Ever heard of extreme ultraviolet lithography, or EUV? This technology produces light beyond normal visible wavelengths with a high-powered laser and is used to etch patterns onto the semiconductor wafers used in silicon chips. To prevent contamination, the EUV process takes place in a hydrogen-rich environment.
Semiconductor manufacturers (semi-fabs) started using EUV in the mid-2000s as it enables smaller, faster and more powerful chips for smartphones and advanced computing.
As semi-fabs scaled EUV adoption they faced three challenges: securing enough hydrogen, accommodating the large vacuum and abatement infrastructure, and cutting emissions.
Leveraging decades of expertise
Edwards, a vacuum technology brand within Atlas Copco Group, took up the innovation challenge. The team had already built up a ‘golden thread’ of expertise in gas chemistry, purification and systems integration for the semiconductor industry since the late 1990s.
“Unlike many semiconductor processes, EUV operates in steady state and there is no nasty chemistry in it,” says Chris Bailey, VP Emerging Technologies in the Group’s Semiconductor division. “We’d already done some work on hydrogen recycling in another technology, so if we could do it on anything, we could do it on this.”
The team collaborated with an electrochemical technology company and system integrator, both based in New York State, and NYSERDA (New York State Energy Research and Development Authority), to develop a hydrogen recovery system (HRS) capable of purifying recovered hydrogen to ultra-pure grade.
The hydrogen recovery system (HRS), developed by Edwards, is capable of purifying recovered hydrogen to ultra-pure grade.
Reduced emissions
Most hydrogen worldwide is made from a fossil-fuel starting point. With hydrogen recovery systems, carbon emissions can be avoided.
“There's absolutely a big environmental factor here,” says Technology Manager Zach Dunbar who joined the team in 2016 as the project began to build the electrochemistry behind the system.
“Typically, hydrogen is generated from methane gas, but it could be coal or petroleum, so you emit a lot of CO2 when you produce it. Clearly if you're recycling the hydrogen, then you’re not using that methane or whatever else that produces CO2.”
Removing supply risks
Another, equally strong customer driver is logistics. Supply chains and safety regulations create additional constraints for on-site storage and deliveries.
“There are logistical limits, especially on an island such as Taiwan where some of the biggest chip-manufacturers are located. Every molecule of hydrogen must be imported,” says Chris.
“In some locations, you’re talking about tube trailers of liquid hydrogen being delivered every day,” adds Anthony Keen, Global EUV Technology and Apps Manager in the Semiconductor division.
By recycling hydrogen at point of use, HRS can reduce delivery convoys, ease supply chain risk, improve safety margins and free up storage.
From theory to technology
What began as an explorative R&D project has matured into a commercial offering aligned with the semiconductor industry’s roadmap.
“By purifying and controlling the gas fed back into the EUV tool, we’re now interfacing at both the output and input sides. We’re making a system that’s got to be stable at both ends,” Chris explains.
“In this industry, you can have a great idea 10 or 15 years ago that only becomes relevant now,” says Anthony.
It’s been a long time developing, but this is a technology whose time has come.
