Power Module Packaging Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
Existing power module packaging technologies suffer from parasitic capacitance issues that lead to electromagnetic interference (EMI) problems, particularly in SiC power modules, due to the presence of a heatsink acting as the protective earth, which limits their suitability for parallel applications.
Innovation Solution
A new packaging structure is proposed where power devices with jumping potentials are placed on separate substrates with insulating layers, reducing parasitic capacitance between these devices and the heat dissipation substrate, thereby minimizing common mode current and EMI noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power devices are directly mounted on heat dissipation substrate, then heat dissipation efficiency is improved, but parasitic capacitance increases causing EMI problems
Solution Approach 1:
The patent introduces an insulating substrate as an intermediary between the heat dissipation substrate and the power devices. This insulating substrate acts as a mediator that provides thermal conduction path while electrically isolating the power devices from the heat dissipation substrate, thereby reducing parasitic capacitance and EMI while maintaining heat dissipation efficiency
Solution Approach 2:
The patent segments the mounting structure into multiple functional layers: heat dissipation substrate, insulating substrate, and power device mounting layer. This segmentation separates the thermal management function from the electrical connection function, allowing optimized performance of each function independently
2Reliability
If DBC substrate structure is used, then integration level and thermal fatigue stability are improved, but parasitic capacitance between power devices and heatsink increases
Solution Approach 1:
The insulating substrate serves as a mediator between the DBC substrate and power devices, providing electrical isolation while maintaining mechanical and thermal connection. This reduces parasitic capacitance between power devices and heatsink while preserving the thermal fatigue stability benefits of DBC structure
Solution Approach 2:
The patent applies local quality by using insulating material specifically at the interface where electrical isolation is needed, while maintaining conductive properties in other areas for thermal management. The insulating substrate is strategically placed only where parasitic capacitance needs to be reduced
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces EMI noise in power modules by minimizing parasitic capacitance between jumping potential points and voltage static points, enhancing electromagnetic compatibility (EMC) performance and allowing for higher power density in electronic devices.
Implementation Method 1
parasitic capacitance C P can be formed between the drain D, the collector C or the kathode K of the power semiconductor chip and a heatsink 21
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
The present application discloses a packaging structure for a power module, comprising: a heat dissipation substrate; at least one first power device disposed on a first substrate having an insulating layer, the first substrate disposed on the heat dissipating substrate; and at least one second power device including a jumping electrode having a jumping potential, wherein the at least one second power device is disposed on at least one second substrate having an insulating layer, and the at least one second substrate is disposed on the first substrate, to reduce a parasitic capacitance between the jumping electrode and the heat dissipation substrate. The packaging structure for the power module according to the present application can reduce the parasitic capacitance between the jumping electrode of the power module and the heat dissipation substrate, thereby greatly reducing the EMI noise of the power module in operation.