Tungsten Nitride Coverage Layer for Semiconductor Defect Reduction
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved performance, quality, and yield due to issues such as defect formation during the fabrication process, particularly with conductive features like tungsten, which are prone to defects when exposed to oxygen or air.
Innovation Solution
A semiconductor device design that includes a coverage layer of tungsten nitride on top of conductive features, such as bit line contacts and vias, formed using reducing agents like titanium tetrachloride or tantalum tetrachloride to prevent exposure to oxygen and reduce defect formation, combined with a fabrication method that positions these features strategically within the device structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive features are exposed to oxygen or air during fabrication, then the fabrication process is simplified, but defect formation increases
Solution Approach 1:
A coverage layer comprising tungsten nitride is introduced as an intermediary between the conductive feature (tungsten) and the oxygen-containing environment. This coverage layer prevents direct contact between oxygen and the conductive feature, thereby reducing defect formation without complicating the fabrication process
Solution Approach 2:
The coverage layer creates an inert environment around the conductive feature by preventing oxygen exposure. This effectively protects the conductive feature from oxidation and defect formation during fabrication and operation
2Productivity
If scaling down is pursued to improve computing ability, then device performance increases, but defect formation and quality issues worsen
Solution Approach 1:
The patent changes the chemical state of the conductive feature surface by forming a coverage layer of tungsten nitride. This parameter change (from pure tungsten to tungsten nitride surface) prevents oxidation and defect formation, enabling continued scaling while maintaining quality and yield
3Area of stationary object
If conductive features are made smaller for scaling, then device density increases, but oxidation and defect formation increase
Solution Approach 1:
A thin film coverage layer of tungsten nitride is applied over the conductive feature. This thin film provides effective protection against oxidation and defect formation while maintaining the small dimensions and high density of the scaled-down device
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 use of tungsten nitride coverage layers effectively reduces defect formation in semiconductor devices, thereby increasing yield and improving the reliability and quality of the devices by protecting the conductive features from oxidation.
Implementation Method 1
cleaning the conductive feature comprises applying a reducing agent to the top surface of the conductive feature, and the reducing agent is titanium tetrachloride, tantalum tetrachloride, or a combination thereof
Implementation Method 2
forming a coverage layer comprising tungsten nitride positioned on a top surface of the conductive feature... to prevent exposure to oxygen and reduce defect formation
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate, a conductive feature comprising tungsten positioned above the substrate, a coverage layer comprising tungsten nitride positioned on a top surface of the conductive feature, and a plurality of capacitor structures positioned above the substrate.