FIB circuit edit
Beginner
Cutting and adding tiny wires on a finished chip with a very fine beam, to try out a fix before new stencils are made.
Novice
Changing the wiring of an individual finished chip with a focused ion beam (FIB): a finely aimed beam of charged atoms that can drill through layers to cut a wire, or lay down metal to add one.
Expert
Proves a wiring fix on a handful of chips in days, before the team pays for new metal masks. Edits are slow and only a few fit on each chip, so a FIB edit validates a fix and never replaces one.
Explained in After tapeout (Extras).
See also: ECO (engineering change order), Spare cell.