DETERMINING THE ABERRATIONS OF AN IMAGING SYSTEM

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).