IC Seal Ring Layout With Tilted Gates for Corner Strength
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Solution Overview
Problem
Existing seal ring structures in semiconductor integrated circuits (ICs) lack sufficient mechanical strength, particularly at corners, making them prone to damage during wafer sawing and other processing steps.
Innovation Solution
The IC die incorporates seal ring structures with active regions that are continuous around the IC die and discontinued segments within corner areas, featuring gate structures that are tilted relative to the active regions to protect the fin top surface during the replacement gate process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If seal ring structures are formed with conventional configurations, then manufacturing is simpler, but mechanical strength is insufficient and structures are prone to damage during processing
Solution Approach 1:
The seal ring structure is divided into multiple discrete elements including active regions, gate structures, and isolation features arranged in a segmented pattern around the circuit region. This segmentation allows each element to contribute to overall mechanical strength while distributing stress during wafer sawing and processing operations.
Solution Approach 2:
Different regions of the seal ring structure are designed with locally optimized properties: active regions provide structural support, gate structures offer mechanical reinforcement at critical locations, and isolation features create stress distribution zones. Each local region is tailored to address specific mechanical demands of that area during processing.
2Reliability
If gate structures are aligned perpendicular to active regions, then manufacturing is easier, but fin top surface is exposed and vulnerable during replacement gate process
Solution Approach 1:
The gate structures are deliberately positioned at asymmetric angles relative to the active regions, specifically oriented to provide coverage and protection of the fin top surface during the replacement gate process. This asymmetric arrangement ensures that the gate structures serve as protective elements while maintaining manufacturability through standardized fabrication processes.
3Strength
If continuous active regions surround the entire IC die, then mechanical strength is improved, but manufacturing complexity increases due to discontinued segments in corner areas
Solution Approach 1:
The continuous active region is intentionally interrupted at corner areas to create discontinued segments. This segmentation provides stress relief zones that prevent crack propagation during wafer sawing while maintaining overall structural integrity. The segmented configuration optimizes mechanical strength distribution without requiring complete continuity around the entire IC die.
Solution Approach 2:
The active regions are positioned and configured in advance during fabrication to create predetermined stress distribution patterns. The discontinued segments at corners are strategically placed to preemptively address potential stress concentration points before wafer processing and sawing operations occur.
Data Source
AI summary
Integrated circuit (IC) chips and seal ring structures are provided. An IC chip according to the present disclosure includes a circuit region and a seal ring region surrounding the circuit region. The seal ring region includes a first active region extending lengthwise in a first direction and a first gate structure disposed on the first active region. The first gate structure extends lengthwise in a second direction that is tilted from the first direction. The first direction and the second direction form a tilted angle therebetween.