Image generation apparatus

An image generation method for generating an image of a specimen by scanning the specimen with a charged-particle beam and detecting secondary electrons emitted from the specimen, said method comprising:

• generating a first image of the specimen on an XY stage without correcting deflection of the charged-particle beam;
• producing a first frequency spectrum by performing a frequency analysis on the first image;
• generating a second image of the specimen on the XY stage while correcting the deflection of the charged-particle beam in a direction to remove vibration of the XY stage;
• producing a second frequency spectrum by performing a frequency analysis on the second image;
• subtracting the second frequency spectrum from the first frequency spectrum to calculate a difference at each of frequencies;
• determining a frequency band in which the difference is larger than a threshold value;
• setting the frequency band to a passband of a band-pass filter;
• producing a first vibration signal representing vibration of an electron-optics column which has an electron gun, a deflector, a condenser lens, and an objective lens;
• passing the first vibration signal through the band-pass filter;
• producing a second vibration signal representing vibration of the XY stage;
• adding the first vibration signal, which has passed through the band-pass filter, to the second vibration signal to produce a deflection correcting signal;
• and
• generating an image of the specimen by scanning the specimen on the XY stage with the charged-particle beam and detecting secondary electrons emitted from the specimen while the deflector is correcting the deflection of the charged-particle beam based on the deflection correcting signal.