TSV Guard Ring Structure for Stress Isolation and Smooth Via Walls
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Solution Overview
Problem
Existing protective structures for through-silicon vias (TSVs) in integrated circuits (ICs) fail to adequately absorb or isolate stress, leading to delamination and failures.
Innovation Solution
A guard ring structure is introduced around the TSV, surrounded by a top metal feature, which eliminates stray capacitance and absorbs stress through dielectric layers, ensuring a smooth inner surface and sufficient spacing to prevent damage to surrounding structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TSVs are formed to route electrical signals, then signal routing capability is improved, but stress is generated on surrounding structures causing delamination
Solution Approach 1:
The patent introduces dielectric layers and protective structures as intermediary elements between the TSV and surrounding structures. These intermediaries absorb and isolate the stress generated by TSV formation, preventing direct transmission of stress to adjacent circuit elements while maintaining the TSV's signal routing function.
Solution Approach 2:
The protective structure is segmented into multiple functional layers including inner and outer protective structures, dielectric layers, and stress-absorbing materials. This segmentation allows each layer to address specific aspects of stress management, with the inner structure providing close protection and the outer structure providing broader stress distribution.
Data Source
AI summary
Integrated circuit (IC) structures and methods for forming the same are provided. An IC structure according to the present disclosure includes a substrate, an interconnect structure over the substrate, a guard ring structure disposed in the interconnect structure, a via structure vertically extending through the guard ring structure, and a top metal feature disposed directly over and in contact with the guard ring structure and the via structure. The guard ring structure includes a plurality of guard ring layers. Each of the plurality of guard ring layers includes a lower portion and an upper portion disposed over the lower portion. Sidewalls of the lower portions and upper portions of the plurality of guard ring layers facing toward the via structure are substantially vertically aligned to form a smooth inner surface of the guard ring structure.