Relative lifetime estimation of EUV pellicle by normalized thermal stress

Abstract

The lifetime of pellicles is difficult to predict accurately due to the influence of various factors. However, even an approximate estimation would be highly useful. To address this, we proposed a criterion for comparing pellicle lifetimes using a fatigue curve. By modeling the EUV exposure environment, we calculated the thermal stress on pellicles and applied it to the fatigue curves to analyze the lifetime variations based on pellicle materials, structures, source power, and defects. As a result, the metal silicide and carbon nanotube structures had stable lifetimes even under high source power, showing their potential as next-generation pellicle materials. Furthermore, we found that pinhole defects within the pellicles significantly reduced their lifetimes.