Iridium Hexafluoride Deposition for Low-Temperature Film Purity
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Solution Overview
Problem
Current deposition techniques for iridium and iridium silicide films face challenges due to limited viable chemical precursors with robust thermal stability, high reactivity, and vapor pressure, leading to films with contaminants like oxygen, nitrogen, and halides, which are detrimental to semiconductor applications.
Innovation Solution
A method involving the sequential exposure of a substrate to iridium hexafluoride and a reactant, such as hydrogen or tetrasilane, at controlled temperatures to deposit iridium-containing films with high selectivity and purity, minimizing fluorine content and ensuring conformal deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD or ALD techniques are used with available precursors, then film deposition can be achieved, but the films contain elevated concentrations of contaminants such as oxygen, nitrogen, and halides
Solution Approach 1:
The patent changes the chemical parameters by using iridium hexafluoride as a novel precursor with different reactivity characteristics compared to conventional precursors. This parameter change in precursor chemistry enables deposition of purer iridium films with significantly reduced contaminant concentrations while maintaining processability
Solution Approach 2:
The patent introduces fluorine as an intermediary element through iridium hexafluoride that facilitates cleaner film formation. The fluorine-containing precursor acts as a mediator that enables more selective and controlled deposition reactions, resulting in films with fewer oxygen, nitrogen, and halide contaminants
2Productivity
If available precursors are used for iridium deposition, then deposition can proceed, but the precursors suffer from poor long-term stability and lead to contaminated thin films
Solution Approach 1:
The patent changes the physical and chemical parameters of the precursor by using iridium hexafluoride, which exhibits superior thermal stability and reactivity compared to available alternatives. This parameter change enables both reliable long-term precursor storage and clean film deposition
3Manufacturing precision
If conformal deposition is required for contact geometry surfaces, then ALD or ALD-like process is needed, but limited viable chemical precursors with robust thermal stability and high reactivity are available
Solution Approach 1:
The patent changes the chemical parameter space by introducing iridium hexafluoride with optimized volatility and reactivity parameters. This enables the material to conform to ALD process requirements for conformal deposition while providing the necessary thermal stability and reactivity that were previously unavailable
Solution Approach 2:
The iridium hexafluoride precursor developed in this patent serves multiple functions: it provides conformal deposition capability, maintains robust thermal stability, delivers high reactivity for efficient film formation, and achieves long-term stability. This multi-functional precursor addresses several requirements simultaneously that were previously met by different materials
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 enables the deposition of iridium and iridium silicide films with high iridium content (>99.8%) and minimal fluorine, achieving conformal coverage and improved purity within a broad temperature window, including low temperatures, thus addressing the limitations of existing methods.
Implementation Method 1
Chemical vapor deposition (CVD) is one of the most common deposition processes employed for depositing films on a substrate
Implementation Method 2
Cyclical deposition is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles
Data Source
AI summary
Processing methods for forming iridium-containing films at low temperatures are described. The methods comprise exposing a substrate to iridium hexafluoride and a reactant to form iridium metal or iridium silicide films. Methods for enhancing selectivity and tuning the silicon content of some films are also described.