Respin
Beginner
Making the chip again with fixes after the first version comes back with a problem.
Novice
A new tapeout of a corrected design after the first chips fail or miss a target. A full respin needs a whole new mask set; a metal-only respin replaces only the masks for the wiring layers.
Expert
Costs new masks plus another trip through the fab, about a quarter of a year at advanced nodes. Metal-only respins rewire spare cells and reuse the transistor-layer masks, so teams scatter spare cells over the design before the first tapeout.
Explained in GDS & tapeout (Design Flow).
See also: ECO (engineering change order), Spare cell, Tapeout.