Patent ID: 8338781

Claim:
A charged particle beam apparatus comprising a deflector for deflecting the scan position of a charged particle beam emitted from a charged particle beam source and a controller for supplying a deflection signal to the deflector, wherein: said controller controls the deflector so that the scan position of said charged particle beam is positioned to a reference target object on a specimen on which the reference target object and a plurality of target objects having known dimensions relative to said reference target object are formed, the scan position of said charged particle beam is so deflected as to scan said plurality of target objects, a position error between the deflected scan position and each of said target objects is detected in respect of each of said plurality of target objects, and after that, said controller controls the deflector so that the scan position of said charged particle beam is positioned to the reference target object again, a second position error between the scan position positioned again and the reference target object is detected, a third position error by dividing said second position error by the number of the scanned target objects is obtained, the obtained third position error is added or subtracted to or from the first position error detected in respect of each of said plurality of target objects, and the deflection signal of said deflector in a deflection area of the scan position of said charged particle beam is extracted.