Oxide-Based Barrier Layer for Copper Interconnect Resistivity
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Solution Overview
Problem
As integrated circuits scale down, the resistivity of copper interconnects increases due to electron scattering at grain boundaries and diffusion barrier layers, leading to increased RC delay, necessitating new methods to reduce resistivity.
Innovation Solution
Incorporating an oxide-based barrier layer directly on the sidewalls of openings and an oxide-based metal compound layer between copper lines and dielectric layers in the damascene process, which enhances elastic scattering and reduces surface-scattering-induced resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If copper interconnect dimensions are down-scaled to maintain circuit scaling, then device density and integration are improved, but resistivity significantly increases due to electron scattering at grain boundaries and barrier layers
Solution Approach 1:
The patent changes the material parameter of the barrier layer from conventional metals (tantalum, tungsten) to oxide-based materials (silicon oxide, silicon nitride). This material parameter change fundamentally alters the electron scattering mechanism at the interface, reducing surface-scattering-induced resistivity while maintaining the barrier function against copper diffusion.
Solution Approach 2:
The patent creates a composite interconnect structure consisting of copper interconnects combined with oxide-based barrier layers. This composite structure leverages the low resistivity of copper while mitigating its diffusion issues through the oxide barrier, achieving both electrical performance and diffusion protection.
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 proposed solution effectively reduces the overall resistivity of interconnect structures, particularly benefiting long metal lines by minimizing surface-scattering-induced resistivity without increasing the cost or complexity of existing fabrication processes.
Implementation Method 1
the scattering of electrons at the boundaries of the copper grains contributes to the increase of the resistivity
Implementation Method 2
enhances elastic scattering and reduces surface-scattering-induced resistivity
Data Source
AI summary
An integrated circuit structure having improved resistivity and a method for forming the same are provided. The integrated circuit structure includes a dielectric layer, an opening in the dielectric layer, an oxide-based barrier layer directly on sidewalls of the opening, and conductive materials filling the remaining portion of the opening.