Conductive Clip Inspection Structure for Semiconductor Packages
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Solution Overview
Problem
Current semiconductor packages using conductive clips face challenges in inspecting conductive solder coverage between the clip and the semiconductor die, relying on inadequate methods such as X-Ray examination and trial-and-error process control, which are time-consuming and costly, and fail to detect all relevant conditions for optimal solder coverage.
Innovation Solution
Incorporating inspection features or openings in the conductive clips that allow conductive material to form a fillet within these openings, enabling automated inspection of solder coverage before encapsulation, thereby improving reliability and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conductive clips are used to connect semiconductor die to conductive leads, then current carrying capability is improved, but ability to inspect solder coverage deteriorates
Solution Approach 1:
The conductive clip is segmented by forming openings or cutouts in its body, which divides the solid structure into regions that allow optical access. This segmentation enables inspection of the solder fillet between the semiconductor die and the clip without compromising the electrical connectivity function of the clip.
Solution Approach 2:
The opening in the conductive clip acts as an intermediary that allows light to access the solder fillet region. This creates an optical pathway through which automated optical inspection systems can detect solder coverage quality without direct line-of-sight to the buried joint.
2Measurement precision
If X-Ray examination is used to detect voiding defects, then detection capability is improved, but manufacturing cost and time consumption deteriorate
Solution Approach 1:
The patent replaces X-Ray examination with automated optical inspection by incorporating openings in the conductive clip that allow light to access the solder fillet. This substitution eliminates the need for expensive and time-consuming X-Ray equipment while achieving comparable or superior inspection capability for solder coverage and void detection.
Solution Approach 2:
The opening in the conductive clip creates an optical copy or representation of the solder fillet condition that can be viewed by optical inspection systems. This allows the inspection process to work with optical images rather than requiring direct X-Ray imaging of the actual joint.
3Manufacturing precision
If trial and error process control methods are used to establish solder attach parameters, then process window characterization is improved, but manufacturing cost and time consumption deteriorate
Solution Approach 1:
The openings in the conductive clip are formed during clip manufacturing, before the solder attach process. This preliminary action enables real-time optical monitoring of the solder fillet during production, allowing immediate feedback and adjustment without requiring separate trial runs or extensive process characterization experiments.
Solution Approach 2:
The optical inspection capability provided by the openings enables real-time feedback on solder fillet quality during the manufacturing process. This allows for continuous process optimization and reduces the need for extensive trial-and-error characterization, as process parameters can be adjusted based on immediate visual feedback from the solder joint.
Data Source
AI summary
An electronic device structure includes a leadframe with a die pad and a lead. A semiconductor die is mounted adjacent to the die pad. A clip having a clip tail section is attached to the lead. The clip further has a clip top section attached to the clip tail section, and the clip top section is attached to a die top side of the semiconductor die with a conductive material. The clip further has an opening disposed to extend through the clip top section. In one embodiment, after a reflow step the conductive material forms a conductive fillet at least partially covering sidewall surfaces of the opening, and has a height within the opening with respect to a bottom surface of the clip top section. The opening and the conductive fillet provide an improved approach to monitoring coverage of the conductive material between the clip top section and the die top side of the semiconductor die.