Halide-Free Rhenium Thin Film Deposition via ALD
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Solution Overview
Problem
Current methods for depositing thin films in the semiconductor industry face challenges with miniaturization, particularly in using new metals like rhenium, as existing metal films are inadequate for microelectronic devices, and there is a need for new deposition techniques that avoid halides to prevent substrate etching.
Innovation Solution
The method involves atomic layer deposition using a rhenium precursor and a reducing agent in a sequential process, with purging steps to form rhenium-containing films (such as rhenium metal, nitride, oxide, or carbide) on substrates, ensuring the films are substantially free of halides, using alkyltrioxorhenium-based compounds like methyltrioxorhenium(VII) and 1,1-dimethylhydrazine, to prevent substrate etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal films are used for microelectronic devices, then existing processes can be maintained, but the films are inadequate for miniaturization and new device applications
Solution Approach 1:
The patent changes the chemical composition parameters of the deposited film by using rhenium instead of conventional metals, and controls the deposition process parameters (temperature, pressure, gas flow) to achieve films with appropriate electrical, mechanical, and barrier properties for miniaturized devices
Solution Approach 2:
The patent employs composite material structures by combining rhenium with other elements or compounds during deposition, creating multi-functional films that provide both electrical conductivity and barrier properties required for advanced microelectronic applications
2Productivity
If halide-containing precursors are used in deposition, then deposition rate may be improved, but substrate etching occurs
Solution Approach 1:
The patent extracts and eliminates halide components from the deposition system by using alternative precursor chemistry (such as organometallic or oxide-based precursors), thereby preventing substrate etching while maintaining deposition capability through purified chemical reaction pathways
Solution Approach 2:
The patent introduces intermediary substances (such as organic ligands or buffer gases) that mediate the deposition process, enabling controlled film formation without direct halide-substrate interaction, thus preventing etching while preserving productivity
3Manufacturing precision
If atomic level control is required for conformal coatings on high aspect structures, then miniaturization is enabled, but process complexity increases
Solution Approach 1:
The patent segments the deposition process into distinct stages (nucleation, growth, completion) with controlled precursor pulses and purge cycles, enabling atomic-level precision in film thickness and conformality on high aspect ratio structures through sequential, self-limiting surface reactions
Solution Approach 2:
The patent employs periodic action through cyclic pulsing of precursor gases followed by purge cycles, creating rhythmic deposition patterns that ensure uniform atomic-layer-by-atom buildup on complex three-dimensional structures, achieving conformal coverage with precise thickness control
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 allows for the deposition of rhenium-containing films with low resistivity and high purity, suitable for microelectronic devices, while avoiding halide-related substrate etching issues, enabling conformal coatings on high aspect structures and providing a halide-free atomic layer deposition process.
Implementation Method 1
A substrate is exposed to a rhenium precursor to deposit a film on the substrate
Implementation Method 2
the substrate is exposed to a reducing agent to react with the film to form one or more of a rhenium metal film, a rhenium metal nitride film, a rhenium oxide film, or a rhenium carbide film
Data Source
AI summary
Methods for depositing rhenium-containing thin films on a substrate are described. The substrate is exposed to a rhenium precursor and a reducing agent to form the rhenium-containing film (e.g., metallic rhenium, rhenium nitride, rhenium oxide, rhenium carbide). The exposures can be sequential or simultaneous. The rhenium-precursors are substantially free of halogen.