CN116314066A - A kind of power device and power module - Google Patents

Abstract

The application provides a power equipment and power module, power equipment includes: the power module is arranged on the circuit board, and the radiator is arranged on one surface of the power module, which is away from the circuit board; the power module includes: a metal-clad substrate, a chip and a plastic package body; the metal-clad substrate and the chip are arranged in a lamination manner and are encapsulated in a plastic package body; the plastic package body comprises a concave part; the concave part is arranged on one surface of the plastic package body, which is away from the radiator, and is positioned between the surface of the plastic package body, which is away from one surface of the radiator, and the circuit board, so that a stress release space is formed between the circuit board and the plastic package body, and the projection of the concave part in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module. The power equipment provided by the application improves the heat dissipation efficiency and the safety of the power equipment.

Description

A kind of power device and power module

technical field

The present application relates to the field of electronic power technology, and in particular to a power device and a power module.

Background technique

In recent years, green energy has developed day by day and has gradually become the main means to solve the energy crisis. Power modules are widely used as the core components of green energy. The Intelligent Power Module (IPM: Intelligent Power Module) integrates logic, control, detection and protection circuits, which is convenient to use, not only reduces the size of the system and development time, but also greatly enhances the reliability of the system, adapting to today's power The development direction of the device has been more and more widely used in the field of power electronics.

First of all, when the chip in the power module fails to release the stress and causes a short circuit, it is easy to cause the insulation failure and leakage of the device shell and chip, causing safety problems; Increase the withstand voltage value of the power module to be suitable for high-voltage miniaturization scenarios; finally, as the power of the current power module is getting higher and higher, the heat dissipation capacity needs to be improved urgently. The above-mentioned problems of the power module seriously restrict the development of the new energy industry, so the industry needs a new type of power module to continue to promote the progress of the industry.

Contents of the invention

The present application provides a power device and a power module. In this application, the power module in the power device is improved, so that the structural safety, pressure resistance and heat dissipation of the entire power device are improved. First, add a recessed part to the corresponding position of the plastic package under the chip, thereby forming a weak point on the plastic package under the chip, so that it is easier to release from the weak point when the chip fails to generate stress, without damaging the metal-clad above the chip layer substrate, which reduces the short circuit between the heat sink and the chip due to the cracking of the insulating layer in the metal-clad substrate and causes serious safety problems; secondly, by adding a high thermal conductivity between the metal-clad substrate and the chip of the power module The special heat sink improves the structural strength between the metal-clad substrate and the chip, making it easier for the stress of the chip to be released from the concave part of the plastic package under the chip, and also enhances the heat dissipation performance of the power module; again, in the plastic package The first groove is added to the edge of the body close to the metal-clad substrate, so that the power module increases the creepage distance between the pin and the heat sink without increasing the thickness of the plastic package, ensuring that the volume of the power module is small. change and the manufacturing cost does not increase; finally, a second groove is provided in the opposite position of the first groove in the plastic package. The risk of cracks at the corresponding positions of the second groove due to crimping of the heat sink can be reduced.

For this reason the embodiment of the application adopts following technical scheme:

In a first aspect, the embodiment of the present application provides a power device. The power equipment includes: a circuit board, a power module, and a radiator, the power module is arranged on the circuit board, and the radiator is arranged on the side of the power module away from the circuit board; the power module The set includes a metal-clad substrate, a chip, and a plastic package; the metal-clad substrate is laminated with the chip and is plastic-packed in the plastic package; the plastic package includes a recess, and the recess is arranged on the The side of the plastic package away from the heat sink is located between the surface of the plastic package away from the side of the heat sink and the circuit board, so as to form a stress relief space between the circuit board and the plastic package, and the recess The projection in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module.

It can be understood that the recessed part added in the plastic package provides a relatively weak position for the power module, and the stress generated by the guide chip is released from the recessed part without damaging the insulating layer in the metal-clad substrate. Reduces the possibility of shorting the chip to the heat sink. Effectively improve the structural stability and safety of the power module, that is, improve the stability and safety of the power equipment.

With reference to the first aspect, in a first possible implementation manner, the power module in the power device further includes a heat sink, and the heat sink is disposed between the metal-clad substrate and the chip, The thickness of the heat sink in the power module is greater than the thickness of the metal layer in the metal-clad substrate, and the projection of the heat sink in the thickness direction of the power module covers the chip on the In the projection on the thickness direction of the power module, the area of the heat sink is larger than the area of the chip. Generally, the length and width of the projection of the heat sink in the thickness direction of the power module are respectively greater than the length and width of the projection of the chip in the thickness direction of the power module by more than 1 mm. It can be understood that the added heat sink makes up for the problem that the metal-clad substrate can bear poor stress due to the thin metal layer, thereby enhancing the structural strength between the metal-clad substrate and the chip in the power module, and the thermal The sinker and the concave part cooperate with each other, so that the stress of the chip can be released from the concave part more easily, thereby reducing the occurrence of the short circuit between the chip and the heat sink due to damage to the insulating layer in the metal-clad substrate, and improving the safety of the power module This improves the safety of power equipment. At the same time, due to the high thermal conductivity of the heat sink, each part of the chip can be fully in contact with the heat sink to maximize the use of the heat dissipation area, thereby further enhancing the thermal conductivity of the power module and improving the efficiency of the power module. The power density of the group increases, which increases the power output of the power device.

With reference to the first aspect, in a second possible implementation manner, the power module in the power device further includes a first groove and pins, and the first groove is arranged on the plastic package near the heat sink. One side of the heat sink, and located between the plastic package and the heat sink, forming a recessed space facing the heat sink, the first groove can increase the creepage between the pin and the heat sink distance; the first part of the pins is arranged in the plastic package, and generally, the power module is arranged on the circuit board by using the second part of the pins in a surface-mount or in-line manner. It can be understood that the recessed space formed by the first groove increases the surface wrinkle degree of the plastic package and prolongs the surface length of the plastic package, thus increasing the distance between the pin and the heat sink. creepage distance.

With reference to the first aspect, in a third possible implementation manner, the power module in the power device further includes a second groove, and the second groove is disposed on a side of the plastic package facing away from the heat sink , and is located between the plastic package and the circuit board, and extends along the surface of the circuit board to form a flat space facing the pin opening. Generally, the second groove is arranged opposite to the first groove, and the projection of the second groove in the thickness direction of the power module covers the first groove in the thickness direction of the power module. projection in the direction. It can be understood that the second groove added to the relative position of the first groove in the plastic package can reduce the risk of cracks at the corresponding position of the second groove due to crimping of the heat sink.

With reference to the first aspect, in a fourth possible implementation manner, the metal-clad substrate includes a first metal layer, a second metal layer, and an insulating layer, and the second metal layer is disposed on the insulating layer close to the On one side of the chip, the thickness of the heat sink is greater than the thickness of the second metal layer. Generally, the thickness of the heat sink is more than twice the thickness of the second metal layer. Generally, the metal-clad substrate is a copper-clad ceramic substrate (Direct Bond Copper, DBC), an active metal brazed copper substrate (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) or an insulating metal Substrate (Insulated metal substrate, IMS), etc. Exemplarily, in order to further increase the power density, the metal-clad substrate may be formed of AlN-DBC, Si3N4-AMB or AlN-AMB with high thermal conductivity, which is not limited herein. It can be understood that making the heat sink exceed the thickness of the first metal layer can improve the heat dissipation efficiency of the heat sink, and at the same time further enhance the strength between the chip and the metal-clad substrate, reducing the stress caused by chip failure and damage to the metal-clad substrate The problem of the insulation layer in the middle, improve the safety of the power equipment.

With reference to the first aspect, in a fifth possible implementation manner, the included angle between the side wall of the first groove and the thickness direction of the power module is not zero, and the width of the bottom of the first groove is smaller than the The top width of the first groove, for example, the first groove is a trapezoidal structure. Generally, the included angle between the side wall of the first groove and the thickness direction of the power module is greater than or equal to 10 degrees, the distance from the top of the first groove to the top of the plastic package, the depth of the first groove and the The width of the bottom of the groove is not less than 1 mm, and the first groove may have two side walls or one side wall. It can be understood that the trapezoidal structure is more stable than the vertical structure, which can effectively improve the damage resistance of the power module, and also improve the reliability and safety of the power equipment.

With reference to the first aspect, in a sixth possible implementation manner, the first groove is a vertical structure. It can be understood that, compared with the trapezoidal structure, the vertical structure can effectively increase the surface length of the first groove, which also increases the creepage distance between the pin and the heat sink, and improves the voltage that the power module can withstand , which increases the maximum voltage that the power equipment can withstand.

With reference to the first aspect, in a seventh possible implementation manner, the sidewall of the first groove is provided with at least one stepped tooth. It can be understood that increasing the stepped teeth can effectively increase the surface length of the first groove, which also increases the creepage distance between the pin and the heat sink. At the same time, the more the stepped teeth, the longer the creepage distance, and the power The greater the voltage the module can withstand.

With reference to the first aspect, in an eighth possible implementation manner, the first groove includes at least one sub-groove. It can be understood that the surface length of the first groove can be effectively increased by setting the sub-grooves, which increases the creepage distance between the pin and the heat sink, and the more the number of sub-grooves, the greater the creepage distance. The longer the voltage, the greater the voltage the power module can withstand.

With reference to the first aspect, in a ninth possible implementation manner, the first groove is disposed on an edge of a side of the plastic package close to the metal-clad substrate. Generally, the first groove can be disposed on one side, two sides, three sides or four sides of the plastic package close to the side of the metal-clad substrate.

With reference to the first aspect, in a tenth possible implementation manner, the power module further includes bonding wires or interconnection sheets, and the chip is electrically connected to the pins through the bonding wires or interconnection sheets, so The above pins are gull-wing or in-line.

With reference to the first aspect, in an eleventh possible implementation manner, the width of the bottom of the depression is smaller than the width of the top of the depression. Generally, the included angle between the side wall of the recess and the thickness direction of the power module is greater than or equal to 10 degrees. The length and width of the projection of the concave portion in the thickness direction of the power module are respectively greater than the length and width of the projection of the chip in the thickness direction of the power module by more than 1 mm. At the same time, the depth of the depression is greater than or equal to 0.2 mm, and the distance between the bottom of the depression and the arc top of the bonding wire or interconnection is greater than or equal to 0.5 mm. It can be understood that the trapezoidal structure is more stable than the vertical structure, which can effectively improve the damage resistance of the power module, and also improve the reliability and safety of the power equipment.

With reference to the first aspect, in a twelfth possible implementation manner, the width of the bottom of the second groove is smaller than the width of the top of the second groove. Generally, the included angle between the side wall of the second groove and the thickness direction of the power module is greater than or equal to 10 degrees. The depth of the second groove is greater than or equal to 0.2mm.

With reference to the first aspect, in a thirteenth possible implementation manner, the heat sink in the power device is disposed on the side of the metal-clad substrate facing away from the chip by welding or sintering. Generally, heat dissipation channels are provided inside the radiators, and the heat dissipation channels have water inlets and water outlets. The cooling liquid enters the heat dissipation channel inside the radiator through the water inlet, absorbs the heat of the radiator, and finally flows out through the water outlet to take away all the heat. It can be understood that the heat sink can absorb the heat transferred from the metal-clad substrate, so as to reduce the temperature of the power module and further reduce the temperature of the power device.

With reference to the first aspect, in a fourteenth possible implementation manner, the side of the metal-clad substrate facing away from the chip is on the same plane as the side of the plastic package close to the heat sink. It can be understood that the above arrangement can make the radiator and the metal layer of the metal-clad substrate adhere smoothly, improve the heat dissipation performance of the power module, and also improve the heat dissipation performance of the power device.

With reference to the first aspect, in a fifteenth possible implementation manner, the metal-clad substrate, the heat sink, and the chip are sequentially stacked by welding or sintering.

With reference to the first aspect, in a sixteenth possible implementation manner, the heat sink in the power module has high thermal conductivity and high electrical conductivity. The high thermal conductivity can conduct the heat generated by the chip during operation to the heat sink, and the high electrical conductivity can meet the internal current flow requirement of the chip during operation and provide a channel for internal current flow. The material of the heat sink includes but not limited to Cu, CuMo composite material, diamond, diamond-copper composite material, Al-SiC composite material and other materials with high thermal conductivity. It can be understood that the heat sink is made of a material with high thermal conductivity and high conductivity, which can not only improve the heat dissipation performance of the chip, but also provide a current channel for the chip, thereby improving the heat dissipation performance of the power module, and further improving the heat dissipation performance of the chip. The power density of the power module.

With reference to the first aspect, in a seventeenth possible implementation manner, there are multiple chips in the power module. Generally, the recessed part can be set according to the number of chips in the power module, and the recessed part can be provided with at least one sub-region, and each sub-region of the recessed part corresponds to at least one chip. Generally, the chip includes an insulated gate bipolar transistor chip, an insulated gate bipolar transistor chip and a diode chip packaged chip, a silicon metal oxide semiconductor field effect transistor, a silicon carbide metal oxide semiconductor field effect transistor, a nitride Power semiconductor chips such as gallium metal oxide semiconductor field effect transistors or IC driver chips, etc.

In a second aspect, the embodiment of the present application provides a power module. The power module includes: a metal-clad substrate, a chip, and a plastic package; the metal-clad substrate is laminated with the chip and is plastic-packed in the plastic package; the plastic package includes a recess; the recess The part is arranged on the side of the plastic package away from the metal-clad substrate, and the projection of the recessed part in the thickness direction of the power module covers the chip in the thickness direction of the power module, so that in the A stress release part is formed on the plastic package of the chip on the side away from the metal-clad substrate.

It can be understood that the recessed part added in the plastic package provides a relatively weak position for the power module, and the stress generated by the guide chip is released from the recessed part without damaging the insulating layer in the metal-clad substrate. Reduces the possibility of shorting the chip to the heat sink. Effectively improve the heat dissipation efficiency, structural stability and safety of the power module.

With reference to the second aspect, in a first possible implementation manner, the thickness of the heat sink in the power module is greater than the thickness of the metal layer in the metal-clad substrate, and the heat sink in the The projection in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module, and the area of the heat sink is larger than the area of the chip. Generally, the length and width of the projection of the heat sink in the thickness direction of the power module are respectively greater than the length and width of the projection of the chip in the thickness direction of the power module by more than 1mm. It can be understood that the added heat sink makes up for the problem that the metal-clad substrate can bear poor stress due to the thin metal layer, thereby enhancing the structural strength between the metal-clad substrate and the chip in the power module, and the thermal The sinker and the concave part cooperate with each other, so that the stress of the chip can be released from the concave part more easily, thereby reducing the problem of short circuit between the chip and the heat sink due to damage to the insulating layer in the metal-clad substrate, and improving the safety of the power module. The safety of the power equipment is also improved. At the same time, due to the high thermal conductivity of the heat sink, each part of the chip can be fully in contact with the heat sink to maximize the use of the heat dissipation area, thereby further enhancing the thermal conductivity of the power module and improving the efficiency of the power module. The power density of the group increases, which increases the power output of the power device.

With reference to the second aspect, in a second possible implementation manner, the power module further includes: a first groove and pins, and the first groove is arranged on the plastic package close to the metal-clad substrate one side of the plastic package to form a recessed area on the side of the plastic package close to the metal-clad substrate, the first groove can increase the creepage distance between the pin and the heat sink; the first groove of the pin can increase the creepage distance between the pin and the radiator; A part is arranged in the plastic package, and generally, the power module is arranged on the circuit board by using the second part of the pins in a surface-mount or in-line manner. It can be understood that the power module also includes: the concave area formed by the first groove increases the surface wrinkle degree of the plastic package and prolongs the surface length of the plastic package, so the first concave The slots can increase the creepage distance between the pins and the heat sink.

With reference to the second aspect, in a third possible implementation manner, the power module further includes: a second groove, the second groove is disposed on a side of the plastic package facing away from the heat sink, and along the The plastic package body extends away from the side of the metal-clad substrate to form a flat space facing the pin opening. Generally, the second groove is arranged opposite to the first groove, and the projection of the second groove in the thickness direction of the power module covers the first groove in the thickness direction of the power module. projection in the direction. It can be understood that the second groove added to the relative position of the first groove in the plastic package can reduce the risk of cracks at the corresponding position of the second groove due to crimping of the heat sink.

In combination with the second aspect, in a fourth possible implementation manner, the included angle between the side wall of the first groove and the thickness direction of the power module is not zero, and the width of the bottom of the first groove is smaller than that of the first groove. A groove top width, for example, the first groove is a trapezoidal structure. Generally, the included angle between the side wall of the first groove and the thickness direction of the power module is greater than or equal to 10 degrees, the distance from the top of the first groove to the top of the plastic package, the depth of the first groove and the The width of the bottom of the groove is not less than 1 mm, and the first groove may have two side walls or one side wall. It can be understood that the trapezoidal structure is more stable than the vertical structure, and can effectively improve the damage resistance of the power module.

With reference to the second aspect, in a fifth possible implementation manner, the first groove is a vertical structure. It can be understood that, compared with the trapezoidal structure, the vertical structure can effectively increase the surface length of the first groove, which also increases the creepage distance between the pin and the heat sink, and improves the voltage that the power module can withstand .

With reference to the second aspect, in a sixth possible implementation manner, the sidewall of the first groove is provided with at least one stepped tooth. It can be understood that increasing the stepped teeth can effectively increase the surface length of the first groove, which also increases the creepage distance between the pin and the heat sink. At the same time, the more the stepped teeth, the longer the creepage distance, and the power The greater the voltage the module can withstand.

With reference to the second aspect, in a seventh possible implementation manner, the first groove includes at least one sub-groove. It can be understood that the surface length of the first groove can be effectively increased by setting the sub-grooves, which increases the creepage distance between the pin and the heat sink, and the more the number of sub-grooves, the greater the creepage distance. The longer the voltage, the greater the voltage the power module can withstand.

With reference to the second aspect, in an eighth possible implementation manner, the first groove is disposed on an edge of a side of the plastic package close to the metal-clad substrate. Generally, the first groove can be disposed on one side, two sides, three sides or four sides of the plastic package close to the side of the metal-clad substrate.

With reference to the second aspect, in a ninth possible implementation manner, the width of the bottom of the depression is smaller than the width of the top of the depression. Generally, the included angle between the side wall of the recess and the thickness direction of the power module is greater than or equal to 10 degrees. The length and width of the projection of the concave portion in the thickness direction of the power module are respectively greater than the length and width of the projection of the chip in the thickness direction of the power module by more than 1mm. At the same time, the depth of the depression is greater than or equal to 0.2 mm, and the distance between the bottom of the depression and the arc top of the bonding wire or interconnection is greater than or equal to 0.5 mm. It can be understood that the trapezoidal structure is more stable than the vertical structure, and can effectively improve the damage resistance of the power module.

With reference to the second aspect, in a tenth possible implementation manner, the width of the bottom of the second groove is smaller than the width of the top of the second groove. Generally, the included angle between the side wall of the second groove and the thickness direction of the power module is greater than or equal to 10 degrees. The depth of the second groove is greater than or equal to 0.2mm.

With reference to the second aspect, in an eleventh possible implementation manner, there are multiple chips in the power module. Generally, the recessed part can be set according to the number of chips in the power module, and the recessed part can be provided with at least one sub-region, and each sub-region of the recessed part corresponds to at least one chip. Generally, the chip includes an insulated gate bipolar transistor chip, an insulated gate bipolar transistor chip and a diode chip packaged chip, a silicon metal oxide semiconductor field effect transistor, a silicon carbide metal oxide semiconductor field effect transistor, a nitride Power semiconductor chips such as gallium metal oxide semiconductor field effect transistors or IC driver chips, etc.

With reference to the second aspect, in a twelfth possible implementation manner, the side of the metal-clad substrate facing away from the chip is on the same plane as the side of the plastic package close to the heat sink. It can be understood that the above arrangement can make the radiator and the metal layer of the metal-clad substrate adhere smoothly, improve the heat dissipation performance of the power module, and also improve the heat dissipation performance of the power device.

In a third aspect, the embodiment of the present application provides a method for manufacturing a power module, the method includes:

Step 1: Laminate the metal-clad substrate, heat sink, and chips sequentially by welding or sintering;

The second step: plastic sealing, using a plastic package to seal the metal-clad substrate, the heat sink, and the chip, the plastic package includes a depression; the depression is arranged on the plastic package away from the cover On one side of the metal layer substrate, the projection of the recessed portion in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module.

With reference to the third aspect, in a first possible implementation manner, the plastic package further includes a first groove, and the first groove is arranged on a side of the plastic package close to the metal-clad substrate, and the The first groove can increase the creepage distance between the pins in the power module and the heat sink.

With reference to the third aspect, in a second possible implementation manner, the plastic package further includes a second groove, the second groove is provided on a side of the plastic package away from the heat sink, and the second The projection of the groove in the thickness direction of the power module covers the projection of the first groove in the thickness direction of the power module.

With reference to the third aspect, in a third possible implementation manner, after the first step, the manufacturing method further includes: welding or sintering the chip to the power module by using the bonding wire or the interconnect sheet. The pins in the group are electrically connected.

With reference to the third aspect, in a fourth possible implementation manner, after the second step, the manufacturing method further includes: stamping the pins so that the pins form a gull-wing shape or an in-line shape .

In a fourth aspect, an embodiment of the present application provides a power conversion circuit, wherein the power conversion circuit includes: a capacitor and at least one power module, the power module is electrically connected to the capacitor, and the capacitor It is used to provide voltage for the power module, and the at least one power module is used for AC/DC conversion. Wherein, the power module further includes: a metal-clad substrate, a heat sink, a chip, and a plastic package; the metal-clad substrate, the heat sink, and the chip are sequentially stacked and packaged in the plastic package The plastic package includes a concave portion; the concave portion is arranged on the side of the plastic package away from the metal-clad substrate, and the projection of the concave portion in the thickness direction of the power module covers the chip on the The projection in the thickness direction of the above power module. It can be understood that the power conversion circuit includes the power module as in the application embodiment of the first aspect. Since the power module has good heat dissipation and higher power density, the motor driver can be improved. power conversion efficiency.

Description of drawings

FIG. 1 is a schematic structural diagram of a power device provided in Embodiment 1;

Fig. 2A is a schematic structural diagram of a power module provided by Embodiment 1;

Fig. 2B is a perspective view of a power module structure provided by Embodiment 1;

Fig. 3 is a schematic structural diagram of another power module provided by Embodiment 1;

Fig. 4 is a schematic structural diagram of another power module provided by Embodiment 1;

Fig. 5 is a schematic structural diagram of another power module provided by Embodiment 1;

6A-6C are front views of a power module structure provided by Embodiment 1;

Fig. 7 is a manufacturing method of a power module provided by the second embodiment.

Reference signs:

Plastic package-1, recessed part 1-1, sub-region 1-1-1, first groove 1-2, stepped teeth 1-2-1, sub-groove 1-2-2, second groove 1- 3. Metal-clad substrate 2, first metal plate 2-1, second metal plate 2-2, insulating layer 2-3, heat sink 3, chip 4, pin 5, bonding wire 6, heat sink 7 , circuit board 8, power module 9.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

Power modules play an important role in power equipment, and are the core components of power equipment in the fields of new energy vehicles and smart photovoltaics. When the power device is working, the power module realizes the conversion of AC/DC power through frequent on and off state switching. However, frequent state switching will bring a lot of heat to the power module, and high temperature will cause the conversion efficiency of the power chip in the power module to decrease or even be damaged. Development in the direction of high voltage, such as high-voltage fast charging of new energy vehicles, smart photovoltaic high-voltage power generation, etc. Therefore, timely exporting the heat generated by the power module in the high-voltage working state, reducing the temperature of the power module in the working state, improving the withstand voltage value of the power module, and maintaining the long-term stable operation of the power module has always been the research of the industry. the key of.

The current power module has many problems. First, in order to improve the heat dissipation efficiency, the current industry first attaches a three-layer structure substrate on the chip, such as a copper-clad ceramic substrate (Direct Bond Copper, DBC) before installing a heat sink or heat sink. , active metal brazed copper (AMB, such as Al2O3-AMB, Si3N4-AMB or AlN-AMB) or insulated metal substrate (Insulated metal substrate, IMS), etc., the upper and lower layers of the three-layer substrate are conductive and thermally conductive materials , the lower layer close to the power chip can not only provide a channel for the internal current flow of the power chip, but also timely export the heat generated by the power chip, and the upper layer close to the heat sink can mainly provide protection for the power chip and reduce the external environment of the power chip. The impact of the impact, and the middle layer is an insulating layer, which can prevent the conductive and heat-conducting material of the lower layer from conducting with the heat sink, and prevent the short circuit of the chip and other problems. However, because the lower layer of the substrate, such as DBC, generally uses a copper layer to connect with the power chip, the thinner copper layer on the lower layer has limited improvement in transient thermal performance, resulting in a small effective thermal diffusion area and suboptimal steady-state thermal performance.

Secondly, in order to improve the withstand voltage value of the power module, the current industry increases the creepage distance between the pins of the power chip and the heat sink by increasing the thickness of the plastic package, but the increase in the thickness of the plastic package will make the power module The process and cost increase, and the increase in the thickness of the plastic package is not conducive to the heat dissipation of the power module, and it is also not conducive to the application of the power module in the miniaturization scene, thus limiting the development of the power module.

Finally, since the power module needs to run for a long time, and its working environment is also varied, the power chips in the power module will inevitably fail due to various reasons. For example, a failure of a power chip generates stress, which damages the insulating layer in the metal-clad substrate, thereby causing a short circuit between the power chip and the heat sink, resulting in serious safety accidents. Therefore, when the power chip fails, how to minimize the damage of the failure without affecting the operation of the entire system puts forward new requirements for the safety and reliability of the power module.

In view of the above problems, the present application provides a novel power device, a power module structure and a manufacturing method, and a power conversion circuit. In this application, firstly, a recess is added to the plastic package to form a weak point on the plastic package under the chip, so that the stress generated by the chip failure can be released from the weak point more easily without damaging the metal-clad substrate above the chip. The short circuit between the heat sink and the chip due to the crack of the insulating layer in the metal-clad substrate is reduced, thereby causing serious safety problems. Compatible with the recessed part, in order to make up for the shortcoming that the metal layer in the metal-clad substrate can withstand poor stress, a heat sink is arranged between the chip and the metal-clad substrate. Generally, the thickness of the heat sink can be It is set to be more than twice the thickness of the metal layer in the metal-clad substrate. The heat sink can also improve the stress bearing capacity between the chip and the heat sink, enhance the structural stability of the power module, further guide the chip stress to be released from the recess, and reduce the insulation in the heat sink caused by the stress caused by chip failure. Possibility of layer damage causing a short circuit between the chip and the heat sink. At the same time, since the heat sink has efficient thermal conductivity, it can improve the overall heat dissipation efficiency of the power module.

In order to improve the pressure resistance of the power module without reducing the heat dissipation capability of the power module, this application adds a first groove to the edge of the plastic package close to the metal-clad substrate, so that the power module does not When the thickness of the plastic package is increased, the creepage distance between the pin and the radiator is increased, which ensures that the heat dissipation capability of the power module does not decrease and the manufacturing cost does not increase. Finally, in order to further improve the structural stability of the power module, a second groove is provided in the opposite position of the first groove in the plastic package, and the second groove and the concave part are also located on the side of the plastic package away from the metal-clad substrate , the second groove can reduce the risk of cracks at the corresponding position of the second groove due to crimping of the heat sink.

The first embodiment provided by the present application is as shown in FIG. 1 , the first embodiment of the present application provides a power device, and the power device includes a circuit board 8 , a power module 9 and a heat sink 7 . The power module 9 is surface-mounted on the circuit board 8 through the pins 5 , and the radiator 7 is arranged on the side of the power module 9 away from the circuit board 8 . Wherein, the power module 9 includes a plastic package 1 , a metal-clad substrate 2 , a heat sink 3 and a chip 4 . The heat sink 3 is placed between the metal-clad substrate 2 and the chip 4, wherein the metal-clad substrate 2 includes a first metal layer 2-1, a second metal layer 2-2 and an insulating layer 2-3, and the second metal layer 2-2 and the heat sink 3 are combined by welding or sintering, because the thickness of the first metal layer 2-1 and the second metal layer 2-2 are relatively thin in the prior art, the structural strength is not enough , cannot meet the safety requirements of power equipment, so in this application, the thickness of the heat sink 3 is twice the thickness of the second metal layer 2-2, of course it can also be thicker, for example, the thickness of the heat sink 3 It is 2.5 times the thickness of the second metal layer 2-2, so the heat sink 3 can enhance the structural strength between the chip 4 and the metal-clad substrate 2, and when the chip 3 is damaged and stress is generated, the heat sink 3 can strengthen the metal-clad substrate 2, reducing the possibility of damage to the insulating layer 2-3 in the metal-clad substrate 2. At the same time, in order to make full use of the contact area of the heat sink, the length and width of the heat sink 3 are respectively 1mm larger than the length and width of the chip 4. Of course, the heat sink 3 can also be larger, and the length and width of the heat sink 3 also It can be 1.5mm larger than the length and width of the chip 4 respectively. In addition, the heat sink 3 can also improve the heat dissipation performance of the power module 9 and ensure the heat dissipation performance of the power device. The material of the heat sink 3 is the same as that of the first metal layer 2-1 and the second metal layer 2-2, both being Cu, but it can also be CuMo composite material, diamond, diamond-copper composite material, Al-SiC composite material materials and other materials with high thermal and electrical conductivity. The heat sink 3 has thermal and electrical properties, which can not only provide heat dissipation for the chip 4 , but also provide a current channel for the internal current of the chip 4 .

The metal-clad substrate 2, the heat sink 3, and the chip 4 are plastic-sealed by the plastic package 1. The heat sink 3 can enhance the structural strength between the chip 4 and the metal-clad substrate 2. Adaptively, in order to further protect the metal-clad layer The insulating layer 2-3 in the substrate 2 adds a recessed part 1-1 in the plastic package 1, so that a weak point can be formed on the plastic package under the chip 4, so that it is easier to recover from the weak point when the chip 4 fails to generate stress. The point is released, thereby protecting the insulating layer 2-3. The shape of the depression 1-1 is a positive trapezoid, the width of the bottom of the depression 1-1 is smaller than the width of the top of the depression 1-1, and the inclination angle of the side wall of the depression 1-1 is 10 degrees. Of course, the inclination angle can be larger, for example , the inclination angle of the side wall of the recessed part 1-1 is 12 degrees. In order to achieve a better protective effect, the length and width of the bottom of the recessed portion 1-1 are 1.0mm larger than the length and width of the chip 4, of course, the recessed portion 1-1 can also be larger, for example, the length and width of the recessed portion 1-1 The length and width of the bottom are 1.2 mm larger than the length and width of the chip 4 . In terms of the depth design of the recessed portion 1-1, the depth of the recessed portion 1-1 in FIG. 1 is 0.2 mm, and of course, it can be deeper. For example, the depth of the recessed portion 1-1 in FIG. 1 is 0.3 mm. It is also necessary to ensure a safe distance between the bottom of the depression 1-1 and the bonding wire 6. The distance between the bottom of the depression 1-1 and the bonding wire 6 is 0.5 mm. Of course, the distance can also be larger. The depression 1-1 The distance between the bottom of -1 and the bonding wire 6 is 0.6 mm. Compared with the vertical structure, this structure is more stable, can effectively improve the damage resistance of the power module 9, and also improves the safety of the power equipment. There may be multiple chips 4, and correspondingly, multiple chip regions may be provided, and each chip region is correspondingly provided with a recessed portion 1-1. As shown in FIG. 2A, the power module 9 has two chips 4 inside, Two subregions 1 - 1 - 1 of the recessed portion 1 - 1 are provided at the bottom of the plastic package 1 , corresponding to two chip regions respectively. As shown in Fig. 2B, it is a perspective view of the power module 9. In order to clearly show the structure of the recessed part 1-1, in Fig. 2B, the part of the recessed part 1-1 is set upwards, and it can be seen Has two subregions. It should be pointed out that there is not a one-to-one correspondence relationship between FIG. 2A and FIG. 2B , and the arrangement direction of the sub-regions of the recessed portion 1 - 1 in FIG. 2A is opposite to that in FIG. 2B .

Add a first groove 1-2 in the plastic package 1, the first groove 1-2 is arranged between the plastic package 1 and the heat sink 7, forming a recessed space facing the heat sink 7, as shown by the arrow in Figure 1 , increasing the surface wrinkle degree of the plastic package 1, prolonging the surface length of the plastic package 1, can increase the creepage distance between the pin 5 and the heat sink 7, thereby increasing the withstand voltage capability of the power module 9, and also improving The withstand voltage capability of the power equipment. The first groove 1 - 2 does not increase the thickness of the plastic package 1 , so the heat dissipation capability of the power module 9 will not be reduced, and the manufacturing cost of the power module 9 will not be increased due to the increase of materials used in the plastic package 1 . As shown in Figure 1, the first groove 1-2 is a trapezoidal structure, and the bottom width of the first groove 1-2 is smaller than the top width of the first groove 1-2, where the first groove 1-2 sidewall inclination angle is 10 degrees, of course, the inclination angle can be larger, for example, the inclination angle of the side wall of the recessed part 1-1 is 12 degrees. The distance from the top of the first groove 1-2 to the top of the plastic package 1, the depth of the first groove 1-2, and the width of the bottom of the first groove 1-2 are 1.0mm. Of course, a larger value can also be set, for example, the first The distance from the top of a groove 1-2 to the top of the plastic package 1, the depth of the first groove 1-2, and the width of the bottom of the first groove 1-2 are 1.2 mm. The trapezoidal structure is more stable than the vertical structure, and can effectively improve the damage resistance of the power module 9, thereby improving the safety of the power equipment.

In the first groove 1-2, as shown in Figure 3, stepped teeth 1-2-1 can be added, and the stepped teeth 1-2-1 can effectively increase the surface length of the first groove 1-2, that is The creepage distance between the pin 5 and the heat sink 7 is further increased, and finally the withstand voltage capability of the power module 9 is improved. It can be inferred that the more the number of stepped teeth 1-2-1, the longer the creepage distance. This application does not make specific restrictions on the number of stepped teeth 1-2-1, which can be one, two or three or four.

In the first groove 1-2, as shown in Figure 4, a sub-groove 1-2-2 can be added in the first groove 1-2, similar to the stepped tooth 1-2-1, the sub-groove 1-2-2 can also increase the surface length of the first groove 1-2, which further increases the creepage distance between the pin 5 and the heat sink 7, and finally improves the withstand voltage capability of the power module 9. It can be inferred that the greater the number of sub-grooves 1-2-2, the longer the creepage distance. This application does not specifically limit the number of sub-grooves 1-2-2. It can be one, or two, three or four.

In some special scenarios, as shown in Figure 5, the first groove 1-2 can also be rectangular, that is, the side wall of the first groove 1-2 can be a vertical structure, and the rectangular structure can effectively increase the The surface length of the first groove also increases the creepage distance between the pin 5 and the heat sink 7 , which can effectively increase the withstand voltage of the power module 9 .

Figures 6A-6C are top views of the power module 9, from which it can be seen that the first groove 1-2 can be arranged on one side or both sides or around the edge of one side of the metal-clad substrate 2 in the plastic package 1 . It can be set according to specific scenarios. This application does not make specific limitations.

The second groove 1-3, the second groove 1-3 is arranged between the plastic package 1 and the circuit board 8, and extends along the surface of the circuit board 8, forming a flat space facing the opening of the pin 5, in the plastic package 1 The relative position of the first groove 1-2 is increased to the second groove 1-3, which can reduce the risk of cracks at the corresponding position of the second groove 1-3 due to the heat sink 7 being crimped. The shape of the second groove 1-3 is also trapezoidal, and the width of the bottom of the second groove 1-3 is smaller than the width of the top of the second groove 1-3. As shown in Figure 1, the angle between the side wall of the second groove 1-3 and the thickness direction of the power module 9 is 10 degrees, of course, the angle can be larger, for example, the side wall of the second groove 1-3 and the power module 9 The included angle in the thickness direction of the module 9 is 12 degrees. The depth of the second groove 1-3 is 0.2mm, of course, it can also be deeper, for example, the depth of the second groove 1-3 is 0.3mm. When the power module 9 is under pressure, the second groove 1-3 can act as a buffer to protect the power module 9 .

As shown in FIG. 1 , the power module 9 also includes pins 5 and bonding wires 6, wherein the bonding wires 6 can also be replaced by interconnecting sheets, and the chip 4 is electrically connected to the pins 5 through bonding wires 6 or interconnecting sheets. The first part of the pin 5 is arranged inside the plastic package 1, and the second part of the pin 5 is used to connect with the circuit board 8. In this embodiment, the shape of the pin 5 is a gull-wing shape, and of course the pin 5 can also be It is in-line type.

As shown in Figure 1, the radiator 7 is arranged on the side of the metal-clad substrate 2 away from the chip 4 by welding or sintering. , phase change materials and other thermal interface materials for lamination. The inside of the radiator 7 is provided with a cooling channel, and the cooling channel has a water inlet and a water outlet. The coolant enters the heat dissipation water channel positioned at the inside of the radiator 7 through the water inlet, absorbs the heat of the radiator 7, and finally flows out through the water outlet to take away all the heat. The heat sink 7 can absorb the heat transferred from the metal-clad substrate 2 to reduce the temperature of the power module 9 . And it can also be seen from FIG. 1 that the radiator 7 is on the same plane as the upper surface of the plastic package 1, so that the radiator 7 can be flatly attached to the second metal layer 2-2 of the metal-clad substrate 2, thereby improving the The heat dissipation performance of the power module 9 is described. The heat sink 7 has heat dissipation fins, which can increase the heat dissipation area and improve the heat dissipation efficiency of the heat sink 7 .

The second embodiment of the present application provides a method for manufacturing a power module, the method includes as shown in FIG. 7 :

S1: The metal-clad substrate 2, the heat sink 3, and the chip 4 are sequentially stacked by welding or sintering; wherein, the thickness of the heat sink 3 is greater than the thickness of the second metal layer 2-2 in the metal-clad substrate 2, The projection of the heat sink 3 in the thickness direction of the power module covers the projection of the chip 4 in the thickness direction of the power module;

S2: plastic packaging, use the plastic packaging body 1 to seal the metal-clad substrate 2, the heat sink 3 and the chip 4, the plastic packaging body 1 is provided with a concave part 1-1, a first groove 1-2 and a second groove 1-3 ; wherein the recessed part 1-1 and the second groove 1-3 are arranged on the side of the plastic package body 1 away from the metal-clad substrate 2, and the projection of the recessed part 1-1 in the thickness direction of the power module covers the chip 4 on the power module Projection in the thickness direction of the group; the first groove 1-2 is set opposite to the second groove 1-3, the first groove 1-2 is set on the side of the plastic package 1 close to the metal-clad substrate 2, and the second groove The projection of the groove 1-3 in the thickness direction of the power module covers the projection of the first groove 1-2 in the thickness direction of the power module.

The molding compound used in the plastic sealing body 1 is a low-modulus molding compound, which can improve the reliability of the power module. The molding compound can be made of a material with an elastic modulus between 0.5GPa and 20GPa, such as epoxy molding compound, etc. It is not limited here. In specific implementation, after the plastic sealing is completed, the upper and lower surfaces of the power module can be ground to make the two sides of the power module parallel. Of course, grinding can also be omitted as required. Exemplarily, after the plastic packaging, the exposed pins 5 outside the power module can also be tin-plated to prevent oxidation of the pins 5 and increase the solderability of the pins 5 .

To make a complete power module, there is S11 after S1, and the chip 4 is electrically connected to the pin 5 by welding or sintering using the bonding wire 6 or the interconnect sheet. At the same time, S21 is also provided after S2, and the pin 5 is stamped and formed so that the pin 5 forms a gull-wing shape or an in-line shape.

The third embodiment of the present application provides a power conversion circuit, the power conversion circuit includes a capacitor and at least one power module as in any of the above application embodiments, the power module is electrically connected to the capacitor, and the capacitor is used for The power module provides voltage, and the power conversion circuit is used for AC/DC conversion. In the embodiment of the present application, the structure and working principle of the power module can refer to the description of the foregoing embodiments, and will not be repeated in the embodiment of the present application.

Generally, the power conversion circuit provided by the embodiment of the present application includes the power module in any of the above application embodiments. Since the power module adopts the structure in the above embodiment, the heat dissipation performance of the power module Greatly improved, and at the same time the withstand voltage is also enhanced, so the same area of the power chip, the power chip using the power module of the embodiment of the application can withstand higher current, thereby obtaining a higher power density, while using this power module The power conversion circuit of the group can therefore output higher power and have higher power conversion efficiency. At the same time, since the power module in the embodiment of the present application is provided with the concave portion and the second groove, the reliability of the power module is further improved, the working life of the chip 4 is extended, and the power conversion circuit in the third embodiment is also improved. reliability.

The above is only the specific implementation of the application, but the scope of protection of the application is not limited thereto. Anyone familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the application, and should cover Within the protection scope of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims (15)

1. A power device, characterized in that the power device comprises: a circuit board, a power module and a heat sink, the power module is arranged on the circuit board, and the heat sink is arranged on the side away from the power module one side of the circuit board; The power module includes a metal-clad substrate, a chip, and a plastic package, the metal-clad substrate is stacked with the chip, and is plastic-packed in the plastic package; The plastic package includes a concave portion, the concave portion is arranged on the side of the plastic package away from the heat sink, and is located between the surface of the plastic package on the side away from the heat sink and the circuit board, so that the A stress release space is formed between the circuit board and the plastic package, and the projection of the recessed portion in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module. 2. The power device according to claim 1, wherein the power module further comprises a heat sink, the heat sink is located between the metal-clad substrate and the chip, and the heat sink The thickness of the sheet is greater than the thickness of the metal layer in the metal-clad substrate, and the projection of the heat sink sheet in the thickness direction of the power module covers the projection of the chip in the thickness direction of the power module. 3. The power device according to claim 1 or 2, wherein the power module further comprises a first groove and pins, and the first groove is arranged on the plastic package close to the heat sink and located between the plastic package and the heat sink to form a recessed space facing the heat sink, so that the creepage distance between the pins and the heat sink is increased; The first part of the lead is arranged in the plastic package, and the power module is arranged on the circuit board through the second part of the lead. 4. The power device according to claim 1-3, wherein the power module further comprises a second groove, the second groove is arranged on the side of the plastic package away from the heat sink, It is located between the plastic package and the circuit board, and extends along the surface of the circuit board to form a flat space facing the pin opening. 5. The power device according to any one of claims 1-4, wherein there are multiple chips in the power module, the recessed portion includes at least one sub-region, and each sub-region of the recessed portion A region corresponds to at least one chip. 6. The power device according to any one of claims 1-5, wherein the plastic package comprises a first groove, comprising: a side wall of the first groove is provided with at least one stepped tooth. 7. The power device according to any one of claims 1-6, wherein the plastic package comprises a first groove, comprising: the first groove includes at least one sub-groove. 8. The power device according to any one of claims 1-7, wherein the included angle between the side wall of the concave portion and the thickness direction of the power module is not zero, and the width of the bottom of the concave portion is less than the width of the top of the depression; The included angle between the side wall of the first groove and the thickness direction of the power module is not zero, and the bottom width of the first groove is smaller than the top width of the first groove; The included angle between the side wall of the second groove and the thickness direction of the power module is not zero, and the width of the bottom of the second groove is smaller than the width of the top of the second groove. 9. A power module, characterized in that the power module includes a metal-clad substrate, a chip, and a plastic package, and the metal-clad substrate and the chip are stacked and packaged in the plastic package; The plastic package includes a concave portion, the concave portion is provided on the side of the plastic package away from the metal-clad substrate, and the projection of the concave portion in the thickness direction of the power module covers the chip on the The projection in the thickness direction of the power module is used to form a stress relief part on the plastic package of the chip on the side away from the metal-clad substrate. 10. The power module according to any one of claims 1-4, wherein the power module comprises a heat sink, and the heat sink is arranged between the metal-clad substrate and the chip , the thickness of the heat sink is greater than the thickness of the metal layer in the metal-clad substrate, and the projection of the heat sink in the thickness direction of the power module covers the chip in the thickness direction of the power module projection. 11. The power module according to claim 1, characterized in that, the power module further comprises a first groove and pins, and the first groove is arranged on the plastic package close to the metal clad layer One side of the substrate, to form a recessed area on the side of the plastic package close to the metal-clad substrate, so that the creepage distance between the first groove and the heat sink is increased; The first part of the pin is set in the plastic package, and the second part of the pin is used to set the power module on the circuit board. 12. The power module according to claim 1 or 2, wherein the power module further comprises a second groove, and the second groove is arranged on the plastic package away from the metal-clad substrate and extend along a side of the plastic package away from the metal-clad substrate to form a flat space facing the pin opening. 13. The power module according to any one of claims 1-3, characterized in that there are multiple chips in the power module, the recessed portion includes at least one sub-region, and each of the recessed portions A sub-region corresponds to at least one chip. 14. The power module according to any one of claims 1-5, wherein the plastic package comprises a first groove, comprising: a side wall of the first groove is provided with at least one stepped tooth. 15. The power module according to any one of claims 1-6, wherein the plastic package comprises a first groove, comprising: the first groove includes at least one sub-groove.

Images