3 ms·

How does 13.5nm light etch features of 7nm and lower? I can sort of see how ultra pure water can focus the light (immersion lithography) and multi patterning (I

How does 13.5nm light etch features of 7nm and lower? I can sort of see how ultra pure water can focus the light (immersion lithography) and multi patterning (I’m not sure how this works really, I would have thought shining light through two masks would make things even more blurry). When the photon hits the silicon why isn’t the dot 13.5nm?

glic3rinu 3y ago
masks dont have the actual shape, but shapes accounting for wave interference patterns that will end up producing the final shape when EUV light passes through. I believe the process of comming up with the correct intereference pattern takes weeks of supercomputing.
- abwizz 3y ago
  sounds legit, any sources?
  - mikewarot 3y ago
    We discussed this 4 months ago in this thread https://news.ycombinator.com/item?id=35301207 https://news.ycombinator.com/item?id=35301207
  - glic3rinu 3y ago
    Jim Keller himself talks about this a little bit here https://www.youtube.com/live/oIG9ztQw2Gc?feature=share&t=1227 https://www.youtube.com/live/oIG9ztQw2Gc?feature=share&t=122... I think I've listen to asianometry (YT channel) talk about this too, but I am unable to find any clip now where he explicitly talks about interference lithography...
atq2119 3y ago
It does seem magical. The one thing I can answer is that multi-patterning does not shine light through two masks simultaneously. Instead, it consists of multiple separate steps. I think for the rest, the point is that light arriving on the waver is not a binary thing, but due to refraction and self-interference light arrives in variable intensities. So within difficult constraints, this allows you to control the area in which the intensity is below our above certain thresholds. I assume that if you then manage to control the chemistry just right, you can then produce features that are smaller than the wavelength of the light -- under severe constraints of what shapes you can produce. You definitely do not get to produce an arbitrary bitmap of sub-wavelength pixel size.
abwizz 3y ago
good question, was also wondering. then again, it's called the wave-lenght, not the wave-width
dist-epoch 3y ago
You just use the "edge" of the light to cut. If you drag a baseball bat through sand, the edge of the cut "channel" is much sharper and narrower than the baseball bat. Now offset the baseball bat a bit and draw another line which is partially overlapped over the first one. You will get the intersection of the two baseball bat wide channels, but it will be much narrower.

glic3rinu 3y ago

masks dont have the actual shape, but shapes accounting for wave interference patterns that will end up producing the final shape when EUV light passes through. I believe the process of comming up with the correct intereference pattern takes weeks of supercomputing.

abwizz 3y ago
sounds legit, any sources?
- mikewarot 3y ago
  We discussed this 4 months ago in this thread https://news.ycombinator.com/item?id=35301207 https://news.ycombinator.com/item?id=35301207
- glic3rinu 3y ago
  Jim Keller himself talks about this a little bit here https://www.youtube.com/live/oIG9ztQw2Gc?feature=share&t=1227 https://www.youtube.com/live/oIG9ztQw2Gc?feature=share&t=122... I think I've listen to asianometry (YT channel) talk about this too, but I am unable to find any clip now where he explicitly talks about interference lithography...

atq2119 3y ago

It does seem magical. The one thing I can answer is that multi-patterning does not shine light through two masks simultaneously. Instead, it consists of multiple separate steps. I think for the rest, the point is that light arriving on the waver is not a binary thing, but due to refraction and self-interference light arrives in variable intensities. So within difficult constraints, this allows you to control the area in which the intensity is below our above certain thresholds. I assume that if you then manage to control the chemistry just right, you can then produce features that are smaller than the wavelength of the light -- under severe constraints of what shapes you can produce. You definitely do not get to produce an arbitrary bitmap of sub-wavelength pixel size.

abwizz 3y ago

good question, was also wondering. then again, it's called the wave-lenght, not the wave-width

dist-epoch 3y ago

You just use the "edge" of the light to cut. If you drag a baseball bat through sand, the edge of the cut "channel" is much sharper and narrower than the baseball bat. Now offset the baseball bat a bit and draw another line which is partially overlapped over the first one. You will get the intersection of the two baseball bat wide channels, but it will be much narrower.