Zero-GWP semiconductor chiller nears commercialization

□ A large-capacity industrial chiller capable of providing cooling at temperatures of −120°C or below has been developed to remove heat generated during semiconductor manufacturing processes. Using nitrogen as a refrigerant with a global warming potential (GWP) of zero, the system combines environmental benefits with large-capacity cooling performance. Most importantly, the technology has advanced to a level suitable for commercialization and practical use in industrial settings.

□ A research team led by Dr. Junseok Ko, Head of the Department of Energy Storage Systems at the Research Institute of Carbon-neutral Energy Machinery of the Korea Institute of Machinery and Materials (KIMM, President Seog-Hyeon Ryu), developed a Turbo-Brayton cryogenic cooling system capable of delivering 15 kW of cooling capacity at −120°C or below. The team independently secured the technologies required throughout the development process, from key components and system design to manufacturing, operation, and control. The system was built into an industrial chiller measuring 1.6 m in width, 1.6 m in depth, and 2.1 m in height, and its performance was successfully verified through testing.

□ As semiconductor devices become increasingly integrated, etching processes that create deep and precise patterns on semiconductor surfaces are becoming more important. These processes require cryogenic chillers that supply cooling fluids at temperatures around −100°C to effectively remove heat generated during manufacturing. However, conventional vapor-compression chillers often use refrigerants with high global warming potential and face technical limitations in increasing cooling capacity.

□ To overcome these challenges, the research team adopted the Turbo-Brayton cycle, which produces a cooling effect through the compression and expansion of nitrogen gas. Nitrogen, used as the refrigerant, has a global warming potential (GWP) of zero and offers environmental and safety advantages. The team further enhanced system safety by designing the cooling system to operate at pressures of 10 atmospheres or less.

□ The turbomachinery, a key component of the system, incorporates magnetic bearing technology that supports the rotating shaft without lubricating oil. The turbomachinery operates at an ultra-high speed of 60,000 revolutions per minute (rpm). At cryogenic temperatures, conventional lubricating oil can freeze, potentially causing equipment failure or reduced performance. The team addressed this challenge by independently developing oil-free turbomachinery, enabling flexible control over cooling temperatures and capacities. In addition, the system was simplified and designed with a compact structure to minimize installation space in industrial facilities.

□ In performance tests conducted by the research team, the chiller reached temperatures of −120°C or below within 30 minutes of startup and successfully operated under its target cooling load of 15 kW within 60 minutes. Under rated operating conditions, the system consumed 90 kW of electrical power and achieved a coefficient of performance (COP) of 0.167, representing the ratio of cooling capacity to power consumption. For the first time in Korea, a large-capacity Turbo-Brayton cryogenic chiller has been developed to a commercialization-ready level, and its operating performance has been verified.

□ This achievement represents a significant advancement from the team's previous results in 2024, when it demonstrated cooling performance exceeding 10 kW at −100°C. The technology has since been advanced into an industrial chiller suitable for practical applications. The related technology has been transferred to CHAGO ENGINEERING Co., Ltd., a Korean semiconductor chiller manufacturer, with a product launch targeted for 2027. The technology is expected to find applications in semiconductor etching equipment and other industries requiring large-capacity cryogenic cooling.

□ Since 2018, KIMM's Department of Energy Storage Systems has continuously conducted research on Turbo-Brayton cryogenic cooling technology and has already secured large-capacity industrial cooling technology capable of reaching temperatures as low as −200°C. The department plans to further develop cooling technologies capable of reaching −250°C and −269°C in stages, expanding their applications to future industries such as superconductivity, space, hydrogen, quantum technologies, and nuclear fusion.

□ Dr. Junseok Ko, Head of KIMM's Department of Energy Storage Systems, said, “Since setting the goal of developing an industrial chiller in 2024, our researchers have worked to advance the technology to a level suitable for commercialization.” He added, “Building on this achievement, we will continue developing industrial cryogenic cooling technologies that can be applied not only to semiconductor manufacturing but also to a wide range of promising future industries.”

□ The research was supported by KIMM's institutional research program through the project titled “Development of ultra-low temperature turbo-Brayton refrigeration system for semiconductor process.”

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The Korea Institute of Machinery and Materials (KIMM) is a non-profit government-funded research institute under the Ministry of Science and ICT. Since its foundation in 1976, KIMM is contributing to economic growth of the nation by performing R&D on key technologies in machinery and materials, conducting reliability test evaluation, and commercializing the developed products and technologies.