Effects of Plasma Power on By-Product Gas Formation from CHF3 and CH2F2 Process Gases in Semiconductor Etching Processes

In semiconductor manufacturing, fluorinated gases such as CHF3 and CH2F2 are widely used as process gases for plasma etching and cleaning. However, their decomposition within the plasma environment leads to the formation of secondary fluorinated by-products with high global warming potential (GWP). Understanding how plasma intensity affects the generation characteristics of these by-products under realistic process conditions is essential for developing country-specific emission factors and improving inventory accuracy. This study analyzes the by-product formation behavior of CHF3 and CH2F2 under three plasma power conditions (500 W, 600 W, and 700 W), based on process data representative of domestic semiconductor facilities. The quantitative analysis revealed distinct reaction trends between the two gas systems. In the CHF3 process, a reaction-pathway bifurcation was observed at 700 W, where the formation of high-GWP perfluorocarbons (PFCs, e.g., CF4, C2F6) decreased, while the production of low-GWP fluorinated compounds such as C4F6 increased, resulting in an overall 18% reduction in CO2eq. emissions. Conversely, CH2F2 showed a continuous increase in fluoromethane (CH3F) generation with higher plasma power due to the higher hydrogen content in its molecular structure, leading to an 18.4% net reduction in total GWP emissions. These results provide scientific evidence for understanding the relationship between plasma intensity and by-product formation in fluorinated gas systems under conditions relevant to the Korean semiconductor industry, and offer a foundation for improving national F-gas emission factor development.