Power devices, power device components and related devices

Abstract

The present application provides a power device, a power device assembly and related devices. The power device includes a package body and a plurality of pins. The package body includes a substrate structure, a semiconductor wafer and a plastic package. The semiconductor wafer is arranged on the substrate structure, and the substrate structure includes a heat dissipation surface for connecting to a heat sink. The first end of the pin is fixed to the substrate structure. The plastic package covers the substrate structure and the semiconductor wafer except for the heat dissipation surface. The second end of the pin and the heat dissipation surface are exposed from the plastic package. The second end of the pin includes a mounting surface for mounting on a circuit board through surface mounting technology for electrical connection. The power device is also provided with a through hole that passes through the substrate structure and the plastic package, and the inner wall of the through hole is covered with the plastic package. Fasteners are provided through the through hole and the heat sink to achieve fixed connection between the heat dissipation surface and the heat sink, thereby pressing the power device onto the heat sink, which is beneficial to reduce the voids on the interface between the power device and the heat sink, thereby improving the heat dissipation efficiency.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a power device, a power device assembly, and related devices. Background Art

[0002] Power devices, also known as power electronic devices, are primarily used as components in circuits to alter electrical energy. Wave soldering is often used to achieve the electrical connection between the device's pins and the circuit board during power device packaging. However, this process is complex, requiring, for example, the creation of component holes on the circuit board and the insertion of pins into the corresponding holes, which impacts processing efficiency. Therefore, surface mounted technology (SMT) is often used to achieve the electrical connection between the power device's pins and the circuit board.

[0003] Power devices generate a significant amount of heat during use, requiring a heat sink to dissipate the heat. However, due to dimensional tolerances and assembly tolerances within the power devices themselves, the contact between the heat sink and the power device is not close when using surface-mount mounting (SMT). This results in increased thermal resistance and poor heat dissipation efficiency. Currently, external fastening is typically required between the circuit board and the heat sink to ensure the power device fits snugly against the heat sink, sandwiching the device between the circuit board and the heat sink. However, the space between the power device and the heat sink remains relatively large. With increasingly stringent heat dissipation requirements for power devices, improving heat dissipation efficiency has become a pressing issue. Summary of the Invention

[0004] Embodiments of the present application provide a power device, a power device assembly, and related apparatuses that can improve processing efficiency and heat dissipation efficiency.

[0005] In the first aspect, the present application provides a power device, comprising a package body and a plurality of pins, the package body comprising a substrate structure, a semiconductor wafer and a plastic package body, the semiconductor wafer being arranged on the substrate structure, the substrate structure comprising a heat dissipation surface for connecting to a heat sink, the plastic package body covering the substrate structure and the semiconductor wafer except for the heat dissipation surface, the first end of the pin being fixed to the substrate structure, the second end of the pin and the heat dissipation surface being exposed from the plastic package body, the second end comprising a mounting surface for mounting to a circuit board; the power device is further provided with a through hole passing through the substrate structure and the plastic package body, the inner wall of the through hole being covered with the plastic package body.

[0006] The power device provided in the first aspect of the present application has a second end of a pin including a mounting surface for mounting on a circuit board. Because the mounting surface of the power device can be directly mounted on the circuit board, steps such as creating component holes in the circuit board and inserting the pins into the holes are omitted, simplifying the manufacturing process, improving efficiency, and reducing costs in assembling the power device on the circuit board.

[0007] In addition, the power device is provided with a through hole that passes through the substrate structure and the plastic package body, which is used to penetrate fasteners to fix the circuit board, power device and heat sink, so that the power device is directly pressed onto the heat sink, increasing the fitting area between the heat dissipation surface of the power device and the assembly surface of the heat sink, and reducing the voids on the interface between the heat dissipation surface of the power device and the heat sink, thereby reducing the thermal resistance between the power device and the power device assembly, and improving the heat dissipation efficiency of the power device.

[0008] According to the first aspect, in a first possible implementation of the first aspect of the present application, the substrate structure includes a first surface and a second surface disposed opposite each other, the semiconductor die is disposed on the first surface of the substrate structure, and the heat dissipation surface is located on the second surface of the substrate structure. The semiconductor die and the heat dissipation surface are located on opposite sides of the substrate structure, respectively, without interfering with each other, thereby facilitating device arrangement.

[0009] According to the first aspect or the first possible implementation of the first aspect of the present application, in the second possible implementation of the first aspect of the present application, the substrate structure includes a metal substrate, the metal substrate including a stacked thermally conductive insulating layer and a metal layer, the semiconductor wafer is disposed on a side of the metal layer facing away from the thermally conductive insulating layer, the through-hole penetrates the thermally conductive insulating layer and the metal layer, and the first end of the pin is fixed to the metal layer. The metal substrate includes a thermally conductive insulating layer and a metal layer with good thermal conductivity, thereby improving the heat dissipation performance and reliability of the power device. The metal substrate is a single-sided metal substrate, which is beneficial for reducing the thickness of the power device, thereby reducing the size of the power device.

[0010] According to the first aspect or the first to second possible implementations of the first aspect of the present application, in a third possible implementation of the first aspect of the present application, the substrate structure includes a metal substrate, the metal substrate includes a thermally conductive insulating layer and two metal layers, the thermally conductive insulating layer is sandwiched between the two metal layers, and the semiconductor wafer is disposed on a side of one of the metal layers facing away from the thermally conductive insulating layer. Since there are two metal layers, i.e., the metal substrate is a double-sided metal substrate, the double metal layer can effectively improve the thermal conductivity of the power device, further improving the heat dissipation performance and reliability of the power device.

[0011] According to the first aspect or the first to third possible implementations of the first aspect of the present application, in the fourth possible implementation of the first aspect of the present application, the substrate structure further includes a heat dissipation substrate, the heat dissipation substrate being fixed to a side of the metal substrate facing away from the semiconductor wafer, and the heat dissipation surface being located on a side of the heat dissipation substrate facing away from the metal substrate. The heat dissipation substrate is used to enhance the heat dissipation performance of the power device and improve the heat dissipation efficiency of the power device.

[0012] According to the first aspect or the first to fourth possible implementations of the first aspect of the present application, in the fifth possible implementation of the first aspect of the present application, the heat dissipation surface is located on a side of the metal substrate facing away from the semiconductor wafer. The heat dissipation surface is directly provided on the metal substrate, that is, the metal substrate and the heat sink can be directly assembled together, which is beneficial for reducing the thickness of the power device and simplifying the structure of the power device.

[0013] According to the first aspect or the first to fifth possible implementations of the first aspect of the present application, in the sixth possible implementation of the first aspect of the present application, the package body further comprises a top and a bottom disposed opposite each other, the bottom facing away from the top being oriented in the same direction as the mounting surface, and the heat dissipation surface being disposed on a side of the top facing away from the bottom. The heat dissipation surface and the mounting surface are oriented differently, and when the power device, circuit board, and heat sink are assembled together, the power device can be sandwiched between the circuit board and the heat sink, thereby increasing flexibility in arranging the devices on the circuit board.

[0014] According to the first aspect or the first to sixth possible implementations of the first aspect of the present application, in the seventh possible implementation of the first aspect of the present application, the package body further includes a top and a bottom that are arranged relative to each other, the bottom side facing away from the top side is oriented in the same direction as the mounting surface, and the heat dissipation surface is arranged on the side of the bottom side facing away from the top side. The heat dissipation surface and the mounting surface are oriented in the same direction, and when the power device, circuit board, and heat sink are assembled together, the heat sink can be inserted through the circuit board, which can effectively reduce the thickness of the component and enrich the assembly form.

[0015] According to the first aspect or the first to seventh possible implementations of the first aspect of the present application, in the eighth possible implementation of the first aspect of the present application, the heat dissipation surface includes at least two heat dissipation surface units, and the gaps between adjacent heat dissipation surface units are filled with the plastic package. The heat dissipation surface includes at least two separately arranged heat dissipation surface units, which can effectively reduce the risk of the heat dissipation surface being too large and easily damaged or broken by force. For example, when the substrate structure includes a metal substrate and a heat dissipation substrate, the side of the heat dissipation substrate facing away from the metal substrate serves as the heat dissipation surface. The heat dissipation substrate can be divided into two or more independent units to alleviate the risk of the heat dissipation substrate being too large and easily broken by mechanical stress. In some embodiments, the substrate structure includes a metal substrate and omits the heat dissipation substrate. A layer of the metal substrate facing away from the semiconductor wafer serves as the heat dissipation surface. The layer of the metal substrate facing away from the semiconductor wafer can be divided into two or more independent units to alleviate the risk of the heat dissipation surface being too large and easily broken by mechanical stress.

[0016] According to the first aspect or the first to eighth possible implementations of the first aspect of the present application, in the ninth possible implementation of the first aspect of the present application, the package body includes a top, a bottom, and a side, the top and the bottom are arranged opposite to each other, the side is connected between the bottom and the top, and the orientation of the bottom is the same as the orientation of the mounting surface; the pin is arranged in an SOP (short for small out-Line package, SOP is also called a small outline package), the first end of the pin is connected to the side, and a plurality of the pins are distributed along the side. The direction and number of the package pins of the power device are flexible, which facilitates the electrical connection of the power device to the circuit board.

[0017] According to the first aspect or the first to ninth possible implementations of the first aspect of the present application, in the tenth possible implementation of the first aspect of the present application, the package body includes a top, a bottom, and a side, the top and the bottom are arranged opposite each other, the side is connected between the bottom and the top, and the orientation of the bottom is the same as the orientation of the mounting surface; the pin is HSOP (short for small out-line package with heat sink, HSOP is also called a small outline package for heat sink), the first end of the pin is connected to the bottom, and a plurality of the pins are distributed along the side. The package pin direction and number of the power device are flexible, which facilitates the electrical connection of the power device to the circuit board.

[0018] According to the first aspect or the first to tenth possible implementations of the first aspect of the present application, in the eleventh possible implementation of the first aspect of the present application, the metal substrate includes at least two mounting units, the number of the semiconductor wafers is at least two, and each mounting unit is provided with at least one semiconductor wafer. The number of mounting units can be set according to the type of semiconductor wafer, thereby increasing flexibility in power device design.

[0019] In a second aspect, the present application provides a power device assembly, comprising a power device, a circuit board, a heat sink and a fastener according to the first aspect or the first to eleventh possible implementation methods of the first aspect, wherein the mounting surface of the second end of the pin of the power device is mounted together with the circuit board to achieve electrical connection, the circuit board is provided with an opening passing through the circuit board, the heat sink includes an assembly surface, the assembly surface is provided with a connecting hole, and the fastener is passed through the opening, the through hole of the power device and the connecting hole, thereby fixedly connecting the heat dissipation surface of the power device to the assembly surface.

[0020] The power device assembly provided in the second aspect of the present application realizes electrical connection by directly mounting the mounting surface of the power device on the circuit board, thereby omitting steps such as opening component holes on the circuit board and inserting pins into the component holes, simplifying the processing process, improving the processing efficiency of assembling the power device on the circuit board, and reducing costs.

[0021] In addition, since the fastener is directly inserted into the through hole of the power device and fixedly connected to the heat sink, the heat dissipation surface and the assembly surface are fixedly connected. In this way, the fitting area between the interface between the heat dissipation surface of the power device and the assembly surface is increased, and the voids at the interface between the heat dissipation surface of the power device and the assembly surface are reduced, thereby reducing the thermal resistance between the power device and the power device assembly and improving the heat dissipation efficiency of the power device.

[0022] The pins of existing power devices are electrically connected to the circuit board using a wave soldering process. When assembling the power device, circuit board and heat sink, first fix the power device, heat sink and circuit board with fasteners, then insert the pins of the power device into the corresponding component holes of the circuit board, and then solder them. If other electronic devices are required on the circuit board, they are usually mounted on the circuit board using surface mount technology (such as reflow soldering). In this way, when power devices and other electronic devices are provided on the circuit board, different processes need to be adopted, which makes the assembly process complicated. However, the present application adopts the method of directly mounting the pins of the power device on the circuit board, which is the same as the installation method of other electronic devices, thereby simplifying the assembly process of the power device component-related devices.

[0023] According to the second aspect, in a first possible implementation of the second aspect of the present application, the package body of the power device further includes a bottom and a top that are relatively arranged, the orientation of the mounting surface is the same as the orientation of the side of the bottom facing away from the top, the heat dissipation surface is located on the side of the top facing away from the bottom, the fasteners penetrate the openings, the through holes and the connection holes in sequence, and the circuit board, the package body and the heat sink are stacked in sequence. The heat dissipation surface and the mounting surface have different orientations. When the power device, the circuit board and the heat sink are assembled together, the power device can be clamped between the circuit board and the heat sink, thereby improving the flexibility of the device arrangement on the circuit board. In addition, the heat sink does not need to be penetrated through the circuit board, and the aperture of the opening on the circuit board does not need to be too large, and only fasteners can be passed through.

[0024] According to the second aspect or the first or second possible implementation of the second aspect of the present application, in the third possible implementation of the second aspect of the present application, the fastener includes a rod and a cap fixed to one end of the rod, the rod fixedly passing through the opening, the through-hole, and the connection hole, the circuit board is clamped between the cap and a side of the package body facing away from the heat sink, and the cap is located on the side of the circuit board facing away from the package body. The cap can effectively prevent the circuit board and power device from detaching from the rod, thereby improving the connection reliability between the circuit board, the power device, and the heat sink, thereby improving the reliability of the power device assembly.

[0025] According to the second aspect or the first to third possible implementations of the second aspect of the present application, in the fourth possible implementation of the second aspect of the present application, the package body further includes a bottom and a top arranged opposite each other, the mounting surface is oriented in the same direction as a side of the bottom facing away from the top, the heat dissipation surface is provided on a side of the bottom facing away from the top, the heat sink is provided through the opening, the fastener is provided through the through hole and the connection hole in sequence, and the package body and the heat sink are stacked. Since the heat sink can be provided through the circuit board, it is beneficial to reduce the size of the power device assembly.

[0026] In combination with the second and fourth possible implementations of the second aspect of this application, the assembly method of the power device, circuit board, and radiator can be selected according to the position of the heat dissipation surface on the power device. For example, when the heat dissipation surface is set on the top side of the power device away from the bottom side of the power device, the pins can be attached to the bottom side of the circuit board, and the radiator does not need to be inserted into the circuit board, that is, the circuit board does not need to be designed with a window corresponding to the radiator; and when the heat dissipation surface is set on the bottom side of the power device away from the top side, the radiator can be inserted into the circuit board, and the pins can be attached to the top side of the circuit board. In this way, different power devices can be combined and packaged in a variety of forms, which improves the flexibility of device layout.

[0027] According to the second aspect or the first to fourth possible implementations of the second aspect of the present application, in the fifth possible implementation of the second aspect of the present application, the fastener includes a rod and a cap fixed to one end of the rod, the rod is fixedly inserted through the through hole, the opening, the mounting hole, and the connection hole, the package body is sandwiched between the cap and the heat dissipation surface, the cap is located on the side of the package body facing away from the heat sink, and the cap is located on the side of the circuit board facing away from the package body. The cap can effectively prevent the circuit board and power device from detaching from the rod, thereby improving the reliability of the power device.

[0028] According to the second aspect or the first to fifth possible implementations of the second aspect of the present application, in the sixth possible implementation of the second aspect of the present application, the power device assembly further includes a thermally conductive interface layer, the thermally conductive interface layer having a mounting hole extending therethrough, the thermally conductive interface layer being sandwiched between the heat dissipation surface and the heat sink, and the fastener being passed through the mounting hole. The thermally conductive interface layer can improve the efficiency of heat transfer from the power device to the heat sink, thereby improving the heat dissipation efficiency of the power device assembly.

[0029] According to the second aspect or the first to sixth possible implementations of the second aspect of the present application, in the seventh possible implementation of the second aspect of the present application, the thermal interface layer includes one of a graphite thermal pad, a nano-copper Velcro, a thermal grease layer, and a thermal gel.

[0030] According to the second aspect or the first to seventh possible implementations of the second aspect of the present application, in the eighth possible implementation of the second aspect of the present application, the power device assembly further includes a washer, the washer being sleeved on the rod body, the washer being clamped between the cap body and the circuit board, or the washer being clamped between the cap body and the package body. The washer is used to increase the force-bearing area of ​​the circuit board to prevent damage to the circuit board caused by excessive stress in a local area of ​​the circuit board.

[0031] In a third aspect, the present application provides an electric energy conversion device, comprising a power device assembly provided according to the second aspect or the first to eighth possible implementations of the second aspect of the present application.

[0032] In a fourth aspect, the present application provides an electric energy conversion device, comprising the electric energy conversion apparatus provided according to the third aspect.

[0033] In a fifth aspect, the present application provides a method for assembling a power device assembly according to the second aspect or any of the first to eighth possible implementations of the second aspect of the present application, wherein the power device assembly comprises a power device, a circuit board, and a heat sink, the power device comprising a package body and a plurality of pins, the package body comprising a substrate structure, a semiconductor die, and a plastic encapsulation body, the substrate structure comprising a heat dissipation surface, the plastic encapsulation body covering the substrate structure and the semiconductor die except for the heat dissipation surface, the first end of the pin being fixed to the substrate structure, the second end of the pin and the heat dissipation surface both being exposed from the plastic encapsulation body, the second end comprising a mounting surface, the package body further comprising a through hole extending through the substrate structure and the plastic encapsulation body, the inner wall of the through hole being covered with the plastic encapsulation body, the circuit board comprising an opening, and the heat sink comprising an assembly surface, the assembly surface comprising a connection hole. The assembly method comprises the following steps: mounting the mounting surface of the pin on the circuit board; and inserting fasteners through the through hole, the opening, and the connection hole to securely connect the heat dissipation surface to the assembly surface.

[0034] According to the fifth aspect, in a first possible implementation of the fifth aspect of the present application, the packaging body further comprises a bottom and a top arranged relative to each other, the orientation of the mounting surface is the same as the orientation of a side of the bottom facing away from the top, and the heat dissipation surface is located on a side of the top facing away from the bottom; the fasteners are passed through the through holes, the openings and the connecting holes, including passing the fasteners through the openings, the through holes and the connecting holes in sequence, so that the circuit board, the packaging body and the radiator are stacked in sequence.

[0035] According to the fifth aspect or the first possible implementation of the fifth aspect of the present application, in the second possible implementation of the fifth aspect of the present application, the fastener includes a rod body and a cap body fixed to one end of the rod body, and the fastener is sequentially inserted into the opening, the through hole and the connecting hole, including: inserting the rod body into the opening, the through hole and the connecting hole in sequence, the circuit board is clamped between the cap body and a side of the packaging body facing away from the radiator, and the cap body is located on the side of the circuit board facing away from the packaging body.

[0036] According to the fifth aspect or the first to second possible implementation methods of the fifth aspect of the present application, in the third possible implementation method of the fifth aspect of the present application, the packaging body also includes a bottom and a top arranged relative to each other, the orientation of the mounting surface is the same as the orientation of the side of the bottom facing away from the top, and the heat dissipation surface is arranged on the side of the bottom facing away from the top; the fastener is inserted into the through hole, the opening and the connecting hole, and further includes inserting the radiator into the opening, and inserting the fastener into the through hole and the connecting hole in sequence, and the packaging body and the radiator are stacked.

[0037] According to the fifth aspect or the first to third possible implementation methods of the fifth aspect of the present application, in the fourth possible implementation method of the fifth aspect of the present application, the fastener includes a rod body and a cap body fixed to one end of the rod body, and the fastener is passed through the through hole, the opening and the connecting hole, including passing the rod body through the through hole and the connecting hole in sequence, the packaging body is clamped between the cap body and the heat dissipation surface, and the cap body is located on the side of the packaging body facing away from the radiator.

[0038] According to the fifth aspect or the first to fourth possible implementation methods of the fifth aspect of the present application, in the fifth possible implementation method of the fifth aspect of the present application, before the mounting surface of the pin is mounted on the circuit board, the assembly method also includes: providing a thermal interface layer between the heat dissipation surface and the assembly surface, the thermal interface layer forming a mounting hole passing through the thermal interface layer; the fastener is inserted into the through hole, the opening and the connecting hole, and further includes: inserting the fastener into the mounting hole.

[0039] According to the fifth aspect or the first to fifth possible implementations of the fifth aspect of the present application, in the sixth possible implementation of the fifth aspect of the present application, before the thermal interface layer is provided between the heat dissipation surface and the assembly surface, the assembly method further includes: coating the assembly surface with a film layer and deoxidizing it, wherein the film layer is a metal layer; deoxidizing the heat dissipation surface; and providing the thermal interface layer between the heat dissipation surface and the assembly surface, including: arranging nano-copper Velcro between the heat dissipation surface and the assembly surface and curing to form the thermal interface layer.

[0040] According to the fifth aspect or the first to fifth possible implementations of the fifth aspect of the present application, in the sixth possible implementation of the fifth aspect of the present application, before providing the thermal interface layer between the heat dissipation surface and the assembly surface, the assembly method further includes prefabricating the thermal interface layer with a graphite thermal pad.

[0041] According to the fifth aspect or the first to sixth possible implementations of the fifth aspect of the present application, in the seventh possible implementation of the fifth aspect of the present application, before providing a thermal interface layer between the heat dissipation surface and the assembly surface, the assembly method further includes coating thermal grease or thermal gel on the assembly surface to form the thermal interface layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic structural diagram of a power device assembly provided in an embodiment of the present application;

[0043] Figure 2 for Figure 1A schematic structural diagram of a power device of the power device assembly shown;

[0044] Figure 3 for Figure 1 A top view of a power device of the power device assembly shown;

[0045] Figure 4 for Figure 1 A cross-sectional view of a power device of the power device assembly shown;

[0046] Figure 5 An assembly diagram of a metal substrate and a semiconductor wafer provided in an embodiment of the present application;

[0047] Figure 6 A schematic diagram of an assembly of a single-sided metal substrate, a heat dissipation substrate, and a semiconductor wafer provided in an embodiment of the present application;

[0048] Figure 7a A schematic diagram of a half-bridge topology of a semiconductor wafer using an IGBT electrical symbol provided in an embodiment of the present application;

[0049] Figure 7b A schematic diagram of a half-bridge topology of a semiconductor wafer using a MOSFET electrical symbol provided in an embodiment of the present application;

[0050] Figure 8 A schematic structural diagram of another power device provided in an embodiment of the present application;

[0051] Figure 9 A schematic structural diagram of another power device provided in an embodiment of the present application;

[0052] Figure 10 A schematic structural diagram of another power device assembly provided in an embodiment of the present application;

[0053] Figure 11 A schematic diagram of another power device structure provided in an embodiment of the present application

[0054] Figure 12 A schematic structural diagram of another power device provided in an embodiment of the present application;

[0055] Figure 13 A schematic structural diagram of another power device provided in an embodiment of the present application;

[0056] Figure 14 、 Figure 15 、 Figure 16 and Figure 17 A flow chart of a possible assembly method for the power device assembly provided in this application. DETAILED DESCRIPTION

[0057] At present, many industrial-grade energy products require a large number of densely arranged high-power devices, which will generate a lot of heat. Therefore, such products need to have good heat dissipation performance.

[0058] In power device packaging, soldering processes are often used to achieve electrical connections between the device and the circuit board. Wave soldering is a common process. Wave soldering involves injecting molten solder (such as a lead-tin alloy) into a designed solder wave using an electric or electromagnetic pump. This process can also be achieved by injecting nitrogen into a solder pool. A circuit board (PCB) pre-populated with components (referred to as a printed circuit board, PCB, plug-in board, or circuit board, for example) is then passed through the solder wave, achieving both mechanical and electrical connections between the component terminals or pins (also known as pins) and the PCB pads. Wave soldering can be either conventional or selective. Both require component holes in the PCB. To make an electrical connection between the power device and the PCB, the device pins are first inserted into the pins in the component holes. The pins are then soldered into the PCB holes. After soldering, if the pins are excessively long perpendicular to the PCB surface, the excess length must be trimmed. It can be seen that there are many steps to achieve electrical connection between power devices and circuit boards by welding, which is inefficient and has high manufacturing costs.

[0059] In order to improve the processing efficiency of power device components and reduce manufacturing costs, SMT can be used to achieve electrical connection between the pins of the power device and the circuit board.

[0060] Power devices are typically equipped with heat sinks to dissipate the large amounts of heat generated during operation. Under SMT, due to the dimensional tolerances of the power devices themselves and the influence of assembly tolerances, the contact between the heat sink and the power device is not tight, resulting in increased thermal resistance and affecting the heat dissipation efficiency of the component. To address this problem of loose contact between the heat sink and the power device, fasteners are generally required to fasten the circuit board and the heat sink, clamping the power device between the circuit board and the heat sink so that the power device can be closely attached to the heat sink. However, the cavity between the power device and the heat sink is still relatively large, resulting in a high thermal resistance of the power device and its components, making it difficult to meet today's increasingly stringent heat dissipation requirements for power devices.

[0061] The present application provides a power device and a corresponding power device assembly (including a heat sink), which are beneficial to reducing voids on the interface between the power device and the heat sink, thereby improving heat dissipation efficiency.

[0062] The power devices and components provided in this application can be applied to various electric energy conversion devices that require high-power devices, and the electric energy conversion device can be mounted on the electric energy conversion equipment to complete various power functions of the equipment. For example, the power device assembly of this application can be applied in the field of electric vehicle power systems, that is, the electric energy conversion device can be an electric vehicle, wherein the electric energy conversion device can be a motor controller, and the power device is a power conversion unit assembled in the motor controller; the electric energy conversion device can also be an on-board charger (OBC), and the power device is an energy conversion unit; the electric energy conversion device can also be a low-voltage control power supply, and the power device is the DC-DC conversion unit therein, etc. In addition, the power device assembly of this application is not limited to the field of electric vehicles, and can also be widely used in the field of traditional industrial control, for example, it can be applied to uninterruptible power supplies (UPS, Uninterruptible Power Supply) in data centers, inverters for photovoltaic power generation equipment, power supplies for servers, etc.

[0063] The present application will be described in further detail below with reference to the accompanying drawings.

[0064] See also Figure 1 A first embodiment of the present application provides a power device assembly 100 , including a power device 20 , a printed circuit board (PCB) 40 , a heat sink 60 , and a fastener 70 .

[0065] The power device 20 is electrically connected to the circuit board 40, and is sandwiched between the circuit board 40 and the heat sink 60. The heat sink 60 is used to dissipate heat from the power device 20 and the circuit board 40. Heat sink 60 can use air cooling, water cooling, or other cooling methods, which are not limited in this application. The circuit board 40 is a board-level structure used to mount the power device 20 and other chip packaging structures.

[0066] The power device 20 is provided with a through hole 21, and the circuit board 40 is provided with an opening 41. The heat sink 60 includes an assembly surface 62, which is provided with a connection hole 64. The fastener 70 is provided through the through hole 21, the opening 41, and the connection hole 64, thereby fixedly connecting the power device 20 to the heat sink 60. Because the fastener 70 is directly provided through the power device 20, the power device 20 is pressed against the heat sink 60, so that the power device 20 and the heat sink 60 are closely fitted, the fitting area between the power device 20 and the heat sink 60 is increased, and the voids at the interface between the power device 20 and the heat sink 60 are effectively reduced, thereby reducing the thermal resistance between the power device 20 and the power device assembly 100 and improving the heat dissipation efficiency of the power device 20 and the power device assembly 100.

[0067] The various components of the power device assembly 100 are described in detail below.

[0068] See also Figure 1 and Figure 2 In the first embodiment of the present application, the power device 20 includes a package body 201 and pins 203. The package body 201 includes a bottom 2011, a top 2013, and a side 2015, with the top 2013 being arranged opposite to the bottom 2011. The side of the top 2013 facing away from the bottom 2011 is arranged toward the heat sink 60. The side of the top 2013 facing the bottom 2011 is arranged toward the circuit board 40. In this embodiment, the pins 203 can be extended in a small out-line package (SOP), that is, the pins 203 are extended from the side 2015 of the package body 201 and have a wing-shaped structure (for example, an L or J shape). The first end of the pin 203 is fixed to the side 2015, and the second end of the pin 203 extends from the side 2015. The second end of the pin 203 includes a mounting surface 2031, and the mounting surface 2031 of the pin 203 is mounted on the circuit board 40 to achieve electrical connection between the power device 20 and the circuit board 40. Mounting surface 2031 is mounted on circuit board 40 using surface mount technology (SMT). SMT is a circuit assembly technique that mounts leadless or short-lead surface-mount components on the surface of a circuit board or other substrate, then assembles them through soldering methods such as reflow or dip soldering. In this embodiment, mounting surface 2031 and bottom 2013 face away from top 2011 in the same direction.

[0069] In the power device assembly 100 provided in the first embodiment of the present application, the electrical connection between the power device 20 and the circuit board 40 is achieved by directly attaching the mounting surface 2031 to the circuit board 40, such as in a reflow soldering process, where air or nitrogen is heated to a sufficiently high temperature and then blown toward the circuit board with the components attached, melting the solder on both sides of the components and bonding them to the circuit board. This eliminates the need to cut off excessively long pins, simplifying the assembly steps between the power device 20 and the circuit board 40 and helping to reduce the manufacturing cost of the power device assembly 100. Furthermore, the pins 203 of the power device 20 can be first soldered to the circuit board 40, and then the power device 20 can be crimped onto the circuit board 40, improving assembly efficiency.

[0070] See also Figure 3From a top view, the package body 201 can be roughly square, i.e., there are four sides 2015, and the multiple pins 203 are distributed along the four sides 2015 of the package body 201, i.e., the multiple pins 203 extend from the four sides 2015 of the package body 201 (i.e., in four directions). It will be understood that this application is not limited to the multiple pins 203 being distributed on the four sides 2015 of the package body 201. In other embodiments, the package of the power device 20 can be configured to extend pins in at least two directions, i.e., the multiple pins 203 are distributed on at least two sides 2015 of the package body 201. This application also does not limit the shape of the package body 201, and the package body 201 can also be circular, triangular, polygonal, or irregular in shape, etc.

[0071] It is understood that the present application does not limit the pin-out method of the pins 203. The pins 203 can be configured according to the internal topology and functional requirements of the power device 20. The pin spacing and shape can be freely allocated as long as the distance between the pins 203 meets the requirements. For example, the pins 203 can be connected to a small out-line package with a heat sink (HSOP), with the pins 203 connected from the side 2015. By connecting the pins 203 from the side 2015 of the package body 201, the direction and number of the pins of the power device 20 package can be flexible.

[0072] See also Figure 4 The package body 201 includes a substrate structure 22, a semiconductor wafer 24 and a plastic package 26. The semiconductor wafer 24 is arranged on the substrate structure 22, and the substrate structure 22 also includes a heat dissipation surface 29 for connecting to the heat sink 60. The plastic package 26 covers the substrate structure 22 and the semiconductor wafer 24 except for the heat dissipation surface 29. The through hole 21 passes through the substrate structure 22 and the plastic package 26, and is used to pass the fastener 70. The inner wall of the through hole 21 is covered with the plastic package 26 to have insulation properties. The first end of the pin 203 is fixed to the substrate structure 22, and the second end of the pin 203 is exposed from the plastic package 26 for electrical connection to the circuit board 40. The heat dissipation surface 29 is exposed from the plastic package 26, and is used to conduct the heat generated by the power device 20 to the heat sink 60.

[0073] The through hole 21 is insulated from the electrical structure (not shown) of the substrate structure 22 to improve the reliability of the power device 20 . Figures 1 to 4 Only one through hole 21 is shown as an example. It can be understood that the present application does not limit the number of through holes 21. In other embodiments, the number of through holes 21 can be 2 or more, which is set according to different requirements of the power device 20.

[0074] The substrate structure 22 includes a first surface 220 and a second surface 221 opposite to each other. The semiconductor chip 24 is disposed on the first surface 220 , and the heat dissipation surface 29 is located on the second surface 221 .

[0075] More specifically, the substrate structure 22 includes a stacked metal substrate 222 and a heat sink substrate 226. Through-holes 21 extend through the metal substrate 222 and the heat sink substrate 226. A first surface 220 is the bottommost surface of the metal substrate 222 facing away from the heat sink substrate 226. A second surface 221 is the side of the heat sink substrate 226 facing away from the metal substrate 222. A heat sink surface 29 is the side of the heat sink substrate 226 facing away from the metal substrate 222. The plastic package 26 covers the metal substrate 222 and the heat sink substrate 226, excluding the heat sink surface 29.

[0076] The metal substrate 222 includes a stacked thermally conductive insulating layer 2222 and a metal layer 2224. The semiconductor die 24 is disposed on a side of the metal layer 2224 facing away from the thermally conductive insulating layer 2222. A through hole 21 extends through the thermally conductive insulating layer 2222 and the metal layer 2224. The first end of the pin 203 is fixed to the metal layer 2224 where the semiconductor die 24 is disposed.

[0077] In this embodiment, the metal substrate 222 is produced using a direct bonded copper (DBC) process, meaning that the metal layer 222 is a copper layer. DBC refers to the process of coating one or both sides of a ceramic substrate with copper and bonding the copper and ceramic layers together using high temperatures. The metal substrate 222 can also be produced using other processes, such as direct plate copper (DPC) vacuum sputtering. DPC is a process in which a ceramic substrate is coated with a copper layer using vacuum sputtering and then a development process is used to create electrical circuits. Another example is active metal bonding (AMB), which utilizes an active metal brazing filler metal to achieve a high-temperature metallurgical bond between aluminum nitride and oxygen-free copper. It is understood that the metal substrate 222 is not limited to a copper-clad ceramic substrate; it can also be a copper-clad metal substrate. A copper-clad metal substrate is a substrate made of a metal (e.g., aluminum, copper, iron, molybdenum, etc.) with a thermally conductive insulating layer applied to the substrate, and then a copper layer applied to the side of the thermally conductive insulating layer facing away from the metal substrate. It is understood that the metal layer 222 is not limited to a copper layer, and may also be other metal layers, such as a gold layer, etc. The thermally conductive insulating layer 2222 includes aluminum nitride, and may also include other insulating materials, such as aluminum oxide.

[0078] Please refer to Figure 5 , Figure 5This is a schematic diagram of the structure of a metal substrate 222 with copper cladding on both sides. There are two metal layers 2224. The thermally conductive insulating layer 2222 includes a first surface 2225 and a second surface 2226 disposed opposite each other. One metal layer 2224 is fixed to the first surface 2225 of the thermally conductive insulating layer 2222, and the other metal layer 2224 is fixed to the second surface 2226 of the thermally conductive insulating layer 2222. The semiconductor wafer 24 is disposed on the side of the metal layer 2224 located on the first surface 2225, facing away from the thermally conductive insulating layer 2222. In other words, the two metal layers 2224 are disposed on opposite surfaces of the thermally conductive insulating layer 2222. In other words, the metal substrate 222 is a double-sided copper-clad metal substrate, and the through-holes 21 extend through the thermally conductive insulating layer 2222 and the metal layers 2224 of the metal substrate 222. The metal layer 2224 is made of copper, a material with good thermal conductivity, which provides the metal substrate 222 with excellent thermal conductivity. The number of the metal layers 2224 of the double-sided copper-clad metal substrate is two, thereby improving the thermal conductivity and reliability of the power device 20 .

[0079] The heat sink substrate 226 is fixed to the side of the metal substrate 222 facing away from the semiconductor wafer 24. In this embodiment, the heat sink substrate 226 is fixed to the metal layer 2224 where the semiconductor wafer 24 is not provided, thereby enhancing the heat dissipation performance of the power device 20 and improving the heat dissipation efficiency of the power device 20. In this embodiment, the heat sink substrate 226 can be fixed to the side of the metal substrate 222 facing away from the semiconductor wafer 24 via a bonding layer 224. The bonding layer 224 can be a solder layer with excellent bonding properties and thermal conductivity. This ensures that the solder layer not only firmly connects the heat sink substrate 226 to the metal substrate 222, but also effectively transfers heat generated by the metal substrate 222 to the heat sink substrate 226 for dissipation.

[0080] It is understood that the present application does not limit the metal substrate 222 to a double-sided metal substrate. In other embodiments, the number of the metal layer 2224 in the metal substrate 222 can be one, that is, the metal substrate 222 is a single-sided metal substrate. Figure 6 , Figure 6 This is a structural diagram of a metal substrate 222 with copper cladding on one side. The heat dissipation substrate 226 is located on the side of the thermally conductive insulating layer 2222 facing away from the metal layer 2224 .

[0081] It is understandable that the above solution may also omit the bonding layer 224 and directly seal the heat dissipation substrate 226 with the metal substrate 222 through the plastic sealing body 26 .

[0082] The semiconductor wafer 24 includes electronic components, such as electronic components with power conversion functions: high-power transistors, thyristors, bidirectional thyristors, metal-oxide-semiconductor field-effect transistors (MOSFET), insulated gate bipolar transistors (IGBT), diodes, silicon controlled rectifiers (SCR), SiC, GaN, etc. The connection method of the internal devices of the semiconductor wafer 24 is not limited. The devices can be connected in series or in parallel to form a functional circuit, or the devices can be independent monomers. In this way, the number of devices can be effectively reduced, the copper wiring connection required for discrete devices on the circuit board can be saved, the size design of the circuit board can be optimized, and the volume of the power device can be reduced. The topology of the semiconductor wafer 24 can be a single tube, half bridge, H bridge, three-phase full bridge, three-level, etc. For example, the semiconductor wafer 24 includes an IGBT (such as Figure 7a As shown) and MOSFET (as Figure 7b The semiconductor wafer 24 may also integrate device drive protection control and temperature junction temperature protection. It is understood that the present application does not limit the type, topology, or quantity of the semiconductor wafer 24. Figure 7a and Figure 7b The letters in the figure represent the pin symbols. For example, P1, P2, and P3 refer to the power pin numbers, T1 and T2 refer to the temperature sampling pin numbers, G1 and S1 refer to the driving pin numbers of the switching tube, Isense1 and Isense2 refer to the current sampling pin numbers, etc., which are not listed here one by one.

[0083] Please refer again Figure 4 The power device 20 further includes a bonding wire 27 located in the plastic package 26 . The bonding wire 27 is connected between the semiconductor wafer 24 and the metal layer 2224 on which the semiconductor wafer 24 is provided, and is used to connect the semiconductor wafer 24 to the internal electrical structure in the metal substrate 222 .

[0084] Please refer again Figure 1The circuit board 40 includes a top surface (also known as the T surface) 43 and a bottom surface (also known as the B surface) 44 that are arranged opposite each other. The opening 41 passes through the top surface 43 and the bottom surface 44 of the circuit board 40. When the power device 20 is mounted on the circuit board 40, the side of the bottom 2011 facing away from the top 2013 is positioned toward the circuit board 40, and the heat dissipation surface 29 of the power device 20 is located on the side of the top 2013 facing away from the circuit board 40. In this embodiment, the heat dissipation surface 29 and the mounting surface 2031 are oriented in opposite directions, that is, the heat dissipation surface 29 is located on the side of the top 2013 facing away from the bottom 2011. The mounting surface 2031 of the pin 203 extends from the side toward the bottom 2011 of the power device 20, and the mounting surface 2031 of the pin 203 is mounted on the bottom surface 44 of the circuit board 40.

[0085] The fastener 70 is inserted through the opening 41, the through-hole 21, and the connecting hole 64, thereby fixedly connecting the power device 20, the circuit board 40, and the heat sink 60. Since the power device 20 has a through-hole 21, the fastener 70 is inserted through the through-hole 21 and the connecting hole 64 to directly press the power device 20 onto the heat sink 60. This allows the heat dissipation surface 29 of the power device 20 to closely fit the assembly surface 62 of the heat sink 60, effectively reducing voids at the interface between the power device 20 and the heat sink 60, thereby reducing the thermal resistance between the power device 20 and the power device assembly 100 and improving the heat dissipation efficiency of the power device 20 and the power device assembly 100.

[0086] The fastener 70 includes a rod body 72 and a cap body 74 fixed to one end of the rod body 72. The rod body 72 is fixedly inserted into the opening 41, the through hole 21 and the connecting hole 64, and the circuit board 40 is clamped between the cap body 74 and the side of the package body 201 facing away from the heat sink 60. The cap body 74 is located on the side of the circuit board 40 facing away from the heat sink 60, and is used to prevent the fastener 70 from being separated from the circuit board 40. The present application does not limit the connection method between the fastener 70 and the heat sink 60. For example, the fastener 70 can be a screw, the outer wall of the rod body 72 is provided with a thread, the connecting hole 64 is a screw hole, and the fastener 70 is screwed to the connecting hole 64. The fastener 70 can also be a stud, a pin, a rivet, etc.

[0087] The power device assembly 100 also includes a washer 80 that is sleeved onto the rod 72. The washer 80 is sandwiched between the cap 74 and the circuit board 40. The cap 74 is located on the side of the washer 80 facing away from the circuit board 40. The surface area of ​​the washer 80 is larger than the inner diameter of the through hole 21, which increases the force-bearing area of ​​the circuit board 40 and prevents damage (e.g., risk of breakage) to the circuit board 40 caused by excessive stress in a localized area of ​​the circuit board 40. The washer 80 can be integrated with the fastener 70 or provided separately.

[0088] The power device assembly 100 also includes a thermally conductive interface layer 90, which is interposed between the power device 20 and the heat sink 70. The thermally conductive interface layer 90 is used to conduct heat generated by the power device 20 to the heat sink 60 for dissipation. The thermally conductive interface layer 90 is formed with a mounting hole 91, and the rod 72 of the fastener 70 is also inserted into the mounting hole 91.

[0089] The thermal interface layer 90 is sandwiched between the heat dissipation surface 29 of the power device 20 and the assembly surface 62 of the heat sink 60. Because the heat dissipation surface 29 of the power device 20 and the assembly surface 62 of the heat sink 60 are in direct contact with each other through the thermal interface layer 90, the heat dissipation path is shortened, effectively improving the heat dissipation efficiency of the power device 20 and the power device assembly 100, thereby increasing the power density of the power device 20 and the power device assembly 100.

[0090] In this embodiment, the thermal interface layer 90 includes nano-copper Velcro. When assembling the power device assembly 100, the assembly surface 62 of the heat sink 60 is coated with a film layer (not shown) and deoxidized. The film layer is a metal layer to improve the fit between the thermal interface layer 90 and the assembly surface 62. The metal layer can include at least one of nickel, copper, silver, gold, and palladium. It is understood that this application does not limit the material of the metal layer. Afterwards, the heat dissipation surface 29 of the power device 20 is deoxidized to improve the fit between the thermal interface layer 90 and the heat dissipation surface 29. Next, the nano-copper Velcro is placed between the heat dissipation surface 29 of the power device 20 and the assembly surface 62 of the heat sink 60. After a certain temperature, pressure, and time (for example, a pressure of 2 MPa, a temperature of less than 100°C, and a time length of 10 minutes), it is cured to form the thermal interface layer 90. The fastener 70 is passed through the opening 41, through-hole 21, and mounting hole 91 of the circuit board 40 and fixedly connected to the connection hole 64 of the heat sink 60.

[0091] It is understandable that the thermal interface layer 90 is not limited to nano copper Velcro, and the thermal interface layer 90 can be made of other materials. For example, the thermal interface layer 90 can be a graphite thermal pad, thermal grease or thermal gel, etc.

[0092] In one embodiment, the thermal interface layer 90 includes a graphite thermal pad. During preparation, a prefabricated graphite thermal pad is first formed into a thermal interface layer 90 according to the area of ​​the power device 20, and the thermal interface layer 90 is formed with a mounting hole 91; when assembling the power device assembly 100, the thermal interface layer 90 is placed between the heat dissipation surface 29 and the heat sink 60, and the fastener 70 is passed through the opening 41 of the circuit board 40, the through hole 21, and the mounting hole 91 of the thermal interface layer 90 and fixedly connected to the connection hole 64 of the heat sink 60.

[0093] In one embodiment, the thermal interface layer 90 includes thermal grease or thermal gel. During preparation, thermal grease or thermal gel is applied to the assembly surface 62 of the heat sink 60 to form the thermal interface layer 90, and then the fastener 70 passes through the opening 41 and the through hole 21 of the circuit board 40 and is fixedly connected to the connection hole 64 of the heat sink 60.

[0094] When the power device assembly 100 is assembled, after the power device 20 is welded to the circuit board 40, it is placed on the heat sink 60 and positioned. The fastener 70 passes through the gasket 80, the circuit board 40, and the through hole 21 of the package body 201 of the power device 20, and is directly driven into the connection hole 64 of the heat sink 60. The fastener 70 applies pressure on the gasket 80, and the gasket 80 presses the circuit board 40 as a whole to achieve a close fit between the heat dissipation surface 29 of the power device 20, the thermal interface layer 90 and the heat sink 70, thereby reducing the void between the assembly surface 62 of the heat sink 60 and the heat dissipation surface 29 of the power device 20, reducing the thermal resistance between the power device 20 and the power device assembly 100, and improving the heat dissipation performance of the power device 20 and the heat dissipation efficiency of the power device assembly 100.

[0095] In the power device 20 and power device assembly 100 provided herein, surface mount technology is used to directly attach the mounting surface 2031 of the pins 203 to the circuit board 40, thereby achieving an electrical connection between the power device 20 and the circuit board 40. Since there is no need to insert the pins into component holes in the circuit board, the assembly steps between the circuit board 40 and the power device 20 are simplified, the manufacturing process of the power device assembly 100 is simplified, the processing efficiency of the power device assembly 100 is improved, and the manufacturing cost of the power device assembly 100 is reduced.

[0096] In addition, on the basis of the power device 20 using surface mount technology to achieve electrical connection with the circuit board 40, the power device 20 is provided with a through hole 21 that penetrates the plastic package 26 and the substrate structure 22, so that the fastener 70 can be directly passed through the through hole 21, and the power device 20, the circuit board 40 and the heat sink 60 are assembled together to realize the power device 20 being directly pressed onto the heat sink 60, so that the power device 20 and the heat sink 60 can be tightly fitted, effectively reducing the voids at the interface between the power device 20 and the heat sink 60, thereby reducing the thermal resistance between the power device 20 and the power device assembly 100, and improving the heat dissipation efficiency of the power device 20 and the power device assembly 100.

[0097] In addition, the power device 200 adopts surface mount technology. The pins 203 of the power device 20 can be mounted on the circuit board 40 first, and then the power device 20 and the heat sink 60 are assembled together. Since no soldering is required, it is helpful to simplify the assembly process of the power device component 100 and related devices.

[0098] See also Figure 8The power device 20 provided in the second embodiment of the present application is substantially the same as the power device 20 provided in the first embodiment, except that the substrate structure omits the heat dissipation substrate. The metal substrate 222 of the substrate structure includes a thermally conductive insulating layer 2222 and two metal layers 2224. The two metal layers 2224 are respectively arranged on opposite sides of the thermally conductive insulating layer 2222. The semiconductor wafer 24 is arranged on the side of one metal layer 2224 facing away from the thermally conductive insulating layer 2222. The plastic package 26 covers the metal substrate 222 and the semiconductor wafer 24 except for the heat dissipation surface to form the package body 201. The side of the other metal layer 2224 away from the thermally conductive insulating layer 2222 without the semiconductor wafer 24 serves as the heat dissipation surface of the power device 20. In other words, one side of the metal substrate 222 can be used directly as the heat dissipation surface, that is, the side of the metal substrate 222 provided with the semiconductor wafer 24 serves as the first surface of the substrate structure, and the side of the metal substrate 222 facing away from the semiconductor wafer 24 serves as the second surface of the substrate structure. The pin 203 can be provided in a SOP manner.

[0099] See also Figure 9 The power device 20 provided in the third embodiment of the present application is substantially the same as the power device 20 provided in the first embodiment, except that the pin 203 can be provided in an HSOP manner, and the second end of the pin 203 is exposed from the bottom 2011 of the package body 201 away from the top 2013 and extends in a direction away from the power device 20 along the stacking direction of the thermally conductive insulating layer 2222 and the metal layer 2224 of the metal substrate 222, and the orthographic projection of the pin 203 along the stacking direction is completely located on the metal substrate 222.

[0100] See also Figure 10 The power device assembly 100 provided in the fourth embodiment of the present application is substantially the same as the power device provided in the first embodiment, except that, please refer to Figure 11 The mounting surface 2031 of the pin 203 is oriented in the same direction as the side of the bottom 2011 of the package body 201 facing away from the top 2013. The heat dissipation surface 29 of the power device 20 is located on the side of the bottom 2011 of the package body 201 facing away from the top 2013. The circuit board 40 is provided with an opening 41 that passes through the top surface 43 and the bottom surface 44. That is, the circuit board 40 has a window design. The mounting surface 2031 of the pin 203 is mounted together with the top surface 43, and the heat sink 60 is provided through the opening 41. The rod 72 of the fastener 70 is provided through the through hole 21 and the mounting hole 91 of the thermal interface layer 90 and is directly fixed to the connection hole 64 of the heat sink 60. The cap body 74 is located on the side of the package body 201 facing away from the heat sink 60, that is, the cap body 74 is located on the side of the top 2013 facing away from the bottom 2011. It is understandable that the heat sink 60 may be provided with a boss that passes through the opening 41 of the circuit board 40 to achieve direct contact heat dissipation with the heat dissipation surface 29 of the power device 20 .

[0101] In this embodiment, the thermal interface layer 90 may also be omitted, and the fastener 70 is passed through the through hole 21 and directly fixed to the connecting hole 64. The fastener 70 may be a screw, a pin, a rivet, or the like.

[0102] Combining the first and fourth embodiments, the assembly method of the power device, circuit board, and heat sink can be selected based on the position of the heat dissipation surface on the power device. For example, when the heat dissipation surface is set on the top of the power device away from the bottom of the power device, the pins can be reflow-soldered to the bottom surface of the circuit board, and the circuit board does not need to be designed with a window corresponding to the heat sink (i.e., the assembly method exemplified in the first embodiment). When the heat dissipation surface is set on the bottom of the power device away from the top of the power device, the circuit board is provided with an opening, and the pins can be reflow-soldered to the top surface of the circuit board. In this way, different power devices can be combined and packaged in a variety of forms, which improves the flexibility of device arrangement.

[0103] See also Figure 12 The power device 20 provided in the fifth embodiment of the present application differs from the power device 20 provided in the first embodiment in that the heat dissipation surface 29 includes two heat dissipation surface units 290, and the gaps 2901 between adjacent heat dissipation surface units 290 are filled with the plastic encapsulation body 26. For example, when the side of the heat dissipation substrate 226 facing away from the metal substrate 222 serves as the heat dissipation surface 29, the heat dissipation substrate can be divided into two independent heat dissipation surface units 290, that is, the heat dissipation surface 29 is divided into two independent heat dissipation surface units 290. It is understood that the number of heat dissipation surface units 290 is not limited, and the number of heat dissipation surface units 290 can be two or more. That is, the heat dissipation surface 290 includes at least two heat dissipation surface units 2260, and the gaps 2901 between adjacent heat dissipation surface units 290 are filled with the plastic encapsulation body 26. The heat dissipation surface 29 includes at least two heat dissipation surface units 290, which can effectively reduce the risk of the heat dissipation surface 29 being too large and easily damaged or broken by stress. In one embodiment, the substrate structure includes a metal substrate and omits a heat dissipation substrate. A layer of the metal substrate facing away from the semiconductor wafer serves as a heat dissipation surface. The side of the metal substrate facing away from the semiconductor wafer can be divided into at least two heat dissipation surface units to alleviate the risk of the heat dissipation surface being too large and easily fractured by mechanical stress.

[0104] See also Figure 13The power device provided in the sixth embodiment of the present application differs from the power device provided in the first embodiment in that the metal substrate 222 includes two mounting units 2220, with a gap provided between the two mounting units 2220, which can be filled with a plastic package 26. In this embodiment, each mounting unit 2220 has two metal layers 2224, with a thermally conductive insulating layer 2222 sandwiched between the two metal layers 2224. A semiconductor die 24 is provided on the side of one of the metal layers 2224 of each mounting unit 2220 facing away from the thermally conductive insulating layer 2222. Since adjacent mounting units 2220 are insulated by the plastic package 26, this helps improve the reliability of the power device. It is understood that the number of mounting units 2220 can be adjusted based on the function of the semiconductor die 24, etc. The metal substrate 222 includes at least two mounting units 2220, and the number of semiconductor die 24 is at least two, with each mounting unit 2220 having at least one semiconductor die 24.

[0105] The present application also provides an assembly method for the power device assembly 100 described above (first to sixth embodiments). The power device assembly 100 includes a power device 20, a circuit board 40, and a heat sink 60. The power device 20 includes a package body 201 and a plurality of pins 203. The package body 20 includes a substrate structure 22, a semiconductor wafer 24, and a plastic package body 26. The substrate structure 22 includes a heat dissipation surface 29. The plastic package body 26 covers the substrate structure 22 and the semiconductor wafer 24 except for the heat dissipation surface 29. The first end of the pin 203 is fixed to the substrate structure 22, and the second end of the pin 203 and the heat dissipation surface 29 are exposed from the plastic package body 26. The second end of the pin 203 includes a mounting surface 2031. The package body 201 is also provided with a through hole 21 that passes through the substrate structure 22 and the plastic package body 26. The inner wall of the through hole 21 is covered with the plastic package body 26. The circuit board 40 is provided with an opening 41. The heat sink 60 includes an assembly surface 62. The assembly surface 62 is provided with a connection hole 64. Please refer to Figure 14 , the assembly method comprises the following steps:

[0106] Step 103: Mount the mounting surface 2031 of the pin 203 on the circuit board 40. In this embodiment, the mounting surface 2031 is mounted on the circuit board 40 by a reflow process.

[0107] In step 105 , the fastener 70 is passed through the through hole 21 , the opening 41 and the connecting hole 64 to securely connect the heat dissipation surface 29 to the assembly surface 62 .

[0108] Specifically, the package body 201 includes a bottom 2011 and a top 2013 disposed opposite each other. The mounting surface 2031 is oriented in the same direction as the side of the bottom 2011 facing away from the top 2013. The heat dissipation surface 29 is located on the side of the top 2013 facing away from the bottom 2011. Fasteners 70 are inserted through the through-hole 21, the opening 41, and the connecting hole 64. This includes sequentially inserting the fasteners 70 through the opening 41, the through-hole 21, and the connecting hole 64, so that the circuit board 40, the package body 201, and the heat sink 60 are stacked in sequence.

[0109] The fastener 70 includes a rod body 72 and a cap body 74 fixed to one end of the rod body 72, and the fastener 70 is sequentially inserted into the opening 41, the through hole 21 and the connecting hole 64. The rod body 72 is inserted into the opening 41, the through hole 21 and the connecting hole 64, and the circuit board 40 is clamped between the cap body 74 and the side of the packaging body 201 facing away from the heat sink 60. The cap body 74 is located on the side of the circuit board 40 facing away from the packaging body 201.

[0110] Before mounting the mounting surface 2031 of the pin 203 of the power device 20 on the circuit board 40, the assembly method further includes providing a thermal interface layer 90 between the heat dissipation surface 29 and the assembly surface 62, wherein the thermal interface layer 90 has mounting holes 91 extending therethrough. Fasteners 70 are inserted through the through-hole 21, the opening 41, and the connection hole 64, and further include inserting the fasteners 70 through the mounting holes 91. The thermal interface layer 90 includes one of nano-copper Velcro, a graphite thermal pad, a thermal grease layer, and a thermal gel.

[0111] In one embodiment, the mounting surface 2031 is oriented in the same direction as the bottom 2011 facing away from the top 2013, and the heat dissipation surface 29 is located on the side of the bottom 2011 facing away from the top 2013. Fasteners 70 are inserted through the through-hole 21, the opening 41, and the connecting hole 64. Furthermore, the heat sink 60 is inserted through the opening 21, and the fasteners 70 are sequentially inserted through the through-hole 21 and the connecting hole 64, with the package body 201 and the heat sink 60 being stacked.

[0112] See also Figure 15 The present application provides another method for assembling a power device assembly 100, the method comprising the following steps:

[0113] Step 201 : Dispose a thermal interface layer 90 between the heat dissipation surface 29 and the assembly surface 62 .

[0114] Step 203 , mounting the mounting surface 2031 of the pin 203 on the circuit board 40 .

[0115] In step 205, fasteners 70 are sequentially fixedly inserted through gasket 80, opening 41, through-hole 21, mounting hole 91, and connection hole 64. Gasket 80, circuit board 40, package body 201, thermal interface layer 90, and heat sink 60 are sequentially stacked. Package body 201 includes a bottom 2011 and a top 2013 that are positioned opposite each other. Mounting surface 2031 is oriented in the same direction as the side of bottom 2011 facing away from top 2013. Heat dissipation surface 29 is located on the side of top 2013 facing away from bottom 2011.

[0116] The fastener 70 includes a rod 72 and a cap 74 fixed to one end of the rod 72. The aperture 41 has a diameter that matches the rod 72. A washer 80 is sandwiched between the circuit board 40 and the cap 74, with the cap 74 located on the side of the washer 80 facing away from the circuit board 40.

[0117] In one embodiment, the opening 41 of the circuit board 40 has a relatively large diameter. The heat sink 60 is inserted into the opening 21. The mounting surface 2031 is oriented in the same direction as the bottom 2011, facing away from the top 2013. The heat dissipation surface 29 is located on the side of the bottom 2011 facing away from the top 2013. The gasket 80 is sandwiched between the side of the package body 201 facing away from the heat sink 60 and the cap 74. The cap 74 is located on the side of the gasket 80 facing away from the package body 201. The cap 74, gasket 80, package body 201, thermal interface layer 90, and heat sink 60 are stacked in this order.

[0118] In one embodiment, the thermal interface layer 90 includes nano copper Velcro. Figure 16 , the assembly method of the power device assembly 100 comprises the following steps:

[0119] Step 301: A film layer is plated and deoxidized on the assembly surface 62. The film layer is a metal layer, which includes at least one of nickel, copper, silver, gold, and palladium. The material of the metal layer is not limited in this embodiment.

[0120] Step 303 : Deoxidize the heat dissipation surface 29 .

[0121] Step 305 , providing a thermal interface layer 90 between the heat dissipation surface 29 and the assembly surface 62 , including providing nano-copper Velcro between the heat dissipation surface 29 and the assembly surface 62 and curing to form the thermal interface layer 90 , wherein the thermal interface layer 90 is provided with a mounting hole 91 passing through the thermal interface layer 90 .

[0122] Step 307 , mounting the mounting surface 2031 of the pin 203 on the circuit board 40 .

[0123] In step 309 , the fastener 70 is fixedly inserted through the through hole 41 , the opening 21 , the mounting hole 91 and the connecting hole 64 , so as to securely connect the power device 20 , the circuit board 40 and the heat sink 60 .

[0124] In one embodiment, the thermal interface layer includes a graphite thermal pad. Figure 17 , the assembly method of the power device assembly 100 comprises the following steps:

[0125] In step 401 , a graphite thermal pad is prefabricated to form a thermal interface layer 90 , wherein the thermal interface layer 90 is formed with a mounting hole 91 penetrating the thermal interface layer 90 .

[0126] Step 403 : Dispose a thermal interface layer 90 between the heat dissipation surface 29 and the assembly surface 62 .

[0127] Step 405 , mounting the mounting surface 2031 of the pin 203 on the circuit board 40 .

[0128] In step 407 , the fastener 70 is fixedly passed through the through hole 21 , the opening 41 , the mounting hole 91 and the connecting hole 64 , so that the power device 20 , the circuit board 40 and the heat sink 60 are fixedly connected.

[0129] In one embodiment, a thermal interface layer 90 is provided between the heat dissipation surface 29 and the assembly surface 64 , including coating thermal grease or thermal gel on the assembly surface 62 to form the thermal interface layer 90 .

[0130] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0131] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0132] In this application, expressions including ordinal numbers such as "first" and "second" may modify various elements. However, such elements are not limited by the above expressions. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used to distinguish one element from other elements. For example, a first user device and a second user device indicate different user devices, even though the first user device and the second user device are both user devices. Similarly, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0133] When a component is referred to as being "connected" or "accessed" to another component, it should be understood that the component is not only directly connected to or accessed to the other component, but also that another component may exist between the component and the other component. On the other hand, when a component is referred to as being "directly connected to" or "directly accessed" to another component, it should be understood that no component exists between them.

[0134] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A power device, characterized in that: including a package body and a plurality of pins; The package body includes a substrate structure, a semiconductor wafer and a plastic package. The semiconductor wafer is arranged on the substrate structure. The substrate structure includes a heat dissipation surface for connecting to a heat sink. The heat dissipation surface includes at least two separately arranged heat dissipation surface units. The gap between adjacent heat dissipation surface units is filled with the plastic package. The first end of the pin is fixed to the substrate structure. The plastic package covers the substrate structure and the semiconductor wafer except for the heat dissipation surface. The second end of the pin and the heat dissipation surface are exposed from the plastic package. The second end includes a mounting surface. The power device is further provided with a through hole passing through the substrate structure and the plastic package body, the inner wall of the through hole is covered with the plastic package body, the through hole is used to pass through a fastener, and the fastener is used to pass through the through hole of the power device to fix the heat dissipation surface of the power device to the radiator; The package body includes a bottom, a top and a side, the top is arranged opposite to the bottom, the side of the bottom facing away from the top is used to be arranged towards the circuit board, the heat dissipation surface is arranged on the side of the top facing away from the bottom or the side of the bottom facing away from the top, the side is connected between the top and the bottom, the orientation of the bottom is the same as the orientation of the mounting surface, a plurality of pins are distributed along the side, the mounting surface of the pins extends from the side to the bottom, and the mounting surface is used to be mounted on the top surface of the circuit board or the bottom surface of the circuit board.

2. The power device according to claim 1, wherein: The substrate structure includes a first surface and a second surface that are oppositely arranged. The semiconductor wafer is arranged on the first surface of the substrate structure, and the heat dissipation surface is located on the second surface of the substrate structure.

3. The power device according to claim 2, characterized in that The substrate structure includes a metal substrate, which includes a stacked thermal insulation layer and a metal layer. The semiconductor wafer is arranged on the side of the metal layer away from the thermal insulation layer. The through hole passes through the thermal insulation layer and the metal layer. The first end of the pin is fixed on the metal layer.

4. The power device according to claim 2, wherein: The substrate structure includes a metal substrate, which includes a heat-conducting insulating layer and two metal layers. The heat-conducting insulating layer is sandwiched between the two metal layers. The semiconductor wafer is arranged on a side of one of the metal layers away from the heat-conducting insulating layer.

5. The power device according to claim 3 or 4, characterized in that: The substrate structure further includes a heat dissipation substrate, which is fixed to a side of the metal substrate facing away from the semiconductor wafer, and the heat dissipation surface is located on a side of the heat dissipation substrate facing away from the metal substrate.

6. The power device according to claim 3, characterized in that The heat dissipation surface is located on a side of the metal substrate facing away from the semiconductor wafer.

7. A power device assembly, characterized in that: The invention comprises a power device, a circuit board, a heat sink and a fastener according to any one of claims 1 to 6, wherein the mounting surface of the second end of the pin of the power device is mounted together with the circuit board to achieve electrical connection, the circuit board is provided with an opening passing through the circuit board, the heat sink includes an assembly surface, the assembly surface is provided with a connection hole, and the fastener is passed through the opening, the through hole of the power device and the connection hole, thereby fixedly connecting the heat dissipation surface of the power device to the assembly surface.

8. The power device assembly according to claim 7, characterized in that: The heat dissipation surface is located on a side of the top away from the bottom, the fasteners penetrate the openings, the through holes and the connecting holes in sequence, and the circuit board, the packaging body and the heat sink are stacked in sequence.

9. The power device assembly according to claim 8, characterized in that: The fastener includes a rod body and a cap body fixed to one end of the rod body, the rod body is fixedly inserted into the opening, the through hole and the connecting hole, the circuit board is clamped between the cap body and a side of the packaging body facing away from the radiator, and the cap body is located on the side of the circuit board facing away from the packaging body.

10. The power device assembly according to claim 7, characterized in that: The heat dissipation surface is located on a side of the bottom away from the top, the radiator is penetrated through the opening, the fasteners penetrate the through holes and the connecting holes in sequence, and the packaging body and the radiator are stacked.

11. The power device assembly according to claim 10, characterized in that: The fastener includes a rod body and a cap body fixed to one end of the rod body, the rod body is fixedly inserted into the through hole, the opening and the connecting hole, the packaging body is clamped between the cap body and the heat dissipation surface, and the cap body is located on the side of the packaging body away from the radiator.

12. The power device assembly according to any one of claims 7 to 11, characterized in that: The power device assembly further includes a thermal interface layer, the thermal interface layer is provided with a mounting hole penetrating the thermal interface layer, the thermal interface layer is sandwiched between the heat dissipation surface and the heat sink, and the fastener is passed through the mounting hole.

13. The power device assembly according to claim 12, characterized in that: The thermal interface layer includes one of a graphite thermal pad, a nano-copper Velcro, a thermal grease layer, and a thermal gel.

14. An electric energy conversion device, characterized in that: Comprising a power device assembly according to any one of claims 7 to 13.

15. An electric energy conversion device, characterized in that: Comprising the electric energy conversion device according to claim 14.

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