Comments by "Winston Smith" (@kryts27) on "What ASML Has Next After EUV" video.

  1. Because in Cassegrain optics, or in a Schmidt-Cassegrain telescope, the final light path needs to pass through the centre of primary mirror with a curved secondary mirror. The improved image resolution over Newtonian mirror optics is a real improvement though. Unfortunately, unlike the Newtonian telescope, you probably don't have the finesse to grind the secondary mirror to the required grade.
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  2. Why not use X-ray lithography? You get the etching capilities down well below sub-nanometre size. Just doing some quick math, X-rays range from 10nm to 0.01nm; up to 100 times smaller than UV etching. Of course, X-rays are much more penetrative than UV light and the ionizing potentially goes much deeper into the silicon xstal lattice (so why not expose it for a shorter time). So maybe why X-ray lithography is not seriously deployed to wafer manufacturing just yet. Anyway, very likely that ASML has already designed X-ray lithography etching anyway, or is working on a prototype.
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