Earlier quoted context omitted.
There are various limits in play: https://www.extremetech.com/computing/97469-is-14nm-the-end-... . At sub-nanometer we're talking about features of 5-10 atoms across. At that scale you get effects like electrons quantum tunneling between transistors: https://www.theverge.com/circuitbreaker/2016/10/6/13187820/o... . We probably won't get there with existing silicon technology.
I read on HN, a couple months ago, these numbers no longer represent the physical size of anything but are now just a marketing label, a sort of 'performance equivalent to a theoretical size of'. Anyone know if there's any truth to this? Might try to find the comment later when I have time.
There is a ton of black magic going on here with layers being stacked vertically and masks not having any obvious visual resemblance to the shape they project on the silicon because of the interaction between the photons / xrays and the masks due to the fact that the required resulting image is small relative to the wavelength of the particles used to project it.
There is a super interesting youtube video floating around about this that I highly recommend, it's called 'indistinguishable from magic':
https://www.youtube.com/watch?v=NGFhc8R_uO4
It's up to date to 22 nm. Highly recommended.