Semiconductor Package Connection Lug Creepage Clearance
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Solution Overview
Problem
High voltage semiconductor devices in densely packed arrangements face challenges with creepage and clearance distances, leading to electrical breakdown and arcing issues, particularly in power electronics circuits where large potential differences need to be routed in congested areas.
Innovation Solution
A semiconductor package design with a connection lug on one side and package leads on the opposite side of the encapsulant body, allowing for increased creepage and clearance distances, and enabling power and reference potential distribution into separate vertical planes, with the connection lug connected to a busbar for voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple discrete power semiconductor packages are arranged in a densely packed arrangement, then the board space utilization is improved, but the creepage distance and clearance distance between load terminals are reduced, leading to electrical breakdown and arcing issues
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional planar arrangement where all terminals are on one side to a three-dimensional configuration with terminals distributed on opposite faces of the encapsulant body. The load terminals are positioned on the rear face while control terminals remain on the front face, creating vertical separation in the z-dimension that increases creepage and clearance distances without increasing the horizontal footprint on the PCB.
Solution Approach 2:
The patent segments the terminal connections by separating load terminals from control terminals into different spatial locations. Load terminals (source/drain, collector/emitter, anode/cathode) are connected to the connection lug on the rear face, while control terminals (gate, base) remain on the front face with package leads. This segmentation allows independent routing paths that maintain required electrical clearances while enabling dense packing.
2Ease of manufacture
If through-hole type leads are used for all terminals, then the manufacturing process is simplified, but the creepage distance requirements increase the overall footprint of the package
Solution Approach 1:
The patent uses dimensionality change by providing load terminals through the connection lug that extends through the encapsulant body from the rear face, rather than requiring all terminals to be accessed from the front face. This through-type connection allows load terminals to be positioned on the opposite face from control terminals, reducing the horizontal spacing requirements while maintaining adequate creepage distances through the vertical dimension.
3Area of stationary object
If load terminals are positioned close together to reduce package footprint, then the board space is reduced, but the risk of electrical arcing and breakdown increases under high voltage conditions
Solution Approach 1:
The patent effectively uses the third dimension (depth/through-thickness of encapsulant) to separate high-voltage load terminals from low-voltage control terminals. The connection lug provides a protected path through the encapsulant body, and load terminals on the rear face are spatially separated from front-face control terminals, maintaining adequate creepage and clearance distances even when the package footprint is minimized.
Solution Approach 2:
The encapsulant body acts as an intermediary that provides electrical insulation and physical separation between load terminals and control terminals. The connection lug serves as a protected intermediary structure that carries high-voltage connections through the encapsulant, shielding the critical clearance paths and preventing direct exposure of high-voltage terminals to the external environment where arcing could occur.
Data Source
AI summary
A semiconductor package includes a first die pad, a first semiconductor die mounted on the first die pad, an encapsulant body of electrically insulating material that encapsulates first die pad and the first semiconductor die, a plurality of package leads that each protrude out of a first outer face of the encapsulant body, a connection lug that protrudes out of a second outer face of the encapsulant body, the second outer face being opposite from the first outer face. The first semiconductor die includes first and second voltage blocking terminals. The connection lug is electrically connected to one of the first and second voltage blocking terminals of the first semiconductor die. A first one of the package leads is electrically connected to an opposite one of the first and second voltage blocking terminals of the first semiconductor die that the first connection lug is electrically connected to.