Tungsten Film Deposition via Nucleation Promoter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional CVD methods for depositing tungsten films face challenges such as incomplete filling of high aspect ratio vias and poor adhesion to dielectric surfaces, requiring additional processes like TiN seed layer deposition, which adds complexity and time.
Innovation Solution
A method involving substrate pre-treatment with a nucleation promoter followed by sequential exposure to a tungsten-containing compound and hydrogen gas in an ALD process, allowing conformal deposition of tungsten films without a seed layer, enhancing uniformity and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CVD methods are used to deposit tungsten films, then deposition throughput is high, but the films exhibit poor conformality and incomplete filling of high aspect ratio vias
Solution Approach 1:
The deposition process is segmented into multiple sequential half-cycles, each consisting of precursor exposure and purge steps. This segmentation allows precise control over film formation in high aspect ratio vias, achieving complete filling while maintaining conformality, unlike conventional CVD which deposits unevenly in such structures.
Solution Approach 2:
The patent employs periodic alternating exposure to tungsten precursor and silicon-based nucleation promoter in sequential half-cycles. This periodic action enables controlled nucleation and growth of tungsten film layer by layer, ensuring uniform deposition on horizontal surfaces and complete filling in vertical vias simultaneously.
2Speed
If conventional CVD methods are used to deposit tungsten films, then deposition speed is fast, but adhesion to dielectric surfaces is poor requiring additional TiN seed layer
Solution Approach 1:
A silicon-based nucleation promoter is deposited on the dielectric surface before tungsten deposition begins. This preliminary action creates a nucleation layer that enhances tungsten adhesion to the dielectric surface, eliminating the need for separate TiN seed layer while maintaining fast deposition speed throughout the process.
Solution Approach 2:
The silicon-based nucleation promoter acts as an intermediary layer between the dielectric surface and tungsten film. This intermediate layer improves interfacial adhesion and provides suitable nucleation sites for tungsten growth, replacing the traditional TiN seed layer function.
3Manufacturing precision
If ALD process is used to deposit tungsten films with good conformality, then step coverage is excellent, but deposition time increases due to sequential cycles
Solution Approach 1:
The patent merges the nucleation promoter deposition and tungsten precursor deposition into a single integrated cyclical process with sequential half-cycles. This combination achieves ALD-like conformal step coverage while reducing total deposition time by eliminating separate process steps and optimizing cycle efficiency.
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 improves the conformality and uniformity of tungsten film deposition on dielectric surfaces, reducing incubation delays and increasing productivity by enabling direct deposition on dielectric materials without the need for a seed layer, thus addressing the limitations of conventional CVD methods.
Implementation Method 1
Cyclical deposition is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles
Implementation Method 2
Chemical vapor deposition (CVD) is one of the most common deposition processes employed for depositing layers on a substrate
Implementation Method 3
CVD is a flux-dependent deposition technique that requires precise control of the substrate temperature
Data Source
AI summary
Processing methods comprising exposing a substrate to a nucleation promoter followed by sequential exposure of a first reactive gas comprising a metal-containing compound and a second reactive gas to form a metal-containing film on the substrate.