Noble Metal Interconnect Resistivity Reduction via Barrier Layer Oxidation
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Solution Overview
Problem
As semiconductor devices approach 5 nm nodes, copper line resistivity increases, necessitating the development of methods to fabricate interconnects with lower resistivity to maintain performance.
Innovation Solution
A method involving the formation of intermediate semiconductor interconnects with a substrate, cap layer, and dielectric matrix, including trenches and vias, where a barrier layer and noble metal interconnect material are deposited, annealed, and planarized, followed by oxidation or removal of the barrier layer to lower resistivity, and a dielectric cap is applied to achieve lower resistivity interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as interconnect material, then ease of manufacture is maintained, but line resistivity increases at 5 nm nodes
Solution Approach 1:
The patent changes the material parameter from copper to cobalt, which has inherently lower resistivity at small dimensions. This material substitution resolves the resistivity increase problem while the established deposition and annealing processes maintain manufacturing feasibility
Solution Approach 2:
The patent applies preliminary annealing treatment to the cobalt interconnect structure before final processing. This pre-treatment optimizes the electrical properties and reduces resistivity early in the fabrication sequence, preventing subsequent resistivity increases
2Reliability
If copper interconnects are used, then existing manufacturing processes are maintained, but surface scatter increases reducing performance
Solution Approach 1:
The patent changes the interconnect material from copper to cobalt, which exhibits different surface scattering characteristics. Cobalt's electronic structure and surface properties reduce surface scatter effects at 5 nm nodes, thereby improving performance without increasing device complexity
3Reliability
If copper interconnects are used, then standard fabrication is maintained, but electromigration reduces reliability
Solution Approach 1:
The patent substitutes cobalt for copper, changing the material parameter to one with superior electromigration resistance. Cobalt's higher melting point and stronger atomic bonds provide inherent protection against electromigration, improving reliability while maintaining compatibility with standard fabrication processes through adjusted deposition and annealing parameters
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 method results in semiconductor devices with lower line resistivity than traditional copper lines, reducing surface scatter and electromigration, while maintaining performance and reliability.
Implementation Method 1
depositing a barrier layer along a top surface of the semiconductor interconnect device
Implementation Method 2
annealing the metal interconnect material
Implementation Method 3
depositing a dielectric cap on a set of outer surfaces of the barrier layer
Data Source
AI summary
Devices and methods of fabricating integrated circuit devices for forming low resistivity interconnects are provided. One method includes, for instance: obtaining an intermediate semiconductor interconnect device having a substrate, a cap layer, and a dielectric matrix including a set of trenches and a set of vias; depositing a barrier layer along a top surface of the semiconductor interconnect device; depositing and annealing a metal interconnect material over a top surface of the barrier layer, wherein the metal interconnect material fills the set of trenches and the set of vias; planarizing a top surface of the intermediate semiconductor interconnect device; exposing a portion of the barrier layer between the set of trenches and the set of vias; and depositing a dielectric cap. Also disclosed is an intermediate device formed by the method.