Pentafluoropropanol Plasma Etching for Low-GWP High-Aspect Profiles

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Solution Overview

Problem

Conventional plasma etching methods using perfluorocarbon (PFC) gases have high global warming potential (GWP), leading to environmental concerns and inefficiencies in achieving high aspect ratio etched structures.

Innovation Solution

A plasma etching method utilizing pentafluoropropanol (PFP) as a discharge gas with a low GWP, combined with argon and optional oxygen, to enhance etching properties and reduce greenhouse gas emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If perfluorocarbon (PFC) gas is used for plasma etching, then mask protection and etching selectivity are improved, but global warming potential increases significantly

Engineering Contradiction:

Improvemask protectionVSAvoidglobal warming potential

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter of the etching gas from conventional PFC gases (CF4, C2F6, C3F6, C3F8, C4F8) to pentafluoropropanol (C3H3F5O), which has significantly lower GWP while maintaining the necessary fluorine content for mask protection and etching selectivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a gas that degrades more readily in the atmosphere (shorter lifetime) compared to persistent PFC gases, effectively treating the etching gas as a consumable that breaks down harmlessly, thereby reducing long-term environmental accumulation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If fluorocarbon thin film is deposited on substrate surface, then mask protection is improved, but etch rate decreases

Engineering Contradiction:

Improvemask protectionVSAvoidetch rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the gas composition from conventional PFC to pentafluoropropanol, which produces a fluorocarbon thin film with optimized properties that provides adequate mask protection while maintaining higher etch rates due to different film characteristics and reactivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite gas mixture of pentafluoropropanol and argon, where the argon component helps control the deposition characteristics of the fluorocarbon film, balancing protection and etching performance

Inventive Principle:

Principle #40Composite materials

3Reliability

If excessive fluorocarbon thin film is deposited on etched structure wall, then mask protection is enhanced, but etching stop occurs and target depth is not achieved

Engineering Contradiction:

Improvemask protectionVSAvoidetched depth control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the gas chemistry to pentafluoropropanol, which produces a fluorocarbon film with controlled deposition rate and thickness, preventing excessive buildup that would cause etching stop while maintaining sufficient protection

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If conventional PFC gas is used, then etching process is established, but annual discharge amount of greenhouse gas continuously increases

Engineering Contradiction:

Improveetching processVSAvoidgreenhouse gas emission

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent fundamentally changes the etching gas from high-GWP PFC compounds to low-GWP pentafluoropropanol, maintaining etching process effectiveness while dramatically reducing greenhouse gas emissions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the environmental harm of PFC gas emissions into a benefit by selecting pentafluoropropanol, which has both lower GWP and adequate etching performance, thereby turning an environmental liability into a sustainable solution

Inventive Principle:

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

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 effectively reduces greenhouse gas emissions, achieves excellent etching properties, and enables the formation of high aspect ratio etched structures with improved etch rates and straighter profiles.

Implementation Method 1

a first container accommodating the liquid pentafluoropropanol (PFP) therein may be heated to a first temperature equal to or higher than a boiling point of the pentafluoropropanol (PFP)

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 2

a first container accommodating the liquid pentafluoropropanol (PFP) therein may be heated to a first temperature equal to or higher than a boiling point of the pentafluoropropanol (PFP)

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

a third step of discharging the discharge gas to generate plasma and of performing plasma etching on the etching target using the generated plasma

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS12278093B2Plasma etching method using pentafluoropropanol

Publication Date: 2025.04.15 AJOU UNIV IND ACADEMIC COOP FOUND

AI summary

A plasma etching method is disclosed. The plasma etching method comprises: a first step for vaporizing liquid pentafluoropropanol (PFP); a second step for supplying discharge gas comprising the vaporized PFP and argon gas into a plasma chamber in which an object to be etched is placed; and a third step for discharging the discharge gas to generate plasma and etching the object by using the plasma.