<p>This review paper provides a comprehensive analysis of the environmental challenges posed by high-global warming potential (GWP) gases used in plasma-based etching and chamber cleaning processes in semiconductor and display manufacturing. Despite their advantages in terms of etching efficiency, process stability, and compatibility with complex material stacks, conventional high-GWP gases have come under increasing scrutiny due to their exceptionally long atmospheric lifetimes and high radiative forcing. As the semiconductor and display industries face growing pressure to align with global carbon neutrality goals, the development and implementation of alternative low-GWP gases have emerged as a critical research and industrial priority. In this context, the review explores recent advances in low-GWP gas technologies and evaluates their feasibility across various applications such as V-NAND, FinFET patterning, silicon thinning for advanced memory, and LTPO display processing. Key performance indicators including anisotropy, selectivity, byproduct formation, residue management, and chamber contamination are assessed, with particular attention to the trade-offs between process performance and environmental footprint. The review also emphasizes the need to assess total greenhouse gas emissions not only based on the GWP value of the gas input but also considering the generation of high-GWP byproducts and their measured concentration in process exhaust. This approach, quantified as MMTCE (Million Metric Tons of Carbon Equivalent), provides a more accurate representation of greenhouse gas emissions. Methodologically, this quantification relies on tracking the real-time volumetric concentrations of individual recombined byproduct species downstream of the vacuum pump using Fourier-transform infrared spectroscopy. By integrating these concentration profiles over the total plasma-on runtime and multiplying by the respective gas density, the total mass of each emitted compound is rigorously calculated. This mass is then converted into MMTCE by incorporating its specific 100-year GWP value scaled by the standardized stoichiometric carbon-to-carbon dioxide mass ratio. To ensure maximum experimental precision, this calculation framework relies on several key operational assumptions and calibration protocols. The methodology assumes a constant nitrogen dilution ballast flow rate at the dry pump exhaust and near-ambient exhaust temperatures. To mitigate measurement uncertainties, the downstream FT-IR system undergoes a comprehensive multi-point calibration procedure using certified reference gas mixtures to directly map baseline infrared absorbance peaks to exact volumetric parts-per-million values. Optical path length drift and water vapor spectral interferences are actively compensated via automated baseline subtraction algorithms. The total expanded measurement uncertainty is tightly maintained within a narrow margin of plus or minus 5%, which is primarily governed by slight fluctuations in the dry pump nitrogen ballast flow and the intrinsic optical resolution limits of the spectrometer, ensuring highly reproducible emission tracking across various low-GWP process evaluations. It should be distinguished from CO2-equivalent metrics, although both are commonly used in emission analysis, as MMTCE directly normalizes the atmospheric radiative forcing relative to a metric ton of elemental carbon rather than a metric ton of carbon dioxide molecules. Mechanistically, while CO2-equivalent metrics normalize the integrated atmospheric radiative forcing relative to a metric ton of complete carbon dioxide molecules, MMTCE directly normalizes that exact same radiative forcing relative to a metric ton of elemental carbon, specifically applying a constant stoichiometric carbon-to-carbon dioxide mass ratio of 12 over 44. This specific distinction is critical in advanced semiconductor and display manufacturing lines, as it allows engineers to directly map gas-phase cracking and recombination efficiency back to baseline elemental carbon consumption trends. Furthermore, recent findings on hydrogen- and hydrocarbon-based plasma chemistries are discussed, which demonstrate promising capabilities in minimizing plasma-induced damage and improving post-process cleaning efficiency. These process innovations highlight the potential of low-GWP gases to enhance device performance and reduce environmental impact; however, their practical implementation requires careful consideration of process trade-offs, safety concerns, and byproduct formation. Overall, this review presents both the scientific basis and industrial relevance of low-GWP plasma processing technologies and aims to contribute to the broader transition toward sustainable and climate-responsible semiconductor and display manufacturing.</p>