Thin absorber EUVL mask with light-shield border for full-field scanner : Flatness and image placement change through mask process

摘要

When thinner absorber mask is practically applied to the EUVL for the ULSI chip production, it is inevitable to introduce EUV light shield area in order to suppress leakage of the EUV light from adjacent exposure shots. We believe that light-shield border of multilayer etching type is promising structure in terms of mask process flexibility for higher mask CD accuracyIn this paper, we evaluate etching impact of absorber and multilayer on mask flatness and image placement change through mask process of thin absorber mask with light-shield border of multilayer etching type structure. And then, we clarify the relation between mask flatness and mask image placement shift.