IC Seal Ring Corner Structure for Wafer Saw 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 proposed IC die design includes a seal ring region with edge and corner areas, featuring continuous and discontinued active regions. The active regions have a channel region and source/drain regions, with gate structures disposed over them. In the corner areas, the active regions tilt at angles like 45° to connect with edge areas, while the gate structures are tilted but not perpendicular to the active region, protecting the fin top surface during the replacement gate process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional seal ring structures are used in corner areas, then the manufacturing process is simple, but the mechanical strength is insufficient and structures are prone to damage during wafer sawing
Solution Approach 1:
The seal ring structure is divided into multiple segments including edge portions and corner portions. The corner portions are further segmented into different configurations (e.g., 45-degree angled corners, rounded corners, or notched corners) to distribute mechanical stress during wafer sawing, thereby improving overall mechanical strength without requiring complete structural redesign
Solution Approach 2:
Different structural qualities are applied to different locations of the seal ring. Edge portions maintain a standard configuration for simplicity, while corner portions are specifically designed with enhanced structural features (such as extended length, different orientation, or reinforced geometry) to withstand the higher mechanical stresses encountered during dicing and handling
2Reliability
If multi-gate device architectures are used in seal ring regions, then transistor performance is improved, but structural stability deteriorates due to active region collapse risk
Solution Approach 1:
The gate structure is designed with preliminary geometric configurations (such as extended gate length, specific orientation angles, or pre-formed support features) that provide inherent mechanical support to the active region before processing steps occur. This preliminary structural reinforcement prevents collapse during subsequent manufacturing steps while maintaining the multi-gate transistor's electrical performance
Solution Approach 2:
Additional structural elements or materials are introduced as intermediaries between the gate structure and the active region to provide mechanical support. These intermediary features (such as mandrel structures, support layers, or extended gate regions) act as temporary or permanent scaffolding that prevents active region collapse while allowing the multi-gate device to function properly
3Ease of manufacture
If gate structures are tilted perpendicular to active regions, then the replacement gate process is simplified, but the fin top surface protection is compromised
Solution Approach 1:
The gate structure is designed with an asymmetric orientation relative to the active region. Instead of being perfectly perpendicular or parallel, the gate is tilted at a specific non-standard angle (such as 30 degrees, 60 degrees, or other optimized angles) that provides both mechanical protection to the fin top surface during processing and facilitates the replacement gate process through improved access and reduced interference
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 fin-shape structure in a form of a continuous ring, a first gate structure disposed on the fin-shape structure, and a second gate structure disposed on the fin-shape structure. The first gate structure is spaced apart from the second gate structure.