Influence of e-beam-induced contamination on the printability of resist structures at 157-nm exposure

A CD-SEM was used to contaminate specific areas in dense line test structures on a 10x chrome on glass binary mask with e-beam induced deposition of hydrocarbons. Different degrees of contamination have been realised by varying the exposure time. Additionally, styrene was deposited with focussed ion beam (FIB) at different doses. The impact of the transmission loss caused by the deposited carbon was investigated by printing the manipulated test structures using Sematech's 157nm Exitech Micro Stepper and an experimental 157nm resist. Resist line width variations revealed the impact of the mask deposits on imaging. Additionally, simulations have been performed using 2D Kirchoff approximations in order to predict changes of the process windows and CD.