TSV Cell Guard Ring and Buffer Zone for Moisture Isolation
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Solution Overview
Problem
Existing through-silicon vias (TSVs) in integrated circuits (ICs) are vulnerable to moisture erosion and electrical interference, which can damage surrounding device structures, necessitating improved protective structures and manufacturing processes.
Innovation Solution
The development of TSV cells with buffer zones incorporating epitaxial features and guard rings, along with a method to form these structures, including the formation of fin-shaped semiconductor layers, dummy gate stacks, and selective deposition of epitaxial layers to enhance protection and minimize stress on surrounding devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TSVs are formed by etching vertical via openings through substrate and filling with conductive material, then electrical signal routing is achieved, but vulnerability to moisture erosion and electrical interference increases
Solution Approach 1:
The patent applies preliminary action by forming buffer zones and guard ring structures around TSVs before completing the TSV formation process. The buffer zones are created by selectively removing sacrificial layers and forming protective structures in advance, which then protect the TSVs from moisture erosion and electrical interference during subsequent processing and operation.
Solution Approach 2:
The patent uses buffer zones as intermediary structures between the TSVs and the surrounding device structures. These buffer zones, formed with specific materials and configurations, act as mediators that protect the TSVs from harmful factors while maintaining electrical signal routing functionality.
2Reliability
If buffer zones with epitaxial features and guard rings are added to protect TSVs, then protection against moisture and electrical interference improves, but device structure complexity increases
Solution Approach 1:
The patent merges the buffer zone formation with the existing device fabrication process by using the same epitaxial growth steps to create both the device structures and the protective buffer zones. The guard ring structures are integrated into the TSV cell design, combining multiple functions into unified structures that reduce overall complexity.
Solution Approach 2:
The buffer zones serve multiple functions simultaneously: they protect TSVs from moisture erosion, provide electrical isolation, and maintain mechanical stress distribution. The guard ring structures also serve dual purposes of electrical protection and structural support, reducing the need for separate protective components.
3Manufacturing precision
If selective deposition of epitaxial layers is performed to form protective structures, then manufacturing precision improves, but manufacturing process difficulty increases
Solution Approach 1:
The patent employs self-service mechanisms where the epitaxial growth process automatically forms the buffer zones with precise dimensions and material composition. The selective removal of sacrificial layers and the in-situ epitaxial growth create self-aligned structures that achieve high manufacturing precision without requiring complex external alignment and control systems.
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 protects TSVs from moisture and electrical interference, reducing damage to surrounding device structures and maintaining the integrity of IC performance.
Implementation Method 1
selective deposition of epitaxial layers to enhance protection and minimize stress on surrounding devices
Data Source
AI summary
A semiconductor structure according to the present disclosure includes a substrate; a through substrate via (TSV) cell over the substrate; and a TSV extending through the TSV cell and the substrate. The TSV cell includes a guard ring structure extending around a perimeter of the TSV cell, and a buffer zone surrounded by the guard ring. The buffer zone includes first dummy transistors, and second dummy transistors. Each of the first dummy transistors includes two first type epitaxial features, a first plurality of nanostructures extending between the two first type epitaxial features, and a first isolation gate structure wrapping over the first plurality of nanostructures. Each of the second dummy transistors includes two second type epitaxial feature, a second plurality of nanostructures extending between the two second type epitaxial features, and a second isolation gate structure wrapping over the second plurality of nanostructures.