Ligand-Exchange Atomic Layer Etching Without Metal Residue
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Solution Overview
Problem
Current atomic layer etching methods using metal precursors face limitations in rate and selectivity, and can cause structural damage to semiconductor devices due to plasma modification, while also leaving metal atoms on the substrate.
Innovation Solution
An atomic layer etching method employing a ligand exchange reaction using a halogenated gas to form a halogenated thin film, followed by etching with a ligand that does not include a metal or metal precursor, such as an imine compound with ketimine groups, to etch fluoride thin films in atomic units without damaging the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal ligand including metal precursor is used to modify metal oxide surface during metal atomic layer etching, then etching can be performed, but rate and selectivity are limited and metal atoms remain on substrate after etching
Solution Approach 1:
The patent extracts and removes the metal precursor component from the ligand structure, using only organic ligands (such as amines or amides) that do not contain metal atoms. This eliminates the source of metal atom residue while maintaining the ligand's ability to facilitate etching through chemical reactions with the oxide surface.
Solution Approach 2:
The patent employs simple organic ligands that can be easily decomposed and removed after etching, rather than complex metal-containing ligands. These organic ligands serve their purpose during etching and then decompose completely, leaving no persistent residue on the substrate.
2Manufacturing precision
If plasma modification is used in atomic layer etching, then surface modification can be achieved, but structural damage occurs to semiconductor device
Solution Approach 1:
The patent replaces the plasma-based physical/chemical modification process with a purely chemical ligand exchange reaction. Instead of using high-energy plasma to modify the surface, organic ligands chemically react with the oxide surface under milder conditions, achieving surface modification without the damaging effects of plasma.
Solution Approach 2:
The patent changes the reaction conditions from high-energy plasma parameters to milder chemical reaction parameters. By using organic ligands at lower temperatures and energies, the surface modification is achieved through chemical exchange rather than physical sputtering or plasma etching, preventing substrate damage.
3Manufacturing precision
If conventional atomic layer etching method is used, then thin film etching can be performed, but manufacturing cost increases due to metal precursor material
Solution Approach 1:
The patent employs inexpensive organic ligands such as amines or amides that are much cheaper than metal-containing precursors. These simple organic compounds can be readily synthesized or obtained, reducing material costs while still providing effective etching functionality through their chemical reactivity with oxide surfaces.
Solution Approach 2:
The patent extracts the expensive metal component from the precursor material, using only inexpensive organic molecules. This removal of metal content dramatically reduces the cost of etching chemicals while maintaining the essential etching capability through organic-ligand-mediated chemical reactions.
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 reduces manufacturing costs, suppresses metal atom residue, and enables precise etching of fluoride thin films in atomic units without substrate damage, improving the quality and uniformity of the etched surface.
Implementation Method 1
forming a halogenated thin film on a surface of the thin film by infusing a halogenated gas into the reaction chamber
Implementation Method 2
etching the halogenated thin film by infusing a ligand without a metal or metal precursor into the reaction chamber with the substrate with the halogenated thin film
Data Source
AI summary
An atomic layer etching method using a ligand exchange reaction may include a substrate providing step of putting a substrate with a thin film formed thereon into a reaction chamber, a halogenated thin film forming step of forming a halogenated thin film on a surface of the thin film by infusing a halogenated gas into the reaction chamber, and an etching step of etching the halogenated thin film by infusing a ligand without a metal or metal precursor into the reaction chamber with the substrate with the halogenated thin film.