A power module, power supply circuit and chip

Abstract

The present application discloses a power module, a power circuit and a chip, wherein the power module includes a first metal-clad substrate and a second metal-clad substrate arranged relatively to each other, a chip and an interconnection 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 using a sintered material, which can improve the bonding reliability, and the chip is electrically connected to the second metal-clad substrate through the interconnection column. Since substrates are arranged on both sides of the chip, the heat generated inside the power module can be discharged from the direction of the two substrates, thereby improving the heat dissipation performance of the power module. In addition, the sintered 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 it can further improve the heat dissipation performance of the power module, thereby improving the power density of the power module.

Description

Technical Field

[0001] The present application relates to the field of semiconductor packaging technology, and in particular to a power module, a power circuit and a chip. Background Art

[0002] With the development of power electronics technology, power modules have attracted more and more attention. At the same time, the demand for energy saving and low cost also urgently requires power modules to be lighter and smaller. However, this demand has brought great challenges to the development of power modules, because lightweight and miniaturization will lead to an increase in module current density, which will cause higher heat to be generated inside the module, thereby causing an increase in junction temperature. If the generated heat cannot be discharged in time, the higher junction temperature will affect the overall thermal mechanical performance and reliability of the power module. Summary of the invention

[0003] The present application provides a power module, a power circuit and a chip, which are used to provide a power module with higher heat dissipation performance, power density and reliability.

[0004] In the first aspect, the present application provides a power module, comprising a first metal-clad substrate and a second metal-clad substrate arranged opposite to each other, a chip and an interconnection column located between the first metal-clad substrate and the second metal-clad substrate; wherein a sintering material is further arranged 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, and the sintering material may include at least one of silver paste, copper paste or silver film; the interconnection column 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 column. Since substrates are arranged 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, thereby improving the heat dissipation performance of the power module. In addition, the sintering material has low stress, and the chip is electrically connected to the first metal-clad substrate by pressure sintering, which can improve the bonding reliability. In addition, the sintering material in the present application has the advantages of low sintering temperature, high melting point and high thermal conductivity, so it can not only further improve the heat dissipation performance of the power module, but also improve the working environment temperature and service life of the power module, thereby improving the power density of the power module.

[0005] In a specific implementation, the first metal-clad substrate and the second metal-clad substrate can be a copper-clad ceramic substrate (Direct Bond Copper, DBC), an active metal brazed copper substrate (Active metal brazed copper, AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) or an insulated metal substrate (Insulated metal substrate, IMS), etc., which is not limited here.

[0006] Exemplarily, in order to further improve the power density, the first metal-clad substrate and the second metal-clad substrate may be formed of AlN-DBC, Si3N4-AMB or AlN-AMB with high thermal conductivity, which is not limited herein.

[0007] Illustratively, the sintering material may be formed of silver paste, copper paste, or silver film.

[0008] In specific implementation, the silver paste may include at least one of micrometer silver paste and nanometer silver paste. Among them, micrometer silver paste refers to a silver paste made of micrometer silver particles and organic solvents, which is low in cost and safe. Generally, it is sintered under pressure, the sintered material has high density, the interface of the bonded body is firmly bonded, and the bonding reliability is high. Nanometer silver paste is a silver paste made of nanometer silver particles and organic solvents, which is high in cost and has the operational safety risk of nanometer particles.

[0009] Optionally, in order to improve the reliability of sintering bonding and reduce costs, the sintering material of the present application may be formed using micrometer silver particle paste.

[0010] In order to further improve the reliability of sintering bonding, the elastic modulus, thermal expansion coefficient (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 (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 properties with the main material, and the thermal expansion coefficient of the filler is less than the thermal expansion coefficient of the main material, thereby improving the sintering bonding reliability.

[0011] Taking the main 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, reduce the bonding stress, and thus improve the bonding reliability of silver sintering. Exemplarily, the filler may include at least one of nickel (Ni), Ni alloy, copper (Cu), copper-plated nickel, titanium (Ti), Ti alloy, iron (Fe), Fe alloy, Kovar (Kovar, iron-nickel-cobalt alloy 4J29) and SiC powder, etc., which are not limited here.

[0012] In the present application, the metal layer coated on the surface of the first metal-clad substrate and the second metal-clad substrate is generally copper. When the sintering material is a silver paste or a silver film, in order 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 location, that is, the first metal-clad 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-clad substrate is relatively good, silver plating is not required. For example, when the sintering material is a copper paste, the first metal-clad substrate does not need to be silver-plated at the sintering location.

[0013] 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 sintering area corresponding to the first metal-clad substrate by a steel mesh printing process or a screen printing process. Then, the copper paste or silver paste printed on the first metal-clad substrate may be pre-dried for 5 min to 40 min at a temperature of 100° C. to 180° C. in an N2 atmosphere. 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 at a temperature of 100° C. to 180° C. for at least 10 ms. When the sintering material is a silver film, the chip may be adsorbed by a metal suction nozzle, and the temperature of the metal suction nozzle is 80° C. to 200° C. Then, the chip is pressed on a large piece of silver film, and a pressure of 0.1 MPa to 5 MPa is applied for a pressurization time of 1 ms to 10000 ms. In this way, the silver film under the chip is compressed and semi-sintered, and adheres to the chip. Then, the chip with the silver film attached is fixed on the first metal-clad substrate by vacuum adsorption, and a pressure of 0.1MPa to 10MPa is applied to the chip mounted on the first metal-clad substrate for at least 10ms at a temperature of 100°C to 180°C. In step (2), a pressure head can be used to perform pressure sintering on the chip mounted on the first metal-clad substrate. Taking the pressure head area of ​​50mm*50mm as an example, the parallelism of the pressure head can be set to ≤5μm, thereby reducing the warping of the sintered product. Exemplarily, the sintering conditions for pressure sintering can be: the sintering temperature is controlled at 200°C to 300°C, the applied pressure is controlled at 5MPa to 30MPa, and the sintering time is controlled at 1min to 10min. In order to prevent the pressure head from damaging the chip during the sintering process, a removable stress relief film can be placed between the chip and the pressure head when the chip mounted on the first metal-clad substrate is pressure sintered. Therefore, during pressure sintering, the stress relief film can prevent the pressure head from directly contacting the chip and reduce the damage caused by the pressure head to the chip caused by stress concentration. After the pressure sintering is completed, the stress relief film can be removed. For example, the stress relief film can be an organic film such as a Teflon film, which is not limited here.

[0014] Furthermore, in order to control the warpage of the sintered product, the sintered first metal-clad substrate and the chip can be cooled under pressure. For example, the cooling conditions can be: the applied pressure is controlled at 5MPa to 20MPa, and the cooling time is controlled at 1min to 10min.

[0015] 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 may be cleaned to remove residual organic matter. For example, a plasma treatment process or an organic solvent cleaning process may be used to remove residual organic matter from the first metal-clad substrate, etc., to increase the interface bonding of the subsequent plastic encapsulation material, prevent the plastic encapsulation material from delamination, and further improve the reliability of the power module.

[0016] Optionally, in order to release the stress generated on the chip during welding or sintering to improve the reliability of the power module, the chip has surface electrodes on the side facing the first metal-clad substrate and the side of the chip away from the first metal-clad substrate, and the surface electrode includes a welding or sintering metal layer; the surface electrode located on the side of the chip facing the first metal-clad substrate also 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 located on the side of the chip away from the first metal-clad substrate also includes a stress buffer metal layer located on the side of the welding or sintering metal layer facing the first metal-clad substrate.

[0017] Exemplarily, the material of the stress buffer metal layer may 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 used to release stress at the joint.

[0018] In a specific implementation, when the material of the stress buffer metal layer is a metal that is not weldable, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be disposed below the welding or sintering metal layer.

[0019] 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, etc.

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

[0021] In specific implementation, the thickness of the solder has an important influence on the reliability of solder joints, etc. In order to ensure the controllability and uniformity of the solder thickness, at least one first support column is provided between the interconnection column and the chip, and the at least one first support column can be formed on the side of the interconnection column facing the chip, that is, formed on the interconnection column; the at least one first support column can also be formed on the side of the chip facing the interconnection column, that is, formed on the chip. And / or, at least one second support column is provided between the interconnection column and the second metal-clad substrate, and the at least one second support column can be formed on the side of the interconnection column facing the second metal-clad substrate, that is, formed on the interconnection column; the at least one second support column can also be formed on the side of the second metal-clad substrate facing the interconnection column, that is, formed on the second metal-clad substrate.

[0022] In the power module of the present application, in addition to the chip and the interconnection column, it may also 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.

[0023] In the present application, the first solder, the second solder and the third solder may be formed by solder paste or solder sheet, which is not limited here.

[0024] Optionally, all solders in the present application can be made 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 welding of the chip and the interconnection column, the welding of the interconnection column and the second metal-clad substrate, and the welding of the electronic components and the first metal-clad substrate can be completed through one reflow soldering, thereby simplifying the process steps and saving costs.

[0025] Of course, in specific implementation, the first solder, the second solder and the third solder may also use different solders, which is not limited here. For example, the first solder and the third solder may use high-temperature solders, such as high-lead solder, Au-based solder, etc., and the second solder may use medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0026] Exemplarily, the electronic components in the present application include any electronic components soldered on the first metal-clad substrate by solder, such as signal terminals, power terminals, thermistors, etc.

[0027] In order to improve the bonding reliability between the electronic component and the first metal-clad substrate, at least one third support column is further provided between the electronic component and the first metal-clad substrate. The at least one third support column can be formed on the side of the electronic component facing the first metal-clad substrate, or on the side of the first metal-clad substrate facing the electronic component, which is not limited here.

[0028] Optionally, the support column is made of 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 coated with aluminum, Cu-Sn high melting point alloy, or high temperature solder.

[0029] Furthermore, the present application also includes a molding compound that is filled between the first metal-clad substrate and the second metal-clad substrate and that molds the first metal-clad substrate and the second metal-clad substrate. In order to prevent delamination of the molding compound and the molding interface to improve the reliability of the power module, the molding compound uses a low-modulus molding compound. 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 here.

[0030] The power module of the present application may also include a first heat sink located on a side of the first metal-clad substrate away from the second metal-clad substrate and a second heat sink located on a 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 module reliability of the power module.

[0031] Optionally, in order to improve the heat dissipation effect, the first heat sink may be connected to the first metal-clad substrate by welding or sintering; and / or the second heat sink may be connected to the second metal-clad substrate by welding or sintering.

[0032] Furthermore, a first supporting component is provided between the first heat sink and the first metal-clad substrate, and the first supporting component can be formed by a plurality of fourth supporting columns, metal wires or metal meshes; and / or, a second supporting component is provided between the second heat sink and the second metal-clad substrate, and the second supporting component can be formed by a plurality of fifth supporting columns or metal wires, thereby utilizing the first supporting component and the second supporting component to control the solder thickness and ensure the reliability of welding.

[0033] In a specific implementation, the metal wire may be bonded and fixed on the joint 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.

[0034] In a second aspect, an embodiment of the present application further provides a power supply circuit, comprising 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 a signal to the power module.

[0035] The technical effects that can be achieved in the second aspect mentioned above can be referred to the description of the technical effects that can be achieved by any possible design in the first aspect mentioned above, and will not be repeated here.

[0036] On the third aspect, an embodiment of the present application further provides a chip, wherein the surface electrode of the chip includes a stacked stress buffer metal layer and a welded or sintered metal layer, wherein the material of the stress buffer metal layer can be a soft metal with a hardness less than HV60, and the softness of the soft metal is used to release the stress of the joint.

[0037] 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., without limitation herein.

[0038] In a specific implementation, when the material of the stress buffer metal layer is a metal that is not weldable, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be disposed below the welding or sintering metal layer.

[0039] 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, without limitation herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of a power module provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of a process for preparing a power module provided in an embodiment of the present application;

[0042] Figure 3 A schematic cross-sectional view of a sintered material filled with fillers provided in an embodiment of the present application;

[0043] Figure 4 A schematic diagram of a process flow of another method for preparing a power module provided in an embodiment of the present application;

[0044] Figure 5 A structural schematic diagram of a preparation process of a power module is provided for an embodiment of the present application;

[0045] Figure 6 A schematic diagram of a process flow of another method for preparing a power module provided in an embodiment of the present application;

[0046] Figure 7 A structural schematic diagram of another power module manufacturing process provided in an embodiment of the present application;

[0047] Figure 8 A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0048] Fig. 9A schematic diagram of the structure of a chip provided in an embodiment of the present application;

[0049] Fig.10 This is an ultrasonic scanning photograph of a sintered layer in one embodiment of the present application;

[0050] Fig.11 This is a schematic diagram of a structure in which a support column is provided between two joined bodies welded by solder in an embodiment of the present application;

[0051] Fig.12 A schematic diagram of the structure of the interconnection column provided in the embodiment of the present application;

[0052] Fig.13 A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0053] Fig.14 A structural schematic diagram of a manufacturing process of another power module provided in an embodiment of the present application;

[0054] Fig.15 A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0055] Fig.16 A schematic diagram of the structure of another power module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] 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 in conjunction with the accompanying drawings.

[0057] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0058] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are 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 cannot be understood as a limitation on the present application. The words expressing position and direction described in the present application are all explained using the accompanying drawings as examples, but changes may be made as needed, and all changes are included in the scope of protection of the present invention. The drawings of the present application are only used to illustrate relative positional relationships and do not represent true proportions. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0059] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0060] In order to facilitate the understanding of the power module provided in the embodiment of the present application, its application scenario is first explained. 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 DC to AC in the motor control part (MCU) of an electric vehicle, as the battery output of the electric vehicle, or converting DC to AC required for vehicle operation.

[0061] In order to save energy and reduce costs, there is an urgent need for power modules to be lighter and smaller. However, this demand has brought great challenges to the development of power modules, because lightweight and miniaturization will lead to an increase in module current density, which will cause higher heat to be generated inside the module, causing the junction temperature to rise. If the generated heat cannot be discharged in time, the higher junction temperature will affect the overall thermal mechanical performance and reliability of the module.

[0062] Based on this, the present application provides a power module with high heat dissipation performance, power density and reliability. In order to facilitate 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 implementation methods.

[0063] See also Figure 1 , Figure 1A schematic diagram of the structure of a power module provided in an embodiment of the present application. The power module 1 includes: a first metal-clad substrate 10 and a second metal-clad substrate 20 arranged opposite to each other, a chip 11 and an interconnection column 12 located between the first metal-clad substrate 10 and the second metal-clad substrate 20; wherein a sintering material 13 is also 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, and the sintering material 13 may include at least one of silver paste, copper paste or silver film; the interconnection column 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 interconnection column 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, thereby improving the heat dissipation performance of the power module. In addition, 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 sintered material 13 in the present 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 working environment temperature and service life of the power module, thereby improving the power density of the power module.

[0064] See also Figure 2 , Figure 2 A schematic flow chart of a method for preparing a power module provided in an embodiment of the present application. The preparation method may include the following steps:

[0065] S101 , providing a first metal-clad substrate and a second metal-clad substrate.

[0066] In a specific implementation, the first metal-clad substrate and the second metal-clad substrate can be a copper-clad ceramic substrate (Direct Bond Copper, DBC), an active metal brazed copper substrate (Active metal brazed copper, AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) or an insulated metal substrate (Insulated metal substrate, IMS), etc., which is not limited here.

[0067] Exemplarily, in order to further improve the power density, the first metal-clad substrate and the second metal-clad substrate may be formed of AlN-DBC, Si3N4-AMB or AlN-AMB with high thermal conductivity, which is not limited herein.

[0068] S102, mounting the chip on the first metal-clad substrate, with a sintering material between the chip and the first metal-clad substrate.

[0069] Illustratively, the sintering material may be formed of silver paste, copper paste, or silver film.

[0070] In specific implementation, the silver paste may include at least one of micrometer silver paste and nanometer silver paste. Among them, micrometer silver paste refers to a silver paste made of micrometer silver particles and organic solvents, which is low in cost and safe. Generally, it is sintered under pressure, the sintered material has high density, the interface of the bonded body is firmly bonded, and the bonding reliability is high. Nanometer silver paste is a silver paste made of nanometer silver particles and organic solvents, which is high in cost and has the operational safety risk of nanometer particles.

[0071] Optionally, in order to improve the reliability of sintering bonding and reduce costs, the sintering material of the present application may be formed using micrometer silver particle paste.

[0072] In order to further improve the reliability of sintering bonding, the elastic modulus, thermal expansion coefficient (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 (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 properties with the main material, and the thermal expansion coefficient of the filler is less than the thermal expansion coefficient of the main material, thereby improving the sintering bonding reliability.

[0073] Taking the main 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, reduce the bonding stress, and thus improve the bonding reliability of silver sintering. Exemplarily, the filler may include at least one of nickel (Ni), Ni alloy, copper (Cu), copper-plated nickel, titanium (Ti), Ti alloy, iron (Fe), Fe alloy, Kovar (Kovar, iron-nickel-cobalt alloy 4J29) and SiC powder, etc., which are not limited here.

[0074] The present application does not limit the shape of the filler, for example, Figure 3 As 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 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.

[0075] In the present application, the metal layer coated on the surface of the first metal-clad substrate and the second metal-clad substrate is generally copper. When the sintering material is a silver paste or a silver film, in order 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 location, that is, the first metal-clad 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-clad substrate is relatively good, silver plating is not required. For example, when the sintering material is a copper paste, the first metal-clad substrate does not need to be silver-plated at the sintering location.

[0076] For example, when the sintering material is copper paste or silver paste, see Figure 4 and Figure 5 The chip can be mounted on the first metal-clad substrate by the following steps:

[0077] Step S1021a: printing the sintered material on the first metal-clad substrate.

[0078] In specific implementation, 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 by using a steel screen printing process or a silk screen printing process. Since the steel screen printing process is low in cost and simple to manufacture compared to the silk screen printing process, therefore, optionally, the present application uses a steel screen printing process to print the copper paste or silver paste on the sintering area corresponding to the first metal-clad substrate.

[0079] For example, the thickness of the printed copper paste or silver paste can be controlled to be between 30 μm and 160 μm, which can be specifically designed according to the actual product and is not limited here.

[0080] 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 20μm to 300μm outward from the target boundary (the boundary of the sintering area of ​​the chip under ideal conditions).

[0081] Step S1022a, pre-drying the printed sintered material.

[0082] In a specific implementation, the printed copper paste or silver paste is pre-dried to prevent the sintered material from collapsing during pressurized sintering.

[0083] For example, Figure 5 As shown in (c), the sintering material 13 (copper paste or silver paste) printed on the first metal-clad substrate 10 can be pre-dried at a temperature of 100° C. to 180° C. for 5 to 40 minutes in a N 2 atmosphere.

[0084] Step S1023a: mounting the chip on the sintered material of the first metal-clad substrate and applying pressure.

[0085] In specific implementation, Figure 5 As shown in (d), the chip 11 can be first sucked up by vacuum adsorption, and then the sintered material 13 (copper paste or silver paste) can be aligned through the image recognition system. After that, the chip 11 can be fixed on the dried sintered material 13 (copper paste or silver paste) and pressurized.

[0086] Exemplarily, the chip mounting conditions may be: temperature controlled at 100°C to 180°C, pressure controlled at 0.1MPa to 10MPa, and time controlled at 10ms to 999ms. That is, a pressure of 0.1MPa to 10MPa is applied to the chip 11 mounted on the first metal-clad substrate 10 for at least 10ms at a temperature of 100°C to 180°C.

[0087] For example, when the sintered material is a silver film, see Figure 6 and Figure 7 The chip can be mounted on the first metal-clad substrate by the following steps:

[0088] Step S1021b: attaching a sintering material to the side of the chip facing the first metal-clad substrate.

[0089] In specific implementation, Figure 7 As shown in (a), the chip 11 can be sucked by a metal suction nozzle, and the temperature of the metal suction nozzle is 80℃~200℃. Then the chip 11 is pressed on a large piece of silver film, and a pressure of 0.1MPa~5MPa is applied for a time of 1ms~10000ms. In this way, the sintering material 13 (silver film) under the chip is compressed and semi-sintered, and adheres to the chip 11.

[0090] Step S1022b: mounting the chip with the sintered material adhered thereto on the first metal-clad substrate and applying pressure.

[0091] In specific implementation, Figure 7 As shown in (b), the chip 11 can be first sucked up by vacuum adsorption, and then the first metal-clad substrate 10 can be aligned through an image recognition system, and then the chip 11 adhered with the sintered material 13 (silver film) can be fixed on the first metal-clad substrate 10 and pressurized.

[0092] Exemplarily, the chip mounting conditions may be: temperature controlled at 100°C to 180°C, pressure controlled at 0.1MPa to 10MPa, and time controlled at 10ms to 999ms. That is, a pressure of 0.1MPa to 10MPa is applied to the chip mounted on the first metal-clad substrate for at least 10ms at a temperature of 100°C to 180°C.

[0093] When the chip mounting is completed, step S103 is executed.

[0094] Step S103: performing pressure sintering on the chip mounted on the first metal-clad substrate.

[0095] Press sintering refers to applying pressure to the body to be joined at high temperature, thereby increasing the density of the sintered body, promoting atomic diffusion between sintered material particles and at the interface between the sintered material and the body to be joined, and enhancing bonding strength and bonding reliability. The present application does not limit the process of press sintering adopted, and it can be any known method.

[0096] In specific implementation, 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 the pressure head area of ​​50mm*50mm as an example, the parallelism of the pressure head can be set to ≤5μm to reduce the warping of the product after sintering.

[0097] Exemplarily, the sintering conditions for pressure 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.

[0098] In a specific implementation, the pressure sintering process can be carried out in an air environment. To prevent product oxidation, the chip mounted on the first metal-clad substrate is pressure 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 or He, etc., which is not limited here.

[0099] To prevent the chip from being damaged by the pressure head during the sintering process, Figure 5 (e) and Figure 7 As shown in (c), when the chip mounted on the first metal-clad substrate is subjected to pressure sintering, a removable stress relief film 30 can be placed between the chip 11 and the pressure head. Thus, during pressure sintering, the stress relief film 30 can prevent the pressure head from making direct contact with the chip 11 and reduce the damage caused by stress concentration of the pressure head on the chip 11. After the pressure sintering is completed, the stress relief film can be removed.

[0100] Optionally, the thickness of the stress relaxation film may be set to 50 μm to 90 μm, which is not limited here.

[0101] For example, the stress relaxation film may be an organic film such as a Teflon film, which is not limited here.

[0102] Furthermore, in order to control the warpage of the sintered product, Figure 5 Middle (f) and Figure 5 As shown in (d), the sintered first metal-clad substrate 10 and chip 11 are cooled under pressure.

[0103] Illustratively, if the pressure sintering process is performed in a protective atmosphere or a vacuum environment, the cooling process is also performed in a protective atmosphere or a vacuum environment.

[0104] Exemplarily, the cooling conditions may be: the applied pressure is controlled within a range of 5 MPa to 20 MPa, and the cooling time is controlled within a range of 1 min to 10 min.

[0105] Optionally, to enhance cooling, water cooling or forced nitrogen cooling may be used, which is not limited here.

[0106] 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 may be cleaned to remove residual organic matter. For example, a plasma treatment process or an organic solvent cleaning process may be used to remove residual organic matter from the first metal-clad substrate, etc., to increase the interface bonding of the subsequent plastic encapsulation material, prevent the plastic encapsulation material from delamination, and further improve the reliability of the power module.

[0107] Plasma treatment refers to the purification of the surface of an object by the bombardment effect of plasma particles on the surface of the object and the reaction of plasma ions with organic matter in plasma.

[0108] Step S104: connecting the chip away from the first metal-clad substrate to the second metal-clad substrate using interconnection pillars.

[0109] In a specific implementation, the interconnection pillar 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.

[0110] For example, the interconnect pillar material may be Cu, Ni, Mo, W, tungsten alloy, Cu-Mo alloy, AlSiC and nickel alloy, etc., or 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, AlSiC composite material surface sensitized and then plated with Ni, Ni(P) or Cu. Of course, Ag or Au may be plated on the surface of the Ni, Ni(P) or Cu coating.

[0111] In the present application, Ni(P) refers to a Ni coating containing phosphorus (P) produced by chemical plating. During chemical plating, P and Ni are simultaneously precipitated from the solution and deposited on the substrate, and P is an inevitable accompanying substance.

[0112] The present application does not limit the type and quantity of chips in the power module, and any number of chips of any type can be used in the power module. For example, Figure 8 As shown, the chip 11 may be an insulated gate bipolar transistor (IGBT) and a fast recovery diode (FRD). The IGBT chip 11 and the FRD chip 11 are both electrically connected to the first metal-clad substrate 10 through the sintered material 13 .

[0113] In the specific implementation, continue to refer to Figure 8 The gate of the IGBT chip 11 can be electrically connected to the first metal-clad substrate 10 through the Al wire 104 .

[0114] In a specific implementation, the chip has surface electrodes on 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 welding or sintering metal layer for welding or sintering with other electrical devices.

[0115] 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, etc.

[0116] In this application, NiV refers to an alloy of Ni and V. When manufacturing the chip surface electrode, a NiV target is used and a coating is manufactured by a sputtering process.

[0117] Optionally, in order to release the stress generated on the chip during welding or sintering to 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 used to release the stress of the joint.

[0118] In a specific implementation, when the material of the stress buffer metal layer is a metal that is not weldable, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be disposed below the welding or sintering metal layer.

[0119] Exemplarily, a stress buffer metal layer may be provided 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 interconnection column, or in the surface electrodes on both sides of the chip, without limitation.

[0120] For example, taking the material of the stress buffer metal layer as aluminum or aluminum alloy, as Fig. 9 As shown, the chip 11 may include a semiconductor body 110, and a surface electrode 111 is arranged on the surface of the semiconductor body 110, wherein a stress buffer metal layer 1111 is arranged in the surface electrode 111 on the side of the chip 11 facing the first metal-clad substrate, and the stress buffer metal layer 1111 is located on the side of the welding or sintering metal layer 1112 away from the first metal-clad substrate, that is, the stress buffer metal layer 1111 is located between the welding or sintering metal layer 1112 and the semiconductor body 110. And / or, a stress buffer metal layer 1111 is arranged in the surface electrode 111 on the side of the chip 11 facing the interconnection column, and the stress buffer metal layer 1111 is located on the side of the welding or sintering metal layer 1112 away from the interconnection column, that is, the stress buffer metal layer 1111 is located between the welding or sintering metal layer 1112 and the semiconductor body 110. Wherein, Fig. 9 An example is given in which the stress buffer metal layer 1111 is provided in the surface electrodes 111 on both sides of the chip 11 .

[0121] In a specific implementation, when forming the surface electrode of the chip, a layer of Al film or Al alloy layer can be first formed by physical vapor deposition (PVD) or other methods. Because the Al surface is easy to form a protective oxide film, it is not weldable. In order to have weldability or sinterability on non-weldable Al, a weldable metal and a surface wettable metal can be chemically plated on the stress buffer metal layer to form a welded or sintered metal layer. Alternatively, a plasma PVD method or other method can be used on the surface to make a welded or sintered metal layer.

[0122] 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, and then, by zincate treatment, the aluminum oxide film is replaced by Zn, and then Ni(P) is chemically plated to replace Zn, or gold (Au) or silver (Ag) can be chemically plated 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.% to 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.

[0123] Of course, when forming the surface electrode, it is also possible not to form a stress buffer metal layer, but to directly use the PVD method to form a welding or sintering metal layer, such as Ti / Ni / Ag, Ti / Ni / Au, Ti / NiV / Ag, Ti / NiV / Au, Ni(P) / Pd / Au, Ni(P) / Pd / Ag, etc.

[0124] In the present application, there is no limitation on the thickness of the surface electrode of the chip, which is set according to the actual product. For example, the thickness of the surface electrode can be controlled between 2 μm and 10 μm.

[0125] For example, a chip with a stress buffer metal layer is sintered onto a metal-clad ceramic substrate using a micron silver paste filled with fillers. The ultrasonic (SAT) scanning photograph of the sintered layer after 1000 times of temperature shock (-40°C to 125°C) under a harsh condition without plastic packaging is shown in FIG. Fig.10 As shown by Fig.10 It can be seen that no peeling of the sintered layer occurs. This shows that combining a chip with a stress buffer metal layer with a silver paste that reduces the elastic modulus and thermal expansion coefficient can achieve high reliability bonding.

[0126] In the present application, after the chip is connected to the first metal-clad substrate by pressure sintering, Figure 1 and Figure 8 As shown, the chip can be connected to the interconnection column 12 through the first solder 14, and the interconnection column 12 is connected to the second metal-clad substrate 20 through the second solder 15. In specific implementation, the first solder can be used to connect the interconnection column on the side of the chip away from the first metal-clad substrate by welding; the second solder can be used to connect the interconnection column on the side away from the chip to the second metal-clad substrate by welding.

[0127] Exemplarily, the first solder and the second solder can be formed by solder paste or solder sheet. The first solder can be high temperature solder, 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.

[0128] In specific implementation, the thickness of the solder has an important influence on the reliability of the solder joint. In order to ensure the controllability and uniformity of the solder thickness, such as Fig.11 As shown, a support column 03 can be provided between two joined bodies 01 and 02 (two objects to be joined by solder, such as a chip and an interconnection column, or an interconnection column and a second metal-clad substrate), so as to control the thickness and thickness uniformity of the solder 04 between the two joined bodies 01 and 02 by using the support column 03. The support column 03 can be formed on any of the two joined bodies 01 and 02.

[0129] For example, in this application, Figure 8 As shown, at least one first support column 16 is arranged between the interconnection column 12 and the chip 11. The at least one first support column 16 can be formed on the side of the interconnection column 12 facing the chip 11, that is, formed on the interconnection column 12; the at least one first support column 16 can also be formed on the side of the chip 11 facing the interconnection column 12, that is, formed on the chip 11.

[0130] For example, in this application, Figure 8 As shown, at least one second support column 17 is arranged between the interconnection column 12 and the second metal-clad substrate 20. The at least one second support column 17 can be formed on the side of the interconnection column 12 facing the second metal-clad substrate 20, that is, formed on the interconnection column 12; the at least one second support column 17 can also be formed on the side of the second metal-clad substrate 20 facing the interconnection column 12, that is, formed on the second metal-clad substrate 20.

[0131] The present application does not limit the number of the first support pillars and the second support pillars, which is specifically determined according to the area of ​​the welding area. The larger the area of ​​the welding area, the greater the number of support pillars.

[0132] In the present application, the size of the support column can be set to a micron-level size, which is mainly used to support the joined bodies located on both sides of the support column to control the thickness of the solder and ensure the uniformity of the solder thickness.

[0133] Optionally, the first support column and the second support column are made of a conductive material. Exemplarily, the first support column and the second support column can be formed of 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.

[0134] In a specific implementation, the height of the support column is determined according to the target thickness of the solder. For example, the thickness of the support column can be controlled between 0.02 mm and 10 mm.

[0135] For example, ultrasonic technology can be used to implant micron-sized support pillars on the body to be joined. Small-sized support pillars have no effect on the soldering process and solder reliability of the solder. The implanted support pillars can be spherical or cylindrical at the beginning, and then the implanted support pillars are flattened to achieve adjustable and controllable height of the implanted support pillars. This allows the thickness and warpage of the solder to be controlled during the welding process.

[0136] For example, Fig.12 As shown, taking the implantation of support pillars on both sides of the interconnection pillar 12 as an example, a metal ball of micron size is implanted on the side of the interconnection pillar 12 facing the chip by using ultrasonic technology, and the implanted metal ball is leveled to form a first support pillar 16, and then the interconnection pillar 12 is placed into the jig with the side of the first support pillar 16 implanted facing downward, so that the implanted first support pillar 16 enters the cavity of the jig. Through the positioning of the jig, the same method is used to implant metal balls on the side of the interconnection pillar 12 facing the second metal-clad substrate, and the implanted metal balls are leveled to form a second support pillar 17, so that support pillars are set at symmetrical positions on both sides of the interconnection pillar 12, which is convenient for recognition and grasping during automatic placement.

[0137] Among them, the flattening treatment of the metal balls can be performed by pressurizing and flattening the metal balls, so that the height of the implanted metal balls is consistent and the height meets the designed solder thickness requirement, thereby controlling the uniform thickness of the solder.

[0138] In the power module of the present application, Fig.13 As shown, in addition to the chip 11 and the interconnection column 12 , an electronic component 101 located on the side of the first metal-clad substrate 10 facing the second metal-clad substrate 20 may also be included, and the electronic component 101 is connected to the first metal-clad substrate 10 through a third solder 102 .

[0139] Exemplarily, the third solder may be a high temperature solder, such as a high lead solder, an Au-based solder, or the like.

[0140] For example, Fig.13 As shown, the electronic components in the present application include any electronic components soldered on the first metal-clad substrate 10 by solder, such as Fig.13 The signal terminals in Fig.13 Power terminals, thermistors, etc.

[0141] In order to improve the bonding reliability between the electronic components and the first metal-clad substrate, Fig.13As shown, at least one third support column 103 is also provided between the electronic component 01 and the first metal-clad substrate 10. The at least one third support column 103 can be formed on the side of the electronic component 101 facing the first metal-clad substrate 10, or can be formed on the side of the first metal-clad substrate 10 facing the electronic component 101, which is not limited here.

[0142] In specific implementation, the implementation of the third support column can refer to the implementation of the first support column and the second support column mentioned above, and will not be described in detail here.

[0143] In the present application, the first solder, the second solder and the third solder may be formed by solder paste or solder sheet, which is not limited here.

[0144] Optionally, all solders in the present application can be made 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 welding of the chip and the interconnection column, the welding of the interconnection column and the second metal-clad substrate, and the welding of the electronic components and the first metal-clad substrate can be completed through one reflow soldering, thereby simplifying the process steps and saving costs.

[0145] Of course, in specific implementation, the first solder, the second solder and the third solder may also use different solders, which is not limited here. For example, the first solder and the third solder may use high-temperature solders, such as high-lead solder, Au-based solder, etc., and the second solder may use medium-temperature solder, such as SAC305, Sn-Sb solder, etc.

[0146] For example, Fig.13 As an example, the power module shown in the figure is combined with Fig.14 After the chip 11 and the first metal-clad substrate 10 are pressure-sintered, the gate of the IGBT chip 11 is bonded to the first metal-clad substrate 10 through an Al wire 104. Afterwards, a first support column 16 and a second support column 17 are formed on both sides of the interconnection column 12. Then, a third support column 103 is implanted on the surface of the first metal-clad substrate 10 by ultrasonic technology. Then, a first solder 14 is formed between the chip 11 and the interconnection column 12, a second solder 15 is formed between the interconnection column 12 and the second metal-clad substrate 20, and a third solder 102 is formed between the electronic component 101 (power terminal and signal terminal) and the first metal-clad substrate 10, wherein the solder may be a solder sheet or a solder paste, the solder sheet may be formed by mounting, and the solder paste may be formed by a printing process, wherein the solder sheet or the solder paste may be a high-temperature solder, such as a high-lead solder, an Au-based solder, etc.

[0147] Then, vacuum reflow is performed to solder the chip 11 to the interconnection column 12, the interconnection column 12 to the second metal-clad substrate 20, and the electronic component 101 (power terminal and signal terminal) to the first metal-clad substrate 10. In this way, the various components of the power module are joined together. Since the support column is implanted in the solder of each joined body, the thickness and warpage of the solder can be controlled.

[0148] After completing the internal interconnection of the power module, it needs to be plastic-sealed. In the specific implementation, such as Fig.15 As shown, the molding compound 40 is filled between the first metal-clad substrate 10 and the second metal-clad substrate 20 , and the molding compound 40 molds the first metal-clad substrate 10 and the second metal-clad substrate 20 .

[0149] In order to prevent delamination between the molding compound and the molding interface and improve the reliability of the power module, the molding compound uses a low modulus molding compound. Exemplarily, the molding compound can be formed of a material with an elastic modulus between 0.5 GPa and 20 GPa, such as epoxy molding compound, etc., which is not limited here.

[0150] In specific implementation, after the plastic encapsulation is completed, the upper and lower surfaces of the power module can be ground to make the two sides of the power module parallel. Of course, grinding is not required according to needs.

[0151] Exemplarily, after the plastic packaging, the exposed terminals (such as signal terminals and power terminals) may be tinned to prevent oxidation of the terminals and to increase the solderability of the terminals.

[0152] In the power module of the present application, Fig.16 As shown, it can 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, so as to cool the module from both sides and improve the power density and module reliability of the power module.

[0153] Exemplarily, the first radiator and the second radiator may be water-cooled radiators, which is not limited here.

[0154] In a specific implementation, the first metal-clad substrate and the first heat sink may be joined by thermally conductive silicone grease, and the second metal-clad substrate and the second heat sink may be joined by thermally conductive silicone grease.

[0155] Optionally, in order to improve the heat dissipation effect, the first heat sink may be connected to the first metal-clad substrate by welding or sintering; and / or the second heat sink may be connected to the second metal-clad substrate by welding or sintering.

[0156] Exemplarily, the first heat sink may be connected to the first metal-clad substrate by welding; and the second heat sink may be connected to the second metal-clad substrate by welding.

[0157] Further, if Fig.16 As shown, there is a first supporting component between the first heat sink 50 and the first metal-clad substrate 10, and the first supporting component can be formed by a plurality of fourth supporting columns 51 or metal wires; and / or, there is a second supporting component between the second heat sink 60 and the second metal-clad substrate 20, and the second supporting component can be formed by a plurality of fifth supporting columns 61 or metal wires, thereby utilizing the first supporting component and the second supporting component to control the solder thickness and ensure the reliability of welding.

[0158] In a specific implementation, the metal wire may be bonded and fixed on the joint 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.

[0159] In a specific implementation, when the first support component is formed by a plurality of fourth support columns, the fourth support column can be formed on the first heat sink or on the first metal-clad substrate, which is not limited here. In a specific implementation, the implementation of the fourth support column can refer to the implementation of the first support column and the second support column, which is not repeated here.

[0160] In a specific implementation, when the second support component is formed by a plurality of fifth support columns, the fifth support column can be formed on the second heat sink or on the second metal-clad substrate, which is not limited here. In a specific implementation, the implementation of the fifth support column can refer to the implementation of the first support column and the second support column, which is not repeated here.

[0161] Accordingly, the embodiment of the present application further provides a power supply circuit, including a circuit board and any of the above-mentioned power modules provided in the embodiment of the present application, the power module is electrically connected to the circuit board, and the circuit board provides a signal to the power module. Since the principle of solving the problem of the power supply circuit is similar to that of the above-mentioned power module, the implementation of the power supply circuit can refer to the implementation of the above-mentioned power module, and the repeated parts will not be repeated.

[0162] Accordingly, the present application embodiment also provides a chip, see Fig. 9 The surface electrode 111 of the chip 11 includes a stacked stress buffer metal layer 1111 and a welding or sintering metal layer 1112, wherein the material of the stress buffer metal layer 1111 can be a soft metal with a hardness less than HV60, and the softness of the soft metal is used to release the stress of the joint.

[0163] 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., without limitation herein.

[0164] In a specific implementation, when the material of the stress buffer metal layer is a metal that is not weldable, such as aluminum, aluminum alloy or magnesium alloy, the stress buffer metal layer can be disposed below the welding or sintering metal layer.

[0165] 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, which are not limited here.

[0166] 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 equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A power module, characterized in that: include: A first metal-clad substrate and a second metal-clad substrate arranged opposite to each other, and a chip and an interconnection column located between the first metal-clad substrate and the second metal-clad substrate; A sintering material is provided 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 includes at least one of silver paste, copper paste and silver film; The interconnection column 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 column; The sintering material includes a main material and a filler 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 smaller than the thermal expansion coefficient of the main body material; The filler includes at least one of nickel, nickel alloy, copper, copper-plated nickel, titanium, titanium alloy, iron, iron alloy, Kovar alloy and SiC powder.

2. The power module according to claim 1, characterized in that: The chip has surface electrodes on a side facing the first metal-clad substrate and a side of the chip away from the first metal-clad substrate, wherein the surface electrodes include a soldered 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 soldering or sintering 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 soft metal, and the hardness of the soft metal is less than HV60.

3. The power module according to claim 2, characterized in that: The soft metal includes at least one of aluminum or 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 welding or sintering 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 to 4, characterized in that: The chip is connected to the interconnection column through a first solder, and the interconnection column is connected to the second metal-clad substrate through a second solder.

6. The power module according to claim 5, characterized in that: Also includes: At least one first supporting column located between the interconnecting column and the chip, wherein the at least one first supporting column is formed on a side of the interconnecting column facing the chip or on a side of the chip facing the interconnecting column; And / or, at least one second support column is located between the interconnect column and the second metal-clad substrate, and the at least one second support column is formed on a side of the interconnect column facing the second metal-clad substrate or on a side of the second metal-clad substrate facing the interconnect column.

7. The power module according to any one of claims 1 to 4, characterized in that: Also included are electronic components located on a side of the first metal-clad substrate facing the second metal-clad substrate; The electronic component is connected to the first metal-clad substrate via a third solder.

8. The power module according to claim 7, characterized in that: Also included is at least one third support column located between the electronic component and the first metal-clad substrate; The at least one third supporting column is disposed on a side of the electronic component facing the first metal-clad substrate or on a side of the first metal-clad substrate facing the electronic component.

9. The power module according to claim 6 or 8, characterized in that: The support column is made of conductive material.

10. The power module according to claim 9, characterized in that: The material of the support column includes at least one of aluminum, aluminum alloy, gold, gold alloy, copper, copper alloy, nickel, nickel alloy, copper coated with aluminum, copper-tin high melting point alloy and high temperature solder.

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

12. The power module according to claim 11, characterized in that: The material of the molding compound includes epoxy molding compound.

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

14. The power module according to claim 13, characterized in that: The first heat sink is 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.

15. The power module according to claim 14, characterized in that: A first supporting component is provided between the first heat sink and the first metal-clad substrate, and the first supporting component includes a plurality of fourth supporting columns or metal wires; And / or, a second supporting component is provided between the second heat sink and the second metal-clad substrate, and the second supporting component includes a plurality of fifth supporting columns or metal wires.

16. A power supply circuit, characterized in that: It comprises a circuit board and a power module as claimed in any one of claims 1 to 15, wherein the power module is electrically connected to the circuit board.

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