Ruthenium Precursor Ligand Design for Contaminant-Free ALD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in achieving uniformity and process control for layer deposition on larger substrates, particularly due to the limited availability of ruthenium precursors with robust thermal stability, high reactivity, and suitable vapor pressure, which often result in films with contaminants like oxygen, nitrogen, and halides, and the incompatibility of oxygen-based co-reagents with other films in device stacks.
Innovation Solution
Development of ruthenium precursors containing diazabutadiene ligands for use in atomic layer deposition (ALD) or chemical vapor deposition (CVD) processes, where a ruthenium-containing compound is sequentially exposed with a second reactive gas to form a ruthenium-containing film without an oxidizing co-reagent, utilizing metal coordination complexes with diazabutadiene ligands like [RN═CH(R′)(R′)HC═NR]2Ru(L)0-2 or [RN═CH(R′)(R′)HC═NR]3Ru, and neutral donor ligands to enhance thermal stability and film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ruthenium precursors are used in CVD or ALD processes, then film deposition can occur, but the films contain elevated concentrations of contaminants such as oxygen, nitrogen, and halides
Solution Approach 1:
The patent changes the chemical parameters of the ruthenium precursor by developing new molecular structures with different ligands (beta-diketiminate, amidinate, diazabutadiene) that fundamentally alter the decomposition behavior and film formation mechanism, enabling contaminant-free deposition without oxidizing co-reagents
Solution Approach 2:
The invention extracts and eliminates the oxidizing co-reagent (oxygen, ozone, water) from the deposition process by using precursors that can form ruthenium films through thermal decomposition alone, thereby removing the source of oxygen and other contaminant incorporation
2Ease of manufacture
If oxygen or oxidizing co-reagents are used to process ruthenium precursors, then ruthenium metal and ruthenium-based thin films can be formed, but the process becomes incompatible with other adjacent films in the device stack
Solution Approach 1:
The patent removes the oxidizing co-reagent from the deposition process by designing precursors that decompose thermally to form ruthenium films without requiring oxygen, ozone, or water, thereby eliminating incompatibility issues with adjacent films
Solution Approach 2:
The invention enables film formation in an inert or reducing atmosphere by using precursors with ligands that decompose to leave pure ruthenium metal, creating a compatible process environment for multi-layer device fabrication
3Productivity
If precursors with robust thermal stability and high reactivity are used, then film growth can occur efficiently, but long-term stability deteriorates and contaminant levels increase
Solution Approach 1:
The patent creates composite precursor molecules combining ruthenium centers with specially designed ligand systems (beta-diketiminate, amidinate, diazabutadiene) that provide both thermal stability for handling and controlled reactivity for film formation, achieving a balance between stability and productivity
Solution Approach 2:
The invention optimizes the molecular structure parameters of the precursor, including ligand choice, steric bulk, and electronic properties, to achieve the optimal balance between thermal stability for long-term storage and controlled decomposition for efficient film growth
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-quality ruthenium-containing films with improved thermal stability and reduced contaminant levels, suitable for advanced microelectronic devices, while avoiding the use of oxidizing co-reagents that might be incompatible with other films in the device stack.
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
a ruthenium-containing compound is sequentially exposed with a second reactive gas to form a ruthenium-containing film without an oxidizing co-reagent
Data Source
AI summary
Metal coordination complexes comprising a metal atom coordinated to at least one diazabutadiene ligand having a structure represented by:where each R is independently a C1-C13 alkyl or aryl group and each R′ is independently H, C1-C10 alkyl or aryl group are described. Processing methods using the metal coordination complexes are also described.