EUV lithography
Printing circuit patterns with light at a wavelength of 13.5 nanometres. The Dutch company ASML is the only maker of the machines, which turns them into a geopolitical question.
The light is produced by firing a laser at molten tin droplets fifty thousand times a second so they vaporise into plasma. At that wavelength radiation is absorbed by everything, including air and ordinary glass, so the whole beam path sits in vacuum and the optics are mirrors built from dozens of atom-thin layers by Zeiss — among the flattest surfaces humanity has manufactured. One machine costs around $150 million, weighs as much as a couple of buses and ships in several planeloads. The technology reached volume production in 2019 and underpins everything below seven nanometres. The next generation, High-NA, costs twice as much and has begun installation at Intel and TSMC.