Stepped Metal Contact Structure for Bubble-Free Potted Power Modules
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Solution Overview
Problem
Existing electrical modules face challenges in meeting clearance and creepage distance requirements due to limitations in the geometry of the top side, leading to potential bubble formation during potting and inadequate insulation, especially when dealing with power semiconductors.
Innovation Solution
The use of stepped metal structures with varying thicknesses on the top side of the electrical module allows for flexible adaptation to the potting process, ensuring reliable filling of potting material and compliance with insulation requirements, while also enabling flexible design and improved tolerance chains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top geometry of the prepackage module is made flexible to meet potting process requirements, then the clearance and creepage distance requirements can be met and bubble-free potting is achieved, but the device complexity increases due to stepped metal structures with varying thicknesses
Solution Approach 1:
The patent applies local quality by creating stepped metal structures with different thicknesses in specific regions. The metal structures have a first region with a first thickness for electrical contact and a second region with a second, greater thickness for potting material filling. This localized variation in thickness provides the necessary gap height for reliable potting and insulation in critical areas while maintaining a simpler overall module design.
2Reliability
If the gap height between the power semiconductor and module top side is increased to ensure bubble-free potting, then the potting process reliability improves, but the module volume increases
Solution Approach 1:
The stepped metal structures create localized increased thickness only in the regions where potting material filling is required, rather than uniformly increasing the entire module height. This allows achieving the necessary gap height for reliable potting while minimizing the overall volume increase of the module.
Solution Approach 2:
The patent solves the volume issue by utilizing the vertical dimension through stepped structures. Instead of increasing the horizontal footprint to create more gap space, the design uses vertical thickness variation of the metal structures to create the necessary gap height, thereby maintaining a compact module volume while ensuring adequate space for bubble-free potting material application.
3Adaptability or versatility
If stepped metal structures with varying thickness are used to contact electrical components, then the adaptability to different chip geometries improves and tolerance chains are optimized, but the manufacturing complexity increases
Solution Approach 1:
The stepped metal structures provide local variation in thickness that can be tailored to match specific chip geometries and contact requirements. Different regions of the metal structure can have different thicknesses to accommodate various electrical component configurations, enhancing adaptability while maintaining a systematic manufacturing approach.
Solution Approach 2:
The patent employs parameter changes by varying the thickness parameter of the metal structures across different regions. This allows the same basic metal structure design to adapt to different chip geometries and electrical component configurations by simply adjusting the thickness parameters of specific regions, thereby achieving versatility without proportionally increasing manufacturing complexity.
Data Source
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AI summary
The invention relates to an electrical module (1) comprising: a ceramic circuit carrier (2), an electrical component (3) arranged on the ceramic circuit carrier (2), a substrate in which the ceramic circuit carrier (2) and the electrical component (3) are arranged, the substrate being formed by a potting material (6), and a top surface (11) of the electrical module (1) forming electrical contact surfaces (713, 723, 733).The electrical module (1) comprises stepped metal structures (72, 73) arranged on the top surface (11) of the electrical module (1), each metal structure (72, 73) having regions (723, 724; 733, 734) of different thicknesses (d1, d2), and each metal structure (72, 73) forming one of the electrical contact surfaces (723, 733) of the electrical module (1) on its top surface (721, 731) and contacting one of the electrical contacts (33, 34) on the top surface (31) of the electrical component (3) on its underside (722, 732) in a region (724, 734) of increased thickness. The invention further relates to a method for manufacturing such an electrical module.