Origin of EUV mask blank defects from ion beam deposition

In EUV lithography mask production, one source of contaminants originates from the targets used to sputter material onto the substrates. In particular, silicon appears to produce more contamination on rough regions of the silicon target. The features were found to be triangular hillocks pointing in the direction of the incident beam. The aim of this research is to prevent this particle formation on the target and thus eventually on the substrate. Both Si and Ru targets were sputtered using different ion beam conditions to understand particle formation mechanisms on the target and explore the ion beam conditions that can mitigate particles. Additionally, SRIM was used to calculate sputtering yields to better understand the mechanisms behind particle formation.