NatRefs meet semiconductors

In semiconductor manufacturing, for which precise temperature control is critically important, the chillers employed have traditionally used f-gas refrigerants.

In 2015, however, ATS Japan, a division of U.S.-based chiller manufacturer ATS, decided to begin moving towards the adoption of CO₂ refrigerant for its semiconductor chillers.

ATS Japan now has a chiller – Model GX-20 – which uses CO₂, and it is the first chiller in the semiconductor industry to use this refrigerant, according to the company.

The unit has already attracted attention as a next- generation chiller in Europe, with the company having begun a field trial of the system in June 2019 at a German semiconductor manufacturing company.

Founded in 2001, ATS Japan manufactures chillers for the semiconductor, solar cell, food, and medical device industries among others. Its decision in 2015 to develop a CO₂ chiller was driven in part by Japan’s “Act on Rational Use and Proper Management of Fluorocarbons,” which came into effect that year.

The company also noticed that this Japanese regulation on f-gas management was part of a larger environmental policy trend that was accelerating globally — especially in Europe, one of the company’s main export markets.

“When I was visiting semiconductor factories in various locations throughout Europe, I would often meet local business people who were even more aware of the Kyoto Protocol than those in Japan,” said Toshihide Haruki, sales and marketing manager for ATS Japan.

Haruki said that it was this general awareness, combined with the adoption of the EU F-gas Regulation, that ultimately drove the increase in demand that the company has been seeing in recent years for chillers using refrigerants with low GWPs.

The EU F-gas Regulation stipulates a ban on using certain HFCs (with GWPs greater than or equal to 150) in new centralized and plug-in commercial refrigeration equipment in Europe in 2022.

“We made a rough draft plan for the development of chillers that used CO₂ in 2015 as a response to the increasingly strict regulations and the demands of end users,” Haruki said.

Following the announcement of this draft plan, the company began to coordinate internal resources and proceed to full-scale product development in 2017.

Collaboration among suppliers of CO₂ components was key to overcoming ATS Japan’s biggest challenge during development of its CO₂ system, said Tomoyuki Kariya, development department manager for ATS Japan.

“Once we began to develop the ‘GX’ series, I immediately understood why other companies did not start to develop any CO₂ refrigeration equipment,” Kariya remarked.

The CO₂ parts and components that were needed were not readily available and it made development of the system very difficult.

Compressors, for example, were often only used by the manufacturers in their own products, and sales to outside companies were rare.

This changed, however, after Panasonic announced its “CO₂ family” concept in 2018, where the company would actively make its technology available to outside companies in an effort to expand the CO₂ market in Japan.

As a result, ATS Japan was able to secure the use of Panasonic’s 2-HP CO₂ compressor for its GX-20 CO₂ chiller.

Several other components, however, were still needed and required the cooperation of other companies such as Japan-based CO₂ component supplier Fujikoki for electronic expansion valves, and overseas suppliers such as Danfoss and Temprite.

The cooperation and openness among these component suppliers for CO₂ technology was the ultimate factor that made the development of the GX-20 successful.

Still, the options for CO₂ were very limited, said Kariya. Nevertheless, with the components currently available, ATS succeeded in ensuring the temperature accuracy of the chiller while considering the specific properties of CO₂, the exchange of temperature and pressure, and the responsiveness of the control valve, he said.

“But in order to achieve further temperature accuracy, the cooperation of parts manufacturers will continue to be needed,” Kariya added.

After ensuring the safety level and optimal performance of the system with internal tests, the company delivered its first system to a German semiconductor manufacturing company to carry out a field trial in June 2019. This was done in cooperation with ATS’s German servicing partner Sachsen Kälte GmbH.

“This is the first CO₂ chiller for this industry, so our first priority was to put it into market after ensuring a sufficient level of safety and performance,” saidKariya. “Due to the hard work of our team, we have finally been able to do it and advance the system to its final stage in June. We expect the field trial in Germany will be successful.”

In addition, the company is continuing to investigate and optimize the performance of its system in Japan. The compressor used in the CO₂ chiller, which was tested internally in Japan up until May 2019, was sent to Panasonic for evaluation. The goal is to further reduce power consumption and evaluate the compressor’s durability.

Kariya said that though the company has filed for a patent and finalized the system’s basic configuration, more work still needs to be done.

“We are continuing to look towards improving the performance of the natural refrigerant chiller in various ways, such as improving energy efficiency, reducing water use, improving temperature response and applying our know-how cultivated from our expertise with f-gas chillers,” said Kariya.

Since ATS Japan first unveiled the concept for its CO₂ chiller at “Semicon Europe,” a semiconductor technology exhibition, in Munich, Germany, in November of 2018, interest from end users has been steadily increasing.

“Because of the impact of the EU F-gas Regulation, more local companies than we expected have become aware of the fact that they will not be able to use their current chillers after 2022,” said Haruki, who has visited Germany, France and other countries in Europe several times this year.

In fact, Haruki revealed, the field trial with the end user in Germany, which was originally scheduled to take two years, has been shortened to about eight months due to the pressing situation with the f-gas phase down in Europe.

Going forward, the company is aiming to secure a position as the top CO₂ chiller manufacturer in Europe.

Elsewhere, ATS Japan says that it is also seeing more interest than expected in North America, especially in California where regulations on f-gas use are becoming increasingly strict as well.

The company has, in fact, already anticipated this. “During the entire development period, we closely collaborated with our U.S. team to make sure the CO₂ chiller’s standards and specifications would make it usable in America,” said Kariya. “So we can bring the GX-20 to the North American market at anytime.”

In Europe, ATS Japan says they plan to sell 30 units in its first year of sales.

The useful life of a semiconductor chiller is about 10 years. Considering the growing number of aging units with leak issues, ATS Japan estimates that the potential market for equipment replacements will be about 1,000 units per year.