Fluorocarbon Etching Gas for Silicon Oxide Selectivity
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Solution Overview
Problem
Current plasma etching techniques for silicon oxide films in semiconductor production face challenges such as environmental unsustainability, complexity in multi-step processes, and the use of corrosive gases like hydrogen bromide, which complicates the production of high-quality contact holes with good shape selectivity.
Innovation Solution
A plasma etching gas comprising a fluorocarbon with 3 or 4 carbon atoms, including unsaturated bonds or ether linkages, and a bromine atom, with specific atomic ratios and a boiling point of 60°C or less, is used for single-step etching, offering improved etching selectivity and environmental compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a halogen-based gas with long atmospheric lifetime is used, then etching selectivity is improved, but environmental acceptability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the etching gas by incorporating fluorocarbon compounds with specific atomic ratios (I or Br ≤ 26% of total halogen content) instead of traditional long-lived halogen gases, achieving both etching selectivity and environmental compatibility through parameter optimization
Solution Approach 2:
The patent employs fluorocarbon compounds with short atmospheric lifetimes as etching gases, which decompose quickly in the environment, replacing persistent halogen-based gases and thereby improving environmental acceptability while maintaining etching performance
2Manufacturing precision
If a multi-step etching technique using hydrogen bromide and fluorine gas is employed, then sidewall protection effect is improved, but device complexity and productivity deteriorate
Solution Approach 1:
The patent combines the sidewall protection function and etching function into a single process gas formulation by incorporating fluorocarbon compounds with specific halogen content, eliminating the need for separate hydrogen bromide and fluorine gas steps while maintaining sidewall protection effects
Solution Approach 2:
The etching gas formulated in the patent performs multiple functions simultaneously: it provides sidewall protection, achieves anisotropic etching, and maintains etching selectivity, replacing the need for multiple specialized gases and process steps
3Manufacturing precision
If hydrogen bromide is used in combination with fluorocarbon, then deposition of carbon-based polymer is promoted, but corrosiveness to metal and process control complexity worsen
Solution Approach 1:
The patent extracts the beneficial carbon-based polymer deposition capability from hydrogen bromide by using fluorocarbon compounds alone, while removing the harmful corrosiveness to metal components associated with hydrogen bromide
Solution Approach 2:
The patent converts the potential harm of using complex multi-gas systems into benefit by demonstrating that a simplified single-gas fluorocarbon formulation can achieve the desired carbon-based polymer deposition for sidewall protection without the corrosive side effects
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 etching rates for silicon oxide films with reduced surface roughness and environmental impact, while simplifying the production process by eliminating the need for hydrogen bromide and enhancing productivity through a single-step etching method.
Implementation Method 1
plasma etching using an organic film layer
Implementation Method 2
subjecting a silicon oxide film on a substrate to plasma etching
Data Source
AI summary
The present invention is a plasma etching gas comprising a fluorocarbon having 3 or 4 carbon atoms, the fluorocarbon including at least one unsaturated bond and/or ether linkage, and including a bromine atom, and a plasma etching method comprising subjecting a silicon oxide film on a substrate to plasma etching through a mask using a process gas, the process gas being the plasma etching gas. This plasma etching gas exhibits excellent etching selectivity, and has a short atmospheric lifetime and a low environmental impact. This plasma etching method makes it possible to selectively subject a silicon oxide film to plasma etching at a high etching rate without causing an increase in surface roughness.