Slanted Lead Frame Structure for Heat Dissipation and Solder Wetting
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Solution Overview
Problem
Existing semiconductor packages face challenges in heat dissipation and solder reflow process wettability, which affect their performance and manufacturing costs.
Innovation Solution
A semiconductor package design featuring a lead frame with slanted sections, where portions are exposed from the top, side, and bottom surfaces of the molding encapsulation, enhancing heat dissipation and solder reflow wettability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lead frame is fully enclosed by molding encapsulation, then the structural integrity is improved, but the heat dissipation capacity deteriorates
Solution Approach 1:
The patent extracts portions of the lead frame (first portion and second portion) from the molding encapsulation. The first portion is exposed from the top surface and the second portion is exposed from the side and bottom surfaces, creating heat dissipation pathways while maintaining the encapsulated structure for structural integrity.
Solution Approach 2:
The patent applies different treatments to different portions of the lead frame. The first portion has a specific thickness configuration for heat dissipation, while the second portion is positioned for wettability. This local differentiation allows each region to serve its specific function optimally.
2Reliability
If the lead frame is fully enclosed by molding encapsulation, then the protection is improved, but the wettability in solder reflow process deteriorates
Solution Approach 1:
The patent extracts the second portion of the lead frame from the molding encapsulation, exposing it from the side surfaces and bottom surface. This exposed portion provides direct contact with solder material during the reflow process, ensuring proper wettability while the rest of the structure remains protected by encapsulation.
3Ease of manufacture
If the top plate thickness is uniform, then the manufacturing simplicity is improved, but the integration with molding encapsulation deteriorates
Solution Approach 1:
The patent implements a non-uniform thickness distribution in the top plate, with a first thickness in a first region and a second thickness in a second region. This local variation optimizes the integration between the top plate and molding encapsulation, allowing for better mechanical interlocking and thermal management at specific locations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design improves heat dissipation and wettability, reducing manufacturing costs and enhancing the overall performance of the semiconductor package.
Implementation Method 1
A top surface of the thicker region of the top plate of the lead frame is exposed from a top surface of the molding encapsulation
Implementation Method 2
a second portion of the lead frame exposed from the side surfaces and the bottom surface of the molding encapsulation facilitating wettability in a solder reflow process
Data Source
AI summary
A semiconductor package comprises a lead frame, a chip, and a molding encapsulation. The lead frame comprises a top plate, a plurality of drain pads, a plurality of slanted sections, a gate pad, and a plurality of source pads. The top plate of the lead frame comprises a thicker region and a thinner region. Each slanted section of the plurality of slanted sections connects a respective drain pad of the plurality of drain pads to the top plate. A respective side surface of each drain pad of the plurality of drain pads is exposed from a side surface of the molding encapsulation. A respective bottom surface of each drain pad of the plurality of drain pads is exposed from a bottom surface of the molding encapsulation. A top surface of the thicker region is exposed from a top surface of the molding encapsulation.