Extreme ultraviolet lithography

Moore's Law faced a hard physical limit. Deep ultraviolet lithography at 193 nanometers had driven semiconductor progress since the 1990s, but by the 2010s, engineers were printing features smaller than the wavelength of light itself. Multiple patterning techniques bought time, but the industry needed fundamentally shorter wavelengths to continue shrinking transistors.

Extreme ultraviolet (EUV) lithography uses light at 13.5 nanometers—more than 14 times shorter than deep UV. At this wavelength, light is absorbed by nearly everything, including air and glass. The entire optical system must operate in a vacuum with reflective rather than refractive optics. These constraints made EUV development one of the most challenging engineering projects in industrial history.

The adjacent possible for EUV had been theoretically known since the 1980s, but the engineering challenges seemed insurmountable. EUV sources were too weak—early systems produced milliwatts when manufacturing required hundreds of watts. Mirrors degraded under EUV exposure. Photoresists didn't respond predictably. Defect-free mask production seemed impossible. Each problem required independent solutions that took decades to mature.

ASML, a Dutch company spun out of Philips in 1984, became the sole developer of EUV production systems. No single company could master all the required technologies, so ASML assembled an ecosystem: Zeiss for optics, Trumpf and Cymer for light sources, and components from suppliers in Germany, Japan, and the United States. The company spent over €6 billion developing EUV before shipping commercial systems.

The light source exemplifies the engineering challenges. EUV systems vaporize 50,000 tiny tin droplets per second with a high-powered CO2 laser, creating a plasma that emits EUV photons. This approach, called laser-produced plasma (LPP), replaced earlier discharge-produced plasma sources that couldn't achieve adequate power. Cymer (acquired by ASML in 2013) developed the technology, which alone required decades of R&D.

Geographic concentration was intense. ASML's Veldhoven headquarters became the sole source of EUV systems, making it arguably the most strategically important manufacturing site in the semiconductor supply chain. Zeiss's precision optics came from Oberkochen, Germany. The interdependencies meant that semiconductor progress depended on a small number of specialized facilities in Western Europe.

Commercial EUV systems shipped in 2017-2018, with Samsung and TSMC leading adoption for 7nm and 5nm processes. By 2025, EUV had become essential for leading-edge chips—every advanced smartphone, data center processor, and AI accelerator depended on this technology. ASML's monopoly and EUV's criticality made it a focal point of technology competition between the US, Europe, and China, with export controls limiting Chinese access.

EUV lithography represents a peculiar triumph: the culmination of a multi-decade, multi-billion dollar, globally distributed R&D effort concentrated in a single company's product line. No comparable technology exists where the entire industry depends so completely on one supplier's success.