WO2023098822A1

WO2023098822A1 - High-reliability low-inductance power module packaging structure

Info

Publication number: WO2023098822A1
Application number: PCT/CN2022/135923
Authority: WO
Inventors: 叶楠; 李道会
Original assignee: 上海蔚兰动力科技有限公司
Priority date: 2021-12-03
Filing date: 2022-12-01
Publication date: 2023-06-08
Also published as: CN116314062A

Abstract

Disclosed in the present application is a power module packaging structure, comprising: a package housing, which comprises a first surface and a second surface, wherein the first surface and the second surface are respectively located on an upper side and a lower side of the package housing; a substrate, which is packaged in the package housing and is parallel to the first surface and the second surface, wherein at least one power element is arranged on the substrate; and a plurality of absorption terminals, which are arranged on the first surface and are respectively connected to a first power supply end and a second power supply end of the at least one power element inside the package housing. The plurality of absorption terminals are coupled to an absorption circuit by means of soldering or bonding, and the absorption circuit is used for eliminating an internal inductance that is generated by the connection between the at least one power element and the plurality of absorption terminals and an external inductance that is generated by the connection between the first power supply end and the second power supply end, as well as an external power supply.

Description

A High Reliability and Low Inductance Power Module Packaging Structure

technical field

The present application relates to a packaging structure of a power module, in particular to a packaging structure of a power module with high reliability and low inductance.

Background technique

Factors such as the energy crisis and climate change have made the scientific and industrial circles strive to develop technologies that replace petrochemical energy with renewable energy. These technologies require the use of power modules to perform electrical energy conversion. For example: in the process of solar power generation, photovoltaic power generation panels generate direct current, transform it into alternating current with fixed frequency and amplitude, and finally connect it to the grid. Another example: the power module of an electric vehicle converts the DC power of the battery into an AC power whose frequency and amplitude can be adjusted to drive the output torque of the motor.

The power semiconductor device is the core component of the power module, which is responsible for the turn-on and turn-off of the circuit. For example, Figure 1 is a level three-phase full-bridge motor driver circuit, in which Q1~Q6 are power semiconductor devices. Commonly used power semiconductors include insulated gate bipolar transistors (IGBTs), silicon field effect transistors (Si MOSFETs) and silicon carbide field effect transistors. Transistors (SiC MOSFETs). The current change of the power semiconductor device when the current is turned off will generate a voltage spike on the parasitic inductance of the circuit. The voltage spike may break down the power semiconductor device or cause electromagnetic interference so that the circuit cannot work normally. In addition, the energy stored in the parasitic inductance will be dissipated in the form of heat, reducing the efficiency of the circuit. Therefore, reducing the parasitic inductance of the circuit has become one of the topics concerned by the industry.

Contents of the invention

One of the main purposes of the present application is to provide a power module packaging structure to solve the above problems.

In order to solve the above problems, according to one aspect of the present application, a power module packaging structure is characterized in that it includes: a packaging case including a first surface and a second surface, wherein the first surface and the The second surface is respectively located on the upper side and the lower side of the packaging casing; a substrate is packaged in the packaging casing and is parallel to the first surface and the second surface, wherein the substrate is provided with at least A power element; and a plurality of absorbing terminals arranged on the first surface and respectively connected to a first power supply end and a second power supply end of the at least one power element in the packaging case; wherein the The plurality of absorbing terminals are coupled to a absorbing circuit by welding or bonding, and the absorbing circuit is used to eliminate an internal inductance generated by connecting the plurality of absorbing terminals to the at least one power element and the first power supply terminal And the second power supply terminal is connected to an external inductance generated by an external power supply. .

Description of drawings

Figure 1 is a level three-phase full-bridge motor driver circuit

FIG. 2 is a schematic diagram of a plurality of parasitic inductances of the level three-phase full-bridge motor driver circuit 1 .

FIG. 3 is a power module packaging structure and an equivalent circuit diagram of a power module according to an embodiment of the present application.

FIG. 4 is a power module packaging structure and an equivalent circuit diagram of a power module according to another embodiment of the present application.

FIG. 5 is a cross-sectional view of a package structure of a power module according to an embodiment of the present application.

FIG. 6 is a cross-sectional view of a package structure of a power module according to an embodiment of the present application.

FIG. 7 is a cross-sectional view of a package structure of a power module according to another embodiment of the present application.

Wherein, the reference signs are explained as follows:

1 level three-phase full-bridge motor driver circuit

10 power modules

12 DC support capacitor

14 batteries

16 motors

30, 40, 50, 60, 70 Power module package structure

32, 42 Equivalent circuit diagram

52, 54, 62, 72 Sections

302 package shell

304, 404 absorbing terminal

306 signal terminal

308 power terminal

Detailed ways

Certain terms are used throughout the specification and following claims to refer to particular components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This description and the following claims do not use the difference in name as a way to distinguish components, but use the difference in function of components as a criterion for distinguishing. "Includes" mentioned throughout the specification and the following claims is an open term, so it should be interpreted as "including but not limited to". In addition, the term "coupled" here includes any direct and indirect means of electrical connection. Therefore, if it is described that the first device is coupled to the second device, it means that the first device may be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

Please refer to FIG. 2 , which is a schematic diagram of a plurality of parasitic inductances of the level three-phase full-bridge motor driver circuit 1 . The level three-phase full-bridge motor driver circuit 1 includes a power module 10 , a DC support capacitor 12 , a battery 14 and a motor 16 . The operation of the level three-phase full-bridge motor driver circuit 1 is a common technology, and will not be repeated here. The multiple parasitic inductances of the level three-phase full-bridge motor driver circuit 1 include: an internal inductance Lc of the DC support capacitor 12, an external inductance Lbus generated by connecting the power module 10 to the DC support capacitor 12 and the battery 14, and the power module 10 An internal inductance Li generated by the package. In detail, the power module 10 includes power semiconductor devices Q1 - Q6 and is packaged in a first packaging case, and the power semiconductor devices Q1 - Q6 are connected to a copper bar outside the first packaging case to generate internal inductance Li. When the power semiconductor devices Q1~Q6 are turned on or off, the current change will generate a voltage spike on the internal inductance Li, and the voltage spike may break down the power semiconductor devices Q1~Q6 so that the level three-phase full-bridge motor driver circuit 1 cannot normal work. Similarly, when the level three-phase full-bridge motor driver circuit 1 is operating, the external inductance Lbus and the capacitor internal inductance Lc may also generate voltage spikes so that the level three-phase full-bridge motor driver circuit 1 cannot work normally. In addition, the energy stored in the multiple parasitic inductances will be consumed in the form of heat, which reduces the efficiency of the level three-phase full-bridge motor driver circuit 1 .

In order to solve the problem that the three-phase full-bridge motor driver circuit 1 cannot work normally or the efficiency is reduced due to a plurality of parasitic inductances, a first snubber circuit can be arranged inside the first packaging case, which is used to eliminate the gap between the first packaging case. The impact of the external inductance Lbus, the internal inductance Lc of the capacitor, and the internal inductance Li in the first packaging shell on the level three-phase full-bridge motor driver circuit 1 . In detail, the first absorption circuit can be a decoupling ceramic capacitor, which couples the power semiconductor devices Q1-Q6 and the DC support capacitor 12 and the battery 14 outside the first packaging case to eliminate the The external inductance Lbus of the capacitor, the internal inductance Lc of the capacitor, and the internal inductance Li in the first packaging shell have an impact on the level three-phase full-bridge motor driver circuit 1 . However, when the decoupling ceramic capacitor is packaged in the first package by potting, the ceramic material of the decoupling ceramic capacitor and the cured epoxy resin used in the potting process may be due to the internal temperature in the first package being too high. high risk of reliability. In addition, since the decoupling ceramic capacitors are packaged in the first packaging case, the capacitance value of the decoupling ceramic capacitors cannot be adjusted according to the actual circuit operation, resulting in a matching problem.

Please refer to FIG. 3 . FIG. 3 is a power module packaging structure 30 and an equivalent circuit diagram 32 of the power module 10 according to an embodiment of the present application. The power module package structure 30 includes a second package case 302 , a substrate, a plurality of sink terminals 304 , a signal terminal 306 and a plurality of power terminals 308 . The second packaging case 302 includes a first surface and a second surface, wherein the first surface and the second surface are respectively located on the upper side and the lower side of the second packaging case 302 . At least one power element is disposed on the substrate and packaged in the second packaging case 302 . In addition, the substrate can be parallel to the first surface and the second surface. A plurality of absorbing terminals 304 are disposed on the first surface of the second package case 302 , and are coupled to the first power terminal and the second power terminal of at least one power element in the second package case 302 by copper bars. The signal terminals 306 and the plurality of power terminals 308 are disposed outside the second packaging case 302 , in other words, they are not limited to be disposed on the upper side, the lower side or the surroundings of the second packaging case 302 . The signal terminal 306 is coupled to a signal end of at least one power element in the second packaging case 302 by using a copper bar, and a plurality of power terminals 308 are coupled to the first terminal of at least one power element in the second packaging case 302 by using a copper bar. power terminal and a second power terminal. It should be noted that FIG. 3 is a top view of the power module packaging structure 30 , so only the first surface is shown, while the second surface and the substrate are respectively on the lower side and the inner side of the module packaging structure 30 .

In detail, when the plurality of power terminals 308 are connected to an external power source, the level three-phase full-bridge motor driver circuit 1 starts to operate. The internal inductance Lc of the capacitor, the external inductance Lbus and the internal inductance Li may cause the problem that the three-phase full-bridge motor driver circuit 1 cannot work normally or the efficiency is reduced. In order to solve this problem, a plurality of absorbing terminals 304 are coupled to a second absorbing circuit by welding or bonding, which is used to eliminate the external inductance Lbus and the internal inductance Lc of the capacitor outside the second package shell and the internal inductance Lc in the second package shell. Effect of internal inductance Li on level three-phase full-bridge motor driver circuit 1. For example, please refer to the equivalent circuit diagram 32 of FIG. 3 , at least one power element may be the power module 10 composed of the first transistor QH and the second transistor QL. The second absorbing circuit may be a decoupling ceramic capacitor, which is coupled to the first power terminal and the second power terminal of at least one power element. In an embodiment, the capacitance value of the decoupling ceramic capacitor can be greater than 1 μF. During the process of turning on or off the first transistor QH and the second transistor QL, the high-frequency current component is mainly provided by the decoupling ceramic capacitor, so the internal The current variation of the inductor Li and the external inductor Lbus decreases, and the voltage spikes caused by the multiple parasitic inductances also decrease accordingly. Therefore, the problem that the multiple parasitic inductances cause the three-phase full-bridge motor driver circuit 1 to fail to work normally or reduce efficiency is solved. In addition, the decoupling ceramic capacitor is disposed on the first surface outside the second packaging case, so the capacitance value of the decoupling ceramic capacitor can be adjusted according to actual circuit operation to avoid matching problems.

Please refer to FIG. 4 . FIG. 4 is a power module packaging structure 40 and an equivalent circuit diagram 42 of the power module 10 according to another embodiment of the present application. The difference between the power module packaging structure 40 and the power module packaging structure 30 is that the plurality of absorbing terminals 404 are coupled to the signal terminal of at least one power element in the second packaging casing 302 using copper bars. A plurality of absorbing terminals 404 are coupled to a third absorbing circuit by welding or bonding, and are used to eliminate the external inductance Lbus and the internal inductance Lc of the capacitor outside the second package shell 302 and the internal inductance Li in the second package shell. level three-phase full-bridge motor driver circuit 1. For example, please refer to the equivalent circuit diagram 42 of FIG. 4 , at least one power element may be the power module 10 composed of the first transistor QH and the second transistor QL. The fourth absorbing circuit may include a first decoupling capacitor, a second decoupling capacitor, a first resistor, and a second resistor, wherein the first decoupling capacitor is connected in series with the first resistor and coupled through a plurality of absorbing terminals Between the first power supply terminal and the signal terminal; the second decoupling capacitor is connected in series with the second resistor, and is coupled between the second power supply terminal and the signal terminal through a plurality of absorbing terminals. In one embodiment, when the first transistor QH and the second transistor QL are turned on or off, the high-frequency current component is mainly provided by the first decoupling capacitor and the second decoupling capacitor, so the internal inductor Li and the external The current variation of the inductor Lbus decreases, and the voltage spikes caused by the multiple parasitic inductances also decrease accordingly. The first resistor and the second resistor can avoid circuit oscillation and reduce voltage spikes caused by multiple parasitic inductances. Therefore, the problem that the multiple parasitic inductances cause the three-phase full-bridge motor driver circuit 1 to fail to work normally or reduce efficiency is solved. In addition, the fourth snubber circuit is disposed on the first surface outside the second packaging case, so the capacitance or resistance of the fourth snubber circuit can be adjusted according to actual circuit operation to avoid matching problems. It should be noted that those skilled in the art may appropriately add other elements of the fourth snubber circuit, such as diodes, according to needs, without limitation thereto.

Please refer to FIG. 5 , which is a cross-sectional view of a package structure of a power module according to an embodiment of the present application. The cutting plane at the cutting plane of the power module packaging structure 50 may be a cut-away view 52 or a cut-away view 54. In one embodiment, the plurality of sink terminals and at least one power element are at a relative position, so that the internal inductance Li is minimized. For example, the plurality of absorbing terminals in the sectional view 52 or the sectional view 54 are all adjacent to at least one power element on the substrate, so that the internal inductance Li is minimized. In another embodiment, the plurality of absorbing terminals are disposed at positions lower than, equal to or higher than the first surface. For example, in the cut-away view 52 , the plurality of absorbing terminals are disposed at a position lower than the first surface. Therefore, when the absorbing circuit is soldered or bonded to the plurality of absorbing terminals, it may also be lower than the first surface. In the cut-away view 54, the plurality of absorbing terminals are arranged at a position equal to the first surface, so when the absorbing circuit is welded or bonded to the plurality of absorbing terminals, it will be higher than the first surface. As for the plurality of absorbing terminals being disposed at a position higher than the first surface, it can be deduced accordingly, which will not be repeated here.

Please refer to FIG. 6 to FIG. 7 . FIG. 6 to FIG. 7 are cross-sectional views of a power module packaging structure according to another embodiment of the present application. The encapsulation case of the power module encapsulation structure 60 is a single-sided cooling module, the tangent plane of the power module encapsulation structure 60 may be a sectional view 62 , and the heat dissipation surface is disposed on the second surface of the encapsulation shell. The encapsulation shell of the power module encapsulation structure 70 is a double-sided cooling module, the tangent plane of the power module encapsulation structure 70 may be a sectional view 72, and the heat dissipation surfaces are arranged on the first surface and the second surface of the encapsulation shell.

To sum up, in the embodiment of the present application, a plurality of absorbing terminals are arranged on the first surface of the packaging case, and the absorbing circuit is welded or bonded to the plurality of absorbing terminals, which solves the problem of the three-phase full-bridge motor driver caused by the plurality of parasitic inductances. Circuit 1 cannot work normally or the efficiency is reduced. In addition, the components of the snubber circuit can be adjusted according to the actual circuit operation to avoid the matching problem.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

A power module packaging structure, characterized in that it comprises:

A packaging case, including a first surface and a second surface, wherein the first surface and the second surface are respectively located on the upper side and the lower side of the packaging case;

A substrate, packaged in the packaging case and parallel to the first surface and the second surface, wherein at least one power element is disposed on the substrate; and

A plurality of absorbing terminals are arranged on the first surface and are respectively connected to a first power supply terminal and a second power supply terminal of the at least one power element in the packaging case;

Wherein the plurality of absorbing terminals are coupled to a absorbing circuit by welding or bonding, and the absorbing circuit is used to eliminate an internal inductance generated by connecting the plurality of absorbing terminals to the at least one power element and the first The power supply end and the second power supply end are connected to an external inductance generated by an external power supply.
The package structure of the power module according to claim 1, wherein the absorbing circuit comprises a decoupling capacitor, which is coupled to the first power supply terminal and the second power supply through the plurality of absorbing terminals between the ends.
The package structure of the power module according to claim 1, wherein the plurality of absorbing terminals are further connected to a signal terminal of the at least one power element in the package case.
The packaging structure of the power module according to claim 3, wherein the absorbing circuit comprises:

a first decoupling capacitor connected in series with a first resistor, coupled between the first power supply terminal and the signal terminal through the plurality of sink terminals; and

A second decoupling capacitor is connected in series with a second resistor, and is coupled between the second power supply terminal and the signal terminal through the plurality of sink terminals.
The package structure of the power module according to claim 1, wherein the plurality of absorbing terminals and the at least one power element are in a relative position, so that the internal inductance is minimized.
The package structure of the power module according to claim 1, wherein the plurality of absorbing terminals are arranged lower than, equal to or higher than the first surface.
The power module package structure according to claim 1, wherein the package case is a single-side cooling module or a double-side cooling module.
The power module packaging structure according to claim 1, wherein the at least one power element is at least one of an insulated gate double transistor and a silicon carbide transistor.