Leadframe on Heat Sink Packages for Thermal and Electrical Optimization
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Solution Overview
Problem
Conventional semiconductor packaging technologies face challenges in achieving both high electrical and thermal performance while maintaining low production costs, particularly in high-speed applications, due to issues with parasitic effects, heat dissipation, and compatibility with standard leadframe processes.
Innovation Solution
The integration of a leadframe on a heat sink with divisional power and ground regions, combined with a system in package (SiP) configuration that includes semiconductor dies attached to the leadframe with wire bonds, and an encapsulation layer that exposes the heat dissipating surface, allowing for reduced lead count and improved thermal and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional semiconductor packaging is used, then production cost is reduced, but thermal performance and electrical performance deteriorate
Solution Approach 1:
The patent merges the heat sink and leadframe into a single integrated component. The leadframe serves dual functions as both electrical interconnect and thermal management structure, eliminating the need for separate heat sink components while improving both thermal and electrical performance simultaneously
Solution Approach 2:
The leadframe is designed to perform multiple functions: electrical interconnection, mechanical support, and thermal dissipation. By making the leadframe thermally conductive and integrating it with the heat sink function, a single component achieves what previously required multiple separate elements
2Reliability
If heat sink acts as ground plane, then electrical performance is improved, but parasitic effects increase
Solution Approach 1:
The leadframe is segmented into multiple functional zones including signal leads, power leads, ground leads, and thermal management regions. This segmentation allows separate optimization of electrical performance and thermal dissipation paths, reducing parasitic coupling between different signal paths while maintaining effective ground planes
3Device complexity
If lead count is reduced, then package complexity is reduced, but electrical performance deteriorates
Solution Approach 1:
The patent combines multiple electrical functions into fewer leadframe elements. The integrated leadframe structure provides multiple ground paths and power distribution networks within a reduced lead count, maintaining electrical performance through clever structural design rather than increased component count
Solution Approach 2:
Each leadframe element is designed to serve multiple functions simultaneously. For example, certain leads provide both mechanical support and electrical connection, while the heat sink portion provides both thermal management and additional ground plane area, effectively reducing the number of discrete components needed
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 approach enhances signal and power integrity, reduces package dimensions, and improves heat removal, leading to better electrical performance and reduced parasitic parameters, while being compatible with standard leadframe processes and allowing for more design flexibility in high-speed applications.
Implementation Method 1
The heat sink can be pre-divided into several PWR and GND regions to reduce number of leads further shrinking package dimensions
Implementation Method 2
a plurality of wire bonds electrically connecting the set of semiconductor dies to the leadframe and to the divisional heat sinks respectively
Data Source
AI summary
The invention relates to leadframe semiconductor packages mounted on a heat-sink and fabrication thereof. A system in package (SiP) comprises a leadframe having extension leads, configured with divisional heat sinks serving as power and ground nets. A set of semiconductor dies is attached by adhesive on the central region of the lead frame. Pluralities of wire bonds electrically connect the set of semiconductor dies to the leadframe and to the divisional heat sinks respectively. An encapsulation encloses the leadframe, but leaves the extension leads and the divisional heat sink uncovered, exposing a heat dissipating surface.