Graphene Barrier Layer for Low-Resistance IC Interconnects
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Solution Overview
Problem
As IC technologies progress towards smaller technology nodes, interconnect structures face significant challenges due to increased contact resistance, which leads to performance degradation and yield issues, exacerbated by the use of conventional barrier layers at contact interfaces.
Innovation Solution
Formation of a graphene barrier layer over a barrier-free interconnect structure, where a carbon layer diffuses to form a graphene layer at the interface between conductive features and dielectric layers, providing superior conductivity and protection against oxygen diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional barrier layers are used in multilayer interconnects, then oxygen diffusion protection is provided, but contact resistance increases causing RC delay
Solution Approach 1:
The patent changes the material parameter from conventional barrier layer materials (such as tungsten, tantalum, or their nitrides) to graphene. This material substitution fundamentally alters the electrical conductivity parameter while maintaining the oxygen barrier property, thereby reducing contact resistance and RC delay in advanced IC interconnects
Solution Approach 2:
The patent employs graphene as a composite material that combines the oxygen barrier functionality of traditional barrier layers with superior electrical conductivity. The graphene layer is integrated into the interconnect structure to provide both protection against oxygen diffusion and enhanced electrical performance, resolving the contradiction between protection and conductivity
2Productivity
If feature size is scaled down to increase functional density, then production efficiency improves, but contact resistance in interconnects increases
Solution Approach 1:
The patent addresses the scaling-induced contact resistance by changing the material parameter of the barrier layer to graphene, which maintains low contact resistance even at reduced feature sizes. This enables continued scaling down of IC features to increase functional density without sacrificing interconnect performance
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 graphene barrier layer reduces resistance-capacitance delay and enhances interconnect performance by offering superior conductivity and impenetrability to oxygen, addressing the challenges of increased contact resistance in advanced IC nodes.
Implementation Method 1
allowing carbon to diffuse through a seed metal layer and form a graphene layer at the interface between conductive features and dielectric layers
Implementation Method 2
graphene barrier layer... impenetrable to oxygen, reducing contact resistance and protecting against oxygen diffusion
Data Source
AI summary
Interconnect structures and method of forming the same are disclosed herein. An exemplary interconnect structure includes a first contact feature in a first dielectric layer, a second dielectric layer over the first dielectric layer, a third dielectric layer over the second dielectric layer, a second contact feature extending through the second dielectric layer and the third dielectric layer, and a graphene layer between the second contact feature and the third dielectric layer.