Environmentally Sustainable Plasma Etching of SiO2 using Fluorinated Ethers with Low Global Warming Potentials

As the semiconductor industry continues to advance toward smaller critical dimensions and increasingly complex multilevel interconnection architectures, high-aspect-ratio SiO₂ contact hole etching has emerged as one of the most challenging and critical processes in advanced device fabrication. Traditionally, perfluorinated compounds (PFCs) such as CF₄ and c-C₄F₈ have been mainly used for plasma etching of SiO₂ in ultra-large-scale integrated circuits. However, PFCs present severe environmental concerns due to extremely high global warming potentials (GWPs), long atmospheric lifetimes, and strong infrared absorption characteristics that contribute significantly to climate change. 

In response to growing environmental awareness and increasingly stringent regulatory frameworks worldwide, many efforts have been made to reduce PFC emissions and develop sustainable manufacturing processes. One of the most promising approaches is the replacement of high-GWP PFCs with environmentally benign alternatives that maintain comparable etching performance while drastically reducing environmental impact. Among various candidate chemistries explored, fluorinated ethers have emerged as attractive options due to their significantly lower GWPs, shorter atmospheric lifetimes, and favorable chemical properties for plasma etching applications. 

In this talk, a comprehensive evaluation of fluorinated ethers as sustainable alternatives for plasma etching of SiO₂ is presented, and their etching characteristics are investigated.