Selective Etching of ALD Silicon Oxide Films Using HF and Alcohol Gases
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Solution Overview
Problem
Current methods using HF and NH3 gases struggle to etch silicon oxide films formed by atomic layer deposition (ALD) with high selectivity compared to thermal oxide films, as they do not effectively differentiate between these films during the etching process.
Innovation Solution
An etching method involving the use of HF gas, F2 gas, and alcohol gas, or water vapor, supplied into a chamber without generating plasma, allows for selective etching of ALD-SiO2 films relative to thermal oxide films or other SiO2 films formed by different methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HF gas and NH3 gas are used for etching silicon oxide film, then etching can be performed without plasma, but etching selectivity between ALD-SiO2 film and thermal oxide film is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the etching gas by replacing NH3 with alcohol (such as isopropanol). This parameter change enables selective etching of ALD-SiO2 films with high selectivity (50 or more) compared to thermal oxide films, while maintaining the non-plasma etching advantage. The alcohol-based gas system achieves both ease of operation and manufacturing precision.
2Manufacturing precision
If conventional COR method is used, then etching can be performed on silicon oxide film, but etching rate is insufficient when high selectivity is required
Solution Approach 1:
The patent optimizes the chemical composition parameters of the etching gas by using HF combined with alcohol gases. This parameter optimization achieves both high etching selectivity (50 or more) and high etching rates (10 nm/min or more), resolving the contradiction between manufacturing precision and productivity that plagues conventional COR methods.
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 high selectivity and etching rates for ALD-SiO2 films, achieving etching selectivity of 50 or more with respect to thermal oxide films, while maintaining a high etching rate of 10 nm/min or more, without plasma generation.
Implementation Method 1
selectively etching the first silicon oxide film with respect to the second silicon oxide film by supplying one selected from the group consisting of HF gas and alcohol gas; HF gas and water vapor; HF gas, F2 gas, and alcohol gas; HF gas, F2 gas, and water vapor
Data Source
AI summary
There is provided an etching method, including: disposing a target substrate within a chamber, the target substrate having a first silicon oxide film formed on a surface of the target substrate and a second silicon oxide film formed adjacent to the first silicon oxide film, the first silicon oxide film being formed by an atomic layer deposition method and the second silicon oxide film being formed by a method other than the atomic layer deposition method; and selectively etching the first silicon oxide film with respect to the second silicon oxide film by supplying one selected from the group consisting of HF gas and alcohol gas; HF gas and water vapor; HF gas, F2 gas, and alcohol gas; HF gas, F2 gas, and water vapor, into the chamber.