Silicon Film Etching With F3NO Plasma for High Selectivity

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Solution Overview

Problem

Existing etching technologies face limitations in achieving high selectivity and eco-friendliness, particularly in etching silicon-containing films, with conventional perfluorinated compounds posing environmental concerns and high global warming potential.

Innovation Solution

Employing F3NO as an etching gas in a direct plasma process, adjusting pressure and power to optimize etching selectivity by controlling the etch rates of silicon nitride and silicon oxide films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional perfluorinated compound etching gases (CF4, C2F6, SF6, NF3) are used, then etching of silicon-containing films can be performed, but the etching selectivity between different silicon-containing films is limited and waste gas processing becomes difficult and costly

Engineering Contradiction:

Improveetching selectivityVSAvoidwaste gas processing difficulty

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter of the etching gas from conventional perfluorinated compounds (CF4, C2F6, SF6, NF3) to F3NO gas. This parameter change enables both high etching selectivity between silicon nitride and silicon oxide films and easier waste gas processing, as F3NO decomposes into less harmful components (HF, HNO3, H2O) that can be more readily neutralized and discharged

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful F3NO gas (which was unknown in etching applications) into a beneficial etching gas by controlling plasma discharge conditions. The F3NO gas, when activated by plasma, generates reactive species that provide high etching selectivity, while its decomposition products can be easily processed through neutralization with ammonia or other bases, turning a potential harmful substance into an environmentally friendly etching solution

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If conventional perfluorinated compound etching gases are used, then etching process can be maintained, but the global warming potential is very high

Engineering Contradiction:

Improveetching process stabilityVSAvoidglobal warming potential

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter from high global warming potential perfluorinated compounds to F3NO gas, which has significantly lower global warming potential. The F3NO gas maintains reliable etching process stability through plasma activation while producing decomposition products (HF, HNO3, H2O) that have minimal environmental impact compared to perfluorinated compounds

Inventive Principle:

Principle #35Parameter changes

3Productivity

If direct plasma technology is used to increase etching rate, then productivity is improved, but etching selectivity between different films cannot be sufficiently enhanced

Engineering Contradiction:

Improveetching rateVSAvoidetching selectivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the etching gas composition parameter to F3NO, which when activated by direct plasma, produces reactive species with different reaction rates with silicon nitride versus silicon oxide films. This enables both high etching rates (improving productivity) and high selectivity (improving manufacturing precision) simultaneously, resolving the contradiction between speed and precision

Inventive Principle:

Principle #35Parameter changes

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

Achieves high selectivity in etching silicon nitride films relative to silicon oxide films while minimizing environmental impact, using eco-friendly F3NO gas.

Implementation Method 1

generating a direct plasma in the process chamber by applying a predetermined power to the process chamber maintained at a predetermined pressure

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

etching the first silicon-containing film on the substrate by radicals of the etching gas activated by the direct plasma

Methodology Applied

Scientific EffectPlasma enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentUS12615981B2Method for etching silicon-containing film and semiconductor device manufacturing method comprising same

Publication Date: 2026.04.28 SK SPECIALTY CO LTD

AI summary

There is provided a method for etching a silicon-containing film. The method includes: introducing a substrate having a first silicon-containing film and a second silicon-containing film into a process chamber of an etching apparatus; supplying at least one etching gas including F3NO into the process chamber; applying a predetermined power to the process chamber maintained at a predetermined pressure to generate direct plasma in the process chamber; and etching the first silicon-containing film on the substrate by reactive species (radicals) of the etching gas activated by the direct plasma. The predetermined pressure is set within a predetermined range in which the slope of the etch rate of the first silicon-containing film with respect to the pressure differs from the slope of the etch rate of the second silicon-containing film with respect to the pressure in terms of sign.