Nanoporous Power Module Assembly for Low-Thermal-Resistance Joining
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Solution Overview
Problem
Existing power electronic modules face challenges with high thermal resistance, complex and costly manufacturing methods, and reliability issues due to soldering and thermal interface materials, especially at high temperatures, leading to potential short-circuiting and limited thermomechanical reliability.
Innovation Solution
A method involving additive manufacturing to deposit a nanoporous material layer on a metallized substrate, followed by sintering to create a mechanical and electrical connection, eliminating the need for soldering and thermal interface materials, and allowing for complex geometries and high-temperature operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is used to connect power semiconductor components to metallized substrates, then electrical connection is achieved, but the risk of short-circuiting increases due to small distances between control and power electrodes
Solution Approach 1:
The patent introduces an intermediary substance (nanoporous material or solder paste with flux) between the power semiconductor components and the metallized substrate. This intermediary layer provides both electrical connection and insulation, preventing short-circuits while enabling reliable electrical contact. The nanoporous material acts as a mediator that fills the space between electrodes, conducting electricity where needed while maintaining isolation where required.
2Temperature
If thermal interface material is used between the base and heat sink, then thermal connection is improved, but the method becomes complex and thermomechanical reliability is limited
Solution Approach 1:
The patent merges the base and heat sink into a single integrated component, eliminating the need for separate thermal interface materials. The heat sink is directly formed as part of the metallized substrate structure, creating a unified thermal management system. This integration removes the interface between base and heat sink, thereby eliminating thermal resistance at that junction and improving thermomechanical reliability by reducing the number of separate components and interfaces.
3Temperature
If lead-based solders are used for high-temperature applications above 200°C, then thermal management is improved, but compatibility with hazardous substance directives is lost
Solution Approach 1:
The patent changes the material parameters by using nanoporous materials or lead-free solder pastes with modified composition and structure. The nanoporous material provides high thermal conductivity and electrical connection capabilities without containing hazardous substances. The material parameters such as porosity, conductivity, and thermal properties are optimized to achieve performance comparable to or better than lead-based solders while meeting environmental regulations.
4Reliability
If complex manufacturing methods are used to achieve reliable connections, then connection reliability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent employs nanoporous materials as a key element in the manufacturing process. These porous materials can be deposited using additive manufacturing techniques, allowing for complex three-dimensional structures to be created in a single manufacturing step. The nanoporous structure provides both mechanical support and electrical connection pathways, eliminating the need for multiple separate manufacturing steps and reducing overall process complexity while maintaining high connection reliability.
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
Enables reliable, cost-effective, and efficient thermal management with reduced thermal resistance, improved reliability, and increased power density, while avoiding soldering complexities and material limitations.
Implementation Method 1
depositing, by electroforming, a second metal layer on the first metal layer
Implementation Method 2
sintering the layer of nanoporous material, so as to ensure a mechanical and electrical connection
Implementation Method 3
The lower metal layer 2e of the substrate 2a is attached to the metal base 9, which has the function of spreading the heat flow and providing a thermal connection to a metal heat sink 11
Implementation Method 4
The heat sink 11, is provided with fins 14 allowing to further reduce the thermal resistance of the latter, the fins 14 being traversed by a cooling fluid, for example air
Implementation Method 5
Due to their imperfections, power semiconductor components 3 are subject to Joule effect losses and therefore represent a significant source of heat
Data Source
AI summary
A method for manufacturing a power electronic module by additive manufacturing includes the step of depositing a layer of an electrically conductive nanoporous material on a substrate that includes an electrically insulating layer and at least one layer of conductive metal material, called a metallized substrate. The method further includes the step of placing an element, for example an active component of the semiconductor power component type, on the layer of nanoporous material and sintering the layer of nanoporous material, so as to ensure a mechanical and electrical connection between said element and the metallized substrate.