Leadframe Package Structure With Thin Lead Extensions for Cooling
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Solution Overview
Problem
Existing package structures with routable leads often lack cooling functions, leading to poor electric properties and reliability issues due to wire breakage or contact with the die periphery, and require redesign to maintain both flexible wiring and cooling capabilities.
Innovation Solution
A leadframe design with leads having main body and extending portions, where the extending portions have a thickness less than the main body portions, allowing for flexible wiring and electrical adjustments while maintaining cooling functionality through a die pad with integrated thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If routable leads are used to allow flexible wiring layout, then wire breakage and contact with die periphery are reduced, but the die pad is excluded and cooling function is lost
Solution Approach 1:
The patent merges the routable lead structure with the die pad cooling function into a single integrated leadframe design. The leads extend from the die pad without excluding it, allowing both flexible wire routing and thermal cooling to coexist in one structure.
Solution Approach 2:
The leadframe structure serves multiple functions simultaneously: it provides flexible routable leads for wire connection and maintains the die pad for cooling. This multi-functional design eliminates the need to choose between reliability improvement and cooling capability.
2Ease of operation
If wires are pulled to lead locations on different sides, then electrical connection is achieved, but wire length increases causing breakage or contact with die periphery
Solution Approach 1:
The patent utilizes three-dimensional leadframe structure with leads extending in multiple directions and levels. This spatial arrangement allows wires to reach connection points more directly, reducing wire length while maintaining electrical connectivity.
Solution Approach 2:
The leadframe is pre-configured with optimally positioned leads during manufacturing, so that wires have shorter and more direct paths to connection points. This preliminary arrangement of connection elements eliminates the need for excessively long wire pulls.
3Adaptability or versatility
If the extending portion of leads has reduced thickness, then flexible wiring and electrical adjustments are enabled, but manufacturing precision requirements increase
Solution Approach 1:
The leadframe features varying thickness along the lead structure, with thinner extending portions for flexibility and thicker main body portions for strength. This localized variation in geometry allows each section to be optimized for its specific function while managing manufacturing tolerances.
Solution Approach 2:
The patent employs parameter changes in lead thickness to achieve different functional requirements. By controlling the thickness parameter across different lead sections, the design balances flexibility needs with manufacturability constraints.
Data Source
AI summary
A package structure includes a leadframe, at least one semiconductor die and a plastic package material. The leadframe includes a die pad and a plurality of leads, wherein the leads are located on two sides of the leadframe, respectively. The semiconductor die is disposed on the die pad of the leadframe. The plastic package material is disposed on the leadframe. At least one of the leads has a main body portion and an extending portion, the extending portion extends towards a side of the die pad, a thickness of the extending portion is less than a thickness of the main body portion, and the plastic package material entirely covers the extending portion.