- What happened: On November 2, the Korea Institute of Machinery and Materials (KIMM) announced that it had developed an industrial chiller that uses nitrogen as its refrigerant and confirmed 15 kW of cooling capacity at below −120°C in the research team's own tests.
- Why it matters: Cryogenic etching in semiconductor manufacturing has relied on nonflammable refrigerants with high global warming potential (GWP), and the EU is tightening its regulations. The new nitrogen-based approach could become an alternative.
- What to watch next: Details of the operating conditions and third-party verification of performance; the 2027 commercialization target of the company receiving the technology; and the efficiency challenge of needing 90 kW of electricity to deliver 15 kW of cooling.
On November 2, 2026, a research team led by Principal Researcher Junseok Ko at the Korea Institute of Machinery and Materials (KIMM) announced that it had developed a turbo-Brayton industrial chiller that compresses and expands nitrogen gas, and had confirmed 15 kW of cooling capacity at below −120°C. The unit fits in a housing measuring 1.6 m wide, 1.6 m deep, and 2.1 m high, and the technology has already been transferred to CHAGO ENGINEERING, a Korean semiconductor chiller maker. The company aims to launch a product in 2027.
Chillers used for cryogenic etching in semiconductor manufacturing have traditionally relied on refrigerants with high global warming potential (GWP). From 2027, the EU will restrict the placing on the market of chillers that use high-GWP refrigerants, but it has granted an exemption through the end of 2029 for some models used in semiconductor manufacturing. The nitrogen-based unit is seen as a promising alternative technology, but its performance figures come from the research team's own tests, and it consumes 90 kW of electricity to deliver 15 kW of cooling. Practical adoption will require verification of detailed operating conditions and efficiency.
Why high-GWP refrigerants have been used in cryogenic etching
As NAND flash memory is stacked ever higher, techniques for precisely machining deep, narrow holes have become increasingly important. One of them is cryogenic etching, which etches in a low-temperature environment. Lam Research says it was the first in the world to bring the technology into volume production, in 2019. In an announcement on July 31, 2024, the company said that about 1,000 of the more than 7,500 high-aspect-ratio dielectric etch chambers it has in use for NAND manufacturing employ cryogenic technology. According to Sesha Varadarajan, the company's senior vice president, the number of wafers produced using cryogenic etching had already reached 5 million.
According to a paper published in the journal Energies in October 2024 by a research team at Pukyong National University, cryogenic etching is performed at below −70°C, and at around −100°C the anisotropy, meaning the tendency for etching to proceed vertically, increases. However, it is not easy to keep such low temperatures stable while absorbing the large heat load flowing in from the etching equipment. For that reason, cascade mixed-refrigerant cycles (CMRC) have mainly been used in chillers for cryogenic etching. In its announcement, KIMM likewise explained that etching processes require chillers that supply a cooling fluid at around −100°C.
What makes the choice of refrigerant difficult is the safety requirements of semiconductor fabs. According to the same paper, the semiconductor industry permits only refrigerants classified as nonflammable A1. Hydrocarbon-based mixed refrigerants, which readily deliver high cooling capacity at low temperatures, are flammable and therefore hard to adopt, so high-GWP refrigerants such as R14 and R23 have been used to achieve −100°C-class cooling while remaining nonflammable. Many existing A1 refrigerants have high GWP, and to look for alternatives the paper widens its scope to the mildly flammable A2L class.
In other words, the challenge for cryogenic etching chillers is not simply to reach low temperatures. They must simultaneously offer nonflammability, high cooling capacity, and low environmental impact, and conventional vapor-compression systems offered only limited refrigerant choices. KIMM tackled the problem by switching the refrigerant to nitrogen and rethinking the cooling method itself.
How compressing and expanding nitrogen produces temperatures below −120°C
The turbo-Brayton refrigerator KIMM adopted is a cooling system that combines a compressor, a heat exchanger, and an expander. Nitrogen gas is first compressed, and the heat generated in the process is released to the outside through the heat exchanger. The high-pressure nitrogen is then expanded in the expander, which lowers its temperature; after absorbing heat from the object being cooled, it returns to the compressor. Whereas the vapor-compression systems used in household air conditioners rely on the evaporation and condensation of a refrigerant, a turbo-Brayton system circulates nitrogen in its gaseous state.
Nitrogen has a GWP of 0, and KIMM cites safety as an advantage in addition to its low environmental impact. The research team designed the system to keep operating pressure at or below 10 atm. The high-speed rotating parts, such as the compressor, use oil-free magnetic bearings that support the rotating shaft magnetically, and the machine runs at 60,000 rpm. This is because ordinary lubricating oil freezes in a cryogenic environment, which could cause breakdowns or performance degradation. According to KIMM, the research team independently secured the technologies from the development of key components through system design, manufacturing, operation, and control, and simplified the structure to reduce the installation footprint in factories.
In the research team's tests, the unit cooled to below −120°C within 30 minutes of startup and reached operation at the target cooling load of 15 kW within 60 minutes. Power consumption at rated operation was 90 kW, giving a coefficient of performance (COP), cooling capacity divided by power consumption, of 0.167. That works out to roughly 6 kW of electricity for every 1 kW of cooling. However, the heat-rejection temperature, type of cooling fluid, temperature stability, and continuous operating time have not been disclosed. No corresponding academic paper or third-party measurement results have been presented either, so for now the figures are limited to the test values released by the research team.
The turbo-Brayton method itself is not new. France's Air Liquide offers its TBF series as industrial and research refrigerators, and the largest model, the TBF-2700, has a maximum cooling capacity of 925 kW at 150 K (about −123°C). KIMM's achievement lies in incorporating an existing cooling principle into a relatively compact industrial chiller suited to semiconductor manufacturing. The research was carried out as part of KIMM's institutional project "Development of an Ultra-Low-Temperature Turbo-Brayton Refrigeration System for Semiconductor Processes."
From neon to nitrogen, with commercialization targeted for 2027
KIMM's Energy Storage Systems Laboratory has been researching turbo-Brayton cryogenic cooling technology since 2018. In 2024 it achieved more than 10 kW of cooling capacity at −100°C, and the cooling industry publication Cooling Post reported on February 22 of that year that this stage used neon as the refrigerant and could adjust cooling capacity between 5.5 and 11 kW. Ko, then a principal researcher, said the next development stage would switch to nitrogen and, within three years, evolve the system into a device suited to industrial chillers.
The latest announcement comes about two years and eight months after that statement. Ko explained that since setting the goal of developing an industrial chiller in 2024, the team has raised the technology to a level suitable for commercialization. The following timeline summarizes this progress along with the main EU developments on refrigerant regulation.
| Date | Key event |
|---|---|
| 2018 | KIMM begins research on turbo-Brayton cryogenic cooling |
| February 2024 | Achieves cooling of more than 10 kW at −100°C with neon refrigerant; announces plan to move to nitrogen in the next stage |
| July 18, 2025 | German authorities apply to the European Commission for an exemption for semiconductor manufacturing chillers |
| February 10, 2026 | European Commission adopts Implementing Regulation 2026/286 granting the exemption |
| November 2, 2026 | KIMM announces test results of below −120°C and 15 kW with nitrogen refrigerant |
| 2027 | CHAGO ENGINEERING, the technology recipient, aims to launch a product |
| January 2027 – December 2029 | Exemption period for semiconductor manufacturing chillers in the EU |
Performance rose from more than 10 kW at −100°C with neon refrigerant in 2024 to 15 kW at below −120°C with nitrogen refrigerant in 2026. The 2027 product launch target also coincides with the first year of the grace period the EU has granted to chillers for semiconductor manufacturing.
Under Annex IV, point 7 of the EU F-gas Regulation (EU 2024/573), from January 1, 2027, the placing on the market of stationary chillers that use fluorinated greenhouse gases will be restricted. The restriction covers models with a rated cooling capacity of 12 kW or less that use refrigerants with a GWP of 150 or more, and models above 12 kW that use refrigerants with a GWP of 750 or more. Exceptions are allowed, however, where necessary to meet safety requirements at the place of operation.
On July 18, 2025, German authorities applied to the European Commission for an exemption, arguing that no compliant chillers for semiconductor manufacturing exist on the market. The application covered models below 12 kW that depend on refrigerants with a GWP of 150 or more, and models above 12 kW operating below −50°C that use refrigerants with a GWP of 750 or more. The reasoning was that although the shift to low-GWP refrigerants such as CO2 is progressing, alternatives meeting all requirements for temperature, safety, and performance have not yet been commercialized for all semiconductor manufacturing applications.
The European Commission accepted the application and concluded that a three-year grace period is needed for the transition to alternative technologies. Under Implementing Regulation 2026/286, adopted on February 10, 2026, the covered models are exempt from January 1, 2027, through December 31, 2029. To benefit from the exemption, however, the labeling required under Article 12(2) of the F-gas Regulation must be provided. Separately, the European Commission also granted an exemption from 2027 to 2030 in Implementing Regulation 2026/1975 of September 8, 2026, covering chillers of 12 kW or less used for drying compressed air, among others.
With 15 kW of cooling capacity and a reachable temperature below −120°C, KIMM's unit overlaps in performance conditions with the category among the EU-exempted semiconductor chillers that operate above 12 kW and below −50°C. Because nitrogen is not a fluorinated greenhouse gas, it falls outside the scope of this regulation's ban. However, this only means that the specifications match the regulatory conditions; neither KIMM nor CHAGO ENGINEERING has announced plans to sell in the EU market.
Comparing with domestic products reveals differences in temperature and efficiency
In Japan too, development of cryogenic chillers for semiconductors that use low-GWP refrigerants is advancing. On January 16, 2024, Mayekawa announced that, together with Shinwa Controls, it had developed "Oberon," a chiller for semiconductor etching equipped with a turbo-Brayton refrigerator. It uses a natural refrigerant and has a cooling capacity of 9 kW at −70°C, and Mayekawa described it as "an industry first, achieving −70°C with a natural refrigerant." Shinwa Controls' estimates put energy savings at 30% compared with conventional vapor-compression systems, and the plan was to aim for sales from 2025 onward after field tests.
Ebara also announced on August 13, 2026, that it had shipped its −60°C cryogenic chiller, the "RJ-TTC type," for the first time to the semiconductor market. According to a report by MONOist, it can cut power and water consumption by roughly 30 to 50% compared with earlier products.
Comparing these products with the refrigeration-cycle simulation results in the Energies paper mentioned above gives the following. Because the evaluation conditions for temperature, cooling capacity, and efficiency differ, the figures are shown as published by each company or paper.
| Method / product | Reachable temperature | Cooling capacity | Refrigerant / GWP | Efficiency | Type of data |
|---|---|---|---|---|---|
| KIMM nitrogen turbo-Brayton | Below −120°C | 15 kW | Nitrogen, GWP 0 | COP 0.167 (based on 90 kW system power consumption) | Research team test values (2026) |
| Conventional mixed-refrigerant cascade | Brine at or below −100°C | 5 kW | Low-temperature-side refrigerant GWP 6997 | Best COP 0.27 (based on compressor power) | Simulation (2024) |
| Low-GWP mixed-refrigerant cascade | Brine at or below −100°C | 5 kW | Low-temperature-side refrigerant GWP 14.1 | Best COP 0.41 (based on compressor power) | Simulation (2024) |
| Mayekawa "Oberon" | −70°C | 9 kW | Natural refrigerant (type not stated) | 30% energy savings vs. conventional vapor compression | Manufacturer announcement / estimate (2024) |
| Ebara "RJ-TTC type" | −60°C | Not disclosed | Not disclosed | Power and water consumption cut by about 30–50% vs. earlier products | Report based on manufacturer announcement (2026) |
Among the published figures, KIMM's unit reaches the lowest temperature, and its refrigerant GWP is also 0. Caution is needed when comparing COP, however. KIMM's 0.167 is a measured value based on total system power consumption, whereas the paper's 0.27 and 0.41 are simulated values based on compressor power. Moreover, cooling temperatures differ (below −120°C versus −100°C or below) and so do cooling capacities (15 kW versus 5 kW), so these values cannot be used to directly judge which method is better. The GWP values given in the paper are also those of the refrigerants used in the low-temperature-side cycle.
Nor does a refrigerant GWP of 0 mean that greenhouse gas emissions from operating the chiller disappear. The Energies paper evaluates life-cycle climate performance (LCCP), which combines direct emissions from refrigerant leakage with indirect emissions from generating the electricity used in operation and from producing and disposing of materials and refrigerants. It found that indirect emissions accounted for 92% of total emissions in the case using conventional refrigerants and 95% in the case using low-GWP refrigerants. In other words, even if the refrigerant is switched to a low-GWP one, indirect emissions from power consumption and the like make up the bulk across the whole system.
With KIMM's nitrogen chiller, there is no direct warming impact from refrigerant leakage, but 90 kW of electricity is needed to obtain 15 kW of cooling. Because the actual environmental impact varies with operating hours and the source of the electricity supply, it is necessary to evaluate not only the refrigerant's GWP but also the energy efficiency and life-cycle emissions of the whole system.
Challenges ahead of 2027 commercialization and the end of the regulatory grace period in 2029
KIMM's technology has already been transferred to CHAGO ENGINEERING, but the 2027 product launch remains only a target at this point. According to a Korean electronics newspaper report in 2023, the company is a semiconductor chiller maker that spun out in 2019 from SK hynix's in-house venture program "Hi-Garage," and it has developed a helium-refrigerant chiller called the "Cryo Engine." For the nitrogen chiller, attention will focus on whether the production version will maintain the specifications of below −120°C and 15 kW, and how far power consumption and continuous-operation performance can be improved.
Research and development itself will also continue. According to KIMM, the laboratory has secured large-capacity cooling technology down to −200°C separately from this unit, and plans to lower the reachable temperature step by step to −250°C and then −269°C. Building on this result, Ko said the team will continue to develop cryogenic cooling technology applicable not only to semiconductor manufacturing but to a wide range of industries.
At the same time, important data are still lacking before this nitrogen chiller can be evaluated as a practical alternative to existing high-GWP refrigerant systems. It would be desirable for the heat-rejection temperature, cooling-fluid conditions, temperature stability, and power consumption during continuous operation to be published, and for performance to be measured by a third party. The COP of 0.167 in particular needs to be verified under evaluation conditions aligned with those of existing methods.
The exemption the EU has granted to semiconductor manufacturing chillers expires on December 31, 2029. KIMM's nitrogen refrigerant approach is significant in achieving cooling below −120°C without using the high-GWP refrigerants subject to regulation. But what determines practicality in semiconductor fabs is not temperature alone. Ahead of the commercialization planned for 2027, the focus of future evaluation will be whether concrete performance, including long-duration stable operation, power consumption, and introduction cost, becomes clear.