Clip Finger Geometry for IC Package Thermal and Inspection Trade-off
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Solution Overview
Problem
The quality of electrical connections between lead frames and the die in integrated circuit (IC) packages is challenging, particularly due to susceptibility to power surges during manufacturing and operation, which can damage circuitry and undermine connection reliability.
Innovation Solution
An electrically-conductive clip is configured with a finger portion that extends beyond the solderable inner region boundaries, providing heat dissipation and exposure for inspection and cleaning, while maintaining sufficient contact area and thermally-conductive mass to manage surge currents and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the clip finger portion is made wider to improve heat dissipation, then thermal management improves, but the inspection and cleaning capability deteriorates
Solution Approach 1:
The clip finger portion is designed with non-uniform width: wider at the base for heat dissipation and narrower at the tip for inspection access. This local variation in geometry allows different regions to serve different functions - thermal management where needed and inspection access where required - resolving the contradiction between heat dissipation and inspection capability.
2Measurement precision
If the clip finger portion is made narrower to improve inspection access, then inspection capability improves, but heat dissipation capability deteriorates
Solution Approach 1:
The gradient width design provides narrow sections for inspection access while maintaining wide base sections for heat dissipation. This spatial differentiation of geometry allows the clip to simultaneously achieve both inspection capability and thermal management without compromising either function.
3Reliability
If the clip extends further beyond the solderable region to improve surge current handling, then reliability improves, but the manufacturing complexity increases
Solution Approach 1:
The clip finger portion is segmented into distinct functional zones: a wide base section for thermal management and surge current handling, and a narrower tip section for inspection access. This segmentation allows each zone to be optimized for its specific function while keeping the overall design manageable and manufacturable.
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 effectively handles significant surge currents, prevents overheating, and ensures reliable electrical connections by dissipating heat and allowing for thorough cleaning and inspection, thereby enhancing the reliability and performance of IC packages.
Implementation Method 1
The solderable inner region is shaped or configured with a width between opposing portions of the outer region, so as to be electrically coupled and secured to the conductor via solder
Implementation Method 2
providing heat dissipation and exposure for inspection and cleaning, while maintaining sufficient contact area and thermally-conductive mass to manage surge currents and prevent overheating
Data Source
AI summary
Various example embodiments concern an integrated circuit (IC) package having a clip with a protruding tough-shaped finger portion. The clip can be used in various IC packages including, for example, soft-soldered compact power packages such as rectifiers with specified surge current capability. Such embodiments can be implemented to allow for a visual inspection capability of the soldering area for connecting a lead frame, via the clip, to a surface of the IC package die, while still providing sufficient thermal mass to limit the temperature increase during forward surge current loads. This results in a simple to manufacture design without compromising too much on performance.