Pellicle factors affecting finished photomask flatness

摘要

Previous work has shown that photomask blank flatness as well as photomask patterning and pelliclization all play an important role in finished photomask flatness. Other work has shown that pellicle mounting techniques and pellicle adhesives play a role as well. In this work, a comparison of the impact of various pellicle types, frame flatness, frame shape and pellicle mounting tools on final photomask flatness will be shown. Pellicles with various adhesives, frame shapes and flatness were mounted on blanks and completed photomasks using several mounting tools and the pellicle induced flatness change was measured. These data will be discussed with the objective of demonstrating the effects of pellicle type and mounting tool on photomask flatness.