EUVL practical mask structure with light shield area for 32nm half pitch and beyond

摘要

The effect of mask structure with light shield area on the printability in EUV lithography was studied. When verythin absorber on EUVL mask is used for ULSI application, it then becomes necessary to create EUV light shield areaon the mask in order to suppress possible leakage of EUV light from neighboring exposure shots. We proposed andfabricated two types of masks with very thin absorber and light shield area structure. For both types of masks wedemonstrated high shield performances at light shield areas by employing a Small Field Exposure Tool (SFET).