Patent ID: 7649172

Claim:
Charged particle beam equipment for irradiating an observed sample with a charged particle beam that is moved in a scanning motion in an X direction and a Y direction to obtain an image of the observed sample, the equipment comprising: magnification error value calculating means which calculates magnification error values in the X direction and the Y direction by performing coordinate transformation in an FFT spatial domain; and data-processing means for obtaining correction subject information from the observed sample and correcting it using the magnification error values, wherein the coordinate transformation in the FFT spatial domain is performed by using a coordinate transformation expression, wherein the coordinate transformation expression is derived by: doing a rotation transform with rotation angle θ to an ideal coordinate system obtained by providing the FFT transformation to a standard size sample whose pattern direction of a periodic structure corresponds with the X direction or the Y direction of the image, the periodic structure having a known periodic pitch, and applying a scaling transformation with magnification (mx, my) to the rotation transformed ideal coordinate system, wherein the magnification error values are calculated by: doing the FFT transformation to the image obtained by imaging the standard size sample, and substituting structure information extracted from the coordinate system of the image in the FFT spatial domain into the coordinate transformation expression.