Electron scattering analysis based on electron ray-tracing in extreme ultraviolet photomask

The electron distribution in extreme ultraviolet (EUV) photomask and its impact on patterning quality are investigated by Monte Carlo simulation and experiments. The simulation of electron ray tracing was accomplished using GEANT4 software to investigate the electron scattering properties within ArF and EUV photomask. The authors showed that EUV photomask has an additional electron distribution in the range of 2 mu m, and that it is generated by the transverse propagation of electrons at the boundary of the Mo and Si layers. Furthermore, the specific electron distribution of EUV photomask results in a size error of the measured pattern, with respect to the design size, according to pattern density and electron dose. To correct this size error, the authors propose the use of an electron beam (100 keV), or H+ ion beam (50 keV), or a mask-process-correction based on data biasing. (c) 2014 American Vacuum Society.