"The prototype, completed in early 2025 by former ASML engineers who reverse-engineered the Dutch company's machines, is operational and generating EUV light". "recruits are working under false identities inside secure facilities"
China must be paying them a fortune for this theft, no wonder they want to remain anonymous. The basic technique ASML uses to create the EUV light is public knowledge and ASML even describes it, but the machinery to do it is not.
They shine a powerful industrial CO laser at microscopic droplets of molten tin inside a vacuum chamber. When the laser energy is absorbed, the tin is turned into an extremely hot plasma that emits extreme ultraviolet light with a peak wavelength of about 13.5 nm.
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fwww.asml.com%2Fen%2Ftechno...
I assume the thieves have been able to replicate that part, but there's a lot more to it. Apparently most of the light is lost. They can't use any refractive lenses so it is all channeled by coated mirrors.
"To get enough brightness for high-volume manufacturing, the tin-droplet and laser interaction is repeated up to about 50,000 times per second. The combination of high repetition rate, precise droplet positioning, and efficient collection optics produces the EUV power at the scanner input needed to expose hundreds of wafers per hour."