Power module and power conversion device

Abstract

A power module and a power conversion device, the power module comprises a first substrate, a second substrate and a conductive member, the first substrate and the second substrate are arranged at an interval, and the conductive member is connected between the first substrate and the second substrate; the first substrate or the second substrate is provided with a first chip, the surface, facing the second substrate, of the first substrate comprises a first area and a second area surrounding the first area, the first area comprises an inner island and a groove surrounding the inner island, and the groove is filled with solder; the mounting end face of the conductive part faces the first area, is supported by the inner island, and is fixedly connected with the solder, so that the first chip is electrically connected with the conductive part. The inner island supporting conductive member can increase the thickness of the solder, thereby improving the welding strength of the first substrate and the conductive member.

Description

Technical Field

[0001] The present application relates to the technical field of power variation, and in particular to a power module and a power conversion device. Background Art

[0002] With the development of power electronics technology, power modules have attracted more and more attention. Power modules integrate multiple power semiconductors and insulation components. Compared with single-tube packaging, they have the characteristics of high integration, convenient assembly and high reliability.

[0003] In the related art, a power module may include a circuit board and a conductive element integrated on the surface of the circuit board, wherein the conductive element is welded to the surface of the circuit board. The welding strength between the conductive element and the circuit board is low, and cracks are easily generated at the connection between the conductive element and the circuit board. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present application is to provide a power module and a power conversion device with high connection strength and good electrical control stability.

[0005] In a first aspect, the present application provides a power module, comprising a first substrate, a second substrate and a conductive member, wherein the first substrate and the second substrate are spaced apart, and the conductive member is connected between the first substrate and the second substrate; a first chip is disposed on the first substrate or the second substrate;

[0006] The surface of the first substrate facing the second substrate includes a first area, the first area includes an inner island and a groove surrounding the inner island, and the groove is filled with solder; the mounting end surface of the conductive component faces the first area, and the mounting end surface of the conductive component is supported by the inner island, and the mounting end surface of the conductive component is fixedly connected to the solder to electrically connect the first chip and the conductive component.

[0007] The first substrate and the second substrate are arranged at intervals and are electrically connected through a conductive member, which can improve the power density of the power module. The first substrate is provided with a first chip. In the power module, the first chip can be a semiconductor field effect transistor (Metal-Oxide-SemiconductorField-Effect Transistor, MOSFET), referred to as MOS tube. The first chip can control the on-off current of the conductive member at a high frequency. The high-frequency on-off current of the conductive member will generate stress, which makes the welding point between the conductive member and the first substrate easy to break, thereby reducing the life of the power module. Solder is filled in the groove, and the inner island can support the conductive member to prevent the conductive member from sinking when welding with the first substrate, so that the solder between the conductive member and the first substrate is very thin (less than 10μm), which can increase the thickness of the welding solder (Bonded Line Thickness, BLT) between the conductive member and the first substrate, thereby improving the welding strength of the conductive member and the first substrate. Reduce the negative impact of the growth of intermetallic compounds (Intermetallic Compound, IMC) and void agglomeration between the conductive member and the first substrate when welding the conductive member and the first substrate. When the first substrate and the conductive member are welded, an intermetallic compound can grow between the metal in the first substrate and the metal in the conductive member, and the thickness of the welding solder between the conductive member and the first substrate is sufficient. When the conductive member and the first substrate are welded, the growth of the intermetallic compound and the coefficient of thermal expansion (CTE) can be matched, so that it is not easy for voids to agglomerate in the solder and reduce the welding strength of the conductive member and the first substrate, which can improve the life of the power module. A groove is opened in the first area of ​​the first substrate, and the thickness of the welding solder between the first substrate and the conductive member can be controlled by controlling the depth of the groove, which is more convenient to control the resistance value of the electrical connection between the conductive member and the first substrate. By filling the solder in the groove, while increasing the welding strength of the conductive member and the first substrate, the solder between the conductive member and the inner island can be made thinner, so that the resistance value of the solder between the conductive member and the first substrate is smaller, thereby reducing the loss of the power module. The resistance value of the solder between the conductive member and the first substrate is positively correlated with the thickness of the solder between the conductive member and the inner island.

[0008] In combination with the first aspect, in a possible implementation, the solder covers the end surface of the inner island facing the conductive member. The solder covering the inner island can increase the contact area between the mounting end surface of the conductive member and the solder, and improve the welding strength between the conductive member and the first substrate.

[0009] In combination with the first aspect, in a possible implementation, a projection of the mounting end surface of the conductive member along the thickness direction of the power module is within the first region, and an area of ​​the mounting end surface of the conductive member is smaller than an area of ​​the first region. The mounting end surface of the conductive member is completely within the first region, which can increase the contact area between the mounting end surface of the conductive member and the solder, and improve the welding strength between the conductive member and the first substrate.

[0010] In combination with the first aspect, in a possible implementation, the groove includes a bottom wall and a side wall surrounding the bottom wall, the side wall connects the second area and the bottom wall, the surface of the first substrate facing the second substrate also includes a second area surrounding the first area, and the projection area of ​​the opening of the groove along the thickness direction of the first substrate is larger than the area of ​​the bottom wall of the groove. The groove can be more easily processed and formed, the groove opening process is simple, and the groove can be formed by etching, stamping, casting, milling and other processes.

[0011] In combination with the first aspect, in a possible implementation, the groove includes a bottom wall and a side wall surrounding the bottom wall, the surface of the first substrate facing the second substrate also includes a second area surrounding the first area, the side wall connects the second area and the bottom wall, and the projection area of ​​the opening of the groove along the thickness direction of the first substrate is smaller than the area of ​​the bottom wall of the groove. After the solder is filled in the groove, the side wall of the groove has a better limiting effect on the solder, which is conducive to improving the welding strength of the solder connecting the conductive member and the first substrate.

[0012] In combination with the first aspect, in a possible implementation, the depth of the groove is D, D ≥ 10μm. Since the inner island can support the conductive part, the sinking degree of the conductive part during welding with the first substrate can be reduced, and the thickness of the solder can be prevented from being too thin (less than 10μm), thereby improving the welding strength between the conductive part and the first substrate. A groove is provided in the first substrate, and the thickness of the solder between the mounting end surface of the conductive part facing the first area and the bottom wall of the groove can be controlled by controlling the depth of the groove, which is beneficial to control the resistance value of the solder between the conductive part and the first substrate, and thus beneficial to control the resistance value of the power module. The resistance value of the solder is positively correlated with the thickness of the solder between the conductive part and the inner island.

[0013] In combination with the first aspect, in a possible implementation, the inner island includes a first end and a second end, the first end is connected to the bottom wall of the groove, the second end supports the conductive member, and along the thickness direction of the first substrate, the projection area of ​​the first end is larger than the projection area of ​​the second end. To facilitate the formation of the inner island, when forming the inner island, etching can be performed in the first region to form the groove, and an unetched portion is retained in the first region to form the inner island.

[0014] In combination with the first aspect, in a possible implementation, the inner island includes a first end and a second end, the first end is connected to the bottom wall of the groove, and along the thickness direction of the first substrate, the projection area of ​​the first end is smaller than the projection area of ​​the second end. When solder is filled in the groove, the inner island can limit the solder and improve the connection strength between the solder and the first substrate.

[0015] In combination with the first aspect, in a possible implementation, the surface of the first substrate facing the second substrate further includes a second region surrounding the first region, and the end surface of the inner island facing the conductive member is flush with the second region. When etching the first region of the first substrate to form the groove and the inner island, the first region is directly etched and the inner island is retained, without reprocessing the inner island, thereby simplifying the step of etching the first substrate.

[0016] In combination with the first aspect, in a possible implementation, the end surface of the inner island facing the conductive member is closer to the bottom wall of the groove than the second region. Since the inner island supports the conductive member, the thickness of the solder between the conductive member and the inner island can reach a certain thickness range. When the groove is filled with solder, the contact area between the conductive member and the solder is increased, thereby improving the welding strength between the conductive member and the first substrate.

[0017] In combination with the first aspect, in a possible implementation, the side surface of the conductive member surrounds the mounting end surface of the conductive member and is connected to the mounting end surface, and the side surface of the conductive member is fixedly connected to the solder. The mounting end surface of the conductive member facing the first area is buried in the solder and is fixedly connected to the solder, and a portion of the side surface of the conductive member extends into the solder and is fixedly connected to the solder. The side surface of the conductive member and the mounting end surface of the conductive member facing the first area are both fixedly connected to the solder, which increases the connection area between the conductive member and the solder and improves the connection strength between the conductive member and the solder.

[0018] In combination with the first aspect, in a possible implementation, the surface of the first substrate facing the second substrate also includes a second area surrounding the first area, and the solder also covers a partial area of ​​the second area close to the first area, which can make the connection between the solder and the first substrate more stable.

[0019] In combination with the first aspect, in a possible implementation manner, the power module further includes a second chip, the first chip is disposed on the first substrate, the second chip is disposed on the second substrate, and the second chip is electrically connected to the conductive member.

[0020] In combination with the first aspect, in a possible implementation, the power module includes a capacitor disposed on the first substrate or the second substrate, and the capacitor is used to implement filtering of the circuit architecture; and / or the power module includes a resistor disposed on the first substrate or the second substrate, and the resistor is used to control the current of the circuit architecture. The capacitor can filter the clutter current flowing through the power module, and setting the resistor is conducive to controlling the magnitude of the current flowing through the power module.

[0021] In a second aspect, the present application discloses a power conversion device, which includes a power module and a circuit board as described in the first aspect, and the circuit board is electrically connected to the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0023] Figure 1 A schematic diagram of the structure of a power conversion device provided in one embodiment of the present application;

[0024] Figure 2 A schematic diagram of an application scenario of a photovoltaic power supply system provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of a power module provided in one embodiment of the present application;

[0026] Figure 4 A top view of a first substrate provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of a structure in which a first substrate and a conductive member are connected to each other according to an embodiment of the present application;

[0028] Figure 6 A cross-sectional view of a first substrate provided in one embodiment of the present application;

[0029] Figure 7 A schematic structural diagram of a first substrate connected to a conductive member provided in another embodiment of the present application;

[0030] Figure 8 A cross-sectional view of a first substrate provided in another embodiment of the present application;

[0031] Fig. 9 A cross-sectional view of a first substrate provided in yet another embodiment of the present application;

[0032] Fig.10 A cross-sectional view of a first substrate provided in yet another embodiment of the present application;

[0033] Fig.11A schematic structural diagram of a first substrate connected to a conductive member provided in yet another embodiment of the present application;

[0034] Fig.12 A cross-sectional view of a first substrate provided in yet another embodiment of the present application.

[0035] Description of reference numerals:

[0036] 1000, power conversion device; 100, power module; 110, first substrate; 111, first area; 112, inner island; 112a, first end; 112b, second end; 113, groove; 113a, bottom wall; 113b, side wall; 114, second area; 115, solder; 120, second substrate; 130, conductive member; 131, mounting end surface; 132, side surface; 140, first chip; 150, second chip; 160, capacitor; 170, resistor; 180, lead; 200, circuit board; 300, energy storage battery; 400, inverter; 500, household appliance; 600, communication base station; 700, photovoltaic module. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0038] See also Figure 1 , Figure 1 A schematic diagram of the structure of a power conversion device provided in one embodiment of the present application. The power conversion device 1000 includes a power module 100 and a circuit board 200, and the circuit board 200 is electrically connected to the power module 100. The power conversion device 1000 can be, but is not limited to, a power module, a rectifier, an inverter, a radio frequency device, an optimizer, an on-board charger (On Board Charger, OBC) and an XPU, etc., wherein XPU is a general term for a series of processors such as a central processing unit (Central Processor Units, CPU), a graphics processor unit (Graphics Processor Units, GPU), etc.

[0039] The power conversion device 1000 can be applied as a power module to a wireless radio unit (Remote Radio Unit, RRU). Specifically, the wireless radio unit includes a power module (power conversion device 1000), a transceiver, a power amplifier and a filter. The power module can supply power to the transceiver, the power amplifier and the filter. The transceiver can receive signals and send signals. The power amplifier can amplify the signals received by the transceiver, and the filter can filter out noise outside the preset frequency. Among them, the power module includes a power module, a circuit board and an AC power supply. The AC power supply is connected to the power module and the circuit board. The circuit board can control the power module to turn on and off at a high frequency. It can be understood that the power module can supply power or cut off power to the transceiver, the power amplifier and the filter at a high frequency.

[0040] Taking the power conversion device 1000 as an on-board charger as an example, the on-board charger can be applied to the on-board charging system, which also 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 power the motor through the on-board charger.

[0041] In order to better explain the power conversion device 1000, taking the power conversion device 1000 as an inverter 400, the inverter 400 is one of the main components of the photovoltaic system. The inverter 400 can be used to convert the variable DC voltage generated by a DC power source such as a photovoltaic solar panel (i.e., a photovoltaic component 700) into AC power of the mains frequency, and output the AC power to the mains power grid (i.e., the AC power grid) for use by the mains power grid, specifically for use by base station equipment or household equipment 500 in the mains power grid.

[0042] See also Figure 2 , Figure 2 Schematic diagram of the application scenario of the photovoltaic power supply system provided in this application. The photovoltaic power supply system provided in this application may include a DC power supply and an inverter 400, wherein the DC power supply may be composed of a photovoltaic array, the output end of the photovoltaic array may be connected to the first end of the inverter 400, and the second end of the inverter 400 may be connected to the AC power grid. Figure 2 In the photovoltaic power supply system shown, the photovoltaic array can be composed of one or more photovoltaic strings connected in parallel, and one photovoltaic string can be obtained by connecting one or more photovoltaic modules 700 in series. The inverter 400 can change (can be boosted, bucked, etc.) the DC power provided by the photovoltaic array, and perform voltage inversion conversion on the transformed DC power to power the battery in the AC power grid, the communication base station 600 or the household appliance 500 and other electrical equipment.

[0043] In some possible implementations, please refer again to Figure 2The DC power supply may also include an energy storage battery 300, the output end of the energy storage battery 300 may be connected to the first end of the inverter 400, and the second end of the inverter 400 may be connected to the AC power grid. The inverter 400 may change (may be boosting, bucking, etc.) the DC power provided by the energy storage battery 300, and perform voltage inversion conversion on the transformed DC power to supply power to the battery in the AC power grid, the communication base station 600, or the household appliance 500 and other electrical devices.

[0044] exist Figure 2 In the application scenario shown, during the actual installation of the photovoltaic module 700 and the inverter 400, the positive and negative terminals of the photovoltaic module 700 may be reversely connected to the positive and negative terminals of the inverter 400 input terminal. The reversed photovoltaic module 700 will cause the reverse current to enter the inverter 400, thereby damaging the inverter 400 (for example, the reverse current damages the switch tube in the inverter 400, resulting in an increase in the heat loss of the inverter 400). At present, an anti-reverse diode can be added to the inverter 400 circuit to block the current path when the photovoltaic module 700 is reversely connected. However, adding an additional anti-reverse diode and a drive circuit to the inverter 400 will cause the components of the inverter 400 to occupy too large a volume, affecting the power density of the inverter 400, and the additional components make the internal heat dissipation capacity of the inverter 400 higher, increasing the design cost.

[0045] In the photovoltaic power supply system provided in the present application, the inverter 400 may include a DC conversion circuit and an inverter circuit, and the switch tube and other devices in the DC conversion circuit may be integrated into a power module 100, one end of the power module 100 is connected to the photovoltaic module 700, and the other end of the power module 100 is connected to the inverter circuit, and the power module 100, the DC conversion circuit and the inverter circuit can be constructed to form a circuit architecture. The power module 100 may include a substrate, an insulating layer, a plurality of diodes and a switch tube (which may be a metal oxide semiconductor field effect transistor (Metal-Oxide-SemiconductorField-Effect Transistor, MOSFET), referred to as a MOS tube, and may also be an insulated gate bipolar transistor (insulatedgatebipolar transistor, IGBT), etc.), the substrate and one side of the insulating layer are welded (which may be welded by a metal layer and a solder 115 layer), and the plurality of diodes and the switch tube and the other side of the insulating layer are welded (which may be welded by a metal layer and a solder 115 layer).

[0046] In one possible implementation, see Figure 3 , Figure 3A schematic diagram of the structure of a power module provided in an embodiment of the present application; the power module 100 includes a first substrate 110, a second substrate 120 and a conductive member 130, the first substrate 110 and the second substrate 120 are arranged at intervals, the conductive member 130 is connected between the first substrate 110 and the second substrate 120, and the first substrate 110 and the second substrate 120 can be packaged by an insulating material. The first substrate 110 can be a printed circuit board (PCB), the first substrate 110 can be a direct copper-clad ceramic substrate (DBC), and the first substrate 110 can be an active metal brazing copper-clad ceramic substrate (AMB). The second substrate 120 can be a printed circuit board (PCB), the second substrate 120 can be a direct copper-clad ceramic substrate (DBC), and the second substrate 120 can be an active metal brazing copper-clad ceramic substrate (AMB). The material of the first substrate 110 can be copper, and the first substrate 110 can also be other metal substrates, organic substrates, ceramic substrates, etc. with a solderable or sinterable surface. The material of the second substrate 120 can be copper, and the second substrate 120 can also be other metal substrates, organic substrates, ceramic substrates, etc. with a solderable or sinterable surface. The number of the conductive member 130 can be multiple, and the conductive member 130 can be but not limited to electronic components such as semiconductor chips, capacitors, resistors, inductors, etc., and the conductive member 130 can also be an electrical connector such as a copper column and a silver column. The conductive member can be an isolation column, a pillar, a main board, and other structural connection elements. The conductive member 130 is used to electrically connect the first substrate 110 and the second substrate 120. The conductive member 130 can also be used to isolate and support the first substrate 110 and the second substrate 120. The first substrate 110 or the second substrate 120 is provided with a first chip 140, and the first chip 140 can be but not limited to a diode, a MOS tube, etc. The present application takes the first chip 140 disposed on the first substrate 110 as an example. The first chip 140 can be directly welded on the first substrate 110, and the first chip 140 can also be electrically connected to the first substrate 110 through the lead 180. The second substrate 120 is provided with a second chip 150, and the second chip 150 can be directly welded on the second substrate 120, and the second chip 150 can also be electrically connected to the second substrate 120 through the lead 180. The second chip 150 can be, but is not limited to, a diode, a MOS tube, etc. The first substrate 110 and the second substrate 120 are connected through a plurality of conductive members 130. The first chip 140 is used to control the conductive members 130 to switch on and off current. In the circuit architecture constructed by the power module 100, the second chip 150 is used to control the startup and shutdown of the circuit architecture.Generally speaking, when the first chip 140 is turned off, the power module 100 is in a closed state. When the first chip 140 is turned on, the first substrate 110 and the second substrate 120 are connected through the conductive member 130, and the power module 100 is in an open state. For example, in the inverter 400, the circuit board 200 can control the switching state of the first chip 140 and the second chip 150. Specifically, the circuit board 200 sends a control signal to the first chip 140, which can control the first chip 140 to turn on or off. The circuit board 200 sends a control signal to the second chip 150, which can control the second chip 150 to turn on or off. The circuit board 200 can control the state of the power module 100 by controlling the opening or closing of the first chip 140, and the state of the power module 100 includes an open state and a closed state. The circuit board 200 can control the startup and shutdown of the circuit architecture by controlling the opening or closing of the second chip 150.

[0047] In the power module 100 provided in the application, the power module 100 also includes a capacitor 160, which is electrically connected to the first substrate 110 or the second substrate 120. The capacitor 160 can be multiple, and the capacitor 160 is used to implement the filtering of the circuit architecture. It should be noted that the capacitor 160 can filter the clutter current flowing through the power module 100. The power module 100 also includes a resistor 170 arranged on the first substrate 110 or the second substrate 120. The resistor 170 can be multiple, and the current flowing through the circuit architecture can be controlled by the resistor 170. It can be understood that the current flowing through the power module 100 can be controlled by setting the resistor 170.

[0048] The two ends of each conductive member 130 are respectively connected to the first substrate 110 and the second substrate 120 by welding. Specifically, one end of the conductive member 130 is welded to the first substrate 110 through the solder 115, and the other end of the conductive member 130 is welded to the second substrate 120 through the solder 115. The solder 115 can be, but is not limited to, tin, silver, gold, etc.

[0049] In one possible implementation, see Figure 4 and Figure 5 , Figure 4 A top view of a first substrate provided in an embodiment of the present application, Figure 5A schematic diagram of a structure in which a first substrate and a conductive member are connected to each other in one embodiment of the present application. The surface of the first substrate 110 facing the second substrate 120 includes a first region 111 and a second region 114 surrounding the first region 111. The first region 111 includes an inner island 112 and a groove 113 surrounding the inner island 112. The groove 113 is filled with solder 115. The partial surface of the solder 115 facing the second substrate 120 can be flush with the end surface of the inner island 112 facing the conductive member 130. The solder 115 can also cover the end surface of the inner island 112 facing the second substrate 120. A mounting end surface 131 of the conductive member 130 faces the first region 111, and the conductive member 130 is supported by the inner island 112. The area of ​​the mounting end surface 131 of the conductive member 130 facing the first region 111 is larger than the end surface of the inner island 112 facing the conductive member 130. The mounting end surface 131 of the conductive member 130 facing the first region 111 is also fixedly connected to the solder 115. The projection of the mounting end surface 131 of the conductive member 130 along the thickness direction of the power module is within the first region 111, and the area of ​​the mounting end surface 131 of the first conductive member facing the first region 111 is smaller than the area of ​​the first region 111. The mounting end surface 131 of the conductive member 130 facing the first region 111 is completely within the first region 111, which can increase the contact area between the mounting end surface 131 of the conductive member 130 and the solder 115, thereby increasing the welding strength. In order to further improve the welding strength between the conductive member 130 and the first substrate 110, the solder 115 also covers a portion of the second region 114 close to the first region 111.

[0050] In a feasible implementation, the side surface 132 of the conductive member 130 surrounds the mounting end surface 131 of the conductive member 130 facing the first area 111, the mounting end surface 131 of the conductive member 130 facing the first area 111 is fixedly connected to the solder 115, and the side surface 132 of the conductive member 130 is fixedly connected to the solder 115. It can be understood that the mounting end surface 131 of the conductive member 130 facing the first area 111 is buried in the solder 115 and fixedly connected to the solder 115, and a part of the side surface 132 of the conductive member 130 extends into the solder 115 and is fixedly connected to the solder 115. The side surface 132 of the conductive member 130 and the mounting end surface 131 of the conductive member 130 facing the first area 111 are both fixedly connected to the solder 115, which increases the connection area between the conductive member 130 and the solder 115, and improves the connection strength between the conductive member 130 and the solder 115.

[0051] In the power module 100 provided in the present application, the first chip 140 and the second chip 150 can both be MOS tubes. The first chip 140 can control the conductive member 130 to switch on and off current at a high frequency. The high frequency switching on and off of current of the conductive member 130 will generate stress, making the welding point between the conductive member 130 and the first substrate 110 prone to breakage, thereby reducing the life of the power module 100. An inner island 112 and a groove 113 surrounding the inner island 112 are provided on the surface of the first substrate 110 facing the second substrate 120, and solder 115 is filled in the groove 113. The inner island 112 can support the conductive member 130 to prevent the conductive member 130 from sinking when being welded to the first substrate 110, thereby making the solder 115 between the conductive member 130 and the first substrate 110 very thin (less than 10 μm), and can increase the bonding line thickness (Bonded Line Thickness, BLT) between the conductive member 130 and the first substrate 110. In this application, the bonding line thickness refers to the solder thickness between the bottom wall of the groove and the mounting end face of the conductive member, thereby improving the welding strength between the conductive member 130 and the first substrate 110, and further improving the service life of the power module. When the conductive member 130 and the first substrate 110 are welded, an intermetallic compound (IMC) will grow between the conductive member 130 and the first substrate 110. If the solder between the conductive member 130 and the first substrate 110 is relatively thin, the growth of the intermetallic compound and the coefficient of thermal expansion (CTE) during welding are difficult to match, and voids are likely to agglomerate, which will have a negative impact on the welding strength of the conductive member 130 and the first substrate 110. If the thickness of the welding solder between the conductive member 130 and the first substrate 110 is thick enough, the growth of the intermetallic compound and the coefficient of thermal expansion can match during welding, so that voids are not likely to agglomerate in the solder 115 and reduce the welding strength of the conductive member 130 and the first substrate 110. A groove 113 is provided in the first region 111 of the first substrate 110. By controlling the depth of the groove 113, the thickness of the solder between the first substrate 110 and the conductive member 130 can be controlled, and the resistance value of the electrical connection between the conductive member 130 and the first substrate 110 can be more conveniently controlled. By filling the solder in the groove, while increasing the welding strength between the conductive member and the first substrate, the solder between the conductive member and the inner island can also be made thinner, so that the resistance value of the solder 115 between the conductive member 130 and the first substrate 110 is smaller, thereby reducing the loss of the power module 100. Among them, the resistance value of the solder 115 between the conductive member 130 and the first substrate 110 is positively correlated with the thickness of the solder between the conductive member 130 and the inner island 112.

[0052] In the power module 100 provided in the present application, in order to increase the thickness of the welding solder between the conductive part 130 and the first substrate 110, a groove 113 is opened on the first substrate 110 and an inner island 112 is formed. The process used to achieve this purpose is simple. When opening the groove 113 on the first substrate 110, etching, stamping, grinding, casting, milling, coating and other means can be used, which can reduce the manufacturing cost of the power module 100.

[0053] Please note that, see Figure 5 and Figure 6 , Figure 6 A cross-sectional view of a first substrate provided in an embodiment of the present application. The depth of the groove 113 provided in the first substrate 110 is D, where D≥10μm. Since the inner island 112 can support the conductive member 130, the sinking degree of the conductive member 130 during welding with the first substrate 110 can be reduced, and the thickness of the solder 115 can be prevented from being too thin (less than 10μm), thereby improving the welding strength between the conductive member 130 and the first substrate 110. The groove 113 is provided in the first substrate 110. By controlling the depth of the groove 113, the thickness of the solder 115 between the mounting end face 131 of the conductive member 130 and the bottom wall 113a of the groove 113 can be controlled, which is beneficial to controlling the resistance value of the solder 115 between the conductive member 130 and the first substrate 110, and thus beneficial to controlling the resistance value of the power module 100. The resistance value of the solder 115 is positively correlated with the solder thickness between the conductive member 130 and the inner island 112.

[0054] In the power module 100 provided in the present application, the groove 113 includes a bottom wall 113a and a side wall 113b, the side wall 113b surrounds the bottom wall 113a, and the side wall 113b connects the bottom wall 113a and the second area 114. The side wall 113b can be perpendicular to the bottom wall 113a, or can be inclined.

[0055] In one possible implementation, see Figure 5 The projection area of ​​the opening of the groove 113 along the thickness direction of the first substrate 110 is larger than the area of ​​the bottom wall 113a of the groove 113. Specifically, the groove 113 can gradually shrink from the connection between the side wall 113b and the second area 114 to the connection between the side wall 113b and the bottom wall 113a. Such a groove 113 is easier to process and form. The process for opening the groove 113 can be but is not limited to etching, stamping, grinding, casting, milling, coating, etc.

[0056] In one possible implementation, see Figure 7 and Figure 8 , Figure 7 A schematic diagram of a structure in which a first substrate and a conductive member are connected to each other according to another embodiment of the present application. Figure 8A cross-sectional view of the first substrate provided in another embodiment of the present application. The projection area of ​​the opening of the groove 113 along the thickness direction of the first substrate 110 is smaller than the area of ​​the bottom wall 113a of the groove 113. The groove 113 gradually shrinks from the connection between the side wall 113b and the bottom wall 113a to the connection between the side wall 113b and the second area 114. After the solder 115 is filled in the groove 113, the side wall 113b of the groove 113 has a better limiting effect on the solder 115, which is conducive to improving the welding strength of the solder 115 connecting the conductive member 130 and the first substrate 110. Exemplarily, the groove 113 can be roughly but not limited to a prism shape, a rectangular parallelepiped shape, a cylindrical shape and a truncated cone shape, and the cross-section of the conductive member 130 can be but not limited to a circle, a rectangle, etc. When the groove 113 is a prism shape or a rectangular parallelepiped shape, the cross-section of the conductive member 130 can be set to a rectangle that matches the shape of the groove 113. When the groove 113 is cylindrical or truncated cone-shaped, the cross section of the conductive member 130 can be set to a circle that matches the shape of the groove 113. In this way, the conductive member 130 can be set at the center of the first area 111, so that the conductive member 130 is more evenly stressed when connected to the solder 115, thereby improving the welding strength between the conductive member 130 and the first substrate 110.

[0057] In the power module 100 provided in the present application, the number of inner islands 112 can be multiple, the multiple inner islands 112 are spaced apart, the multiple inner islands 112 can be arranged in an array, and the multiple inner islands 112 can be arranged in a regular pattern. Exemplarily, the multiple inner islands 112 can be arranged in a triangle, a quadrilateral, a circle, a hexagon, etc. The pattern composed of the multiple inner islands 112 is symmetrically arranged, and each inner island 112 supports the conductive member 130, which can make the supporting force on the conductive member 130 more uniform.

[0058] The inner island 112 includes a first end 112 a and a second end 112 b . The first end 112 a is connected to the bottom wall 113 a of the groove 113 , and the second end 112 b supports the conductive member 130 .

[0059] In a feasible implementation, along the thickness direction of the first substrate 110, the projection area of ​​the first end 112a is larger than the projection area of ​​the second end 112b. Specifically, the inner island 112 gradually shrinks from the first end 112a to the second end 112b, which facilitates the formation of the inner island 112. When forming the inner island 112, etching can be performed in the first region 111 to form the groove 113, and the unetched portion of the first region 111 is retained to form the inner island 112.

[0060] In one possible implementation, see Fig. 9 , Fig. 9This is a cross-sectional view of a first substrate provided in another embodiment of the present application. Along the thickness direction of the first substrate 110, the projection area of ​​the first end 112a is smaller than the projection area of ​​the second end 112b, and the inner island 112 gradually shrinks from the second end 112b to the first end 112a. When the solder 115 is filled in the groove 113, the inner island 112 can limit the solder 115, thereby improving the connection strength between the solder 115 and the first substrate 110.

[0061] In one possible implementation, see Fig.10 , Fig.10 This is a cross-sectional view of a first substrate provided in yet another embodiment of the present application, in which the cross-section between the first end 112 a and the second end 112 b in the inner island 112 is the same everywhere.

[0062] The shape of the inner island 112 can be regular or irregular, and can be, but not limited to, a cylinder, a truncated cone, a cuboid, or a prism. The shape of the inner island 112 is regular, which facilitates etching the inner island 112 in the first region 111, and the inner island 112 provides a more uniform support force for the conductive member 130.

[0063] In the power module 100 provided in the present application, the end surface of the inner island 112 facing the conductive member 130 is flush with the second region 114. It can be understood that when the first region 111 of the first substrate 110 is etched to form the groove 113 and the inner island 112, the first region 111 is directly etched and the inner island 112 is retained, and there is no need to reprocess the inner island 112, thereby simplifying the step of etching the first substrate 110.

[0064] In one possible implementation, see Fig.11 and Fig.12 , Fig.11 A schematic structural diagram of a first substrate connected to a conductive member provided in yet another embodiment of the present application. Fig.12A cross-sectional view of a first substrate provided for another embodiment of the present application. The end surface of the inner island 112 facing the conductive member 130 is closer to the bottom wall 113a of the groove 113 than the second region 114. It can be understood that when the first region 111 of the first substrate 110 is etched, the first region 111 is etched to form the inner island 112 and the groove 113, and the inner island 112 is also etched, wherein the etching thickness of the inner island 112 is less than the depth of the first substrate 110 to form the groove 113, so that the end surface of the inner island 112 facing the conductive member 130 is closer to the bottom wall 113a of the groove 113 than the second region 114. Since the inner island 112 supports the conductive member 130, the thickness of the solder 115 between the conductive member 130 and the inner island 112 is generally within a certain range. When the solder 115 is filled in the groove 113, when the conductive member 130 is welded to the first substrate 110, the conductive member 130 will sink and sink into the groove 113, which will increase the contact area between the conductive member 130 and the solder 115. The inner island 112 supports the conductive member 130 so that the thickness between the conductive member 130 and the bottom wall 113a of the groove 113 is not too thin, thereby improving the welding strength between the conductive member 130 and the first substrate 110.

[0065] In the power module 100 provided in the present application, the welding method of the conductive member 130 and the second substrate 120 is the same as the welding method of the conductive member 130 and the first substrate 110, and the structural form of the second substrate 120 opening a groove 113 and forming an inner island 112 is the same as the structural form of the first substrate 110 opening a groove 113 and forming an inner island 112, which will not be repeated in the present application.

[0066] The first, second and various numerical numbers involved in this document are only distinguished for the convenience of description and are not intended to limit the scope of the present application.

[0067] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0068] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power module, characterized in that: The method comprises a first substrate, a second substrate and a conductive member, wherein the first substrate and the second substrate are spaced apart, and the conductive member is connected between the first substrate and the second substrate; the first substrate or the second substrate is provided with a first chip; The surface of the first substrate facing the second substrate includes a first area, the first area includes an inner island and a groove surrounding the inner island, and the groove is filled with solder; the mounting end surface of the conductive component faces the first area, and the mounting end surface of the conductive component is supported by the inner island, and the mounting end surface of the conductive component is fixedly connected to the solder to electrically connect the first chip and the conductive component.

2. The power module according to claim 1, characterized in that: The solder covers the end surface of the inner island facing the conductive member.

3. The power module according to claim 2, characterized in that: The projection of the mounting end surface of the conductive member along the thickness direction of the power module is within the first region, and the area of ​​the mounting end surface of the conductive member is smaller than the area of ​​the first region.

4. The power module according to any one of claims 1 to 3, characterized in that: The groove includes a bottom wall and a side wall surrounding the bottom wall, the surface of the first substrate facing the second substrate also includes a second area surrounding the first area, the side wall connects the second area and the bottom wall, and the projection area of ​​the opening of the groove along the thickness direction of the first substrate is larger than the area of ​​the bottom wall of the groove.

5. The power module according to any one of claims 1 to 3, characterized in that: The groove includes a bottom wall and a side wall surrounding the bottom wall, the surface of the first substrate facing the second substrate also includes a second area surrounding the first area, the side wall connects the second area and the bottom wall, and the projection area of ​​the opening of the groove along the thickness direction of the first substrate is smaller than the area of ​​the bottom wall of the groove.

6. The power module according to any one of claims 1 to 5, characterized in that: The depth of the groove is D, and D≥10 μm.

7. The power module according to any one of claims 1 to 6, characterized in that: The inner island includes a first end and a second end, the first end is connected to the bottom wall of the groove, the second end supports the conductive member, and along the thickness direction of the first substrate, the projection area of ​​the first end is larger than the projection area of ​​the second end.

8. The power module according to any one of claims 1 to 6, characterized in that: The inner island includes a first end and a second end, the first end is connected to the bottom wall of the groove, and along the thickness direction of the first substrate, the projection area of ​​the first end is smaller than the projection area of ​​the second end.

9. The power module according to any one of claims 1 to 8, characterized in that: The surface of the first substrate facing the second substrate further includes a second region surrounding the first region, and the end surface of the inner island facing the conductive member is flush with the second region.

10. The power module according to any one of claims 1 to 8, characterized in that: The surface of the first substrate facing the second substrate further includes a second region surrounding the first region, and the end surface of the inner island facing the conductive member is closer to the bottom wall of the groove than the second region.

11. The power module according to any one of claims 1 to 10, characterized in that: The side surface of the conductive member surrounds the mounting end surface of the conductive member and is connected to the mounting end surface, and the side surface of the conductive member is fixedly connected to the solder.

12. The power module according to any one of claims 1 to 11, characterized in that: The surface of the first substrate facing the second substrate further includes a second region surrounding the first region, and the solder further covers a portion of the second region close to the first region.

13. The power module according to any one of claims 1 to 12, characterized in that: The power module further includes a second chip. The first chip is disposed on the first substrate. The second chip is disposed on the second substrate. The second chip is electrically connected to the conductive member.

14. The power module according to claim 13, characterized in that: The power module includes a capacitor disposed on the first substrate or the second substrate; and / or the power module includes a resistor disposed on the first substrate or the second substrate.

15. A power conversion device, characterized in that: include: The power module according to any one of claims 1 to 14; A circuit board is electrically connected to the power module.

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