Comparing the mechanical stability of the pellicle under mask stage acceleration with different defect conditions

Abstract

In the scanner, various forces act on the EUV pellicle. Identifying the underlying causes of pellicle destruction is challenging, and the criteria for evaluating the lifetime of the pellicle are ambiguous. Therefore, it is essential to analyze the complex forces that affect the pellicle and investigate how they impact its durability. Particle defects, in particular, can significantly reduce the lifetime of the pellicle, leading to mechanical damage such as deformation or destruction. To investigate these effects, we examined how particle defects impact the pellicle in the scanner environment, classifying them based on the type of defect. We modeled a scenario involving mask stage acceleration and compared the impact of defect conditions on pellicles, considering the increased scanner speed of a high-NA scanner. The results show that the stress around the defect increases rapidly due to the acceleration of the pellicle after being deflected by gravity. The embedded defect shows the highest stress, which has the potential to decrease the lifetime of the pellicle due to repeated acceleration. © 2023 SPIE. All rights reserved.