Electrical rule check (ERC)
Beginner
Checking for wiring mistakes that make no sense, like an input joined to nothing.
Novice
Checks for connections that make no electrical sense, such as a gate input connected to nothing (it would drift unpredictably), two outputs wired together, or a piece of the silicon that isn’t tied to the supply as it must be.
Expert
Checks on extracted connectivity: floating gates, shorted outputs, wells without taps, and gates tied directly to a supply rather than through a tie cell. Usually run with the LVS deck. Designs with several supplies produce false reports unless the deck knows which supply each region uses.