Dry etching method, method for producing semiconductor device, and dry etching gas composition
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Solution Overview
Problem
Existing dry etching methods for silicon oxide films suffer from insufficient etching rates, residue formation, and require high temperatures, leading to potential heat damage and reduced productivity.
Innovation Solution
A dry etching method using gaseous hydrogen fluoride and organic amine compounds, specifically an organic amine mixture containing at least two compounds represented by a specific formula, allows for efficient etching of silicon oxide at low temperatures without residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dry etching methods are used, then etching can be performed without plasma, but the etching rate is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the etching gas composition by introducing organic amine compounds (such as trimethylamine, diethylamine) in combination with hydrogen fluoride gas. This parameter change enables significantly higher etching rates compared to conventional methods while maintaining etching quality, directly resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent uses a composite gas composition comprising hydrogen fluoride and organic amine compounds. This composite approach creates a synergistic effect where the organic amine compounds enhance the reactivity and etching speed while the hydrogen fluoride provides the primary etching mechanism, achieving both high etching rate and high etching quality simultaneously.
2Reliability
If high temperature heating is applied to remove thick AFS layer, then complete removal is achieved, but heat damage occurs to other parts
Solution Approach 1:
The patent changes the temperature parameter from high temperature (required in conventional methods) to low temperature (200°C or lower). The organic amine compound-based etching chemistry enables complete residue removal at these lower temperatures, eliminating heat damage while maintaining reliability of residue removal.
Solution Approach 2:
The patent replaces the thermal mechanism (high-temperature heating) with a chemical mechanism (organic amine compound reaction). This substitution allows residue removal through chemical reaction at low temperatures rather than requiring high-temperature thermal processes, thus avoiding heat damage to temperature-sensitive components.
3Reliability
If chamber heating and cooling is performed for temperature switching, then etching and heating steps are completed, but productivity is reduced
Solution Approach 1:
The patent merges the etching step and the residue removal step into a single integrated process. By using organic amine compounds, the etching reaction itself produces volatile products that are easily removed at low temperatures, eliminating the need for separate high-temperature heating steps and chamber temperature cycling, thus improving productivity while maintaining process completeness.
Solution Approach 2:
The patent enables continuous etching operation at low temperatures without interruption for heating and cooling cycles. The organic amine compound-based process maintains steady-state low-temperature operation throughout the etching process, ensuring continuous useful action and eliminating productivity losses associated with temperature transitions.
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
The method enables high-rate etching of silicon oxide at 200°C or lower, avoiding residue and reducing heat-related damage, thereby enhancing productivity and selectivity in semiconductor device production.
Implementation Method 1
reacting silicon oxide with: gaseous hydrogen fluoride and a gaseous organic amine compound; a hydrogen fluoride salt of a gaseous organic amine compound; or gaseous hydrogen fluoride, a gaseous organic amine compound, and a hydrogen fluoride salt of a gaseous organic amine compound
Implementation Method 2
the reaction product sublimates at a much lower temperature than ammonium fluorosilicate and thus can be removed at a low temperature
Data Source
AI summary
A dry etching method including reacting silicon oxide with: gaseous hydrogen fluoride and a gaseous organic amine compound; a hydrogen fluoride salt of a gaseous organic amine compound; or gaseous hydrogen fluoride, a gaseous organic amine compound, and a hydrogen fluoride salt of a gaseous organic amine compound. The organic amine compound is an organic amine mixture containing at least two compounds represented by the following formula (1):R1—N═R2R3 (1)wherein N is a nitrogen atom; R1 is a C1-C10 hydrocarbon group optionally having a ring, a heteroatom, or a halogen atom; R2 and R3 are each a hydrogen atom or a C1-C10 hydrocarbon group optionally having a ring, a heteroatom, or a halogen atom; provided that the hydrocarbon group, when it has a carbon number of 3 or more, may have a branched chain structure or a ring structure.