Charged-particle beam system

A charged-particle beam system used to fabricate or inspect semiconductor devices comprises the charged-particle beam accurately brought into position on a workpiece. The system has a workpiece stage, a laser metrology system for measuring movement of the stage, a first calculation unit for calculating the difference between the amount of movement of the stage measured and a target amount of movement of the stage. The amount of movement of the stage produced between the instant when the difference is calculated and the instant when the beam deflection system is started is calculated. Signals indicative of the calculated amounts are supplied to the deflection system.