EUV mask infrastructure and actinic pattern mask inspection

With the persistent drive to enable EUV lithography (EUVL) for the continuation of pattern scaling and the close collaborations between suppliers and customers, tremendous progress has been made in the last five years in EUV mask infrastructure development. With the advent of actinic pattern mask inspection (APMI) tool, the only remaining EUV mask infrastructure gap until recently has been closed. We will present real-case examples from inspection of 7nm and 5nm logic node EUV masks with APMI in operation at Intel mask shop and demonstrate that actinic inspection provides defect detection capability beyond the traditional DUV optical and e-beam mask inspection (EBMI) tools for defect control and the guaranty of mask quality. In addition to the main focus on APMI and through-pellicle inspection in this paper, we also provide a brief discussion of other key EUV infrastructure modules for mask production in current EUVL at 0.33NA and future technology extension to enable high NA EUVL at 0.55NA.