VLSI Concept · Physical Design
Antenna Effect
Long wires can accidentally become tiny lightning rods during manufacturing.
During plasma etching, long metal wires connected to a transistor gate but not yet connected to the rest of the circuit can accumulate static charge, which discharges through the thin gate oxide and damages it before manufacturing even finishes. This is fixed by adding antenna diodes to bleed off the charge, or by jumping the wire to a higher metal layer partway through routing.