Effects of pupil discretization and Littrow illumination in the simulation of bright-field defect detection.
The simulation of optical defect detection on wafers by microscopy requires several approximations. For the simulation with Fourier modal methods, the number of modes is limited by memory and time consumption. Furthermore, the illumination pupil has to be divided into discrete incidence angles for plane waves. We present a way to save the computation of most of these incidence angles. It works only for certain configurations of grating period and illumination wavelength but is an accurate and robust approximation in these cases. We present sample calculations for one- and two-dimensional periodic structures with defects.
Rafler
Stephan
S
Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart, Germany.
Petschow
Matthias
M
Seifert
Uwe
U
Frenner
Karsten
K
Göckeritz
Jens
J
Osten
Wolfgang
W