Through-Via Guard Ring Layout for Stress Relief and Grounded PID Protection
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Solution Overview
Problem
BEOL-only TSVs and guard ring structures in integrated circuits generate stress on surrounding structures, cause delamination, and have poor plasma-induced damage (PID) protection, leading to reliability issues and unevenness during surface planarization.
Innovation Solution
Incorporating a combination of BEOL and FEOL features, with the TSV extending through active regions and a guard ring that is radially spaced apart and electrically isolated, to reduce stress and improve PID protection by providing a discharging path to ground, while corner stress relief regions are added to mitigate stress at corner regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If BEOL-only TSV and guard ring structures are used, then manufacturing simplicity is maintained, but stress on surrounding structures increases causing delamination and reliability problems
Solution Approach 1:
The guard ring structure is segmented into multiple sections with varying configurations. Some sections have guard rings while others use alternative stress management approaches, allowing the structure to distribute and manage stress more effectively across different regions of the substrate.
Solution Approach 2:
Different regions of the substrate receive different treatments. Areas with high stress concentration get enhanced guard ring structures or modified TSV configurations, while low-stress regions maintain simpler BEOL-only structures. This localized approach optimizes stress management without unnecessarily complicating the entire manufacturing process.
2Device complexity
If BEOL-only TSV structures are used, then process complexity is reduced, but plasma-induced damage protection is poor
Solution Approach 1:
FEOL features such as pre-formed guard rings or protective layers are created before the TSV formation process begins. This preliminary structuring provides inherent protection against plasma-induced damage during subsequent manufacturing steps, eliminating the need for complex post-processing repairs or reinforcements.
Solution Approach 2:
Protective structures are built in advance to cushion and absorb the impact of plasma processing. These pre-formed features act as buffers that protect critical TSV structures from damage during plasma-based manufacturing steps, reducing defect rates without adding significant process complexity.
3Productivity
If TSVs are formed without FEOL features, then manufacturing steps are reduced, but stress distribution is poor causing unevenness during surface planarization
Solution Approach 1:
The formation of TSVs is merged with the creation of FEOL features rather than being separate sequential steps. Guard rings and other protective structures are formed simultaneously with or integrated into the TSV fabrication process, maintaining manufacturing efficiency while ensuring proper stress distribution for uniform surface planarization.
Data Source
AI summary
Semiconductor structures and methods for forming the same are provided. A method according to the present disclosure includes forming active regions on a substrate, forming an interconnect structure over the active regions, the interconnect structure including a plurality of dielectric layers and a guard ring disposed within the dielectric layers, etching an opening through the interconnect structure and at least a first portion of the active regions, the opening extending into the substrate, and forming a via structure within the opening. The via structure is surrounded by the guard ring when viewed along a direction perpendicular to a top surface of the substrate.