A wafer grounding apparatus and method adaptable to a charged particle beam apparatus is disclosed. A wafer substrate is supported by a wafer mount. A grounding pin is arranged to be in contact with a backside film formed on a backside of the wafer substrate. A grounding pulse generator provides at least one pulse to drive the grounding pin such that dielectric breakdown occurring at the backside film leads to establishment of a current path through the backside films. Accordingly, a current flows in the wafer substrate through this current path and then flows out of the wafer substrate via at least one current return path formed from capacitive coupling between the wafer substrate and the wafer mount.