“The voltage induced by the plasma can destroy the transistor by blowing a hole through the gate oxide or it can degrade the transistor’s performance by embedding charges inside the oxide layer.”
The original Pentium has 3.1 million transistors, and some of its wires connect to the substrate for no reason visible in the working chip. They are diodes that drain charge picked up from plasma etching, a few hundred atoms of oxide away from a dead transistor. Once the chip runs they are reverse-biased and do nothing. Part of the die exists only to survive being made.