Passivation Layer Protrusions for Terminal Adhesion
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Solution Overview
Problem
The difference in coefficients of thermal expansion between electronic components and printed circuit boards leads to stress concentration and potential cracking of connection terminals, such as solder balls, when electronic component packages are mounted on main boards, especially in harsh environments.
Innovation Solution
The electronic component package incorporates passivation layer openings with protrusion parts instead of a circular shape, increasing the supporting area and anchoring effect of terminal connection pads, enhancing adhesion and preventing crack generation due to thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circular-shaped openings are used in the passivation layer, then the manufacturing process is simple, but the adhesion between connection terminals and terminal connection pads is insufficient, leading to cracks under thermal stress
Solution Approach 1:
The patent applies asymmetry by changing the opening shape from a symmetric circular form to an asymmetric shape that follows the contour of the terminal connection pad. This asymmetric opening shape increases the wetted perimeter and contact area between the terminal connection pad and the connection terminal, thereby improving adhesion and preventing cracks under thermal stress without significantly complicating the manufacturing process.
2Strength
If the supporting area of terminal connection pads is increased, then adhesion improves and cracks are prevented, but the opening shape becomes more complex
Solution Approach 1:
The patent applies local quality by concentrating the increased supporting area and adhesion enhancement specifically at the terminal connection pad locations where thermal stress concentrates. The opening shape is locally optimized to match the pad contour, providing enhanced adhesion strength precisely where needed to prevent cracks, while maintaining simpler shapes in other areas of the passivation layer.
Data Source
AI summary
An electronic component package includes an electronic component, a redistribution layer electrically connected to the electronic component and having terminal connection pads, a passivation layer disposed on one side of the redistribution layer and having openings exposing at least portions of the terminal connection pads, and connection terminals disposed in the openings of the passivation layer and connected to the terminal connection pads. At least one of the openings of the passivation layer has a plurality of protrusion parts.