Method for correcting deflection distortion in an apparatus for charged particle lithography

A method for correcting deflection distortion which appears in an apparatus for delineating a pattern on a sample by scanning a charged particle beam, comprising:

• scanning the charged particle beam on a mark and obtaining deflection data necessary for deflecting the beam to a center of said mark each time said mark is moved by a fixed interval, said mark being provided at a part of a movable work table on which the sample is to be placed and having at least two unequal reference levels whose relative heights are known;
• calculating correction magnitudes of the deflection distortions concerning the respective reference levels of said mark at each moved position of said mark from said deflection data and the distance of the movement of said mark;
• measuring the height of a portion-to-be-delineated on said sample;
• and
• correcting the deflection distortions on the basis of said correction magnitudes and in accordance with said height of said portion-to-be-delineated on said sample.