Flexible Display Bonding Pads With Rounded Corners and Variable Density
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Solution Overview
Problem
The bonding of semiconductor devices to flexible displays often results in cracks and mechanical defects, particularly around conductive pads with right-angle corners, which can lead to moisture infiltration and reduced reliability due to stress concentrations during the attachment process.
Innovation Solution
Designing a semiconductor device with conductive pads that are free of right-angle corners, allowing for a more stress-distributed attachment to flexible displays, and incorporating a substrate with low and high pad density areas to manage pressure effectively during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive pads with right-angle corners are used for bonding semiconductor devices to flexible displays, then the bonding process is simple and straightforward, but cracks and mechanical defects occur around the conductive pads due to stress concentrations
Solution Approach 1:
The patent applies curvature by replacing the right-angle corners of conductive pads with rounded corners. This geometric modification eliminates stress concentration points that occur at sharp angles during the bonding process to flexible displays. The rounded corners distribute mechanical stress more evenly across the pad structure, preventing crack formation while maintaining the bonding process simplicity.
2Ease of manufacture
If uniform pad density is used across the substrate, then the manufacturing process is simple, but stress cannot be effectively distributed during bonding to flexible displays
Solution Approach 1:
The patent implements local quality by creating regions of different pad densities on the substrate. Specifically, it defines low pad density areas and high pad density areas in different regions of the substrate. This non-uniform distribution allows stress to be effectively managed and distributed during the bonding process to flexible displays, with higher density regions providing additional bonding support where needed and lower density regions reducing overall stress accumulation.
Data Source
AI summary
A semiconductor device includes a substrate, conductive features on the substrate, and a passivation layer over the conductive features to define conductive pads in the respective conductive features through exposed portions of each of the conductive features. Each corner of the conductive pads is free of right angle, the substrate has a pair of long sides from a top view perspective, the shape of each of the conductive pads is a parallelogram. Each of the conductive pads has a pair of long sides and a pair of short sides from a top view perspective, a portion of the conductive pads have the long sides sloped away from a first pad density area of the substrate and toward one long side of the substrate, and the rest of the conductive pads have the long sides sloped toward the first pad density area and toward the other long side of the substrate.