Leadframe Die Pad Cooling Fins for Compact Package Heat Dissipation
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Solution Overview
Problem
Semiconductor packages face challenges in effectively dissipating heat due to limited heat dissipation paths, which can lead to thermal integrity issues and require additional cooling devices.
Innovation Solution
The integration of cooling fins into the die pad of leadframe semiconductor packages, formed by recesses in the die pad, provides enhanced heat dissipation and anchoring within the encapsulation material, eliminating the need for separate cooling devices like heat sinks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional flat leadless packages are used, then small package size is achieved, but heat dissipation capability is insufficient
Solution Approach 1:
The patent introduces cooling fins that extend vertically from the bottom surface of the die pad, transforming the heat dissipation structure from a two-dimensional flat surface to a three-dimensional configuration. This dimensional change increases the heat transfer surface area without significantly increasing the package footprint, allowing improved heat dissipation while maintaining compact package size.
Solution Approach 2:
The die pad is segmented by forming recesses that create multiple cooling fins. Instead of a single solid die pad, the structure is divided into fin elements separated by recesses, which increases the surface area available for heat transfer to the molding compound and surrounding environment, thereby enhancing heat dissipation capability.
2Reliability
If thicker die pad is used, then heat dissipation and anchoring are improved, but package complexity increases
Solution Approach 1:
The thicker die pad structure serves multiple functions simultaneously: it provides enhanced heat dissipation through increased thermal mass and surface area, and it improves mechanical anchoring within the molding compound. This multi-functional design eliminates the need for separate cooling devices and reinforces, achieving reliability improvements without proportionally increasing structural complexity.
Solution Approach 2:
The patent combines the heat dissipation function and mechanical anchoring function into a single integrated thicker die pad structure. The same die pad that provides electrical connection also serves as the heat sink and mechanical anchor, eliminating the need for separate heat sink components and reducing overall package complexity despite the increased thickness.
3Area of stationary object
If cooling fins are added to die pad, then heat dissipation surface area is increased, but manufacturing complexity increases
Solution Approach 1:
The cooling fins are formed by creating recesses in the die pad before the die is mounted and before the molding compound is applied. This preliminary formation of the heat dissipation structure allows the fins to be integrated into the package manufacturing process without requiring additional post-assembly steps, thereby increasing surface area while managing manufacturing complexity.
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 solution improves heat dissipation and thermal integrity by increasing the surface area for heat transfer, allowing for efficient cooling without the need for external cooling devices, thus enhancing the overall performance and reliability of semiconductor packages.
Implementation Method 1
The cooling fins are defined by recesses formed in the die pad. The recesses extend into the die pad at a bottom surface of the semiconductor package, such that the bottom surfaces of the cooling fins of the die pad are flush or coplanar with a surface of the package body
Data Source
AI summary
Embodiments of the present disclosure are directed to leadframe semiconductor packages having die pads with cooling fins. In at least one embodiment, the leadframe semiconductor package includes leads and a semiconductor die (or chip) coupled to a die pad with cooling fins. The cooling fins are defined by recesses formed in the die pad. The recesses extend into the die pad at a bottom surface of the semiconductor package, such that the bottom surfaces of the cooling fins of the die pad are flush or coplanar with a surface of the package body, such as an encapsulation material. Furthermore, bottom surfaces of the cooling fins of the die pad are flush or coplanar with exposed bottom surfaces of the leads.