친환경 혼합 냉매를 적용한 ‒100℃ 칠러의 4E 분석

Abstract

Recent advancements in cryogenic etching have led to its adoption for high aspect ratio etching and enhanced etching rates, driven by the increasing demand for improved performance and reduced power consumption in electronic devices. Given that cryogenic etching chillers require precise temperature regulation under substantial loads, the Cascade Mixed Refrigerant Cycle (CMRC) has emerged as a preferred solution. However, many of the cryogenic refrigerants currently employed in semiconductor etching processes have high Global Warming Potential (GWP), raising concerns about their environmental impact. This study proposes a -100°C chiller utilizing a cryogenic mixed refrigerant (MR) with both low GWP and low flammability, designed to meet the increasingly stringent environmental regulations while contributing to sustainability efforts. Building upon prior research that established a methodology for selecting the optimal MR composition, we have identified the most suitable composition for the proposed CMRC. A comprehensive analysis encompassing energy, exergy, environmental, and exergoeconomic cost was conducted to evaluate the potential of the proposed system to replace existing high-GWP refrigerants. The results of the energy analysis indicate that the use of an eco-friendly mixed refrigerant enhances the Coefficient of Performance (COP) by 89%, significantly reducing compressor discharge amount, enabling compressor compactness. Exergy analysis reveals a 72% improvement in exergy efficiency, reflecting a notable reduction in exergy destruction. From an environmental perspective, the adoption of the eco-friendly MR leads to a 48% reduction in carbon emissions. Economic analysis further demonstrates that the evaporator and condenser account for more than 60% of the total exergy cost, with the use of the eco-friendly MR contributing to a 25% reduction in exergy-related costs. This study demonstrates the feasibility of employing environmentally friendly refrigerants in ultra-low temperature semiconductor etching processes, where high-GWP refrigerants are predominantly used. Furthermore, it highlights the potential benefits in terms of environmental regulatory compliance and sustainability in ultra-low temperature applications.