Nitrosyl Fluoride Etching Selectivity for Silicon Nitride
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Solution Overview
Problem
High-temperature etching processes for silicon nitride using nitrosyl fluoride result in non-uniform temperature control, particle generation, and excessive etching, leading to reduced semiconductor production yield and potential structural damage.
Innovation Solution
An etching method employing an etching gas with more than 20% nitrosyl fluoride, selectively etching silicon nitride without plasma, at temperatures between 50°C and 250°C, to maintain uniformity and prevent particle generation, using silicon oxide or amorphous carbon as non-etching objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature etching is used to increase etching selectivity, then etching selectivity is improved, but temperature uniformity deteriorates and particle generation increases
Solution Approach 1:
The patent changes the chemical composition parameter of the etching gas by increasing nitrosyl fluoride concentration to more than 20% by volume. This chemical parameter change enables achieving high etching selectivity at lower temperatures, thereby resolving the contradiction between etching selectivity and temperature uniformity.
2Manufacturing precision
If high temperature etching is used to increase etching selectivity, then etching selectivity is improved, but particle generation increases
Solution Approach 1:
The patent changes the temperature parameter by reducing etching temperature to 250°C or lower while compensating with increased nitrosyl fluoride concentration. This parameter change combination achieves high etching selectivity while suppressing particle generation from thermal wear and excessive etching.
3Manufacturing precision
If low concentration nitrosyl fluoride is used, then etching selectivity is improved at high temperature, but temperature control difficulty increases
Solution Approach 1:
The patent changes the gas composition parameter by using high concentration nitrosyl fluoride (>20% by volume), which enables achieving high etching selectivity at lower temperatures. This reduces the complexity of temperature control systems while maintaining or improving etching selectivity.
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 method achieves high selectivity in etching silicon nitride over non-etching objects, reduces particle formation, and maintains etching rate consistency, thereby enhancing semiconductor production yield and preventing structural damage.
Implementation Method 1
Nitrosyl fluoride (NOF) is usable as an etching gas for etching a silicon material in a semiconductor production process
Data Source
AI summary
Provided is an etching method capable of selectively etching an etching object containing silicon nitride as compared with a non-etching object while the generation of particles and a variation in etching rate are suppressed. The etching method includes an etching step of bringing an etching gas containing more than 20% by volume of nitrosyl fluoride into contact with a member to be etched (12) having an etching object that is to be etched by the etching gas and having a non-etching object that is not to be etched by the etching gas, to selectively etch the etching object as compared with the non-etching object without plasma. The etching object contains silicon nitride.