Every advanced chip in your phone owes its existence to a machine that boils tin with a laser 50,000 times a second. This is EUV lithography, and it is arguably the most complex tool humanity has ever mass-produced. The problem is wavelength. To print transistor features only a few nanometers wide, you need light with a tiny wavelength. EUV uses 13.5 nm photons, roughly 14x shorter than the deep ultraviolet light that came before it. But generating and steering that light is brutal. Here is how the light itself is born: • A generator fires molten tin droplets, about 25 microns each, into a vacuum chamber • A pre-pulse from a CO2 laser flattens each droplet into a pancake • A main pulse vaporizes it into a plasma hotter than the Sun’s surface, near 220,000 C • That plasma radiates the precise 13.5 nm light needed, then the cycle repeats tens of thousands of times per second Now the harder part. EUV is absorbed by literally everything, including air and glass. You cannot use lens...