Semiconductor Die Leadframe Cantilevered Fingers Thermal Dissipation
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Solution Overview
Problem
Current semiconductor packaging methods face challenges in heat exchange with PCBs, leading to insufficient cooling and complex, costly testing procedures due to limited electrical and thermal access.
Innovation Solution
An electronic device with a semiconductor die and a leadframe structure that includes a die-attach pad and cantilevered fingers, where the die is encapsulated with a polymeric layer, allowing for electrical access from both sides and enhanced thermal dissipation through a conductive sheet or leadframe surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bottom surface region of the leadframe is designed to lie in the same plane as the bottom surface of the package to provide electrical connections, then electrical coupling with PCB is achieved, but heat exchange with PCB is insufficient for adequate cooling
Solution Approach 1:
The invention transitions from a two-dimensional planar contact interface to a three-dimensional protruding structure. The fingers extend vertically from the bottom surface of the package, creating multiple elevation levels that increase both electrical contact area and thermal exchange surface with the PCB, thereby resolving the contradiction between electrical coupling and heat exchange.
Solution Approach 2:
The leadframe structure is divided into multiple separate fingers instead of a single continuous bottom surface. Each finger acts as an independent electrical and thermal contact element, allowing simultaneous optimization of electrical coupling (through multiple contact points) and heat exchange (through increased surface area), thus resolving the contradiction.
2Reliability
If the bottom surface region of the leadframe provides electrical-contact regions, then electrical connections are established, but testing operations become complex and costly requiring dedicated PCB bonding
Solution Approach 1:
The protruding fingers provide self-contained electrical access that eliminates the need for external dedicated test PCBs. The structure serves its own testing needs by providing accessible electrical contacts that can be probed directly, thereby simplifying testing operations and reducing complexity while maintaining reliable electrical connections.
3Area of stationary object
If the package uses flat bottom surface for electrical connections, then package dimensions are minimized, but thermal dissipation capability is limited
Solution Approach 1:
The invention adds vertical dimension to the contact interface by protruding fingers extending from the bottom surface. This maintains the minimal package footprint area while dramatically increasing the thermal dissipation surface area through the vertical extent of the fingers, thereby resolving the contradiction between compact dimensions and thermal performance.
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 design improves thermal dissipation and simplifies testing by enabling flexible circuit design and independent power supply and signal control, reducing testing complexity and enhancing heat exchange efficiency.
Implementation Method 1
enhanced thermal dissipation through a conductive sheet or leadframe surface
Data Source
AI summary
An electronic device comprising: a semiconductor die integrating an electronic component; a leadframe housing the semiconductor die; a protection body, which surrounds laterally and at the top the semiconductor die and, at least in part, the leadframe structure, defining a top surface, a bottom surface, and a thickness of the electronic device; and a conductive lead electrically coupled to the semiconductor die. The conductive lead is modelled in such a way as to extend throughout the thickness of the protection body for forming a front electrical contact accessible from the top surface of the electronic device, and a rear electrical contact accessible from the bottom surface of the electronic device.