The Lawrence Livermore National Laboratory (LLNL) in the United States is spearheading the development of a cutting-edge thulium-based petawatt laser, which could revolutionize the efficiency of extreme ultraviolet (EUV) lithography systems. This groundbreaking innovation is projected to enhance the efficiency of EUV light sources by approximately 10 times, potentially replacing the current CO₂ lasers used in EUV tools. The implications? Faster chip manufacturing at significantly reduced energy costs.

The Energy Challenge of EUV Lithography

EUV lithography, while critical to advanced semiconductor production, is notorious for its energy consumption. Current Low-NA (numerical aperture) and High-NA EUV systems consume as much as 1,170 kW and 1,400 kW, respectively. The high energy demand stems from the process of generating EUV light:

High-energy laser pulses vaporize tin droplets (heated to approximately 500,000°C).

The resulting plasma emits EUV light with a wavelength of 13.5 nm.

This process necessitates extensive infrastructure, including laser systems, vacuum chambers to prevent light absorption by air, and robust cooling systems. Even the advanced EUV mirrors used can only reflect a small fraction of EUV light, driving the need for ever-stronger lasers.

Introducing BAT: Big Aperture Thulium Laser

LLNL’s Big Aperture Thulium (BAT) laser aims to tackle these challenges head-on. Unlike the 10-micron wavelength CO₂ lasers, BAT operates at a 2-micron wavelength, theoretically enabling a much higher conversion efficiency of tin plasma to EUV light. Additional advantages include:

Higher energy efficiency: BAT employs diode-pumped solid-state technology, which is inherently more energy-efficient compared to gas-based CO₂ lasers.

Better thermal management: The design is optimized to handle heat more effectively, reducing overall power consumption.

The BAT system is also compact and capable of high-repetition rates, making it ideal for pairing with EUV light source systems. Initial experiments have already validated its theoretical potential, with LLNL physicist Brendan Reagan expressing optimism about its transformative impact on EUV technology.

Challenges Ahead

Despite its promise, implementing BAT in semiconductor manufacturing will require overcoming significant hurdles:

Infrastructure upgrades: Semiconductor fabs have been built around existing CO₂ laser-based EUV systems, and adapting to BAT would necessitate extensive modifications.

Timeframe for maturity: EUV technology itself took decades to reach commercial viability. BAT may similarly require years of refinement and integration.

Why BAT Matters

With semiconductor manufacturing projected to consume 54,000 GW annually by 2030—exceeding the total annual energy consumption of countries like Singapore or Greece—the industry is under pressure to develop more energy-efficient technologies. The introduction of Hyper-NA EUV lithography in the future could further exacerbate energy demands, making innovations like BAT critical for sustainable growth.

LLNL’s BAT laser offers a promising alternative, potentially reducing the environmental and economic costs of chip production while enabling higher yields and faster production cycles.

Looking Ahead

If successful, the BAT laser could reshape the future of semiconductor manufacturing by providing a more efficient and sustainable light source for EUV lithography. While significant technical and logistical challenges remain, this innovation highlights the industry’s relentless pursuit of advancing chip-making technologies.