1-4, characterized in that, It further includes: a first heat sink located on the side of the first metal-clad layer substrate away from the second metal-clad layer substrate; a second heat sink located on the side of the second metal-clad layer substrate away from the first metal-clad layer substrate.

14. The power module according to claim 13, characterized in that, The first heat sink is connected to the first metal-clad layer substrate by welding or sintering; And / or, the second heat sink is connected to the second metal-clad layer substrate by welding or sintering.

15. The power module according to claim 14, characterized in that, There is a first support member between the first heat sink and the first metal-clad layer substrate, and the first support member includes a plurality of fourth support pillars or metal wires; And / or, there is a second support member between the second heat sink and the second metal-clad layer substrate, and the second support member includes a plurality of fifth support pillars or metal wires.

16. A power supply circuit, characterized in that, It includes a circuit board and a power module as described in any one of claims 1-15, and the power module is electrically connected to the circuit board.

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