Work Function Tuning Layer Oxygen Barrier for FinFET Threshold Control
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving precise control over the integration density and performance of FinFETs due to limitations in the manufacturing process, particularly in reducing oxygen-related defects and optimizing the thickness of the work function tuning layer, which affects the threshold voltage and overall device performance.
Innovation Solution
The introduction of an anti-reaction layer with active element dopants, such as aluminum or titanium, during the chemical soaking process helps reduce oxygen diffusion into the work function tuning layer, thereby minimizing defects and allowing for a thinner, more effective layer formation, which is crucial for advanced processing nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the work function tuning layer is made thinner to improve device performance and threshold voltage control, then device performance and threshold voltage control are improved, but oxygen-related defects increase due to insufficient barrier capability
Solution Approach 1:
The patent applies composite materials by combining the work function tuning layer with an anti-reaction layer containing active element dopants (aluminum, titanium, or chromium). This composite structure provides both the thin-layer benefits for threshold voltage control and the oxygen barrier properties through the anti-reaction layer, resolving the contradiction between thinness and defect reduction.
Solution Approach 2:
The anti-reaction layer acts as an intermediary between the gate dielectric and the work function tuning layer. This intermediate layer prevents oxygen diffusion into the work function tuning layer while allowing the work function tuning layer to remain thin for improved device performance and threshold voltage control.
2Productivity
If conventional manufacturing processes are used, then process simplicity is maintained, but integration density and device performance cannot be adequately controlled at advanced nodes
Solution Approach 1:
The patent changes the chemical and physical parameters of the gate stack by introducing active element dopants (aluminum, titanium, or chromium) into the anti-reaction layer. This parameter change enables better control over oxygen diffusion and work function tuning, allowing improved integration density and device performance control at advanced processing nodes while maintaining process feasibility.
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 enhances the control over the work function tuning layer, reducing oxygen-related defects and enabling the formation of a thinner, more efficient layer that improves device performance and threshold voltage control, essential for smaller node processes.
Implementation Method 1
modifying a surface of the work function layer is performed at least in part with a chemical soak that implants an active element
Implementation Method 2
a chemical soak that implants an active element
Implementation Method 3
the modifying the surface is performed at least in part with a chemical soak that implants an active element
Implementation Method 4
reacting the active element with oxygen
Data Source
AI summary
A semiconductor device and method of manufacture are provided. In some embodiments a treatment process is utilized to treat a work function layer. The treatment prevents excessive oxidation of the work function layer during subsequent processing steps, such as application of a subsequent photoresist material, thereby allowing the work function layer to be thinner than otherwise.