Rounded Lead Frame Edges for High-Voltage Flip-Chip Reliability
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Solution Overview
Problem
High voltage semiconductor packages face challenges due to sharp edges on lead frames that cause adverse electrical field buildup, leading to potential reliability failures.
Innovation Solution
The lead frame edges are smoothened to form geometric shapes, such as rounded corners, to achieve radial and uniform distribution of electromagnetic fields, reducing electrical field buildup and enhancing package reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead frame edges are sharp or perpendicular, then manufacturing is easier, but electrical field buildup occurs causing reliability failures
Solution Approach 1:
The patent applies curvature by rounding the edges of the lead frame instead of using sharp or perpendicular edges. This geometric modification creates a smooth transition that prevents electrical field buildup and corona discharge, thereby improving package reliability while maintaining manufacturability through standard rounding processes.
Solution Approach 2:
The patent changes the geometric parameters of the lead frame edges from sharp angles to rounded contours with specific radius values. This parameter modification alters the electrical field distribution characteristics, reducing peak field intensities and preventing reliability failures without significantly complicating the manufacturing process.
2Object-affected harmful factors
If lead frame edges are smoothened to form geometric shapes, then electromagnetic field distribution becomes uniform, but manufacturing complexity increases
Solution Approach 1:
The patent implements a moderate degree of curvature at lead frame edges, forming rounded geometric shapes that achieve uniform electromagnetic field distribution. The curvature radius is optimized to balance field uniformity with manufacturing simplicity, avoiding excessive geometric complexity while effectively eliminating electrical field buildup and associated harmful effects.
3Ease of manufacture
If standard lead frame edges are used, then manufacturing is simple, but adverse electrical field buildup causes potential reliability failures
Solution Approach 1:
The patent introduces edge rounding as a modification to standard lead frame fabrication. This curvature implementation prevents adverse electrical field buildup and corona discharge while remaining compatible with existing manufacturing processes, thus improving reliability without significantly increasing manufacturing complexity.
Solution Approach 2:
The patent modifies the edge geometry parameters of the lead frame by implementing specific rounding radii. This parameter change transforms the electrical field distribution characteristics, eliminating peak field intensities and associated reliability issues while maintaining ease of manufacture through standardized rounding operations.
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 smoothened lead frame edges provide a radial and uniform distribution of electromagnetic fields, prolonging the life of the semiconductor package and preventing reliability failures.
Implementation Method 1
the lead frame edge is formed to provide a geometric shape that uniformly distributes electromagnetic field due to above 600V potential on the high voltage portion on the lead frame
Data Source
AI summary
Described herein is a technology or a method for fabricating a flip-chip on lead (FOL) semiconductor package. A lead frame includes an edge on surface that has a geometric shape that provides a radial and uniform distribution of electric fields. By placing the formed geometric shape along an active die of a semiconductor chip, the electric fields that are present in between the lead frame and the semiconductor chip are uniformly concentrated.