Method of and system for determining the aberration of an imaging system test object and detector for use with the method

摘要

For determining aberrations of an optical imaging system (PL), a test object ( 12,14 ) comprising at least one delta test feature ( 10 ) is imaged either on an aerial scanning detector ( 110 ) or in a resist layer ( 71 ), which layer is scanned by a scanning device, for example a SEM. A new analytical method is used to retrieve from the data stream generated by the aerial detector or the scanning device different Zernike coefficients (Zn).