Copper-Cobalt Interconnect Structure for High-Aspect-Ratio Reliability
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Solution Overview
Problem
The miniaturization of semiconductor devices has led to finer and denser wirings and via plugs with high aspect ratios, necessitating improved reliability, but existing technologies struggle to maintain the integrity and connectivity of these structures.
Innovation Solution
A semiconductor device configuration featuring a wiring structure with a copper conductor, a cobalt-containing film on the conductor's side and bottom surfaces, and copper-silicon and cobalt-silicide films on its upper surfaces, supported by a silicon-based insulating film stack, which enhances interfacial adhesion and breakdown voltage by forming conformal layers and controlling diffusion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If wirings and via plugs are miniaturized to achieve finer and denser structures, then device integration density is improved, but reliability and structural integrity deteriorate due to high aspect ratios
Solution Approach 1:
The patent employs a composite wiring structure consisting of multiple materials: a copper base wiring, a cobalt-containing film layer, and a silicon-containing film layer. This composite structure enhances the mechanical strength and reliability of miniaturized wirings while maintaining their fine dimensions, directly resolving the contradiction between wiring density and reliability.
Solution Approach 2:
The patent applies different material properties to different regions of the wiring structure. The cobalt-containing film is specifically positioned at the interface between the copper wiring and insulating film where adhesion is critical, while the silicon-containing film is applied where barrier and structural properties are needed. This localized application of material properties enhances overall wiring reliability without compromising density.
2Length of moving object
If via plugs are made finer with higher aspect ratios, then device miniaturization is achieved, but connectivity and adhesion between layers deteriorate
Solution Approach 1:
The via plug structure utilizes a composite configuration with a copper base, cobalt-containing film, and silicon-containing film. The cobalt-containing film specifically enhances interfacial adhesion between the via plug and surrounding insulating materials, while the silicon-containing film provides barrier properties. This composite structure maintains strong connectivity in high aspect ratio via plugs, enabling further miniaturization.
Solution Approach 2:
The patent changes the chemical composition and physical properties of the films surrounding the via plug. By incorporating cobalt and silicon in specific configurations, the interfacial adhesion strength and barrier properties are enhanced, allowing via plugs to maintain connectivity even at higher aspect ratios and finer dimensions.
3Strength
If conformal films are formed to enhance adhesion, then interfacial strength is improved, but manufacturing process complexity increases
Solution Approach 1:
The cobalt-containing film is formed as a preliminary layer before the silicon-containing film, creating a staged deposition process. This preliminary action ensures that adhesion-critical interfaces are established first, while subsequent layers are added systematically. This approach enhances interfacial strength while keeping the manufacturing process organized and manageable.
Solution Approach 2:
The patent utilizes changes in film composition and deposition parameters to achieve conformal coverage. By controlling the chemical composition (cobalt content, silicon content) and deposition conditions, uniform conformal films are formed over complex three-dimensional wiring structures. This approach enhances interfacial adhesion while maintaining process feasibility through parameter optimization rather than increasing fundamental process complexity.
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
This configuration improves the reliability and breakdown voltage of semiconductor device wirings by preventing void formation and ensuring reliable connectivity between layers, thus addressing the challenges of high aspect ratio structures.
Implementation Method 1
a first film formed on a side surface and a bottom surface of the first conductor and containing cobalt
Implementation Method 2
a second film formed on an upper surface of the first conductor and containing copper and silicon; and a third film formed on an upper surface of the first film and containing cobalt and silicon
Data Source
AI summary
A semiconductor device includes a first insulating film; and a wiring disposed in the first insulating film. The wiring includes a first conductor containing copper; a first film formed on a side surface and a bottom surface of the first conductor and containing cobalt; a second film formed on an upper surface of the first conductor and containing copper and silicon; and a third film formed on an upper surface of the first film and containing cobalt and silicon. Respective positions of the second film and the third film are each lower than an upper surface of the first insulating film.