[News] Breakthrough in Lithography: U.S. Develops Laser to Boost EUV Efficiency

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According to reports, the Lawrence Livermore National Laboratory (LLNL) in the United States is developing a petawatt-level laser based on the element thulium. This laser is said to have the potential to improve the efficiency of extreme ultraviolet (EUV) lithography light sources by approximately ten times. It could potentially replace the carbon dioxide lasers currently used in EUV systems, enabling faster chip manufacturing with lower energy consumption.

The energy consumption of EUV lithography systems has long been a major concern. For example, Low-NA (Numerical Aperture) and High-NA EUV lithography systems consume as much as 1,170 kW and 1,400 kW of power, respectively.

This high energy demand stems from the EUV process itself, which involves using high-energy laser pulses to vaporize tin droplets (heated to approximately 500,000°C) at tens of thousands of times per second to create plasma and emit 13.5-nanometer wavelength light.

This requires massive laser infrastructure, cooling systems, and a vacuum environment to prevent EUV light from being absorbed by air. Additionally, advanced EUV mirrors can only reflect a fraction of the light, necessitating more powerful lasers to increase production efficiency.

The “Big Aperture Thulium (BAT) Laser” project led by LLNL aims to address these challenges. Unlike carbon dioxide lasers, which have a wavelength of about 10 microns, the BAT laser operates at a wavelength of 2 microns, theoretically improving the plasma-to-EUV light conversion efficiency during interactions with tin droplets.

Furthermore, the BAT system uses diode-pumped solid-state technology, which offers higher overall electrical efficiency and better thermal management compared to gas-based carbon dioxide lasers.

Initially, the LLNL team plans to integrate this compact, high-repetition-rate BAT laser with EUV light source systems to test its interaction with tin droplets at the 2-micron wavelength.

Brendan Reagan, an LLNL laser physicist, stated that over the past five years, the team has completed theoretical plasma simulations and proof-of-concept experiments, laying the foundation for the project. He believes this development could significantly impact EUV technology and is optimistic about the next steps in research.

However, significant challenges remain in adapting existing infrastructure to deploy the BAT laser for semiconductor production. EUV technology itself has taken decades to mature, and the practical application of BAT may also require considerable time.

Data indicates that by 2030, the annual electricity consumption of semiconductor manufacturing facilities will reach 54,000 GW—more than the annual consumption of countries like Singapore or Greece.

If next-generation Hyper-NA EUV systems are introduced, energy demands could escalate further. The industry’s need for more efficient and energy-saving EUV solutions is growing, and LLNL’s BAT laser undoubtedly offers a promising new option.

(Photo credit: Lawrence Livermore National Laboratory)