Multi-Liner TSV Structure for Moisture Isolation and Low Leakage
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Solution Overview
Problem
Existing through-silicon via (TSV) structures face challenges in effectively preventing moisture from reaching low-k dielectric layers and metal lines, leading to defects such as copper nodule formation, and existing methods do not adequately address the need for both moisture resistance and low leakage in dielectric liners.
Innovation Solution
A multi-liner TSV structure is introduced, comprising a first dielectric liner with high moisture resistance, such as silicon nitride or silicon carbide, and a second liner with lower leakage, like silicon oxide, to protect low-k dielectric layers and metal features from moisture and byproducts, using conformal deposition methods to maintain uniform thickness and prevent direct contact with low-k dielectric materials.
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 resistance and leakage protection cannot be simultaneously optimized
Solution Approach 1:
The single dielectric liner is segmented into multiple liners with different materials and functions. The first liner (e.g., silicon nitride) provides moisture resistance, while the second liner (e.g., silicon oxide) provides leakage protection. This segmentation allows each layer to optimize its specific function, resolving the contradiction between reliability and simplicity.
Solution Approach 2:
The patent uses composite material structure with different dielectric materials (silicon nitride, silicon oxide, silicon carbide) stacked together. Each material contributes its unique properties: silicon nitride for moisture barrier, silicon oxide for low leakage, and silicon carbide for etch resistance. This composite approach achieves superior reliability compared to single-material liners.
2Reliability
If conformal deposition is used to maintain uniform liner thickness, then the deposition process time and cost increase, but moisture isolation effectiveness is improved
Solution Approach 1:
The first dielectric liner is deposited conformally before the second liner to establish a uniform moisture barrier foundation. This preliminary conformal deposition ensures that the critical moisture-blocking layer has uniform thickness and coverage, preventing moisture penetration pathways that would occur with non-uniform deposition.
Solution Approach 2:
The patent specifies controlled thickness parameters for each liner layer (first liner: 50-500 nm, second liner: 50-500 nm) to optimize both protection effectiveness and deposition efficiency. By defining specific thickness ranges, the patent balances the need for uniform conformal deposition with practical manufacturing constraints.
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 from moisture and byproducts, reducing defects and enhancing the reliability of TSVs by providing both moisture resistance and low leakage properties, thereby improving the integrity of the TSVs.
Implementation Method 1
depositing a first dielectric liner extending into the opening; depositing a second dielectric liner over the first dielectric liner
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.