You might assume global trade always offers a backup option. It does not. The answer is 0. Carl Zeiss SMT is an absolute monopoly. There is no alternative. ASML recognized this physical reality and quietly bought a quarter stake in the Zeiss subsidiary just to secure their own existence. Cornering a market like this requires manufacturing at tolerances that border on the absurd. Extreme ultraviolet light has a wavelength of exactly 13.5 nanometers. Reflecting it without scattering the beam and destroying a $30,000 silicon wafer requires an impossibly smooth surface.