Interconnect Via Barrier Deposition With Air-Stable SAM Protection
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Solution Overview
Problem
As microelectronic devices scale to the 3 nm node and beyond, interconnect via resistance increases due to barrier layers, leading to performance throttling and power dissipation issues, and existing self-assembled monolayers (SAMs) degrade when exposed to air breaks in vacuum processing, limiting manufacturing flexibility.
Innovation Solution
The use of air-stable, densely packed SAM molecules resistant to degradation in ambient conditions, allowing for selective deposition of barrier layers on sidewalls without forming on metal surfaces, and subsequent removal of the SAM to reduce via resistance and enhance processing flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional barrier layers are deposited on sidewalls to prevent copper diffusion, then adhesion and diffusion prevention are improved, but via resistance increases significantly
Solution Approach 1:
The patent applies different materials with different properties to different locations: a first barrier material (e.g., tantalum nitride) is deposited on the sidewalls for diffusion prevention, while a second barrier material (e.g., ruthenium) with lower resistivity is deposited on the bottom surface. This local differentiation allows each region to optimize for its specific function, reducing overall via resistance while maintaining adhesion and diffusion prevention.
2Adaptability or versatility
If substrate is exposed to ambient atmosphere during processing, then manufacturing flexibility is improved, but existing SAMs degrade and lose protective function
Solution Approach 1:
The patent changes the chemical composition and structural parameters of the SAM to create an air-stable formulation. The modified SAM incorporates oxygen-containing functional groups and adjusted molecular structure that prevent degradation when exposed to ambient atmosphere, allowing the substrate to be removed from vacuum conditions without compromising the protective monolayer's integrity or selective deposition capability.
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 approach significantly reduces via resistance and improves interconnect performance by maintaining SAM stability during vacuum breaks, enabling more flexible manufacturing processes and optimal barrier layer deposition.
Implementation Method 1
selectively depositing a self-assembled monolayer (SAM) on the bottom of the gap and the metal surface
Implementation Method 2
the SAM comprising densely packed molecules on the metal surface that protect the metal surface from exposure to an ambient atmosphere
Data Source
AI summary
Methods of forming devices comprise forming a dielectric layer on a substrate, the dielectric layer comprising at least one feature defining a gap including sidewalls and a bottom. A self-assembled monolayer (SAM) is formed on the bottom of the gap which resists degradation when exposed to the ambient atmosphere. A barrier layer is selectively deposited on the sidewalls but not on the bottom of the gap. The SAM is removed after selectively depositing the barrier layer on the sidewalls.