Chromium Precursor Ligand Design for Semiconductor Film Purity
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Solution Overview
Problem
Current chromium-containing thin film precursors for semiconductor patterning lack robust thermal stability, high reactivity, and suitable vapor pressure, and often result in films with contaminants like carbon, nitrogen, and halides, which are detrimental to device manufacturing.
Innovation Solution
The use of chromium precursors with cyclopentadienyl ligands or chromium-diazadiene bonds, combined with specific reactants and oxidants, in atomic layer deposition or chemical vapor deposition processes to form etch-selective chromium-containing films, allowing for precise control over film growth and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chromium precursors are used for thin film deposition, then film formation can proceed, but the films contain elevated concentrations of contaminants such as carbon, nitrogen, and halides that are deleterious to the target film application
Solution Approach 1:
The patent changes the chemical parameters of the precursor molecules by selecting specific chromium precursors with particular ligand structures (cyclopentadienyl, diazadiene) that inherently produce cleaner films with lower contaminant concentrations during deposition
Solution Approach 2:
The patent employs sacrificial organic ligands in the chromium precursors that decompose during deposition to leave clean chromium films, where the ligands serve as temporary carriers that are discarded in the process
2Reliability
If conventional chromium precursors are used, then deposition can occur, but the precursors suffer from poor long-term stability and lack robust thermal stability
Solution Approach 1:
The patent changes the thermal and chemical stability parameters by selecting chromium precursors with specific ligand structures (cyclopentadienyl, diazadiene) that provide enhanced thermal stability and robustness during the deposition process
3Productivity
If conventional precursors are used, then film growth can occur, but the precursors lack high reactivity and suitable vapor pressure
Solution Approach 1:
The patent optimizes the vapor pressure and reactivity parameters by selecting chromium precursors with specific molecular structures that provide suitable volatility for deposition while maintaining high reactivity for efficient film growth
4Productivity
If standard etch processes are used on chromium-containing films, then etching can proceed, but other materials in the device are also affected without sufficient etch selectivity
Solution Approach 1:
The patent applies local quality by creating chromium films with specific compositional characteristics that provide high etch selectivity, allowing the chromium to be etched differently from other materials in the device structure
Solution Approach 2:
The patent uses chromium films with specific composite compositions containing organic ligands that create etch-selective properties, forming a composite material system where chromium combined with specific ligands provides differential etching behavior
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 formation of high etch-selective chromium-containing films with improved long-term stability and reduced contaminant levels, facilitating advanced semiconductor patterning techniques such as gapfill and precise contact patterning.
Implementation Method 1
A substrate in a processing chamber is exposed to a deposition cycle comprising exposure to a chromium precursor and a reactant
Implementation Method 2
At least a portion of the chromium-containing film is etched from the substrate, leaving at least a portion of the chromium-containing film in the feature, by exposing the substrate to an oxidant comprising one or more of water, molecular oxygen, peroxide, organic alcohol, ozone, nitrous oxide or plasma versions thereof to form a chromium oxide film
Implementation Method 3
The substrate is held at an elevated temperature to remove the chromium oxide film
Data Source
AI summary
Chromium containing precursors and methods of forming chromium-containing thin films are described. The chromium precursor has a chromium-diazadiene bond or cyclopentadienyl ligand and is homoleptic or heteroleptic. A suitable reactant is used to provide one of a metallic chromium film or a film comprising one or more of an oxide, nitride, carbide, boride and/or silicide. Methods of forming ternary materials comprising chromium with two or more of oxygen, nitrogen, carbon, boron, silicon, titanium, ruthenium and/or tungsten are also described. Methods of filling gaps in a substrate with a chromium-containing film are also described.