Patent ID: 7175952

Claim:
A method of generating mask distortion data of a first thin film of a production mask formed with first positional accuracy measurement marks and having at least one first thin film formed with a transmittance portion and a blocking portion of a charged particle beam of a predetermined pattern, comprising steps of: obtaining a positional accuracy measurement mask by forming second positional accuracy measurement marks at substantially same positions as those of said first positional accuracy measurement marks on mask blanks having at least one second thin film, and forming third positional accuracy measurement marks on said second thin film; measuring positions of said second positional accuracy measurement marks and said third positional accuracy measurement marks of said positional accuracy measurement mask; calculating a correlation function between positions of said second positional accuracy measurement marks and said third positional accuracy measurement marks of said positional accuracy measurement mask; measuring positions of said first positional accuracy measurement marks of said production mask; and generating mask distortion data on said first thin film of said production mask from positions of said first positional accuracy measurement marks of said production mask by using said correlation function.