Imaging effects of particles on the surface of EUV mask and wafer

The high spatial resolution of EUV lithography makes it highly sensitive to defects caused by particle contamination on the surface of the mask and the wafer. These particles can degrade imaging quality, cause defects, and ultimately lead to yield loss. This paper investigates the effect of common particle types (BN, SiO2, and C) on the printed image under different conditions. It focuses on determining the range of particle sizes relevant for pattern defectivity for a set of typical use cases (dense line/spaces and dense hexagonal contact holes) in 0.33 NA and 0.55 NA (high-NA) EUV lithography scanners. The ultimate objective is to provide guidelines to prevent unnecessary mask cleaning and facilitate wafer and mask inspection. The study is conducted by modeling the EUV scanners and conducting rigorous electromagnetic field (EMF) simulations using the lithography simulator HyperLith (TM) by Panoramic Technology.