Power Module Encapsulation Zoning for Thermostability at Lower Cost
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Solution Overview
Problem
High-performance encapsulation materials required for power semiconductor modules to handle extreme temperatures are costly, leading to increased module costs and material inefficiencies.
Innovation Solution
A method involving a power semiconductor module with a first encapsulation material of high thermostability covering selective portions of the die and connector, and a second, less expensive encapsulation material filling the remaining volume, where the first material is confined to high-temperature areas and the second to lower-temperature areas within a housing divided by compartments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high performance encapsulation materials are used to handle extreme temperatures, then thermostability is improved, but material cost and overall module cost increase significantly
Solution Approach 1:
The patent applies local quality by using different encapsulation materials in different spatial regions of the power semiconductor module. The first encapsulation material with high thermostability is applied selectively to portions experiencing extreme temperatures (such as near power semiconductor dies and electrical connectors), while the second, less expensive encapsulation material is used in regions with lower temperature requirements. This resolves the contradiction by maintaining necessary thermostability only where needed, thereby reducing overall material cost while preserving reliability in critical areas.
Solution Approach 2:
The patent segments the encapsulation system into multiple distinct materials with different thermostability characteristics. Instead of using a single high-performance encapsulation material throughout the entire module, the system is divided into zones: a first encapsulation material for high-temperature regions and a second encapsulation material for lower-temperature regions. This segmentation allows the module to achieve adequate thermostability at reduced cost by matching material performance to actual thermal requirements of different areas.
2Reliability
If high performance encapsulation materials are used throughout the entire module, then thermostability is improved, but material consumption and cost increase
Solution Approach 1:
The patent implements local quality by restricting the use of the first, high-thermostability encapsulation material to only those portions of the module that require it, specifically areas experiencing extreme temperatures such as around power semiconductor dies and electrical connectors. The second, lower-cost encapsulation material is used in all other areas with lower thermal demands. This approach maintains necessary thermostability in critical regions while significantly reducing the total quantity of high-performance material consumed throughout the module.
3Ease of manufacture
If selective portions are covered with high thermostability material, then cost is reduced, but protection in low-temperature areas may be insufficient
Solution Approach 1:
The patent applies local quality by matching the encapsulation material properties to the specific thermal requirements of different module regions. The first encapsulation material with high thermostability is applied to portions experiencing extreme temperatures (power semiconductor dies, electrical connectors), while the second encapsulation material is applied to portions with lower temperature requirements. This ensures that each region receives appropriate protection levels, maintaining reliability where needed while optimizing cost across the entire module.
Solution Approach 2:
The patent employs the principle of using cheaper materials where high performance is not necessary. The second encapsulation material, which is less expensive and has lower thermostability, is used in regions that do not require extreme temperature resistance. This allows the module to achieve adequate protection in low-temperature areas at reduced cost, while the expensive high-performance material is reserved only for critical high-temperature zones.
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 2A~2B
AI summary
A method for fabricating a power semiconductor module comprises: arranging a power semiconductor die on a power substrate, electrically connecting the power semiconductor die to the power substrate using an electrical connector, covering at least selective portions of the power semiconductor die and the electrical connector with a first encapsulation material, enclosing the power semiconductor die and the power substrate with a housing, and arranging a second encapsulation material on the first encapsulation material, such that the first and second encapsulation materials at least partially fill an interior volume formed by the housing, wherein the first encapsulation material exhibits a higher thermostability than the second encapsulation material.