Semiconductor Package Dummy Lead Mechanical Anchoring
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Solution Overview
Problem
The packaging of semiconductor devices, particularly power semiconductor packages, faces challenges in mechanical stability due to limited electrical leads, which restrict the number of functional leads and hinder secure anchoring to circuit boards, especially in small packages where creepage and clearance requirements are stringent.
Innovation Solution
The introduction of dummy leads that are not electrically or thermally coupled to other components within the package, positioned in corner regions to enhance mechanical stability without compromising creepage or clearance distances, allowing for improved anchoring and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the number of electrical leads is increased to improve mechanical stability and anchoring, then the mechanical stability improves, but the creepage and clearance requirements cannot be met
Solution Approach 1:
The patent segments the leads into two distinct types: electrical leads that maintain creepage and clearance distances for proper electrical isolation, and dummy leads that provide mechanical stability without electrical coupling. This segmentation allows each type of lead to fulfill its specific function without compromising the other requirement.
Solution Approach 2:
The dummy leads act as intermediaries that provide mechanical anchoring and stress distribution without creating electrical coupling paths. They mediate between the structural support function and the electrical isolation requirement by being present in the package structure while explicitly not being electrically coupled to other components.
2Stability of the object's composition
If dummy leads are added to improve mechanical anchoring, then the anchoring improves, but the device complexity increases
Solution Approach 1:
The dummy leads provide multiple functions: they serve as mechanical anchors to improve stability, distribute stress uniformly across the package, and maintain proper spacing from electrical leads. By consolidating these functions into a single structural element, the overall device complexity is managed while achieving multiple objectives.
3Area of stationary object
If leads are placed closer together to reduce package size, then the package dimensions are reduced, but the creepage distance requirements are violated
Solution Approach 1:
The patent applies different spacing rules to different regions and lead types. Electrical leads maintain the required creepage and clearance distances from each other, while dummy leads can be positioned more flexibly. This local differentiation of quality requirements allows compact packaging while preserving electrical isolation where needed.
Data Source
AI summary
In accordance with an embodiment of the present invention, a semiconductor package includes a die paddle, and an encapsulant disposed around the die paddle. The semiconductor package has a first sidewall and a second sidewall. The second sidewall is perpendicular to the first sidewall. The first sidewall and the second sidewall define a corner region. A tie bar is disposed within the encapsulant. The tie bar couples the die paddle and extends away from the die paddle. A dummy lead is disposed in the corner region. The dummy lead is not electrically coupled to another electrically conductive component within the semiconductor package. The distance between the dummy lead and the tie bar is less than a shortest distance between the tie bar and other leads or other tie bars in the semiconductor package.