Top-Side Heat Slug Structure for Compact Semiconductor Cooling
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Solution Overview
Problem
Conventional semiconductor packages for GaN and SiC transistors have limited heat dissipation due to a small thermal contact area with the semiconductor die, leading to ineffective cooling, especially for lateral power FETs where heat dissipation is insufficient.
Innovation Solution
An open cavity is created in the mold compound on the top side of the semiconductor package to accommodate a larger heat slug, which is thermally conductive and attached to the DAP, enhancing heat spreading and dissipation across the package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional DAP configuration is used with small area, then the package size can be kept small, but the heat dissipation capability is insufficient
Solution Approach 1:
The patent extends the heat dissipation path from the traditional bottom-side-only approach to include both bottom and top sides of the package. By creating a cavity in the mold compound and placing a heat slug on the top side, the invention utilizes the third dimension (vertical space) to increase thermal contact area without expanding the package footprint, thereby resolving the contradiction between heat dissipation capability and package size.
2Temperature
If the thermal contact area with the semiconductor die is increased, then heat dissipation improves, but the package structure becomes more complex
Solution Approach 1:
The patent extracts the heat slug from the traditional DAP configuration and places it separately on the top side of the package within a cavity. This separation allows the heat slug to be independently optimized for thermal contact with the semiconductor die while the DAP maintains its electrical connection function, thereby improving heat dissipation without significantly complicating the overall package structure.
3Reliability
If a larger heat slug is used to improve cooling, then thermal resistance decreases, but the mold compound structure becomes more complex
Solution Approach 1:
The patent incorporates the cavity formation into the mold compound manufacturing process itself, creating the cavity structure during molding. This preliminary action allows the larger heat slug to be accommodated without requiring post-processing modifications or additional assembly steps, thereby improving cooling performance while minimizing the complexity of the mold compound structure.
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
This solution improves cooling performance by increasing the thermal contact area, reducing thermal resistance by at least 20% and ensuring better temperature uniformity across the semiconductor die, even in constrained package sizes.
Implementation Method 1
the heat slug is attached by its bottom side with a thermally conductive material to a top side portion of the DAP
Data Source
AI summary
A semiconductor package includes a leadframe including leads and a die attach pad (DAP) inside the leads, and at least one semiconductor die having a top side including circuitry electrically connected to bond pads and a bottom side attached to a bottom side portion of the DAP. The package includes a mold compound and a heat slug having a top side and a bottom side positioned within a cavity defined by sidewalls of the mold compound. The heat slug has an area greater than an area of the DAP is attached by its bottom side with a thermally conductive adhesive material to a top side portion of the DAP. Bondwires are between the leads and the bond pads. Exposed from the mold compound is a bottom side surfaces of the leads and the top side of the heat slug.