Continuous Lead Frame Assembly for Lower MOSFET On-Resistance
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Solution Overview
Problem
Existing lead frame arrangements for semiconductor devices result in increased connection resistance between the semiconductor die and external leads, leading to higher device resistance, particularly in MOSFETs where the clip member acts as a source connection.
Innovation Solution
A lead frame assembly with a continuous, merged lead portion integrally formed with a die connection portion, featuring slots or holes, and gull-wing bends to maximize current handling and minimize spreading resistance, while maintaining low inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lead frame arrangement with separate lead portions is used, then the manufacturing process is simpler, but the connection resistance increases
Solution Approach 1:
The patent merges the first lead portion and second lead portion into a single continuous lead structure that extends from the first external lead through the die connection portion to the second external lead. This continuous integration eliminates the discontinuity and potential high-resistance joints between separate lead portions, thereby reducing overall connection resistance while maintaining a relatively simple manufacturing process.
2Reliability
If a continuous merged lead portion is used, then spreading resistance is minimized, but the manufacturing complexity increases
Solution Approach 1:
While the lead portion is continuous, the patent incorporates slots or holes at specific locations along the lead structure. These segmented features serve multiple purposes: they reduce material usage and weight, provide expansion compensation, and facilitate manufacturing processes such as stamping and forming. The segmentation allows the continuous lead to be fabricated using standard sheet metal processes without requiring complex multi-step assembly.
3Reliability
If the lead portion is made continuous and merged, then inductance is reduced, but the structural complexity increases
Solution Approach 1:
The patent utilizes three-dimensional shaping of the continuous lead portion, including bends and spatial arrangements, to optimize electrical performance. The lead is formed with specific geometric configurations in multiple dimensions that minimize loop area and optimize current flow paths, thereby reducing inductance. This dimensional optimization is achieved through standard lead frame forming processes rather than complex assembly.
Data Source
AI summary
This disclosure relates to a lead frame assembly for a semiconductor device, a semiconductor device and an associated method of manufacture. The lead frame assembly includes a die attach structure and a clip frame structure. The clip frame structure includes a die connection portion configured to contact a contact terminal on a top side of the semiconductor die; and a continuous lead portion extending along the die connection portion. The continuous lead portion is integrally formed with the die connection portion.