nx_cleanroom.nx

nx_cleanroom.nx -- LIB: the fab CLEANLINESS twin. Answers "can an enclosed (3D-printer-type) chamber match a clean room?" mechanistically. The required cleanliness scales with FEATURE SIZE: a killer particle is ~half the feature, so a micron node tolerates particles a HEPA filter removes trivially, while a nanometer node needs ISO-1 air. Methods: open bench (room air ~ISO9), an ENCLOSED HEPA laminar-flow chamber (mini-environment, ~ISO5), enclosed ULPA + positive pressure + sealed handling (~ISO3), and a full clean room (~ISO1, which ITSELF uses mini-environments at the tool). Lower ISO number = cleaner. This models the established mini-environment / SMIF practice + the DIY proof (Zeloof, CMU Hacker Fab build working ICs at micron nodes with NO clean room). never-brick #26: pure logic. license_tier: ORIGINAL