US Patent 7714288 Charged particle beam apparatus

Electrification affected on a surface of a sample which is caused by irradiation of a primary charged particle beam is prevented when plural frames are integrated to obtain an image of a predetermined area of the sample in a charged particle beam apparatus. The predetermined area of the sample is scanned with a primary electron beam from an electron gun, and plural frames are generated and integrated while detecting generated secondary electrons with a detector to obtain the image of the predetermined area. If it is determined by a detection signal of the detector that an electrification amount at the predetermined area becomes a specified value when generating plural frames, an electricity removal voltage is applied to a boosting electrode to remove or reduce the electrification, prior to generation of the next frame. Accordingly, the signal-to-noise ratio of the image obtained by integrating plural frames can be improved.