Bi-layered Liner for TSV Stress Mitigation
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Solution Overview
Problem
TSV structures in 3D integrated circuits face stress issues at the interface, leading to cracking and delamination during the BEOL process due to mismatched material properties.
Innovation Solution
A bi-layered liner is introduced, comprising a stiffer first liner and an elastic second liner with different Young's moduli, positioned between the conductive layer and the substrate to act as a buffer, mitigating stress and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layered liner is used in TSV structure, then the manufacturing process is simple, but stress at the interface causes cracking and delamination
Solution Approach 1:
The liner is divided into two distinct layers: a first liner layer and a second liner layer with different material properties. This segmentation allows each layer to perform different functions - the first liner provides structural support while the second liner acts as a stress buffer, thereby improving interface reliability without requiring complex multi-material deposition processes
Solution Approach 2:
The patent employs composite material structure by combining two different liner materials with distinct Young's moduli. The first liner material provides rigidity for structural integrity, while the second liner material with different mechanical properties serves as a stress buffer, creating a composite system that resolves the stress-induced delamination problem
2Strength
If the liner is made stiffer to improve structural integrity, then structural support is enhanced, but stress buffering capability decreases
Solution Approach 1:
The liner functionality is segmented into two layers with different mechanical characteristics. The first liner layer is designed with higher stiffness to provide structural integrity, while the second liner layer has different Young's modulus to provide stress buffering capability, allowing both functions to coexist without compromise
Solution Approach 2:
Different regions of the liner structure are assigned different material qualities - the first liner layer has high stiffness for structural support where needed, while the second liner layer has different mechanical properties for stress accommodation, optimizing local functionality throughout the liner structure
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 bi-layered liner effectively reduces stress at the interface, preventing delamination and enhancing the reliability of TSV structures by acting as a buffer between the conductive layer and the substrate, while maintaining a thinner profile than conventional single-layered liners.
Implementation Method 1
the bi-layered liner includes a first liner and a second liner, and a Young's modulus of the first liner is different from a Young's modulus of the second liner
Data Source
AI summary
A TSV structure includes a substrate comprising at least a TSV opening formed therein, a conductive layer disposed in the TSV opening, and a bi-layered liner disposed in between the substrate and the conductive layer. More important, the bi-layered liner includes a first liner and a second liner, and a Young's modulus of the first liner is different from a Young's modulus of the second liner.