Thermomechanical stability evaluation of various pellicle structures with contaminant particles

Extreme ultraviolet lithography in high-volume manufacturing requires a longer pellicle lifetime; however, the thermal deformation of pellicles due to repeated exposure can shorten the pellicle lifetime. Thermal stress is used as an indicator in most studies to predict the pellicle lifetime, but because the material can break under low thermal stress depending on the mechanical properties, evaluation of thermomechanical stability including thermal stress and mechanical durability is required. In this study, the thermal stress and mechanical stability of pellicles were evaluated through a comparative analysis of crack occurrence points resulting from thermal deformation for various pellicle structures and contaminant particles. The results show that the thermal stress was lower and the crack time was relatively longer for the metal silicide-based material compared with other pellicle structures. Moreover, it was found that the presence of contaminant particles could be the main cause of pellicle breakage.