Continuous Lead Frame Clip Structure for Lower MOSFET 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, integrally formed lead portion that extends across the width of the die connection portion, featuring bends to contact a carrier, maximizes operating current and minimizes spreading resistance by eliminating bifurcation and optimizing the footprint for maximum current handling and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lead frame arrangement with separate lead portions is used, then the structure is simpler to manufacture, but the connection resistance increases
Solution Approach 1:
The patent merges multiple separate lead portions into a single continuous lead portion that is integrally formed with the die connection portion. This continuous lead structure eliminates the need for separate leads and their associated solder connections, thereby reducing connection resistance while maintaining manufacturability through integral forming processes.
2Reliability
If a solder connection is used to connect the clip member to external leads, then the assembly process is simplified, but the connection resistance increases
Solution Approach 1:
The continuous lead portion is integrally formed with the die connection portion, creating a unified structure that eliminates the need for separate solder connections between the clip member and external leads. This integral construction reduces connection resistance while the continuous forming process maintains ease of manufacture.
Solution Approach 2:
The continuous lead portion provides an uninterrupted conductive path from the die connection portion to the external leads, eliminating discontinuities introduced by solder joints. This continuous structure maintains low resistance while the integral forming process ensures manufacturability.
3Reliability
If the lead portion is made continuous and integrally formed, then the spreading resistance decreases, but the manufacturing precision requirements increase
Solution Approach 1:
By integrating the continuous lead portion with the die connection portion in a single formed structure, the patent achieves low spreading resistance through continuous conductivity. Modern integral forming processes can achieve the required geometric precision, balancing the reduced resistance with manufacturable tolerance levels.
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.