Emission Behavior of SF6 and NF3 in Etching Processes: Effects of Wafer Size and Plasma Intensity

Accurate estimation of greenhouse gas (GHG) emissions from semiconductor etching processes requires process-specific information on the unreacted fraction (1−Ui) of process gases and the by-product generation rate (Bi). However, the default emission factors provided in the 2019 IPCC Guidelines have limited ability to reflect variations in actual process conditions, such as wafer size and plasma intensity. In this study, the 1−Ui and Bi values of SF6 and NF3 were measured using a semiconductor etching testbed designed to simulate representative Korean manufacturing conditions. Experiments were conducted using 200 mm and 300 mm wafers under three plasma intensity conditions (bias voltages of 150, 200, and 250 V). The measured values were compared with the default emission factors provided in the 2019 IPCC Guidelines. The results showed that the 1−Ui values of both SF6 and NF3 varied with wafer size and plasma intensity, and generally decreased as plasma intensity increased. In contrast, Bi exhibited different response patterns depending on the by-product species, with no consistent trend observed across process conditions. Comparison with the IPCC default emission factors revealed noticeable differences according to process gas, wafer size, and by-product species, indicating that generalized default factors may either overestimate or underestimate actual emissions under certain operating conditions. These findings provide measurement-based process-level data that can support the development of country-specific (Tier 2) and facility-specific (Tier 3) emission factors and contribute to improving the accuracy of greenhouse gas emission estimation in semiconductor etching processes.