Defect printability and defect inspection simulations of patterned EUVL mask using rigorous coupled-wave analysis

Rigorous coupled-wave analysis(RCWA) is applied to computing near-field of mask scattered by patterned absorber and defects buried in Mo/Si multilayer. Especially, a method of modeling phase defect for application of RCWA is provided, which transforms the multilayer structure deformed by defect into straight multilayer structure with inhomogeneous dielectric constant. This mask near-field is used to get the aerial image as well as mask inspection image of confocal microscope. Using these simulation methods, printability of both phase and amplitude defect are investigated over various size of defect. This study shows that the change in critical dimension(CD) of line and space pattern increases linearly with defect height of phase defect, while increases nonlinearly with that of amplitude defect. A modeling of confocal microscopy is also shown with an example of actinic inspection simulation.