Patent ID: 8008631

Claim:
A method of acquiring an offset deflection amount for a shaped beam, comprising: forming reference images of first and second figures which can be shaped by first and second aperture plates placed on a lithography apparatus; forming, using design data of a mark, a reference image of the mark; forming a first convolution reference image obtained by a convolution calculation of the reference image of the mark and the reference image of the first figure and a second convolution reference image obtained by a convolution calculation of the reference image of the mark and the reference image of the second figure; respectively scanning over the mark with charged particle beams having shaped into the first and second figures by using the first and second aperture plates to acquire optical images of the first and second figures; forming a first convolution synthesis image obtained by a convolution calculation of the first convolution reference image and the optical image of the first figure and a second convolution synthesis image obtained by a convolution calculation of the second convolution reference image and the optical image of the second figure; calculating center-of-gravity positions of the first and second convolution synthesis images; and calculating an offset deflection amount for the charged particle beam having shaped into the second figure to match reference positions of the first and second figures based on the center-of-gravity positions of the first and second convolution synthesis images to output a result calculated.