Patent ID: 6573015
Filing Date: 2003-06-03
Classification: G03F

Abstract:
A method of measuring an optical aberration of a target projecting optical system by use of a measuring mask having measuring patterns, wherein each of said measuring patterns comprises plural pattern parts being separated from each other, and said plural pattern parts provide individual widths which are simply increased on first and second directional axes non-parallel to each other and vertical to a plane of said mask, provided that said width of each of said plural pattern parts is unchanged at least on the first and second directional axes, andwherein said method comprising the steps of: projecting said measuring patterns of said measuring mask through said target projecting optical system onto a resist film over a measuring wafer to form photo-resist patterns representing said plural pattern parts over said measuring wafer; carrying out a pattern recognition of said photo-resist patterns by irradiating a light beam onto said measuring wafer with scannings in both first and second directions parallel to said first and second directional axes to obtain pattern recognition signals for said photo-resist patterns; calculating best focus positions on the basis of said pattern recognition signals; and calculating said optical aberration of said target optical system on the basis of said best focus positions.