3 ms·

You can use lenses and curved mirrors to make a larger mask focus the light onto a smaller area.

naasking 4y ago
That still seems pretty delicate. The lenses and mirrors would have to be aberration-free to an extreme degree so as to not introduce too many artifacts, and moving the mask further from the surface would increase risk of diffraction artifacts, no?
- haneefmubarak 4y ago
  It is, but that's how modern semiconductor lithography is done. Massive lenses and mirrors (both made of different materials that normal, since they need to have optical properties at wavelengths much smaller than human vision) are manufactured at great cost to ensure that it is free of aberrations. The extremely limited supply of these is actually one of the many factors that restricts the ability to move to newer processes and scale production capability of newer lithographies.
  - naasking 4y ago
    For good telescope optics, we look for something like 1/4 - 1/6 wavelength tolerance, minimum. That's for optical wavelengths, but photolithography is in the UV range, so that's already stricter tolerance in absolute terms because of the shorter wavelength, but how does the tolerance in relative terms compare? Thanks for the info!
    - voldacar 4y ago
      Read up on the Zeiss optics that go into the ASML EUV machines. (or at least what is publicly available knowledge). It's truly insane
- deleted 4y ago
  [deleted]
- Tuna-Fish 4y ago
  They go pretty hardcore on the optics. Have a look at their light path: https://www.asml.com/-/media/asml/images/technology/43679-inside-nxe3400.jpg?mw=1200&rev=117e2fba11004fc7a59362167df27a8a&hash=3B700AAB58CEB68BF0FB956073BEFC37 https://www.asml.com/-/media/asml/images/technology/43679-in...
- kosievdmerwe 4y ago
  One youtube video[1] I watched had someone state that if you scaled up one of the curved mirrors to the size of the Earth, the largest imperfection would be the width of a hair. [1] https://www.youtube.com/watch?v=en7hhFJBrAI https://www.youtube.com/watch?v=en7hhFJBrAI around 7:30

That still seems pretty delicate. The lenses and mirrors would have to be aberration-free to an extreme degree so as to not introduce too many artifacts, and moving the mask further from the surface would increase risk of diffraction artifacts, no?

haneefmubarak 4y ago
It is, but that's how modern semiconductor lithography is done. Massive lenses and mirrors (both made of different materials that normal, since they need to have optical properties at wavelengths much smaller than human vision) are manufactured at great cost to ensure that it is free of aberrations. The extremely limited supply of these is actually one of the many factors that restricts the ability to move to newer processes and scale production capability of newer lithographies.
- naasking 4y ago
  For good telescope optics, we look for something like 1/4 - 1/6 wavelength tolerance, minimum. That's for optical wavelengths, but photolithography is in the UV range, so that's already stricter tolerance in absolute terms because of the shorter wavelength, but how does the tolerance in relative terms compare? Thanks for the info!
  - voldacar 4y ago
    Read up on the Zeiss optics that go into the ASML EUV machines. (or at least what is publicly available knowledge). It's truly insane
deleted 4y ago
[deleted]
Tuna-Fish 4y ago
They go pretty hardcore on the optics. Have a look at their light path: https://www.asml.com/-/media/asml/images/technology/43679-inside-nxe3400.jpg?mw=1200&rev=117e2fba11004fc7a59362167df27a8a&hash=3B700AAB58CEB68BF0FB956073BEFC37 https://www.asml.com/-/media/asml/images/technology/43679-in...
kosievdmerwe 4y ago
One youtube video[1] I watched had someone state that if you scaled up one of the curved mirrors to the size of the Earth, the largest imperfection would be the width of a hair. [1] https://www.youtube.com/watch?v=en7hhFJBrAI https://www.youtube.com/watch?v=en7hhFJBrAI around 7:30