Electrical Rules Checking (ERC)

ERC Rules check for things such as:

• Floating gates.
• Wrong transistor connections (Source and Drain connected together for instance).
• Floating interconnect, Metal, Poly
• Shorted Drain & Source of a MOS 
• No substrate- or well contact ('figure having no stamped connection') 
• Different contacts of substrate / well are connected to different nets
• Distance of MOS to next substrate / well contact too large (Latchup rule) 

Often reported errors are deliberate, for example a gate may have its source and drain connections deliberate connected together to produce a capacitor.