Multi-Liner TSV Structure for Moisture Isolation and Low Leakage
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Solution Overview
Problem
Existing Through-Silicon Via (TSV) technologies face challenges in effectively preventing moisture from reaching low-k dielectric layers and metal lines, leading to defects such as copper nodule formation, and require a solution that provides both moisture resistance and low leakage characteristics for the dielectric liners.
Innovation Solution
A multi-liner structure is implemented, where a moisture-resistant dielectric liner, typically formed of silicon nitride or silicon carbide, is deposited as an outer layer, and a lower leakage dielectric liner, such as silicon oxide, is used as an inner layer, with both layers being conformally deposited to prevent moisture ingress and reduce current leakage through the TSVs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single dielectric liner is used in TSV structure, then the manufacturing process is simple, but moisture can reach low-k dielectric layers and metal lines causing defects
Solution Approach 1:
The single dielectric liner is segmented into multiple liners with different materials (first dielectric liner and second dielectric liner). Each liner serves a specific function: the first liner provides moisture barrier protection, while the second liner provides mechanical support and stress relief. This segmentation resolves the contradiction by achieving superior moisture resistance through multi-layer structure while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The patent employs composite material structure by combining different dielectric materials (silicon oxide, silicon nitride, silicon oxynitride) in a multi-layer liner configuration. Each material is selected for its specific properties: silicon oxide for low leakage, silicon nitride for moisture barrier, and silicon oxynitride for intermediate properties. This composite approach resolves the contradiction by achieving both moisture resistance and low leakage characteristics that a single material cannot provide.
2Reliability
If moisture-resistant dielectric liner is deposited, then moisture ingress is prevented, but current leakage may increase
Solution Approach 1:
The protective function is segmented between two liners: the first dielectric liner (silicon nitride or silicon oxynitride) provides moisture barrier protection, while the second dielectric liner (silicon oxide) provides low leakage current protection. This functional segmentation resolves the contradiction by assigning different protection aspects to different layers, allowing each layer to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions of the liner structure have different material compositions tailored to local requirements: the first liner near the TSV opening provides moisture barrier, the second liner provides electrical isolation. This local quality differentiation resolves the contradiction by providing moisture protection where needed while maintaining low leakage characteristics in other regions.
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 multi-liner structure effectively isolates low-k dielectric layers and metal lines from moisture, reducing defects and ensuring reliable electrical connectivity while maintaining low leakage characteristics, thereby enhancing the reliability and performance of TSVs in integrated circuits.
Implementation Method 1
a moisture-resistant dielectric liner, typically formed of silicon nitride or silicon carbide, is deposited as an outer layer
Implementation Method 2
both layers being conformally deposited to prevent moisture ingress
Implementation Method 3
a lower leakage dielectric liner, such as silicon oxide, is used as an inner layer, with both layers being conformally deposited
Data Source
AI summary
A method includes etching a substrate to form an opening, depositing a first dielectric liner extending into the opening, and depositing a second dielectric liner over the first dielectric liner. The second dielectric liner extends into the opening. A conductive material is filled into the opening. The method further includes performing a first planarization process to planarize the conductive material so that a portion of the conductive material in the opening forms a through-via, performing a backside grinding process on the substrate until the through-via is revealed from a backside of the substrate, and forming a conductive feature on the backside of the substrate. The conductive feature is electrically connected to the through-via.