Power Module With Dielectric Interlayer Reducing Parasitic Inductance
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Solution Overview
Problem
Conventional power modules, such as single-sided and double-sided cooling power modules, face issues with low cooling performance, increased parasitic inductance, and reduced reliability due to multiple soldering processes, as well as interference between bonding wires and substrates, leading to higher costs and complexity.
Innovation Solution
A power module structure featuring a substrate with a dielectric layer interposed between power semiconductor devices on upper and lower parts, reducing parasitic inductance through dielectric and insulating layers, and simplifying the manufacturing process by eliminating the need for additional spacers and reducing soldering times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a double-sided cooling power module is used with substrates on both upper and lower surfaces, then cooling performance is improved, but parasitic inductance increases due to current flowing through substrate patterns
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the upper and lower substrates. This dielectric layer provides a direct thermal conduction path while allowing current to flow through optimized metal patterns, thereby maintaining cooling performance while reducing parasitic inductance caused by substrate pattern routing
Solution Approach 2:
The module is divided into separate upper and lower substrate assemblies that are connected through the dielectric layer. This segmentation allows independent optimization of each substrate's cooling and electrical functions, reducing the overall parasitic inductance while maintaining effective heat dissipation from both sides
2Temperature
If substrates are disposed on both upper and lower sides of the power semiconductor device, then cooling performance is improved, but bonding wires may contact substrates causing interference
Solution Approach 1:
The dielectric layer acts as a mediator that physically separates the upper and lower substrates, preventing bonding wires from contacting the substrates while still allowing effective thermal conduction. This eliminates the interference issue while maintaining the double-sided cooling advantage
3Temperature
If substrates are disposed on both upper and lower sides, then cooling performance is improved, but additional spacers are required increasing unit price
Solution Approach 1:
The dielectric layer serves multiple functions simultaneously: it provides thermal conduction for cooling, acts as an electrical insulator to prevent bonding wire contact, and serves as a mechanical spacer to maintain proper spacing between substrates. This multi-functionality eliminates the need for separate spacer components, reducing device complexity and cost while maintaining improved cooling performance
4Temperature
If soldering or sintering is performed two or more times for wire bonding, then double-sided cooling structure is achieved, but reliability is reduced due to solder remelting
Solution Approach 1:
The dielectric layer is pre-installed between the substrates before the final assembly process. This preliminary action ensures that when substrates are positioned on both sides of the power semiconductor device, the correct spacing and alignment are already established, allowing soldering or sintering to be performed only once for wire bonding, thereby maintaining solder joint reliability while achieving the double-sided cooling structure
Data Source
AI summary
A power module includes a substrate having a dielectric layer, a first power semiconductor device disposed on an upper part of the substrate, and a second power semiconductor device disposed on a lower part of the substrate.