2D Barrier Wiring Structure for Low-Resistance Interconnects
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to enhance the performance and reliability of semiconductor devices with decreasing feature sizes, particularly in achieving stable connections between wiring structures while maintaining low power consumption and high integration.
Innovation Solution
The semiconductor device incorporates a unique wiring structure with an upper barrier film made of two-dimensional materials like tantalum sulfide, an upper liner film of tantalum nitride, and an upper filling film, where the barrier film extends along the side walls of the wiring trench but not the bottom, and the liner film is in contact with the lower wiring structure, effectively reducing resistance and preventing electromigration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional barrier film structure is used in wiring trenches, then the wiring connection can be established, but resistance increases and electromigration occurs reducing reliability
Solution Approach 1:
The patent applies local quality by using different materials for different regions of the barrier structure: a first barrier material (e.g., tantalum nitride) for the bottom portion and a second barrier material (e.g., tungsten) for the side wall portions. This regional differentiation optimizes electrical properties at the interface with the lower wiring structure while maintaining structural integrity elsewhere, thereby reducing resistance and preventing electromigration in critical areas.
Solution Approach 2:
The patent employs composite materials by combining multiple barrier materials with different properties within a single barrier structure. The first barrier material provides excellent adhesion and low resistance at the wiring interface, while the second barrier material provides structural stability and electromigration resistance. This composite approach resolves the contradiction between maintaining low resistance and ensuring structural reliability as feature sizes decrease.
2Productivity
If feature size decreases to achieve higher integration, then more devices can be packed, but wiring connection stability deteriorates
Solution Approach 1:
As feature sizes decrease for higher integration, the patent maintains wiring connection stability by applying local quality principles: the first barrier material is specifically positioned at the bottom interface where electrical contact is critical, ensuring low resistance and stable connection even in miniaturized structures. This localized optimization allows scaling without sacrificing reliability.
Solution Approach 2:
The composite barrier structure with different materials optimized for different functions enables continued scaling. The first barrier material ensures stable electrical contact in reduced-size features, while the second barrier material maintains structural integrity. This material composition strategy allows higher integration density while preserving wiring connection stability in smaller feature sizes.
3Strength
If barrier film covers the bottom surface of wiring trench, then structural support is provided, but resistance increases and electromigration is not prevented
Solution Approach 1:
The patent applies local quality by selectively positioning the first barrier material only at the bottom portion of the wiring trench where it contacts the lower wiring structure, while using the second barrier material for the side wall portions. This localized placement provides structural support where needed while preventing electromigration at the critical interface, resolving the contradiction between structural strength and electromigration resistance.
Solution Approach 2:
The barrier structure is segmented into distinct bottom and side wall portions with different materials. The bottom portion uses a material optimized for electrical contact and electromigration prevention, while the side wall portions use a material optimized for structural support. This segmentation allows each region to perform its primary function without compromise, achieving both structural strength and electromigration resistance.
Data Source
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AI summary
A semiconductor device includes a lower wiring structure, an upper interlayer insulating film on the lower wiring structure and including an upper wiring trench and an upper wiring structure in the upper wiring trench. The upper wiring structure includes an upper barrier structure, and an upper filling film on the upper barrier structure. The upper barrier structure includes side wall portions extending along side walls of the upper wiring trench, and a bottom portion extending along a bottom face of the upper wiring trench. The upper barrier structure includes an upper barrier film, and an upper liner film between the upper barrier film and the upper filling film. The side wall portions of the upper barrier structure include a two-dimensional material (2D material), and the bottom face of the upper barrier structure is free of the two-dimensional material.