Patent ID: 7126120
Filing Date: 2006-10-24
Classification: G01N,H01J

Abstract:
1. A specimen observing method based on an electron microscope, comprising: a step of picking up enlarged specimen images by changing focal position of an electron beam in relation to a specimen; a step of image-calculating image sharpness coefficients of the enlarged specimen images; and a step of deciding the number of peaks on a curve indicative of the relation between focal position of the electron beam and image sharpness coefficient, wherein when two peaks are determined to exist in said decision, an astigmatism correction process proceeds, said astigmatism correction process including: a step of picking up enlarged specimen images by changing astigmatism correction current of a stigmator in X direction; a step of image-calculating image sharpness coefficients of the enlarged specimen images; a step of determining a minimum position sandwiched by two peaks on a curve indicative of the relation between the astigmatism correction current of said stigmator in X direction and the image sharpness coefficient; a step of setting the astigmatism correction current of said stigmator in X direction to a current value corresponding to said minimum position; a step of picking up enlarged specimen images by changing astigmatism correction current of a stigmator in Y direction; a step of image-calculating image sharpness coefficients of the enlarged specimen images; a step of determining a minimum position sandwiched by two peaks on a curve indicative of the relation between astigmatism correction current of said stigmator in Y direction and image sharpness coefficient; and a step of setting the astigmatism correction current of said stigmator in Y direction to a current value corresponding to said minimum position.