Halogen Fluoride Etching Gas Composition for Selective Silicon Compound Removal
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Solution Overview
Problem
Conventional etching methods for semiconductor substrates face challenges such as non-selective etching, plasma damage, and contamination, particularly when dealing with silicon-based compounds, and require plasma which restricts apparatus operation and introduces impurities.
Innovation Solution
A halogen fluoride-based etching gas composition comprising ClF, BrF, IF, F2, HF, O2, and halogen gases, used without plasma, which allows for precise and selective etching of silicon-based compounds across various temperatures, minimizing reactivity and apparatus damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is used for etching to increase etching rate, then productivity is improved, but plasma damage occurs to the semiconductor device
Solution Approach 1:
The patent extracts and eliminates plasma from the etching process, using only chemical reactions between halogen fluoride gases and silicon-based compounds. This removes the harmful plasma effects while maintaining effective etching capability through purely chemical mechanisms.
Solution Approach 2:
The patent changes the physical and chemical parameters of the etching process by using specific halogen fluoride gas compositions (ClF, BrF, IF combined with F2, HF, O2, and halogen gases) at controlled temperatures and pressures, achieving high etching rates without plasma activation.
2Manufacturing precision
If conventional etching methods are used to achieve selective etching, then manufacturing precision is improved, but apparatus complexity increases due to plasma generation requirements
Solution Approach 1:
The patent removes plasma generation equipment and associated complex apparatus components, simplifying the etching system to use only gas delivery and temperature control mechanisms while maintaining selective etching capability through chemical specificity.
Solution Approach 2:
The patent replaces the mechanical/electrical plasma generation system with a purely chemical reaction system using halogen fluoride gases, eliminating the need for complex plasma sources, power supplies, and associated control systems.
3Productivity
If ClF3 is used as etching gas to increase etching rate of silicon oxide film, then productivity is improved, but etching selectivity deteriorates causing non-selective etching
Solution Approach 1:
The patent applies local quality by using different halogen fluoride gases with specific reactivities toward different materials. The gas composition is tailored to provide high reactivity toward silicon-based compounds while maintaining low reactivity toward other materials, achieving both high etching rate and high selectivity.
Solution Approach 2:
The patent uses composite gas compositions combining multiple halogen fluoride gases (ClF, BrF, IF) with F2, HF, O2, and halogen gases to achieve synergistic effects that provide both high etching rate and high selectivity, overcoming the limitations of single-gas systems like ClF3.
4Productivity
If ultraviolet light or laser light is used to excite halogen fluoride gas for etching, then productivity is improved, but the light damages the object to be treated
Solution Approach 1:
The patent extracts and removes the ultraviolet light or laser light excitation step from the etching process. Instead, it relies on thermal energy and direct chemical reactivity of halogen fluoride gases to achieve etching, eliminating light-induced damage while maintaining etching efficiency.
Solution Approach 2:
The patent replaces optical excitation mechanisms with thermal and chemical reaction mechanisms, using heated halogen fluoride gas compositions that react chemically with silicon-based compounds without requiring ultraviolet or laser light, thereby avoiding light damage.
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 solution enables controlled etching rates and selectivity, reducing apparatus downtime and improving operational efficiency by allowing etching at high and low temperatures without plasma, thus addressing the limitations of existing methods.
Implementation Method 1
etching a semiconductor substrate by excitation of an etching gas by thermal energy
Implementation Method 2
etching gas composition comprising (1) a halogen fluoride compound represented by XF (X is Cl, Br, or I)
Data Source
AI summary
Provided are an etching gas composition and an etching method which enable an object, such as a substrate to be etched, to be efficiently precision processed during thin film formation, and which enable efficient removal of an accumulated or adhered silicon-based compound, other than the object such as the substrate to be etched, by means of plasma etching. The etching gas composition is characterized by containing: (1) a fluorinated halogen compound represented by XF (X is Cl, Br or I) as a primary component; (2) F2; (3) a fluorinated halogen compound represented by XFn (X is Cl, Br or I, and n is an integer of 3 or higher); (4) HF; (5) O2; and (6) at least one type of halogen gas molecule selected from among Cl2, Br2 and I2.