Leadframe Notch for Clip Alignment in Semiconductor Packages
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Solution Overview
Problem
Semiconductor packages face inconsistencies due to manufacturing variations in clip tail length and bend angle, affecting planar alignment and coupling between conductive clips and semiconductor dies.
Innovation Solution
Incorporating a top notch on the leadframe that accommodates variations in clip length by allowing the clip edge to sink into the notch, preventing tilting and ensuring consistent alignment and coupling through the use of a conductive material like copper and its alloys, and forming the notch via etching or mechanical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional semiconductor packaging methods are used without alignment notches, then the manufacturing process is simpler, but manufacturing variations in clip tail length and bend angle cause inconsistencies in planar alignment and coupling between conductive clips and semiconductor dies
Solution Approach 1:
The alignment notch is pre-formed on the leadframe before the clip attachment process. This preliminary structural feature guides the clip into proper alignment during subsequent manufacturing steps, compensating for variations in clip tail length and bend angle that occur during clip formation and attachment.
Solution Approach 2:
The alignment notch acts as an intermediary element between the leadframe and the conductive clip. It provides a physical reference and constraint that mediates the alignment relationship, ensuring consistent positioning of the clip relative to the semiconductor die despite manufacturing variations in the clip itself.
2Ease of manufacture
If manufacturing variations in clip tail length and bend angle are tolerated, then the manufacturing process remains simple and cost-effective, but planar alignment and coupling consistency between conductive clips and semiconductor dies deteriorates
Solution Approach 1:
The invention changes the geometric parameters of the leadframe by adding the alignment notch feature. This structural modification allows the system to tolerate a wider range of clip tail lengths and bend angles while maintaining consistent coupling, effectively decoupling the reliability of the joint from the precision of the clip manufacturing parameters.
Solution Approach 2:
By pre-forming the alignment notch on the leadframe, the system establishes a reference geometry before clip attachment. This allows clips with varying dimensions to be accommodated within the notch structure, maintaining coupling consistency without requiring tight control over clip manufacturing parameters, thus preserving manufacturing simplicity while improving reliability.
Data Source
AI summary
An electronic component includes a leadframe and a first semiconductor die. The leadframe includes a leadframe top side, a leadframe bottom side opposite the leadframe top side, and a top notch at the leadframe top side. The top notch includes a top notch base located between the leadframe top side and the leadframe bottom side, and defining a notch length of the top notch, and can also include a top notch first sidewall extended, along the notch length, from the leadframe top side to the top notch base. The first semiconductor die can include a die top side a die bottom side opposite the die top side and mounted onto the leadframe top side, and a die perimeter. The top notch can be located outside the die perimeter. Other examples and related methods are also disclosed.