C2H2F2 Dielectric Plasma Etching With Lower GWP Emissions
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Solution Overview
Problem
Conventional fluorocarbon and hydrofluorocarbon gases used in plasma etching for semiconductor manufacturing have high Global Warming Potential (GWP), and their breakdown products in plasma etching processes also contribute to high GWP emissions, posing environmental concerns.
Innovation Solution
The use of C2H2F2 as an etching gas in plasma etching processes, combined with an inert co-reactant like N2, reduces CO2 equivalent emissions from the reaction chamber by at least 10% compared to traditional gases like CF4.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fluorocarbon or hydrofluorocarbon gases (CF4, CHF3) are used for plasma etching of dielectric materials, then etching performance is achieved, but Global Warming Potential (GWP) of emissions becomes extremely high
Solution Approach 1:
The patent changes the chemical composition parameter of the etching gas from traditional high-GWP fluorocarbons (CF4, CHF3) to alternative gases with lower GWP values. This substitution maintains the etching functionality while reducing the environmental harm parameter, directly resolving the contradiction between manufacturing performance and harmful emissions.
2Object-generated harmful factors
If lower GWP etching gases are used, then greenhouse gas emissions are reduced, but etching performance and selectivity may deteriorate
Solution Approach 1:
The patent employs composite gas mixtures combining multiple etching gases (e.g., SF6, C4F8, CHF3) in specific ratios rather than using a single gas. This composite approach allows the system to achieve both low GWP emissions and high etching performance by leveraging the complementary strengths of different gases - some providing low GWP while others enhance etching rate and selectivity.
3Manufacturing precision
If fluorocarbon polymer is formed to protect mask surfaces during etching, then selectivity is improved, but additional fluorinated byproducts are created increasing GWP emissions
Solution Approach 1:
The patent applies local quality by using oxygen or nitrogen specifically at the mask surface region to form protective polymers, while the bulk etching process uses low-GWP gases. This localized application of fluorocarbon-containing species ensures selectivity protection where needed (at the mask interface) while minimizing overall fluorinated byproduct generation in the bulk plasma, thus resolving the contradiction between selectivity and emissions.
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
C2H2F2 offers improved etching performance and selectivity while significantly reducing greenhouse gas emissions, making it a more environmentally friendly option for plasma etching in semiconductor manufacturing.
Implementation Method 1
introducing an etching gas containing C2H2F2 into the reaction chamber; converting the etching gas to a plasma
Implementation Method 2
allowing an etching reaction to proceed between the plasma and the one or more dielectric films so that the one or more dielectric films are selectively etched
Data Source
AI summary
An etching method for forming a structure by selectively etching one or more dielectric films in a substrate using a patterned mask layer deposited on top of the one or more dielectric films comprises mounting the substrate in a reaction chamber, introducing an etching gas containing C2H2F2 into the reaction chamber, converting the etching gas to a plasma, and allowing an etching reaction to proceed between the plasma and the one or more dielectric films so that the one or more dielectric films are selectively etched versus the patterned mask layer to form the structure.