Power module and power conversion device

Abstract

Embodiments of the present application provide a power module and a power conversion device. The power module comprises a metal substrate, a first insulating layer, a power chip, and a first external circuit layer. The metal substrate comprises a metal base material, a dielectric layer, and a substrate circuit layer that are stacked in a first direction. The first insulating layer covers the substrate circuit layer and the dielectric layer; the power chip is embedded in the first insulating layer and connected to the substrate circuit layer; the first external circuit layer covers the side of the first insulating layer away from the metal substrate; and the first external circuit layer is connected to the substrate circuit layer and / or the power chip. Compared with circuit boards and ceramic substrates, metal materials have high strength and are not prone to fracture, enhancing the machinability. Since the heat generated by the power chip is directly conducted to the metal substrate through a connection layer, the heat dissipation path is shorter, which is conducive to improving the heat dissipation efficiency of the power module.

Description

Power modules and power conversion devices

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on April 3, 2024, with application number 202410405649.5 and application name “Power Module and Power Conversion Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of semiconductor technology, and in particular to a power module and a power conversion device. Background Art

[0003] To increase power density, embedded component technology has become a key development direction. By embedding power chips in the printed circuit board (PCB) substrate and using blind vias to achieve electrical connection between the power chip and the outer circuit, miniaturization and integration are achieved. Conventional embedded component technology uses FR4 board or ABF (Ajinomoto Build-up Film) materials as PCB substrates, which are limited in thermal conductivity due to the inherent material properties. While ceramic substrates have good heat dissipation capabilities, they are prone to cracking and have limited processability, making them difficult to apply to the embedded packaging process of power devices. Summary of the Invention

[0004] The embodiments of the present application provide a power module and a power conversion device that can improve strength and heat dissipation efficiency.

[0005] In a first aspect, an embodiment of the present application provides a power module, which includes a metal substrate, a first insulating layer, a power chip and a first outer circuit layer. The metal substrate includes a metal base material, a dielectric layer, and a substrate circuit layer stacked along a first direction. The first insulating layer covers the substrate circuit layer and the dielectric layer. The power chip is buried in the first insulating layer and connected to the substrate circuit layer. The first outer circuit layer covers the side of the first insulating layer away from the metal substrate. The first outer circuit layer is connected to the substrate circuit layer and / or the power chip.

[0006] The power module provided in this application uses a metal base as a carrier and embeds the power chip into the insulating layer on the metal base. Since the metal substrate is made of metal, compared with circuit boards and ceramic substrates made of FR4 boards or ABF materials, the metal material has the characteristics of high strength and not easy to break, thereby improving the processability.

[0007] In addition, the first outer circuit layer covers the side of the first insulating layer away from the metal substrate, and the power chip is connected to the first outer circuit layer along the first direction to realize an integrated packaging architecture that is conductive with the first outer circuit layer, that is, the power chip can be embedded in the power module by adding layers.

[0008] In addition, the metal substrate has good thermal conductivity. The heat generated by the power chip is conducted out of the power module through the substrate circuit layer, the dielectric layer and the metal substrate. That is, the heat dissipation path of the power chip can be power chip-substrate circuit layer-dielectric layer-metal substrate. The heat dissipation path is short, thereby improving the heat dissipation efficiency of the power module.

[0009] According to the first aspect, a groove is formed on a side of the substrate circuit layer facing away from the metal base material, and the power chip is accommodated in the groove.

[0010] In this possible implementation, the power chip is housed in the groove, which helps to reduce the thickness and volume of the power module.

[0011] According to the first aspect, in a possible implementation, the substrate circuit layer includes a first part and a second part distributed along a direction perpendicular to the first direction, and a power chip is provided on the side of at least one of the first part and the second part facing away from the metal base, and in the first direction, the thickness of the first part is less than the thickness of the second part.

[0012] In this possible implementation, the substrate circuit layer includes a first part and a second part with different thicknesses. The first part with a smaller thickness can be used for signal transmission, and the second part with a larger thickness is used for current flow, thereby improving the layout flexibility of the power module.

[0013] According to the first aspect, in a possible implementation, a portion of the circuit layer of the substrate protrudes out of the first insulating layer to form a pin, and the pin is used to be electrically connected to the circuit board.

[0014] In this possible implementation, electrical connection between the internal power chip of the power module and an external device (eg, a circuit board) can be achieved by setting pins.

[0015] According to the first aspect, in a possible implementation, a first connection hole and a second connection hole are provided on the first insulating layer, and the first connection hole and the second connection hole are located between the substrate circuit layer and the first outer circuit layer in the first direction. The first outer circuit layer is connected to the power chip through the first connection hole, and the first outer circuit layer is connected to the power chip through the second connection hole.

[0016] In this possible implementation, holes are punched on the first insulating layer, the first outer circuit layer is connected to the power chip through the first connection hole, and the first outer circuit layer is connected to the power chip through the second connection hole, thereby facilitating the electrical connection between the first outer circuit layer and the substrate circuit layer.

[0017] According to the first aspect, in one possible implementation, the power module further includes a second insulating layer and a second outer circuit layer, the second insulating layer covering a side of the first outer circuit layer facing away from the metal substrate, and the second outer circuit layer being located on a side of the second insulating layer facing away from the metal substrate. A third connection hole is defined in the second insulating layer, the third connection hole being located between the first outer circuit layer and the second outer circuit layer in the first direction, and the second outer circuit layer being connected to the first outer circuit layer through the third connection hole.

[0018] In this possible implementation, the power module is multiplied by adding an outer circuit layer and an insulation layer, thereby improving the wiring flexibility of the power module.

[0019] According to the first aspect, in a possible implementation, the metal substrate includes a main body and heat dissipation teeth, the main body, the dielectric layer and the substrate circuit layer are stacked along a first direction, and the heat dissipation teeth are arranged on a side of the base away from the power chip.

[0020] In this possible implementation, the heat dissipation teeth increase the contact area between the metal base and the external air, thereby increasing the heat dissipation area of ​​the power module, which is beneficial to improving the heat dissipation efficiency of the power module to the power chip.

[0021] According to the first aspect, in a possible implementation, a flow channel for circulating a liquid cooling medium is provided in the metal substrate.

[0022] In this possible implementation method, the heat transferred from the power chip to the radiator can be taken away by the flow of liquid cooling medium in the flow channel. Since liquid cooling has the characteristics of large specific heat capacity and strong heat absorption, it can effectively enhance the heat dissipation efficiency of the power module, thereby achieving a higher heat dissipation effect.

[0023] According to the first aspect, in a possible implementation manner, the substrate circuit layer is formed by a lamination process, and the thickness of the substrate circuit layer is in the range of (0.8 mm, 3 mm).

[0024] When using a ceramic substrate, the circuit layer can only be formed by attaching copper foil of fixed thickness to the ceramic substrate through a sintering process, and the thickness range of the copper foil is [0.2mm, 0.8mm].

[0025] Since a metal substrate is used to support the substrate circuit layer, the metal substrate is stronger than the ceramic substrate. During the production process, the substrate circuit layer can be formed into a smaller or thicker circuit layer through a pressing process. In some embodiments of the present application, the thickness range of the substrate circuit layer can be [0.025mm, 3mm]. For example, the thickness range of the substrate circuit layer can be [0.025mm, 0.2mm]. The thickness range of the substrate circuit layer can be (0.8mm, 3mm). Since the thickness range of the substrate circuit layer can be wider, it is beneficial to improve the flexibility of the circuit layout of the substrate circuit layer.

[0026] According to the first aspect, in a possible implementation manner, the material of the connection layer includes solder or sintered material.

[0027] In this possible implementation, the material of the connection layer includes solder or sintering, that is, the connection layer is formed by a welding process or a sintering process.

[0028] According to the first aspect, in a possible implementation, the orthographic projection of the power chip on the first plane is located on the orthographic projection of the connecting layer in the first plane, the area of ​​the orthographic projection of the power chip is less than or equal to the area of ​​the orthographic projection of the connecting layer, and the first plane is the contact surface between the dielectric layer and the metal substrate.

[0029] In this possible implementation, the orthographic projection of the power chip on the first plane is located on the orthographic projection of the connecting layer in the first plane, the area of ​​the orthographic projection of the power chip is less than or equal to the area of ​​the orthographic projection of the connecting layer, the first plane is the contact surface between the dielectric layer and the metal substrate, and the orthographic projection of the power chip on the first plane completely overlaps with the orthographic projection of the connecting layer in the first plane. In this way, the contact area between the power chip and the connecting layer is guaranteed, the heat dissipated by the power chip to the insulating layer is reduced, and the heat dissipation efficiency of the power module is improved.

[0030] In a second aspect, some embodiments of the present application also provide a power conversion device, which includes a circuit board and a power module according to any possible implementation method of the first aspect, wherein the power module is arranged on the circuit board and is used for AC / DC conversion.

[0031] In a third aspect, the present application further provides a method for manufacturing a power module, comprising the following steps:

[0032] The power chip is fixed on a side of the substrate circuit layer of the metal substrate facing away from the metal substrate, wherein the metal substrate comprises a metal substrate, a dielectric layer, and a substrate circuit layer stacked along a first direction;

[0033] Laminating a first insulating layer to the metal substrate, wherein the first insulating layer covers the power chip, the substrate circuit layer and the dielectric layer;

[0034] A first outer circuit layer is formed on a side of the first insulating layer facing away from the metal substrate, and the first outer circuit layer is connected to the power chip.

[0035] According to the third aspect, in a possible implementation, after the first insulating layer is pressed onto the metal substrate and before the first outer circuit layer is formed on the side of the first insulating layer facing away from the metal substrate, the manufacturing method further includes: forming a first connection hole and a second connection hole on the first insulating layer, the first connection hole and the second connection hole being located between the substrate circuit layer and the first outer circuit layer in the first direction; filling the first connection hole and the second connection hole with a conductive medium; forming the first outer circuit layer on the side of the first insulating layer facing away from the metal substrate, and further including: the first outer circuit layer is electrically connected to the substrate circuit layer through the conductive medium in the first connection hole, and the first outer circuit layer is electrically connected to the power chip through the conductive medium in the second connection hole.

[0036] According to the third aspect, in one possible implementation, after forming a first outer circuit layer on a side of the first insulating layer facing away from the metal substrate, the manufacturing method further includes: forming a second insulating layer on a side of the first outer circuit layer facing away from the metal substrate; forming a second outer circuit layer on a side of the second insulating layer facing away from the metal substrate, and the second outer circuit layer is connected to the first circuit layer.

[0037] According to the third aspect, in one possible implementation, after forming the second insulating layer on the side of the first outer circuit layer facing away from the metal substrate, and before forming the second outer circuit layer on the side of the second insulating layer facing away from the metal substrate, the manufacturing method further includes: forming a third connection hole on the first insulating layer, the third connection hole being located between the first outer circuit layer and the second outer circuit layer in the first direction; filling the third connection hole with a conductive medium; forming the second outer circuit layer on the side of the second insulating layer facing away from the metal substrate, and further including electrically connecting the second outer circuit layer to the first outer circuit layer through the conductive medium in the third connection hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a schematic structural diagram of a vehicle provided in one embodiment of the present application;

[0039] FIG2 is a structural block diagram of a powertrain provided in one embodiment of the present application;

[0040] FIG3 is a schematic structural diagram of a photovoltaic system provided in one embodiment of the present application;

[0041] FIG4A is a schematic diagram of a stacked structure of a power module provided in a first embodiment of the present application;

[0042] FIG4B is a schematic diagram of a process for manufacturing a power module according to some embodiments of the present application;

[0043] FIG4C is a schematic diagram of a process for manufacturing a power module according to some embodiments of the present application;

[0044] FIG5 is a schematic diagram of a stacked structure of a power module provided in second embodiments of the present application;

[0045] FIG6 is a schematic diagram of a stacked structure of a power module provided in a third embodiment of the present application;

[0046] FIG7 is a schematic diagram of a stacked structure of a power module provided in a fourth embodiment of the present application;

[0047] FIG8 is a schematic diagram of a stacked structure of a power module provided in a fifth embodiment of the present application;

[0048] FIG9A is a schematic diagram of a stacked structure of a power module provided in a sixth embodiment of the present application;

[0049] FIG9B is a schematic flow chart of a method for manufacturing a power module according to some embodiments of the present application. DETAILED DESCRIPTION

[0050] Please refer to Figure 1, which is a schematic structural diagram of a vehicle provided in one embodiment of the present application. Vehicle 1000 includes a vehicle body 300, a battery pack 200, and a powertrain 100. The battery pack 200 and the powertrain 100 are both mounted on the vehicle body 300. The battery pack 200 is used to provide direct current to the powertrain 100. The powertrain 100 is used to provide power for the vehicle 1000. Vehicle 1000 also includes other necessary or non-essential structures, which are not detailed here in this application.

[0051] Please refer to Figure 2, which is a structural block diagram of a powertrain provided in one embodiment of the present application. The powertrain 100 includes a power conversion device 101 and a drive motor 103. The power conversion device 101 includes a circuit board 10 and a power module 30 provided on the circuit board 10. The power module 30 includes an input terminal 301 and an output terminal 303. The input terminal 301 is a DC input terminal, and the output terminal 303 is an AC output terminal. The input terminal 301 of the power module 30 is electrically connected to the battery pack 200, and the output terminal 303 of the power module 30 is electrically connected to the drive motor 103. The power module 30 is used to convert the DC power output by the battery pack 200 into AC power and transmit the AC power to the drive motor 103. Among them, the power module 30 is a semiconductor device that converts the voltage, current, frequency, etc. of the DC power output by the battery pack 200. It can be understood that the power module 30 can also be used to convert AC power into DC power. The power module 30 is the core component of the power conversion device 101. When the power conversion device 101 is working, the power module 30 realizes the conversion between AC power and DC power by frequently switching between on and off states.

[0052] Please refer to FIG3 , which is a schematic diagram of the structure of a photovoltaic system provided in one embodiment of the present application. The power module 30 of the present application can also be used in a photovoltaic system 2000. The photovoltaic system 2000 includes a power conversion device 101 and a photovoltaic module 105. The photovoltaic module 105 is electrically connected to the power conversion device 101. The direct current generated by the photovoltaic module 105 is converted into alternating current by the power module 30. The alternating current output by the power module 30 is transmitted to power-consuming equipment, such as base stations and data centers.

[0053] To increase power density, embedded component technology has become a key development direction. By embedding power chips within the PCB substrate and using blind vias to electrically connect the power chips to the outer circuitry, miniaturization and integration are achieved. Conventional embedded component technology uses FR4 or ABF materials, which have limited thermal conductivity due to their inherent material properties. While ceramic substrates offer excellent heat dissipation, they are prone to cracking and have limited processability, making them poorly suited for embedded power electronics packaging.

[0054] Based on this, as shown in FIG4A , the first embodiment of the present application provides an embedded power module 30, comprising a metal substrate 31, a first insulating layer 32, a power chip 33, and a first outer circuit layer 34. The metal substrate 31 comprises a metal base material 311, a dielectric layer 312, and a substrate circuit layer 313 stacked in sequence along a first direction Z. The first insulating layer 32 covers the substrate circuit layer 313 and the dielectric layer 312, and the power chip 33 is embedded in the first insulating layer 32.

[0055] The power chip 33 is embedded in the first insulating layer 32 . In other words, the first insulating layer 32 wraps and encapsulates the power chip 33 and the connection layer 330 .

[0056] The power module 30 provided in this application utilizes a metal substrate 31 as a carrier, with a power chip 33 embedded within a first insulating layer 32 on the metal substrate 31. Since the metal substrate 311 is made of metal, compared to circuit boards, metal is stronger and less prone to breakage, improving workability. Heat generated by the power chip 33 is transferred to the substrate circuit layer 313, which in turn conducts the heat out of the power module 30 via the dielectric layer 312, the metal substrate 311, and the dielectric layer 312. This shortens the heat dissipation path from the power chip 33 to the substrate circuit layer 313, the dielectric layer 312, and the metal substrate 311. This shortens the heat dissipation path, thereby improving the heat dissipation efficiency of the power module 30.

[0057] When using a ceramic substrate, the circuit layer can only be formed by attaching copper foil of fixed thickness to the ceramic substrate through a sintering process, and the thickness range of the copper foil is [0.2mm, 0.8mm].

[0058] The material of the substrate circuit layer 313 and the first outer circuit layer 34 includes copper. Since a metal substrate 311 is used to support the substrate circuit layer 313, the metal substrate 311 is stronger than the ceramic substrate. During production, the substrate circuit layer 313 can be formed into a smaller or thicker circuit layer through a pressing process. In some embodiments of the present application, the thickness range of the substrate circuit layer 313 can be [0.025mm, 3mm]. For example, the thickness range of the substrate circuit layer 313 can be [0.025mm, 0.2mm]. The thickness range of the substrate circuit layer 313 can be (0.8mm, 3mm]. Since the thickness range of the substrate circuit layer 313 can be wider, it is beneficial to improve the flexibility of the circuit layout of the substrate circuit layer 313. The material of the substrate circuit layer 313 and the first outer circuit layer 34 is not limited to copper. The material of the substrate circuit layer 313 and the first outer circuit layer 34 can be made of other conductive materials. The present application does not limit the thickness of the substrate circuit layer 313.

[0059] In addition, the present application uses a metal substrate 31 as a carrier to implement an embedded packaging process for the power chip 33, shorten the loop, reduce stray inductance, and at the same time meet the requirements of high heat dissipation, high insulation and large current flow, and solve the problems of low thermal conductivity of PCB boards in traditional embedded processes, easy cracking of ceramic substrates, poor processability, and difficult implementation of asymmetric structures. The thickness of the substrate circuit layer 313 in the metal substrate 31 is not restricted, and can meet large current flow scenarios. In particular, the power chip 33 generates a large amount of heat during operation, and the heat can be dissipated through the dielectric layer 312 and the metal substrate 311. It can be well applied to third-generation semiconductor packaging scenarios, laying the foundation for product upgrades and enhanced competitiveness.

[0060] Metal substrate 311 can be made of copper, aluminum, or iron, among other metals with excellent heat dissipation and heat distribution. Substrate circuit layer 313 is securely connected to metal substrate 311 via dielectric layer 312. Exemplarily, dielectric layer 312 can include an epoxy resin layer, a polyimide layer, thermally conductive silicone, or thermally conductive gel.

[0061] The first insulating layer 32 can be formed by a lamination process. The first insulating layer 32 can be made of insulating materials such as ABF material and polypropylene (PP) material. The power chip 33 can include one or more, and the substrate circuit layer 313 can include one or more sub-copper layers. The power chip 33 can be set on one or more sub-copper layers, and this application is not limited to this. The first insulating layer 32 forms a closed space outside the power chip 33, thereby protecting the power chip 33 and reducing the possibility of accidental damage to the power chip 33 during transportation and operation.

[0062] The power chip 33 can be a gallium nitride (GaN) chip. GaN has the characteristics of high operating temperature, high breakdown voltage, and strong radiation resistance. It has a very broad prospect in the field of power semiconductor applications. Due to its high-frequency characteristics, it is necessary to reduce the parasitic parameters brought by the signal loop and reduce signal delay. The packaging form has evolved from pinned packaging to pinless packaging, and then to embedded technology. The packaging process is continuously optimized to shorten the circuit loop and reduce stray inductance. Currently, in photovoltaic optimizers, data center UPS, site power rectifiers and other products, we continue to explore how GaN devices can increase frequency and reduce magnetic field, miniaturize, integrate, improve power density, and reduce end-to-end costs in the next generation of products. It can be understood that this application does not limit the material and type of the power chip 33.

[0063] In some embodiments of the present application, the power chip 33 is connected to the substrate circuit layer 313 via a connection layer 330. The connection layer 330 is located between the substrate circuit layer 313 and the power chip 33 in the first direction Z. The orthographic projection of the power chip 33 on the first plane is located on the orthographic projection of the connection layer 330 within the first plane. The area of ​​the orthographic projection of the power chip 33 is less than or equal to the area of ​​the orthographic projection of the connection layer 330. The first plane is the contact surface between the dielectric layer 312 and the metal substrate 311. The orthographic projection of the power chip 33 on the first plane completely overlaps with the orthographic projection of the connection layer 330 within the first plane. In this way, the contact area between the power chip 33 and the connection layer 330 is ensured, the heat dissipation of the power chip 33 into the first insulating layer 32 is reduced, and the heat dissipation efficiency of the power module 30 is improved.

[0064] The connection layer 330 can be formed by soldering or sintering. When the connection layer 330 is formed by soldering, the solder can be selected from at least one of tin solder and lead solder, wherein the tin solder can be selected from at least one of SnSb5, SnSb8, SnSbAg, SAC305, SAC multi-reinforced, and SnSb10. The solder material can be selected as needed. SnSb5 refers to a Sn element containing 5% by weight of Sb, SnSb8 refers to a Sn element containing 8% by weight of Sb, and SnSb10 refers to a Sn element containing 10% by weight of Sb. The "SAC" in SAC306 stands for Sn, Ag, and Cu, indicating that the product is composed of Sn (tin), Ag (silver), and Cu (copper). "3" represents 3% Ag, and "05" represents 0.5% Cu. SAC multi-component strengthening includes other metal components in addition to the three metal components Sn (tin), Ag (silver), and Cu (copper) to enhance the reliability of the solder.

[0065] In the case where the connecting layer 330 is formed by sintering, illustratively, the sintered material can be formed of silver paste, copper paste or silver film. In a specific embodiment, the silver paste can include at least one of micrometer silver paste (Micrometer silver particle paste) and nanometer silver paste (Nano meter silver particle paste). Among them, micrometer silver paste refers to a silver paste made using micrometer silver particles and organic solvents, which is low in cost and safe. Generally, sintering is carried out under pressure, the sintered material SJ has high density, the interface bonding of the bonded body is firm, and the bonding reliability is high. Optionally, in order to improve the reliability of sintered bonding and reduce costs, the sintered material of the present application can be formed using micrometer silver paste (Micrometer silver particle paste). In order to improve the reliability of sintered bonding, the elastic modulus, thermal expansion coefficient (CTE), etc. of the sintered material can be adjusted by adding materials to the sintered material. Exemplarily, the sintering material includes a main body 3112 material and a filler filled in the main body 3112 material; the main body 3112 material includes at least one of silver paste, copper paste, or silver film; the filler is formed from a material that has good bonding properties with the main body 3112 material, and the filler's thermal expansion coefficient is smaller than that of the main body 3112 material, thereby improving the bonding reliability during sintering. For example, if the main body 3112 material is micronized silver paste, the filler is added to the micronized silver paste to reduce the thermal expansion coefficient of the micronized silver paste, thereby reducing bonding stress and improving the bonding reliability of silver sintering. 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., without limitation herein.

[0066] A first connection hole 321 and a second connection hole 323 are provided on the first insulating layer 32. The first connection hole 321 and the second connection hole 323 are located between the substrate circuit layer 313 and the first outer circuit layer 34 in the first direction Z. The first outer circuit layer 34 is connected to the power chip 33 through the first connection hole 321, and the first outer circuit layer 34 is connected to the power chip 33 through the second connection hole 323.

[0067] The first connection holes 321 and the second connection holes 323 can be opened in the first insulating layer 32 using a laser. The first connection holes 321 and the second connection holes 323 are filled with a conductive medium. The conductive medium can be made of the same material as or different from that of the first outer circuit layer 34. The power chip 33 is electrically connected to the first outer circuit layer 34 through the first connection holes 321, and the substrate circuit layer 313 is electrically connected to the first outer circuit layer 34 through the second connection holes 323.

[0068] After the substrate circuit layer 313 is formed on the metal substrate 31, the power chip 33 is connected to the substrate circuit layer 313 through the connecting layer 330. The power chip 33 is connected to the first outer circuit layer 34 along the first direction Z through the conductive medium or the connecting hole to realize an integrated packaging architecture that is conductive with the first outer circuit layer 34. The power chip 33 is embedded in the power module 30 by adding layers.

[0069] 4A and 4B , the present application further provides a method for manufacturing a power module 30 , comprising the following steps:

[0070] S102 , fixing the power chip 33 on the side of the substrate circuit layer 313 of the metal substrate 31 away from the metal base material 311 . The metal substrate 31 includes a metal base material 311 , a dielectric layer 312 , and a substrate circuit layer 313 stacked along a first direction.

[0071] S104 , pressing the first insulating layer 32 onto the metal substrate 31 , wherein the first insulating layer 32 covers the power chip 33 , the substrate circuit layer 313 and the dielectric layer 312 .

[0072] S106 , forming a first outer circuit layer 34 on a side of the first insulating layer 32 away from the metal substrate 311 , wherein the first outer circuit layer 34 is connected to the power chip 33 .

[0073] The present application can achieve the arrangement of an outer circuit layer in the power module 30 by means of layer build-up. Some embodiments of the present application also provide a method for preparing the power module 30. Please refer to FIG. 4A and FIG. 4C in combination. The preparation method may include the following steps:

[0074] S201 , forming a metal substrate 31 . The metal substrate 31 includes a metal base material 311 , a dielectric layer 312 , and a substrate circuit layer 313 stacked along a first direction.

[0075] In some embodiments, S201 may include: forming a dielectric layer 312 on the metal substrate 311 , and forming a substrate circuit layer 313 on a side of the dielectric layer 312 facing away from the metal substrate 311 , thereby obtaining the metal substrate 31 .

[0076] S202 , fixing the power chip 33 on the side of the substrate circuit layer 313 of the metal substrate 31 facing away from the metal base material 311 .

[0077] In some embodiments of the present application, the power chip 33 is soldered or sintered to the side of the substrate circuit layer 313 facing away from the metal substrate 311 , and the solder or sintered material forms a connection layer 330 .

[0078] S203 , pressing the first insulating layer 32 onto the metal substrate 31 , the first insulating layer 32 covering the power chip 33 , the substrate circuit layer 313 and the dielectric layer 312 , and completing embedding the power chip 33 into the metal substrate 31 .

[0079] S204 , forming a first connection hole 321 and a second connection hole 323 on the first insulating layer 32 . The first connection hole 321 and the second connection hole 323 are both located between the substrate circuit layer 313 and the first outer circuit layer 34 in the first direction Z.

[0080] In some embodiments of the present application, the first connection hole 321 and the second connection hole 323 are formed on the first insulating layer 32 by laser lithography.

[0081] S205 , filling the first connection hole 321 and the second connection hole 323 with a conductive medium.

[0082] S206: A first outer circuit layer 34 is formed on the side of the first insulating layer 32 facing away from the metal substrate 311. The first outer circuit layer 34 is connected to the power chip 33. The first outer circuit layer 34 is electrically connected to the substrate circuit layer 313 via the conductive medium in the first connection holes 321. The first outer circuit layer 34 is electrically connected to the power chip 33 via the conductive medium in the second connection holes 323. The first outer circuit layer 34 can be fixed to the side of the first insulating layer 32 facing away from the metal substrate 311 by pressing and gluing.

[0083] It is understood that the present application does not limit the steps of the method for manufacturing the power module 30 . For example, S201 may be omitted, and the existing metal substrate 31 may be used directly.

[0084] As shown in FIG5 , the power module 30 provided in the second embodiment of the present application has a substantially similar structure to the power module 30 provided in the first embodiment, with the difference being that the substrate circuit layer 313 includes a first portion 3132 and a second portion 3133 distributed along a second direction X perpendicular to the first direction Z. In the first direction Z, the thickness of the first portion 3132 is less than the thickness of the second portion 3133. The first portion 3132 is used to accommodate the power chip 33 for signal transmission. The thicker thickness of the second portion 3133 can improve the flow capacity. Separating the first portion 3132 for signal transmission and the second portion 3133 for flow at different heights helps to improve the layout flexibility of the substrate circuit layer 313.

[0085] Since the thickness of the substrate circuit layer 313 can range from 0.025 mm to 3 mm, the structural layout of the substrate circuit layer 313 can be more flexible. A recess 314 is formed on the side of the second portion 3133 facing away from the metal substrate 311. The power chip 33 is accommodated in the recess 314, which helps reduce the thickness and volume of the power module 30.

[0086] It is understandable that the power chip 33 may also be provided on the first part 3132, that is, at least one of the first part 3132 and the second part 3133 is provided with the power chip 33.

[0087] It is understandable that a groove 314 may also be provided on the first portion 3132 .

[0088] The substrate circuit layer 313 is made of copper. The metal substrate 31 utilizes a thin-thick copper process to achieve thin copper in the signal area and thick copper in the flow area, further reducing its size and separating the signal and flow areas. The power chip 33 is embedded in the metal substrate to achieve electrical connection with the first outer circuit layer 34 in the first direction Z, dissipating heat downward and providing insulation.

[0089] As shown in Figure 6, the power module 30 provided in the third embodiment of the present application has a substantially similar structure to the power module 30 provided in the first embodiment, except that a portion of the substrate circuit layer 313 protrudes from the insulating layer 32 to form a pin 3131, and the pin 3131 is used to electrically connect to the circuit board. The substrate circuit layer 313 can be a frame made of a conductive material such as copper. The pin 3131 is used to electrically connect to the circuit board. It can be understood that by providing the pin 3131, an electrical connection between the internal power chip 33 of the power module 30 and an external device (such as a circuit board) can be achieved.

[0090] The pins 3131 are integrally provided with the portion of the substrate circuit layer 313 located within the first insulating layer 32 . The pins 3131 can be surface mounted for reflow soldering or plug-in soldering.

[0091] The dielectric layer 312 is pressed together with the substrate circuit layer 313 to form a metal substrate 31 with a frame with the metal base material 311. The power chip 33 is connected to the first outer circuit layer 34 along the first direction Z upward through the embedding process, and has the functions of heat dissipation and insulation downward, finally forming an integrated packaging module.

[0092] As shown in Figure 7, the power module 30 provided in the fourth embodiment of the present application has a structure roughly the same as the power module 30 provided in the first embodiment. The difference is that the metal substrate 311 can be a metal heat sink. The metal substrate 311 can include a main body 3112 and heat dissipation teeth 3114. The main body 3112, the dielectric layer 312 and the substrate circuit layer 313 are stacked along the first direction Z. The heat dissipation teeth 3114 are arranged on the side of the main body 3112 away from the power chip 33. The heat dissipation teeth 3114 increase the contact area between the metal substrate 31 and the external air, thereby increasing the heat dissipation area of ​​the power module 30, which is beneficial to improving the heat dissipation efficiency of the power module 30 to the power chip 33.

[0093] The material of the radiator can be copper, aluminum, etc.

[0094] The heat sink may be a pin-fin heat dissipation structure, that is, the heat dissipation teeth 3114 of the heat sink may adopt a cylindrical or square columnar structure, thereby obtaining a larger heat dissipation area and improving the heat dissipation efficiency of the power module 30 to the power chip 33 .

[0095] In another possible implementation, the heat sink may have a fin-like structure, i.e., the heat dissipation teeth 3114 of the heat sink may be similar in structure to a thin sheet. It should be understood that, compared to a pin-fin heat dissipation structure, the heat dissipation teeth 3114 of a heat sink with a fin-like structure are narrower, resulting in a relatively smaller heat dissipation area and a relatively poorer heat dissipation effect.

[0096] A surface of the dielectric layer 312 close to the substrate circuit layer 313 is parallel to a surface of the dielectric layer 312 close to the metal substrate 311 .

[0097] In the embodiment of the present application, the metal substrate 311 includes a main body 3112 and heat dissipation teeth 3114, that is, the metal substrate 31 is an integrated heat dissipation metal base. By using an integrated heat dissipation metal base, the heat of the power chip 33 can be directly transferred from the power chip 33 to the integrated heat dissipation metal base, reducing the thermal resistance on the heat dissipation path of the power chip 33 and improving the heat dissipation efficiency of the power chip 33. In addition, the side of the dielectric layer 312 close to the substrate circuit layer 313 is parallel to the side of the dielectric layer 312 close to the metal substrate 311. The dielectric layer 312 has a uniform thickness and a flat surface, which makes the heat conduction more uniform and has a better heat conduction effect. In addition, the present application directly uses the integrated heat dissipation metal base to directly source materials, integrates circuit connection, heat dissipation, insulation and other functions, saves the assembly process of connecting the power device and the radiator, reduces the connection interface, and solves the heat dissipation problem caused by interface defects. At the same time, because the materials are integrated into one, the management cost of power devices, radiators, thermal insulation media, and tooling and curing equipment required during the assembly process is reduced.

[0098] As shown in FIG8 , the power module 30 provided in the fifth embodiment of the present application has a substantially similar structure to the power module 30 provided in the first embodiment, with the difference being that a flow channel 3116 for circulating a liquid cooling medium is provided within the metal substrate 311. In other words, the metal substrate 311 can be a heat sink having the flow channel 3116. In other words, the heat transferred from the power chip 33 to the metal substrate 311 can be carried away by the flow of the liquid cooling medium in the flow channel 3116. Since liquid cooling has the characteristics of large specific heat capacity and strong heat absorption, it can effectively enhance the heat dissipation efficiency of the power module 30, thereby achieving a higher heat dissipation effect.

[0099] In the embodiment of the present application, a flow channel 3116 is provided in the metal substrate 311, that is, the metal substrate 31 is an integrated heat dissipation metal base. By using the integrated heat dissipation metal base, the heat of the power chip 33 can be directly transferred from the power chip 33 to the integrated heat dissipation metal base, thereby reducing the thermal resistance on the heat dissipation path of the power chip 33 and improving the heat dissipation efficiency of the power chip 33. In addition, the side of the dielectric layer 312 close to the substrate circuit layer 313 is parallel to the side of the dielectric layer 312 close to the metal substrate 311. The dielectric layer 312 has a uniform thickness and a flat surface, thereby making the heat conduction more uniform and having a better heat conduction effect. In addition, the present application directly uses the integrated heat dissipation metal base as the raw material, integrating circuit connection, heat dissipation, insulation and other functions, saving the assembly process of connecting the power device and the radiator, reducing the connection interface, and solving the heat dissipation problem caused by interface defects. At the same time, because the raw materials are integrated into one, the management cost of the power device, radiator, thermal insulation medium, and the tooling and curing equipment required in the assembly process is reduced.

[0100] The liquid cooling medium can be a coolant, such as water, ethylene glycol solution, propylene glycol solution, or fluorinated liquid, and can also include a gas. The working fluid can be a single component or a mixture of at least two liquid cooling media (for example, a mixed liquid formed by mixing at least two coolants). The liquid cooling medium can maintain a single phase (i.e., no phase change) during the flow process, or it can be two-phase (i.e., converting between a liquid phase and a gas phase). It is understood that the required type of liquid cooling medium can be selected according to needs.

[0101] As shown in FIG9A , the power module 30 provided in the sixth embodiment of the present application has a substantially similar structure to the power module 30 provided in the first embodiment, except that the power module 30 further includes a second insulating layer 35 and a second outer circuit layer 36. The second insulating layer 35 covers the side of the first outer circuit layer 34 facing away from the metal substrate 311. The second outer circuit layer 36 covers the side of the second insulating layer 35 facing away from the metal substrate 311 and is connected to the first outer circuit layer 34. A third connection hole 351 is defined in the second insulating layer 35. The third connection hole 351 is located between the first outer circuit layer 34 and the second outer circuit layer 36 in the first direction Z. The second outer circuit layer 36 is connected to the first outer circuit layer 34 through the third connection hole 351. The second insulating layer 35 can be made of an insulating material such as ABF or polypropylene (PP). The material of the second insulating layer 35 can be the same as that of the first insulating layer 32, or it can be different from the material of the first insulating layer 32. The material of the second outer circuit layer 36 includes copper. The material of the second outer circuit layer 36 may be the same as that of the first outer circuit layer 34 , or the material of the second outer circuit layer 36 may be the same as or different from that of the first outer circuit layer 34 .

[0102] The present application utilizes a build-up method to achieve the arrangement of three circuit layers in the power module 30. The three circuit layers include a substrate circuit layer 313, a first outer circuit layer 34, and a second outer circuit layer 36. Some embodiments of the present application also provide a method for preparing the power module 30. Referring to FIG. 9A and FIG. 9B , the method may include the following steps:

[0103] S301 , forming a metal substrate 31 . The metal substrate 31 includes a metal base material 311 , a dielectric layer 312 , and a substrate circuit layer 313 stacked along a first direction.

[0104] In some embodiments, S201 may include: forming a dielectric layer 312 on the metal substrate 311 , and forming a substrate circuit layer 313 on a side of the dielectric layer 312 facing away from the metal substrate 311 , thereby obtaining the metal substrate 31 .

[0105] S302 , fixing the power chip 33 on the side of the substrate circuit layer 313 of the metal substrate 31 facing away from the metal base material 311 .

[0106] In some embodiments of the present application, the power chip 33 is soldered or sintered to the side of the substrate circuit layer 313 facing away from the metal substrate 311 , and the solder or sintered material forms a connection layer 330 .

[0107] S303 , pressing the first insulating layer 32 onto the metal substrate 31 , the first insulating layer 32 covering the power chip 33 , the substrate circuit layer 313 and the dielectric layer 312 , and completing embedding the power chip 33 into the metal substrate 31 .

[0108] S304 , forming a first connection hole 321 and a second connection hole 323 on the first insulating layer 32 . The first connection hole 321 and the second connection hole 323 are both located between the substrate circuit layer 313 and the first outer circuit layer 34 in the first direction Z.

[0109] In some embodiments of the present application, the first connection hole 321 and the second connection hole 323 are formed on the first insulating layer 32 by laser lithography.

[0110] S305 , filling the first connection hole 321 and the second connection hole 323 with a conductive medium.

[0111] S306: A first outer circuit layer 34 is formed on the side of the first insulating layer 32 facing away from the metal substrate 311. The first outer circuit layer 34 is connected to the power chip 33. The first outer circuit layer 34 is electrically connected to the substrate circuit layer 313 via the conductive medium in the first connection holes 321. The first outer circuit layer 34 is also electrically connected to the power chip 33 via the conductive medium in the second connection holes 323. The first outer circuit layer 34 can be secured to the side of the first insulating layer 32 facing away from the metal substrate 311 by lamination or gluing.

[0112] S307 , pressing the second insulating layer 35 onto the first outer circuit layer 34 , so that the second insulating layer 35 covers the first outer circuit layer 34 .

[0113] S308 , forming third connection holes 351 on the second insulating layer 35 . The third connection holes 351 are located between the second outer circuit layer 36 and the first outer circuit layer 34 in the first direction Z.

[0114] In some embodiments of the present application, the third connection hole 351 is formed on the second insulating layer 35 by laser lithography.

[0115] S309 , filling the third connection hole 351 with a conductive medium.

[0116] At step S310, a second outer circuit layer 36 is formed on a side of the second insulating layer 35 facing away from the metal substrate 311. The second outer circuit layer 36 is electrically connected to the first outer circuit layer 34 via the conductive medium in the third connection hole 351. The second outer circuit layer 36 can be secured to the side of the second insulating layer 35 facing away from the metal substrate 311 by lamination or gluing.

[0117] It is understood that the present application does not limit the number of outer circuit layers. For example, the power module 30 may further include a third outer circuit layer or more circuit layers. In the first direction Z, adjacent circuit layers are insulated from each other by an insulating layer.

[0118] In the absence of conflict or contradiction, the first to sixth embodiments of the present application can be combined with each other.

[0119] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0120] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0121] In this application, expressions including ordinal numbers such as "first" and "second" may modify various elements. However, such elements are not limited by the above expressions. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used to distinguish one element from other elements. For example, a first user device and a second user device indicate different user devices, even though the first user device and the second user device are both user devices. Similarly, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0122] When a component is referred to as being "connected" or "accessed" to another component, it should be understood that the component is not only directly connected to or accessed to the other component, but also that another component may exist between the component and the other component. On the other hand, when a component is referred to as being "directly connected to" or "directly accessed" to another component, it should be understood that no component exists between them.

[0123] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An embedded power module, characterized in that: The power module includes a metal substrate, a first insulating layer, a power chip and a first outer circuit layer. The metal substrate includes a metal base material, a dielectric layer and a substrate circuit layer stacked along a first direction. The first insulating layer covers the substrate circuit layer and the dielectric layer. The power chip is buried in the first insulating layer and connected to the substrate circuit layer. The first outer circuit layer covers the side of the first insulating layer facing away from the metal substrate and is connected to the substrate circuit layer.

2. The power module according to claim 1, characterized in that: A groove is formed on a side of the substrate circuit layer facing away from the metal base material, and the power chip is accommodated in the groove.

3. The power module according to claim 1 or 2, characterized in that: The substrate circuit layer includes a first part and a second part distributed in a direction perpendicular to the first direction. A power chip is provided on a side of at least one of the first part and the second part facing away from the metal base. In the first direction, the thickness of the first part is less than the thickness of the second part.

4. The power module according to claim 3, characterized in that: Part of the circuit layer of the substrate protrudes out of the first insulating layer to form a pin, and the pin is used to be electrically connected to the circuit board.

5. The power module according to any one of claims 1 to 4, characterized in that: A first connection hole and a second connection hole are provided on the first insulating layer. The first connection hole and the second connection hole are located between the substrate circuit layer and the first outer circuit layer in the first direction. The first outer circuit layer is connected to the power chip through the first connection hole, and the first outer circuit layer is connected to the power chip through the second connection hole.

6. The power module according to claim 5, characterized in that: The power module further includes a second insulating layer and a second outer circuit layer, wherein the second insulating layer covers a side of the first outer circuit layer away from the metal substrate, and the second outer circuit layer is located on a side of the second insulating layer away from the metal substrate; A third connection hole is provided on the second insulating layer. The third connection hole is located between the first outer circuit layer and the second outer circuit layer in the first direction. The second outer circuit layer is connected to the first outer circuit layer through the third connection hole.

7. The power module according to any one of claims 1 to 6, characterized in that: The metal substrate includes a main body and heat dissipation teeth. The main body, the dielectric layer and the substrate circuit layer are stacked along a first direction. The heat dissipation teeth are arranged on a side of the main body away from the power chip.

8. The power module according to any one of claims 1 to 7, characterized in that: A flow channel for circulating a liquid cooling medium is provided in the metal substrate.

9. The power module according to any one of claims 1 to 8, characterized in that: The substrate circuit layer is formed by a lamination process, and the thickness of the substrate circuit layer is in the range of (0.8 mm, 3 mm).

10. A power conversion device, characterized in that: The power conversion device includes a circuit board and a power module according to any one of claims 1 to 9, wherein the power module is arranged on the circuit board and is used for AC-DC conversion.

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