Interconnect Barrier Layer With Minimal Recess Width Loss
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Solution Overview
Problem
The challenge of forming interconnect structures in semiconductor devices with reduced dimensions leads to issues such as poor sidewall adhesion, void formation, increased contact resistance, and reduced yield due to the use of conventional barrier layers, which affect device performance and reliability.
Innovation Solution
A plasma-based deposition process is used to form a barrier layer on the sidewalls of recesses in semiconductor devices, consuming a portion of the silicon-rich surface to create a silicon-rich barrier layer that promotes adhesion and minimizes cross-sectional width reduction, thereby improving the adhesion and reducing roughness of the interconnect structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional barrier layer is formed on sidewalls of recesses, then adhesion is improved, but cross-sectional width is reduced and roughness increases
Solution Approach 1:
The patent changes the deposition parameters by using plasma-based deposition at controlled temperature and pressure conditions. This allows the barrier layer to be formed with better adhesion while controlling the layer thickness and morphology to minimize cross-sectional width reduction and surface roughness. The plasma activation enables lower deposition temperatures that reduce stress and improve adhesion without excessive width consumption.
Solution Approach 2:
The patent employs composite barrier layer structures combining multiple materials such as titanium nitride (TiN), tungsten nitride (WN), or tantalum carbon nitride (TaCN) in specific sequences. These composite structures provide enhanced adhesion properties while the carefully controlled thickness ratios of each layer minimize overall width reduction and maintain smooth surfaces for subsequent interconnect formation.
2Reliability
If a barrier layer is formed to promote adhesion, then device reliability is improved, but contact resistance increases
Solution Approach 1:
The patent optimizes deposition parameters including plasma power, pressure, and temperature to control the barrier layer's electrical properties. By maintaining lower deposition temperatures and controlling plasma chemistry, the barrier layer achieves good adhesion while preserving lower contact resistance. The parameter optimization ensures the barrier layer does not form excessive stress or roughness that would increase contact resistance.
Solution Approach 2:
The patent uses composite barrier layer configurations where certain materials like tungsten nitride or tantalum carbon nitride are selected for their dual properties of good adhesion and acceptable electrical conductivity. The composite structure allows the first barrier layer to provide adhesion while subsequent layers or interface engineering minimizes contact resistance, achieving both reliability and low resistance.
3Ease of manufacture
If conventional deposition methods are used, then process simplicity is maintained, but void formation and poor sidewall adhesion occur
Solution Approach 1:
The patent replaces conventional thermal or physical vapor deposition with plasma-based deposition. The plasma activation provides chemical reactivity that enhances adhesion to sidewalls without requiring complex mechanical pretreatment. The plasma environment enables direct chemical bonding between the barrier layer and substrate, improving sidewall adhesion while maintaining a relatively simple single-step deposition process.
Solution Approach 2:
The patent modifies deposition parameters by introducing plasma activation and controlling plasma chemistry. This changes the deposition mechanism from purely physical to chemically-enhanced deposition, which improves sidewall adhesion and eliminates void formation. The plasma parameters (power, pressure, gas composition) are optimized to ensure complete coverage and strong adhesion while keeping the process integrated into existing fabrication flows.
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 method enhances device performance, reduces contact resistance, increases yield, and minimizes defects by ensuring better adhesion and smoother interconnect structure formation.
Implementation Method 1
A plasma is used to cause a diffusion of silicon (Si) in the sidewalls toward the surface of the sidewalls to create a silicon-rich surface on the sidewalls
Implementation Method 2
The barrier layer is formed in the portion of the thickness of the sidewalls by a plasma-based deposition operation
Data Source
AI summary
A barrier layer is formed in a portion of a thickness of sidewalls in a recess prior to formation of an interconnect structure in the recess. The barrier layer is formed in the portion of the thickness of the sidewalls by a plasma-based deposition operation, in which a precursor reacts with a silicon-rich surface to form the barrier layer. The barrier layer is formed in the portion of the thickness of the sidewalls in that the precursor consumes a portion of the silicon-rich surface of the sidewalls as a result of the plasma treatment. This enables the barrier layer to be formed in a manner in which the cross-sectional width reduction in the recess from the barrier layer is minimized while enabling the barrier layer to be used to promote adhesion in the recess.