Power Semiconductor Module Encapsulation for Thermal Crack Sealing
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Solution Overview
Problem
Power semiconductor modules often experience cracks due to thermal expansion mismatches between different materials, leading to operational failures and reduced reliability.
Innovation Solution
A power semiconductor module arrangement featuring a substrate with a dielectric insulation layer and metallization layers, covered by an encapsulant that releases a liquid or oil at elevated temperatures, with a viscosity below 1 mPas or surface tension less than 25 mNm^-1, to fill and seal cracks formed by thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different materials (substrate layer, metallization layers, solder/sinter layers, semiconductor elements) are used to assemble the power semiconductor module, then the module achieves functional performance and electrical connectivity, but cracks form in the substrate layer due to CTE mismatch during thermal cycling
Solution Approach 1:
The patent introduces a crack sealing layer as an intermediary component between the substrate layer and the encapsulant. This layer specifically targets and seals cracks in the substrate layer, mediating the harmful effects of CTE mismatch. The sealing layer acts as a buffer that prevents crack propagation while allowing the different materials to maintain their functional properties
Solution Approach 2:
The encapsulant is designed to release liquid or oil at temperatures exceeding a defined threshold, providing beforehand cushioning against crack formation. The low viscosity (<1 mPas) or low surface tension (<25 mNm^-1) of the released fluid allows it to penetrate and seal cracks before they can propagate through the complete substrate layer, preventing catastrophic failure
2Object-affected harmful factors
If a rigid encapsulant is used to protect the semiconductor components, then mechanical protection is provided, but cracks still form and propagate due to thermal expansion differences
Solution Approach 1:
The patent changes the physical parameters of the encapsulant by incorporating temperature-responsive properties. The encapsulant releases liquid or oil at temperatures exceeding a defined threshold, transforming from a static protective layer to a dynamic system that adapts to thermal conditions. This parameter change allows the encapsulant to actively respond to thermal expansion stresses
Solution Approach 2:
The released liquid or oil from the encapsulant acts as an intermediary that penetrates into cracks and prevents their propagation. This fluid intermediary fills the voids created by thermal expansion mismatch between different materials, providing a cushioning effect that protects the substrate layer from complete failure
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
The encapsulant effectively seals cracks in the dielectric insulation layer, enhancing the module's reliability and preventing short-circuits, thereby increasing the lifespan of the power semiconductor module.
Implementation Method 1
the first layer is configured to release liquid or oil at temperatures exceeding a defined threshold temperature
Data Source
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Figure 6
AI summary
A power semiconductor module arrangement (100) comprises a substrate (10) comprising a dielectric insulation layer (11), and a first metallization layer (111) attached to the dielectric insulation layer (11), at least one semiconductor body (20) mounted on the first metallization layer (111), and a first layer comprising an encapsulant (5), the first layer being arranged on the substrate (10) and covering the first metallization layer (111) and the at least one semiconductor body (20), wherein the first layer is configured to release liquid or oil at temperatures exceeding a defined threshold temperature.