TSV Guard Ring Enclosure with Dielectric Stress Absorption
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Solution Overview
Problem
Existing protective structures for through-silicon vias (TSVs) in integrated circuits are inadequate in reducing stress-induced delamination and failures, as they do not effectively absorb or isolate the stress generated by TSVs, leading to potential device failures.
Innovation Solution
An enclosure structure is provided around the sidewalls and top surface of TSVs, including a guard ring structure with a top metal feature that eliminates parasitic capacitance and absorbs stress by using dielectric layers radially spaced between the TSV and the guard ring, ensuring sufficient thickness to mitigate stress on surrounding structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing protective structures are used around TSVs, then device fabrication can proceed, but stress-induced delamination and failures occur due to inadequate stress absorption and isolation
Solution Approach 1:
The protective structure is divided into multiple functional segments: a stress-absorbing dielectric layer positioned between the TSV and guard ring structure, and a guard ring structure with vertically aligned portions. This segmentation allows each component to specialize in specific stress management functions, improving overall reliability while preventing delamination.
Solution Approach 2:
A dielectric layer is introduced as an intermediary element between the TSV and the guard ring structure. This intermediate layer absorbs and isolates stress generated by the TSV, preventing direct stress transmission to surrounding structures that would cause delamination and failures.
2Manufacturing precision
If guard ring structure is formed with vertically aligned sidewalls, then manufacturing precision is improved, but device complexity increases due to additional structural requirements
Solution Approach 1:
The guard ring structure is designed with vertically aligned inner and outer sidewalls that extend through multiple dielectric layers to the same depth. This equipotential-like alignment creates a uniform, balanced structure that simplifies manufacturing by establishing consistent reference planes across different layers, improving precision without proportionally increasing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively reduces stress-induced delamination and failures by eliminating parasitic capacitance and absorbing stress, thereby enhancing the reliability and stability of integrated circuit interconnect structures.
Implementation Method 1
dielectric layers radially spaced between the TSV and the guard ring structure, the dielectric layers having a sufficient thickness to reduce, absorb, or isolate the stress generated by the TSV to surrounding structures
Implementation Method 2
a guard ring structure with a top metal feature that eliminates parasitic capacitance and absorbs stress
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.