Power module and power converter

Abstract

A power module and a power converter. In the present application, the number of layers of at least one second metal layer is less than the number of layers of at least one first metal layer, so that the substrate core layer is in an asymmetric structure on two opposite sides, and the metal traces on the side of the metal substrate facing the at least one second metal layer are relatively less than the metal traces on the side of the metal substrate facing the first metal layer, which can reduce the thermal resistance of the heat link on the side of the second metal layer, and the heat generated by the pre-package can be dissipated to the outside through the second metal layer, improving the heat dissipation effect.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging technology, and in particular to a power module and a power converter. Background Technology

[0002] Power semiconductors are the core of power conversion and circuit control in electronic devices. Utilizing the unidirectional conductivity of semiconductors to achieve power switching and power conversion can improve energy conversion efficiency and reduce power loss. A power module provides physical packaging for power semiconductors, resistors, and other components, forming a complete power conversion unit.

[0003] With the rapid development of electrification and digitalization in the energy industry, the application market for power modules has increased significantly. Simultaneously, the rapid development of electronic products demands that packaged modules evolve towards smaller size, thinner thickness, and higher integration. This has led to the development of technology that embeds power chips within printed circuit boards (PCBs) for interconnection. However, because embedded power modules are encased in PCB materials with poor thermal conductivity, the heat generated by the embedded power module is difficult to dissipate quickly and effectively, resulting in excessively high localized temperatures of the power chip and affecting its reliability. Utility Model Content

[0004] This application provides a power module and a power converter.

[0005] In a first aspect, this application provides a power module comprising a substrate core layer, at least one first metal layer, a metal connection via, at least one second metal layer, a pre-packaged body, and a first molding compound. The first molding compound partially encapsulates the substrate core layer, the pre-packaged body, the at least one first metal layer, the metal connection via, and the at least one second metal layer. The substrate core layer has a recessed location for mounting the pre-packaged body. The pre-packaged body is disposed between the at least one first metal layer and the at least one second metal layer. The at least one first metal layer and the metal connection via are located on the same side of the substrate core layer, and the at least one second metal layer is located on the side of the substrate core layer opposite to the at least one first metal layer. Along the stacking direction of the substrate core layer and the second metal layer, adjacent first metal layers are connected by a metal connection via, and the number of at least one second metal layer is less than the number of at least one first metal layer.

[0006] In the power module of this application, at least one first metal layer and a metal connection via are provided on one side of the substrate core layer, and at least one second metal layer is provided on the opposite side of the substrate core layer, wherein the number of at least one second metal layer is less than the number of at least one first metal layer. Thus, the two opposite sides of the substrate core layer have an asymmetrical structure. The metal traces on the side of the pre-package facing the second metal layer are fewer than the metal traces on the side of the pre-package facing away from the second metal layer, which can reduce the thermal resistance of the thermal link on the side facing the second metal layer. The heat generated by the pre-package can be dissipated to the outside through at least one second metal layer, improving the heat dissipation effect. The pre-package is a packaged power module, and the pre-package is embedded in the substrate core layer.

[0007] Along the stacking direction of the substrate core layer and the second metal layer, adjacent first metal layers are connected by metal interconnect vias. This reduces parasitic inductance and resistance in the power circuit, decreases oscillation, improves the efficiency of the pre-package, and reduces electrical stress. Compared to direct connection of two first metal layers, this enhances the power module's resistance to mechanical stress and reduces the risk of cracking in the embedded pre-package.

[0008] In conjunction with the first aspect, in one possible implementation, the pre-package includes a metal substrate, a chip, and a first metal pillar, with the metal substrate disposed between the chip and at least one second metal layer. The first metal pillar is disposed on the side of the chip facing away from the metal substrate, and the chip is connected to the first metal layer via the first metal pillar.

[0009] The metal substrate is made of metal, which has a higher thermal conductivity than a ceramic substrate. The side of the metal substrate facing away from the chip can directly contact the second metal layer. The heat generated by the chip can be quickly conducted through the metal substrate to the second metal layer and then dissipated to the outside. The chip is led out and interconnected with the first metal layer through the first metal pillar, which can reduce the surface stress on the chip when the first metal layer is connected to the chip, and reduce the risk of chip surface cracking.

[0010] In conjunction with the first aspect, in one possible implementation, the pre-packaged body further includes a second metal pillar disposed on the side of the metal substrate facing away from the second metal layer, and the second metal pillar connects the metal substrate and the first metal layer. The metal substrate is connected to the first metal layer via the second metal pillar, which can reduce lateral thermal crosstalk of the metal substrate towards the first metal layer.

[0011] In conjunction with the first aspect, in one possible implementation, the first metal layer furthest from the substrate core layer is exposed relative to the first molding compound, and the first metal layer furthest from the substrate core layer is used to connect other devices.

[0012] In conjunction with the first aspect, in one possible implementation, along the stacking direction of the substrate core layer and the second metal layer, the size of the second metal layer is smaller than the size of the metal substrate.

[0013] In this design, the stacking direction of the substrate core layer and the second metal layer is the thickness direction of both the second metal layer and the metal substrate. Specifically, the dimension of the second metal layer along the stacking direction of the substrate core layer and the second metal layer is the thickness of the second metal layer, and the dimension of the metal substrate along the stacking direction of the substrate core layer and the second metal layer is the thickness of the metal substrate. The thickness of the metal substrate is greater than the thickness of the second metal layer. A thicker metal substrate can provide a larger heat capacity and heat dissipation area, reducing localized heat accumulation and improving heat dissipation. The second metal layer is relatively thinner than the metal substrate, resulting in a lower overall thermal resistance and further enhancing heat dissipation.

[0014] In conjunction with the first aspect, in one possible implementation, along the stacking direction of the substrate core layer and the second metal layer, the size of the second metal layer is greater than or equal to 100 micrometers and less than or equal to 200 micrometers.

[0015] The thickness of the second metal layer should not be less than 100 micrometers to avoid increasing the lateral (perpendicular to the stacking direction of the substrate core layer and the second metal layer) thermal resistance due to the thickness of the second metal layer being too small. In addition, the second metal layer with too small a thickness is prone to deformation and cracking during use due to stress, vibration, thermal expansion or contraction. The thickness of the second metal layer should not be greater than 200 micrometers to avoid the increase in thermal resistance caused by the second metal layer being too thick.

[0016] In conjunction with the first aspect, in one possible implementation, along the stacking direction of the substrate core layer and the second metal layer, the size of the metal substrate is greater than or equal to 300 micrometers and less than or equal to 800 micrometers.

[0017] A metal substrate that is too thin increases the risk of breakage during power module fabrication and can lead to localized hotspots during chip heat dissipation. Conversely, a metal substrate that is too thick increases thermal resistance, affecting heat dissipation and increasing the overall thickness of the power module. In this application, the thickness of the metal substrate is between 300 micrometers and 800 micrometers. This allows the metal substrate to provide greater heat capacity and heat dissipation area, while also reducing the risk of breakage and preventing an excessively thick power module due to an overly thick pre-packaged body, thus reducing costs.

[0018] In conjunction with the first aspect, in one possible implementation, there are multiple pre-packages, and at least one second metal layer is connected to the metal substrate of each pre-package. A portion of the first molding compound is provided between the at least one second metal layer connecting different pre-packages.

[0019] Since the side of the metal substrate facing away from the chip is connected to the second metal layer, at least one second metal layer connecting different pre-packages is insulated and protected by the first molding compound. At the same time, the thermal impact between different pre-packages can be reduced.

[0020] In conjunction with the first aspect, in one possible implementation, the metal connection via is also connected between the metal substrate and at least one second metal layer, and / or, the metal connection via is also connected between two adjacent second metal layers.

[0021] Metal interconnect vias connect the second metal layer closest to the substrate core layer and the metal substrate. Metal interconnect vias can reduce the stress between the second metal layer and the metal substrate. Metal interconnect vias connect two adjacent second metal layers along the stacking direction of the substrate core layer and the second metal layer, which can reduce the stress between two adjacent second metal layers.

[0022] In conjunction with the first aspect, in one possible implementation, the pre-packaged body further includes a second molding compound, which partially encapsulates the chip, the metal substrate, the first metal pillar, and the second metal pillar of the pre-packaged body. The side of the metal substrate facing away from the chip, the side of the first metal pillar facing away from the chip, and the side of the second metal pillar facing away from the metal substrate are all exposed relative to the second molding compound.

[0023] After the chip, metal substrate, first metal pillar, and second metal pillar are assembled, they are encapsulated by a second molding compound to form a pre-packaged structure, which is then embedded within the substrate core layer. During embedding, the second molding compound protects the chip. When the pre-packaged structure is embedded in the substrate core layer and forms the first molding compound on the core layer, the protective effect of the second molding compound reduces the requirements on the chip and lowers the risk of chip cracking. Simultaneously, pre-encapsulation with the second molding compound locally strengthens the chip, effectively improving junction temperature reliability and moisture resistance.

[0024] In conjunction with the first aspect, in one possible implementation, the power module further includes a heat sink and a thermally conductive insulating layer. Both the heat sink and the thermally conductive insulating layer are disposed on the side of the second metal layer furthest from the substrate core layer, facing away from the metal substrate. The thermally conductive insulating layer is attached between the heat sink and the second metal layer furthest from the substrate core layer. The thermally conductive insulating layer, with its orthographic projection along the stacking direction of the substrate core layer and the second metal layer, covers the side of the heat sink facing the substrate core layer.

[0025] The metal substrate is connected to the heat sink via a second metal layer and a thermally conductive insulating layer. The thermally conductive insulating layer fills the gap between the second metal layer and the heat sink, allowing the second metal layer to adhere more tightly to the thermally conductive insulating layer, effectively reducing thermal resistance. Furthermore, the thermally conductive insulating layer also provides insulation and protection for the pre-packaged assembly. The orthogonal projection of the thermally conductive insulating layer along the stacking direction of the substrate core layer and the second metal layer covers the side of the heat sink facing the substrate core layer, significantly increasing the lateral heat dissipation area of ​​the thermally conductive insulating layer and improving the heat dissipation efficiency of the chip, thereby enhancing the overall heat dissipation effect.

[0026] In a second aspect, this application provides a power converter, which includes a power device and a power module as provided in any implementation of the first aspect, wherein the power device and the power module are electrically connected. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0028] Figure 1 A simplified structural diagram of a power converter provided in an embodiment of this application;

[0029] Figure 2 This is a schematic diagram of the architecture of a photovoltaic energy storage system provided in an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the structure of a power module provided in one embodiment of this application;

[0031] Figure 4 This is a schematic diagram of another power module provided in an embodiment of this application;

[0032] Figure 5 This is a partial structural diagram of a pre-packaged body provided in one embodiment of this application;

[0033] Figure 6 This is a cross-sectional structural diagram of a pre-packaged body provided in an embodiment of this application;

[0034] Figure 7 This is a schematic diagram of the structure of another power module provided in an embodiment of this application;

[0035] Figure 8 This is a schematic diagram of the structure of a pre-packaged body provided in an embodiment of this application;

[0036] Figure 9 This is a schematic diagram of the structure of another power module provided in an embodiment of this application;

[0037] Figure 10 This is a schematic diagram of the structure of another power module provided in an embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 10-Power module; 11-Substrate core layer; 111-Recessed position; 12-Pre-package; 121-Metal substrate; 1211-First part; 1212-Second part; 122-Chip; 1221-Source; 1222-Gate; 1223-Drain; 123-First metal pillar; 124-Second metal pillar; 125-Third metal pillar; 126-Bonding wire; 127-Second molding compound; 128-Inverted 129 - Rounded corner structure; 13 - First metal layer; 14 - Metal connection through hole; 15 - Second metal layer; 16 - First molding compound; 18 - Heat sink; 19 - Thermally conductive insulating layer; 20 - Power device; 100 - Power converter; 101 - Photovoltaic inverter; 102 - Energy storage converter; 200 - Photovoltaic module; 300 - Box-type substation; 400 - Step-up substation; 500 - Power grid; 600 - Energy storage battery. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0041] Please see Figure 1 , Figure 1 This is a simplified structural diagram of a power converter 100 provided in one embodiment of this application. The power converter 100 includes a power module 10 and a power device 20, which are electrically connected. The power converter 100 may be a power module, a photovoltaic inverter, an energy storage converter, a radio frequency device, an optimizer, an on-board charger (OBC), a motor control unit (MCU), and an XPU, etc., where XPU is a collective term for a series of processors such as a central processing unit (CPU) and a graphics processing unit (GPU).

[0042] In this application, a pre-package 12 is embedded inside the power module 10. The pre-package 12 is used for power conversion, for example, for converting direct current to alternating current. The pre-package 12 is a packaged power module, which can be an insulated gate bipolar transistor (IGBT) module or a silicon carbide (SiC) module. The power device 20 can be an inductor, capacitor, or other device.

[0043] When the power converter 100 is an on-board charger, the on-board charger can be used in the on-board charging system, which includes an AC charging pile, a motor, and an on-board battery. The AC charging pile charges the on-board battery through the on-board charger, and the on-board battery can supply power to the motor through the on-board charger.

[0044] To better explain the power converter 100, we will take its application in a photovoltaic energy storage system as an example.

[0045] Please see Figure 2 , Figure 2 This is a schematic diagram of the architecture of a photovoltaic-storage system provided in an embodiment of this application. The photovoltaic-storage system includes a photovoltaic system and an energy storage system. In the photovoltaic system, a photovoltaic inverter 101 is used to convert direct current (DC) from photovoltaic modules 200 into alternating current (AC), and then transmits the AC to a prefabricated substation 300 corresponding to the photovoltaic inverter 101 for voltage transformation. The prefabricated substation 300 corresponding to the photovoltaic inverter 101 can convert the low-voltage AC output from the photovoltaic inverter 101 into medium-voltage AC, and then further transmit the AC to a step-up substation 400 and then to the power grid 500 or a load, or further transmit the AC to a prefabricated substation 300 corresponding to the energy storage converter 102.

[0046] In the energy storage system, the energy storage battery 600 is used to store the unstable electrical energy from the photovoltaic module 200, and provides stable electrical energy to the grid 500 or the load through the energy storage converter 102 and the corresponding box-type substation 300. In addition, the energy storage converter 102 can also convert the AC power from the grid 500 into DC power to charge the energy storage battery 600 and store the electrical energy in the energy storage battery 600.

[0047] Figure 2 In the photovoltaic-storage system shown, the photovoltaic inverter 101 and the energy storage converter 102 are the core of power conversion, and they are collectively referred to as the power converter 100. The power converter 100 provided in this application can be applied to residential photovoltaic systems, and the grid connection method of residential photovoltaic systems is similar to... Figure 2 Similarly, I will not elaborate further.

[0048] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a power module 10 provided in an embodiment of this application. The power module 10 includes a substrate core layer 11, a pre-packaged body 12, at least one first metal layer 13, a metal connection through hole 14, at least one second metal layer 15, and a first molding compound 16.

[0049] The substrate core layer 11 has a recessed position 111 for mounting the pre-packaged body 12. At least one first metal layer 13 and a metal connection via 14 are located on the same side of the substrate core layer 11, and at least one second metal layer 15 is located on the side of the substrate core layer 11 opposite to the at least one first metal layer 13. Two adjacent first metal layers 13 along the stacking direction of the substrate core layer 11 and the second metal layer 15 are connected by the metal connection via 14. The number of at least one second metal layer 15 is less than the number of at least one first metal layer 13.

[0050] The pre-package 12 is disposed between the first metal layer 13 closest to the substrate core layer 11 and the second metal layer 15 closest to the substrate core layer 11. The pre-package 12 is embedded in the substrate core layer 11, and the pre-package 12 achieves electrical connection with the outside through the first metal layer 13.

[0051] The first molding compound 16 partially encapsulates the substrate core layer 11, the pre-packaged body 12, at least one first metal layer 13, the metal connection via 14, and at least one second metal layer 15, wherein the first metal layer 13 furthest from the substrate core layer 11 is exposed relative to the first molding compound 16 so as to facilitate the connection of the first metal layer 13 furthest from the substrate core layer 11 to other power devices 20 in the power converter 100.

[0052] In the power module 10 of this application, at least one first metal layer 13 and a metal connection via 14 are provided on one side of the substrate core layer 11, and at least one second metal layer 15 is provided on the opposite side of the substrate core layer 11. The number of at least one second metal layer 15 is less than the number of at least one first metal layer 13, thus the two opposite sides of the substrate core layer 11 have an asymmetrical structure. The metal traces on the side of the pre-package 12 facing the second metal layer 15 are fewer than the metal traces on the side of the pre-package 12 away from the second metal layer 15, which can reduce the thermal resistance of the thermal link on the side facing the second metal layer 15. The heat generated by the pre-package 12 can be dissipated to the outside through the second metal layer 15, improving the heat dissipation effect.

[0053] Along the stacking direction of the substrate core layer 11 and the second metal layer 15, two adjacent first metal layers 13 are connected by metal connection vias 14. This reduces parasitic inductance and resistance in the power circuit, decreases oscillation, improves the efficiency of the pre-package 12, and reduces electrical stress. Compared to a direct connection between the two first metal layers 13, this enhances the power module 10's ability to resist mechanical stress and reduces the risk of cracking in the embedded pre-package 12.

[0054] For example, the substrate core layer 11 is made of FR-4 substrate and supports at least one first metal layer 13 and metal connection via 14. A recessed position 111 formed on the substrate core layer 11 extends through both opposite sides of the substrate core layer 11. When the pre-packaged body 12 is installed in the recessed position 111, the side of the pre-packaged body 12 facing the second metal layer 15 is flush with the side of the substrate core layer 11 facing the second metal layer 15, so that the pre-packaged body 12 and the substrate core layer 11 can contact the second metal layer 15.

[0055] There are one or more recessed positions 111, and a pre-packaged body 12 is installed in one recessed position 111. When there are multiple recessed positions 111 and a pre-packaged body 12 is installed in each of two adjacent recessed positions 111, there is a partial substrate core layer 11 between the two adjacent pre-packaged bodies 12. This partial substrate core layer 11 can reduce the mutual influence between the two adjacent pre-packaged bodies 12.

[0056] Please combine Figure 3 and Figure 4 , Figure 4 This is a schematic diagram of another power module 10 provided in an embodiment of this application. The pre-packaged body 12 includes a metal substrate 121 and a chip 122. The metal substrate 121 is disposed between the chip 122 and at least one second metal layer 15. The side of the metal substrate 121 facing the second metal layer 15 is in contact with the second metal layer 15, and the chip 122 is disposed on the side of the metal substrate 121 facing away from the second metal layer 15. The pre-packaged body 12 is a packaged power module used for power conversion. The chip 122 and the metal substrate 121 are connected to the first metal layer 13 closest to the substrate core layer 11. Furthermore, the metal substrate 121 is made of metal, such as a copper substrate, an aluminum substrate, or a silver substrate. The metal substrate 121 has a higher thermal conductivity than a ceramic substrate. The side of the metal substrate 121 facing away from the chip 122 can directly contact the second metal layer 15, allowing the heat generated by the chip 122 to be quickly conducted through the metal substrate 121 to the second metal layer 15 and dissipated to the outside.

[0057] When there are multiple pre-packaged bodies 12, each pre-packaged body 12 has at least one second metal layer 15 connected to its metal substrate 121, and a portion of the first molding compound 16 is provided between the at least one second metal layer 15 connecting different pre-packaged bodies 12. For example, as Figure 3 As shown, there are two pre-packaged bodies 12, each pre-packaged body 12 is connected to a second metal layer 15, the distances of the two second metal layers 15 to the substrate core layer 11 are basically the same, the two second metal layers 15 are staggered laterally, and a portion of the first molding compound 16 is provided between the two second metal layers 15. For example, such as... Figure 4As shown, there are two pre-packages 12, each pre-package 12 is connected to two second metal layers 15, and the two second metal layers 15 connected to the same pre-package 12 are stacked along the arrangement direction of the substrate core layer 11 and the second metal layers 15. A portion of the first molding compound 16 is provided between the two second metal layers 15 connecting one pre-package 12 and the two second metal layers 15 connecting the other pre-package 12. Since the side of the metal substrate 121 facing away from the chip 122 is connected to the second metal layers 15, at least one second metal layer 15 connecting different pre-packages 12 is insulated and protected by the first molding compound 16, which can reduce the thermal impact between different pre-packages 12.

[0058] Please see Figure 4 , Figure 5 and Figure 6 , Figure 5 This is a partial structural diagram of a pre-packaged body 12 provided in an embodiment of this application. Figure 6 This is a cross-sectional view of a pre-packaged body 12 according to an embodiment of this application. The chip 122 includes a source 1221, a gate 1222, and a drain 1223. The source 1221 of the chip 122 is disposed away from the metal substrate 121 and is used to connect to the first metal layer 13 closest to the substrate core layer 11. The gate 1222 is disposed on the chip 122 away from the metal substrate 121 and is used to connect to the first metal layer 13 closest to the substrate core layer 11. The drain 1223 of the chip 122 is disposed facing the metal substrate 121 and can be directly soldered to the side of the metal substrate 121 away from the second metal layer 15. For example, the drain 1223 can be connected to the metal substrate 121 through a silver sintering layer or solder paste. Thus, the drain 1223 is connected to the first metal layer 13 closest to the substrate core layer through the metal substrate 121.

[0059] The source electrode 1221 of chip 122 has an orthographic projection shape on metal substrate 121 including an "L" shape (e.g., Figure 5 (as shown) or a rectangle, wherein the number of source poles 1221 can be one or more.

[0060] For example, the pre-package 12 includes a first metal pillar 123, a second metal pillar 124, and a third metal pillar 125. The first metal pillar 123 is disposed between the side of the chip 122 facing away from the metal substrate 121 and the first metal layer 13 closest to the substrate core layer 11, and the first metal pillar 123 is used to connect the chip 122 and the first metal layer 13 closest to the substrate core layer 11. The second metal pillar 124 and the third metal pillar 125 are both disposed between the side of the metal substrate 121 facing away from the second metal layer 125 and the first metal layer 13 closest to the substrate core layer 11, and the second metal pillar 124 and the third metal pillar 125 are both used to connect the metal substrate 121 and the first metal layer 13 closest to the substrate core layer 11. The first metal pillar 123, the second metal pillar 124, and the third metal pillar 125 can be copper layers, used to realize the electrical connection between the chip 122 and the first metal layer 13. The side of the first metal pillar 123 facing away from the metal substrate 121, the side of the second metal pillar 124 facing away from the metal substrate 121, and the side of the third metal pillar 125 facing away from the metal substrate 121 are flush.

[0061] In one embodiment, the source 1221 of the chip 122 is connected to the first metal layer 13 closest to the substrate core layer 11 via a first metal pillar 123. For example, a first metal pillar 123 is formed on the source 1221 of the chip 122. The shape of the first metal pillar 123 connecting the source 1221 is adapted to the shape of the source 1221. When the orthographic projection of the source 1221 onto the metal substrate 121 is rectangular, the orthographic projection shape of the first metal pillar 123 connected to it onto the metal substrate 121 is also rectangular; when the orthographic projection of the source 1221 onto the metal substrate 121 is "L" shaped, the orthographic projection shape of the first metal pillar 123 connected to it onto the metal substrate 121 is also "L" shaped. This can reduce the stress on the chip 122 when the first metal pillar 123 is connected to the source 1221.

[0062] The gate 1222 of chip 122 is directly connected to the first metal layer 13 closest to the substrate core layer 11 via the third metal pillar 125. For example... Figure 6 As shown, a third metal pillar 125 is formed on the side of the gate 1222 of the chip 122 that is away from the metal substrate 121.

[0063] Please combine Figure 7 , Figure 7 This is a schematic diagram of another power module 10 provided in an embodiment of this application. The gate 1222 of the chip 122 can also be connected to the gate drive pad on the metal substrate 121 via a bonding wire 126. The gate drive pad is then connected to the first metal layer 13 closest to the substrate core layer 11 via a third metal pillar 125. The third metal pillar 125 and the first metal pillar 123 are spaced apart to ensure electrical insulation between them.

[0064] Chip 122 is led out through the first metal pillar 123 and interconnected with the first metal layer 13 closest to the substrate core layer 11. This can reduce the surface stress on chip 122 when the first metal layer 13 is connected to chip 122, and reduce the risk of surface cracking of chip 122.

[0065] In one embodiment, the metal substrate 121 may include a first portion 1211 and a second portion 1212, which are spaced apart from each other. Specifically, the first portion 1211 and the second portion 1212 are partially filled with a first molding compound 16 to achieve insulation between them. The first portion 1211 is used to mount the chip 122, and the second portion 1212 is used to connect to the gate 1222 of the chip 122. Specifically, the source 1221 of the chip 122 is interconnected with the first metal layer 13 closest to the substrate core layer 11 via a first metal pillar 123. Since the drain 1223 of the chip 122 is connected to the first portion 1211, a second metal pillar 124 can be formed on the side of the first portion 1211 facing away from the second metal layer 15 to achieve interconnection between the drain 1223 and the first metal layer 13 closest to the substrate core layer 11. The gate 1222 of chip 122 is connected to the second portion 1212 via bonding wire 126. A third metal pillar 125 extends from the side of the second portion 12122 away from the second metal layer 15, realizing the interconnection between the gate 1222 and the first metal layer 13 closest to the substrate core layer 11. The metal substrate 121 is connected to the first metal layer 13 via the second metal pillar 124 and the third metal pillar 125, which can reduce the thermal crosstalk of the metal substrate 121 towards the first metal layer 13.

[0066] The first metal pillar 123 is connected to the first metal layer 13 closest to the substrate core layer 11, the second metal pillar 124 is connected to the first metal layer 13 closest to the substrate core layer 11, and the third metal pillar 125 is connected to the first metal layer 13 closest to the substrate core layer 11 through metal connection through holes 14.

[0067] Please combine Figure 8 , Figure 8This is a schematic diagram of a pre-packaged body 12 provided in an embodiment of this application. The pre-packaged body 12 further includes a second molding compound 127, which partially encapsulates the chip 122, metal substrate 121, first metal pillar 123, second metal pillar 124, and third metal pillar 125. The second molding compound 127 encapsulates the chip 122, metal substrate 121, first metal pillar 123, second metal pillar 124, and third metal pillar 125. The second molding compound 127 can be a highly thermally conductive and high-temperature resistant insulating material. The side of the metal substrate 121 facing away from the chip 122, the side of the first metal pillar 123 facing away from the metal substrate 121, the side of the second metal pillar 124 facing away from the metal substrate 121, and the side of the third metal pillar 125 facing away from the metal substrate 121 are all exposed relative to the second molding compound 127, i.e., they may not be covered by the second molding compound 127. After the chip 122, metal substrate 121, first metal pillar 123, second metal pillar 124, and third metal pillar 125 are assembled, they are encapsulated by a second molding compound 127 to form a pre-package 12, which is then embedded within the substrate core layer 11. During embedding, the second molding compound 127 protects the chip 122. When the pre-package 12 is embedded in the substrate core layer 11 and a first molding compound 16 is formed on the substrate core layer 11, the protective effect of the second molding compound 127 reduces the requirements on the chip 122 and lowers the risk of cracking. Simultaneously, the pre-encapsulation by the second molding compound 127 locally strengthens the chip 122, effectively improving its junction temperature reliability and moisture resistance.

[0068] The pre-package 12 also includes a chamfer structure 128, which is located at the corner of the pre-package 12. Correspondingly, a chamfer is also formed at the corner of the side wall of the recessed position 111. When the pre-package 12 is assembled into the recessed position 111, the chamfer structure 128 of the pre-package 12 is aligned with the chamfer of the recessed position 111 for installation, thus preventing mistaken installation. The pre-package 12 may also be provided with a rounded corner structure 129, which is located at the corner of the pre-package 12. The rounded corner structure 129 and the chamfer structure 128 are located at different corners of the pre-package 12. Correspondingly, a rounded corner is also formed at the corner of the side wall of the recessed position 111. When installing the pre-package 12, the rounded corner structure 129 of the pre-package 12 is aligned with the rounded corner of the recessed position 111 to fix the pre-package 12 in the recessed position 111. When the pre-package 12 is embedded into the recessed position 111, there is a uniform tolerance fit range between the outer peripheral surface of the pre-package 12 and the sidewall of the recessed position 111. When the power module 10 is packaged, a portion of the first molding compound 16 is wrapped between the outer peripheral surface of the pre-package 12 and the sidewall of the recessed position 111 to provide insulation protection for the pre-package 12.

[0069] The top surface of the first molding compound 16 is flush with the top surface of the first metal layer 13 furthest from the substrate core layer 11, and the bottom surface of the first molding compound 16 is flush with the side of the metal substrate 121 facing the second metal layer 15. The first molding compound 16 provides insulation protection and flame retardancy for at least one first metal layer 13, metal connection via 14, second metal layer 15 and pre-packaged body 12. The first molding compound 16 is different from the second molding compound 127.

[0070] There can be multiple first metal layers 13, which are stacked at intervals along the stacking direction of the substrate core layer 11 and the second metal layer 15. Two adjacent first metal layers 13 along the stacking direction of the substrate core layer 11 and the second metal layer 15 are connected to each other through metal connection vias 14. The cross-sectional area of ​​the metal connection via 14 is smaller than the cross-sectional area of ​​the first metal layer 13, and the cross-section is perpendicular to the stacking direction of the substrate core layer 11 and the second metal layer 15. For example, the metal connection via 14 can be formed by forming a via in the first molding compound 16 between two adjacent first metal layers 13, and then depositing a metal layer on the inner wall surface of the via.

[0071] Please see Figure 4 and Figure 9 , Figure 9 This is a schematic diagram of the structure of another power module 10 provided in an embodiment of this application. A metal connection via 14 is also connected between the metal substrate 121 and at least one second metal layer 15, and / or, the metal connection via 14 is also connected to two adjacent second metal layers 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15. For example, as... Figure 9 As shown, a metal connection via 14 connects between a metal substrate 121 and at least one second metal layer 15. When there are multiple second metal layers 15 connecting a pre-package 12, the multiple second metal layers 15 are directly connected. For example, as... Figure 4As shown, when there are multiple second metal layers 15 connecting a pre-package 12, the metal connection vias 14 also connect two adjacent second metal layers 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15, with the second metal layer 15 closest to the substrate core layer 11 directly connected to the metal substrate 121. Alternatively, when there are multiple second metal layers 15 connecting a pre-package 12, the metal connection vias 14 also connect between the metal substrate 121 and the second metal layer 15 closest to the substrate core layer 11, and also connect two adjacent second metal layers 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15. The metal connection vias 14 connect the second metal layer 15 closest to the substrate core layer 11 and the metal substrate 121, reducing the stress between the second metal layer 15 and the metal substrate 121. The metal connection vias 14 also connect two adjacent second metal layers 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15, further reducing the stress between adjacent second metal layers 15.

[0072] The first metal layer 13, the first metal pillar 123, the second metal pillar 124, the third metal pillar 125, and the metal connecting through hole 14 can all be made of any one of gold, silver, copper, tin, aluminum, or an alloy thereof.

[0073] For example, along the stacking direction of the substrate core layer 11 and the second metal layer 15, the size of the second metal layer 15 is smaller than the size of the metal substrate 121. The stacking direction of the substrate core layer 11 and the second metal layer 15 is the thickness direction of the second metal layer 15 and the metal substrate 121. That is, the size of the second metal layer 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15 is the thickness of the second metal layer 15, and the size of the metal substrate 121 along the stacking direction of the substrate core layer 11 and the second metal layer 15 is the thickness of the metal substrate 121. The thickness of the metal substrate 121 is greater than the thickness of the second metal layer 15. A thicker metal substrate can provide a larger heat capacity and heat dissipation area, reducing local heat accumulation and improving heat dissipation. The second metal layer 15 is relatively thinner than the metal substrate 121, resulting in a lower overall thermal resistance and further improving heat dissipation.

[0074] Furthermore, along the stacking direction of the substrate core layer 11 and the second metal layer 15, the size of the second metal layer 15 is greater than or equal to 100 micrometers and less than or equal to 200 micrometers. For example, the thickness of the second metal layer 15 can be 100 micrometers, 115 micrometers, 130 micrometers, 145 micrometers, 150 micrometers, 170 micrometers, 180 micrometers, 190 micrometers, or 200 micrometers, and so on. The thickness of the second metal layer 15 is not less than 100 micrometers to avoid increasing the lateral (perpendicular to the stacking direction of the substrate core layer 11 and the second metal layer 15) diffusion thermal resistance due to an excessively small thickness. Also, a second metal layer 15 with an excessively small thickness is prone to deformation and cracking during use due to stress, vibration, thermal expansion, or contraction. The thickness of the second metal layer 15 is not greater than 200 micrometers to avoid increasing the thermal resistance due to an excessively thick second metal layer 15.

[0075] When the size of the metal substrate 121 is larger than the size of the second metal layer 15 along the stacking direction of the substrate core layer 11 and the second metal layer 15, the size of the metal substrate 121 is greater than or equal to 300 micrometers and less than or equal to 800 micrometers. For example, the thickness of the metal substrate 121 can be 300 micrometers, 360 micrometers, 400 micrometers, 410 micrometers, 450 micrometers, 500 micrometers, 520 micrometers, 580 micrometers, 600 micrometers, 650 micrometers, 700 micrometers, 750 micrometers, or 800 micrometers, etc., and is not listed one by one. If the thickness of the metal substrate 121 is too small, it will increase the risk of breakage when forming the power module 10, and it will easily cause the problem of local hot spot concentration when dissipating heat from the chip 122; if the thickness of the metal substrate 121 is too large, it will easily increase the thermal resistance, affect heat dissipation, and cause the overall thickness of the power module 10 to increase. In this application, the thickness of the metal substrate 121 is between 300 micrometers and 800 micrometers. The metal substrate 121 can provide a larger heat capacity and heat dissipation area. At the same time, it can reduce the risk of the metal substrate 121 breaking and avoid the overall thickness of the power module 10 being too large due to the excessive thickness of the pre-package 12, thereby reducing costs.

[0076] Please see Figure 10 , Figure 10This is a schematic diagram of another power module 10 provided in an embodiment of this application. The power module 10 may further include a heat sink 18 and a thermally conductive insulating layer 19. Both the heat sink 18 and the thermally conductive insulating layer 19 are disposed on the side of the second metal layer 15 furthest from the substrate core layer 11 that faces away from the metal substrate 121. The thermally conductive insulating layer 19 is attached between the heat sink 18 and the second metal layer 15 furthest from the substrate core layer 11. In one embodiment, the thermally conductive insulating layer 19 uses a highly thermally conductive insulating material, such as epoxy resin, silicone, or epoxy resin filled with aluminum nitride (AlN), which can provide insulation and protection for the pre-packaged body 12. When the thermally conductive insulating layer 19 uses a flexible insulating material, it can be injection molded or coated on the side of the second metal layer 15 furthest from the substrate core layer 11 that faces away from the metal substrate 121 and the chip 122, thereby filling the gap between the second metal layer 15 and the heat sink 18, allowing the second metal layer 15 to fit more tightly against the thermally conductive insulating layer 19, which can effectively reduce thermal resistance. In addition, the thermally conductive insulating layer 19 can also improve the warping problem of the asymmetrical structure on both sides of the substrate core layer 11.

[0077] The thermally conductive insulating layer 19, with its orthogonal projection along the stacking direction of the substrate core layer 11 and the second metal layer 15, covers the side of the heat sink 18 facing the substrate core layer 11. The lateral (perpendicular to the stacking direction of the substrate core layer 11 and the second metal layer 15) heat dissipation area of ​​the thermally conductive insulating layer 19 is greatly increased, which can improve the heat dissipation efficiency of the chip 122 and thus improve the heat dissipation effect.

[0078] In this application, unless otherwise expressly specified and limited, the terms "connection" and "fixed" shall be interpreted broadly. For example, "fixed" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction between two elements, unless otherwise expressly limited.

[0079] Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. The use of "first," "second," and various numerical designations herein is for descriptive convenience only and is not intended to limit the scope of this application.

[0080] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A power module, characterized in that, The device includes a substrate core layer, at least one first metal layer, a metal connection via, at least one second metal layer, a pre-package, and a first molding compound. The first molding compound partially encapsulates the substrate core layer, the pre-package, the at least one first metal layer, the metal connection via, and the at least one second metal layer. The substrate core layer has a recessed position for mounting the pre-package. The pre-package is disposed between the at least one first metal layer and the at least one second metal layer. The at least one first metal layer and the metal connection via are disposed on the same side of the substrate core layer, and the at least one second metal layer is disposed on the side of the substrate core layer away from the at least one first metal layer. Along the stacking direction of the substrate core layer and the second metal layer, two adjacent first metal layers are connected by the metal connection via, and the number of the at least one second metal layer is less than the number of the at least one first metal layer.

2. The power module according to claim 1, characterized in that, The pre-package includes a metal substrate, a chip, and a first metal pillar. The metal substrate is disposed between the chip and the at least one second metal layer. The first metal pillar is disposed on the side of the chip facing away from the metal substrate. The chip is connected to the first metal layer through the first metal pillar.

3. The power module according to claim 2, characterized in that, The pre-packaged body further includes a second metal pillar, which is disposed on the side of the metal substrate opposite to the second metal layer, and the second metal pillar connects the metal substrate and the first metal layer.

4. The power module according to claim 2 or 3, characterized in that, The first metal layer furthest from the substrate core layer is exposed relative to the first molding compound, and the first metal layer furthest from the substrate core layer is used to connect other devices.

5. The power module according to any one of claims 2-4, characterized in that, Along the stacking direction of the substrate core layer and the second metal layer, the size of the second metal layer is smaller than the size of the metal substrate.

6. The power module according to claim 5, characterized in that, Along the stacking direction of the substrate core layer and the second metal layer, the size of the second metal layer is greater than or equal to 100 micrometers and less than or equal to 200 micrometers.

7. The power module according to claim 5 or 6, characterized in that, Along the stacking direction of the substrate core layer and the second metal layer, the size of the metal substrate is greater than or equal to 300 micrometers and less than or equal to 800 micrometers.

8. The power module according to any one of claims 2-7, characterized in that, The number of pre-packaged bodies is multiple, and the metal substrate of each pre-packaged body is connected to at least one second metal layer. A portion of the first molding compound is provided between the at least one second metal layer connecting different pre-packaged bodies.

9. The power module according to any one of claims 2-8, characterized in that, The metal connection via is also connected between the metal substrate and the at least one second metal layer, and / or, the metal connection via is also connected between two adjacent second metal layers.

10. The power module according to any one of claims 2-9, characterized in that, The pre-packaged body further includes a second molding compound, which partially encapsulates the chip, the metal substrate, the first metal pillar, and the second metal pillar of the pre-packaged body. The side of the metal substrate facing away from the chip, the side of the first metal pillar facing away from the chip, and the side of the second metal pillar facing away from the metal substrate are all exposed relative to the second molding compound.

11. The power module according to any one of claims 2-10, characterized in that, The power module further includes a heat sink and a thermally conductive insulating layer. The heat sink and the thermally conductive insulating layer are both disposed on the side of the second metal layer furthest from the substrate core layer that faces away from the metal substrate. The thermally conductive insulating layer is attached between the heat sink and the second metal layer furthest from the substrate core layer. The orthographic projection of the thermally conductive insulating layer along the stacking direction of the substrate core layer and the second metal layer covers the side of the heat sink facing the substrate core layer.

12. A power converter, characterized in that, The power converter includes a power device and a power module as described in any one of claims 1-11, wherein the power device is electrically connected to the power module.

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