[d_silin]

I read somewhere that scaling semiconductor fabs is incredibly difficult affair, as every minute detail have to be faithfully replicated - down to using the same color of lighting. All that is required to get consistent output quality.

[jamiek88]

You even need identical seismic environments it’s that delicate.

[derefr]

Seems like the best idea would just be to try to plop the new plant next-door to the existing plant, then (and to keep doing that.) Would make the logistics of sourcing the same "everything" a lot simpler.

Intuitively, I'd expect that fabs would plan for this in advance, ensuring that 1. everything they buy, they have ways to get N of the exact same of that thing down the line — the same way that NASA missions contract to ensure they can get precisely-specced replacement parts decades down the line; and 2. that they build their first plant for a given process node in a huge empty expanse of land (much larger than what Plant No. 1 needs) where they either buy all that land ahead of time, or at least have a contract with the municipality to retain right-of-first-refusal on purchases of that land.