Zeiss covers their mirrors and lenses. The smoothness is extreme: "If you were to enlarge such a mirror to the size of Germany, the largest unevenness – the Zugspitze, so to speak – would be a whole 0.1 millimeters high."
Then they have positioning / tilt accuracy.
"If one of these EUV mirrors were to redirect a laser beam and aim it at the Moon, it would be able to hit a ping pong ball on the Moon’s surface."
What they don't say is what the yield is on these. I've heard they have to try and make X to get y that can hit all the specs.
In the machines themselves didn't they have to build in both an electron microscope and an atomic force microscope for defect detection?
And then the environment they operate in is terrible from a wavelength absorption energy / contamination (tin?) issues etc.
