3D Thermal Pad for Electronic Device Heat Transfer
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Solution Overview
Problem
The existing thermal management in packaged electronic devices is limited by the size of thermal pads and the quality of solder connections, which restricts heat transfer and makes visual inspection of solder joints impossible due to their location underneath the device package.
Innovation Solution
The implementation of a three-dimensional thermal pad structure with a first portion extending along one side and a second portion extending at a non-zero angle from the first portion, allowing for enhanced heat transfer and visually observable solder joints for quality inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thermal pad is located along the bottom of the device package, then heat transfer is achieved, but the usable thermal pad area is limited by isolation spacing requirements and the solder joint quality cannot be visually inspected
Solution Approach 1:
The thermal pad is extended from a two-dimensional bottom surface configuration to a three-dimensional structure that includes side portions extending along the leads. This dimensional expansion allows the thermal pad to utilize vertical and lateral space that would otherwise be unavailable, effectively increasing the heat transfer area without violating bottom side isolation spacing requirements.
2Temperature
If the thermal pad is located along the bottom of the device package, then heat transfer is achieved, but the solder joint quality cannot be visually inspected
Solution Approach 1:
The side portions of the thermal pad extending along the leads serve as intermediary elements that are visible from the side of the device package. These portions act as proxies for the hidden bottom solder joints, allowing inspection of solder joint quality through visual examination of the side extensions without requiring X-ray or other complex inspection methods.
3Temperature
If the thermal pad size is increased to improve heat transfer, then thermal performance is enhanced, but the device package bottom side space is insufficient due to isolation spacing requirements
Solution Approach 1:
The thermal pad configuration transitions from a purely planar bottom surface layout to a three-dimensional structure with vertical and lateral extensions along the leads. This allows the thermal pad to occupy space in multiple dimensions rather than being constrained to the two-dimensional bottom surface, effectively increasing heat transfer area while maintaining compliance with bottom side isolation spacing.
4Reliability
If the solder joint is placed underneath the device package for thermal connection, then heat transfer is achieved, but the quality of solder joint cannot be inspected visually
Solution Approach 1:
The side portions of the thermal pad extending along the leads function as visible intermediaries that correlate with the hidden bottom solder joints. By examining the solder joints on these side extensions, inspectors can assess the quality of the primary bottom solder connections without direct visual access, thereby maintaining reliability assessment capability.
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 configuration enhances thermal performance by increasing the heat transfer area and facilitates visible inspection of solder joints, reducing the need for costly x-ray inspections and improving manufacturing efficiency.
Implementation Method 1
Thermal pads, sometimes referred to as power pads, can be located along the bottom of the electronic device package for soldering to conductive pads of the host PCB to draw heat away from the electronic device
Data Source
AI summary
An electronic device includes a package structure with opposite first and second sides spaced apart along a first direction, opposite third and fourth sides spaced apart along a second direction, opposite fifth and sixth sides spaced apart along a third direction, the first, second, and third directions being orthogonal to one another. A set of first leads extend outward from the first side along the first direction, a set of second leads extend outward from the second side along the first direction, and a thermal pad includes a first portion that extends along a portion of the fifth side, and a second portion that extends along a portion of the third side to facilitate cooling and visual solder inspection when soldered to a host printed circuit board.