Semiconductor Package With Asymmetric Lead Lengths
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Solution Overview
Problem
The challenge is to reduce the space occupied by semiconductor packages on printed circuit boards (PCBs) to enable smaller electronic devices or to accommodate more packages without increasing the device size, while maintaining efficient electrical coupling and minimizing short circuits.
Innovation Solution
The design incorporates a semiconductor package with a lead frame featuring a die pad, first leads, and multiple second leads, where the second leads extend farther than the first leads, allowing for efficient packaging and reduced PCB space usage by enabling direct electrical coupling without shorting, and utilizing a mold material to encapsulate the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leads are made longer to extend beyond the package, then electrical coupling efficiency is improved, but PCB space usage increases
Solution Approach 1:
The patent applies local quality by making different leads have different lengths based on their specific functional requirements. The first lead extends beyond the package to enable direct coupling with adjacent packages, while the second lead is shorter and remains encapsulated, optimizing each lead's length for its particular electrical coupling need rather than using a uniform length for all leads.
2Area of stationary object
If multiple packages are placed closer together to reduce device size, then space efficiency is improved, but risk of short circuits increases
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric lead configuration where the first lead extends beyond the package while the second lead is shorter and encapsulated within the mold material. This asymmetric design allows adjacent packages to be placed closer together for space efficiency, while the extended first lead provides sufficient electrical isolation to prevent short circuits between packages.
3Reliability
If lead length is reduced to minimize resistance, then electrical efficiency is improved, but coupling distance capability worsens
Solution Approach 1:
The patent applies segmentation by dividing the lead structure into two distinct segments: a first lead that extends beyond the package for long-distance coupling with adjacent packages, and a second lead that is shorter for minimizing resistance in local connections. This segmented approach allows the system to optimize for both coupling distance and electrical efficiency simultaneously by assigning different lead lengths to different functional requirements.
Data Source
AI summary
A semiconductor package includes a die pad, a die, a first lead, a plurality of second leads, and a mold material. The die is electrically coupled to the die pad. The first lead is electrically coupled to the die. The plurality of second leads are electrically coupled to the die. The plurality of second leads are adjacent to the first lead. The mold material encapsulates at least a portion of the die pad, the die, the first lead, and the plurality of second leads. Each of the plurality of second leads extends a farther distance from the mold material than the first lead.