Ask HN: What happens after 1nm process nodes in semiconductor manufacturing?

Nothing. Xnm stopped having clear physical meaning when manufacturing moved to non-planar process. TSMC already has 2 nm nodes in research and sub-nm process research is next. sub-1 nm should be coming around 2025.

Best way to track progress is to follow MTr/mm² Millions of transistors per square millimeter (it's not exactly transistors but transistors and flip-flops with different weights) It tells us how many logical components tehre are per mm².

It's likely that the nm number will continue to get smaller, since the node name is marketing at this point, and isn't related to any physical semiconductor measurement anymore.

As for quantum tunneling, it is likely to be mitigated or exploited at some point. If not, maybe we'll have to use something else, like gallium arsenide[0] instead of silicon.

[0] https://en.wikipedia.org/wiki/Gallium_arsenide