Semiconductor Guard Ring Grid for Latch-Up Isolation
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Solution Overview
Problem
Guard rings in semiconductor devices often fail to provide sufficient charge carrier absorption due to limited surface area coverage, leading to potential latch-up and electrical shorting between integrated circuits.
Innovation Solution
A semiconductor device with a guard ring structure comprising a conductive grid formed by elongated conductive structures extending in intersecting directions to cover the active region, forming a conductive grid above the active region, providing increased charge carrier absorption and reducing the likelihood of latch-up while maintaining high integrated circuit density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional guard ring structures are used, then electrical isolation and ESD protection are provided, but charge carrier absorption is insufficient due to limited surface area coverage
Solution Approach 1:
The guard ring structure is segmented into multiple elongated conductive structures arranged in a grid pattern, where each conductive structure acts as an independent charge carrier absorption element. This segmentation increases the total effective surface area coverage compared to a traditional continuous guard ring, thereby improving charge carrier absorption capability while maintaining electrical isolation functionality
Solution Approach 2:
The conductive structures are arranged in intersecting directions (e.g., first direction and second direction perpendicular to each other) to form a two-dimensional grid pattern. This dimensional arrangement maximizes the surface area coverage within the available footprint, enabling enhanced charge carrier absorption without increasing the overall device area
2Reliability
If guard ring structures are added around integrated circuits, then electrical isolation and latch-up prevention are achieved, but device area increases reducing integrated circuit density
Solution Approach 1:
The continuous guard ring is segmented into discrete elongated conductive structures spaced apart from each other. This segmentation maintains the essential electrical isolation and latch-up prevention functions while reducing the total material usage and allowing for more compact integration, thereby preserving integrated circuit density
Solution Approach 2:
Instead of providing complete 360-degree continuous coverage, the guard ring function is achieved through partial coverage using strategically positioned elongated conductive structures. This partial action approach provides sufficient electrical isolation and latch-up prevention while minimizing the area occupied, thus maintaining high integrated circuit density
Data Source
AI summary
A semiconductor device includes an integrated circuit and one or more guard rings around the integrated circuit in a top view of the semiconductor device. At least one guard ring of the one or more guard rings includes an active region in the substrate, a first plurality of elongated conductive structures extending in a first direction in the top view of the semiconductor device and arranged in a second direction in the top view of the semiconductor device, and a second plurality of elongated conductive structures extending in the second direction and arranged in the first direction. The combination of the first and second pluralities of elongated conductive structures forms a conductive grid above the active region, and provides increased coverage of the surface area of the active region relative to including only the first plurality of elongated conductive structures or only the second plurality of elongated conductive structures.