EUVL Mask Fabrication for the 45-nm Node

摘要

The extreme ultraviolet lithography (EUVL) mask differs from its predecessors in many ways. The most significant change is that the EUVL mask is reflective, introducing many new film layers and mask sensitivities. An additional complication is the small linewidths associated with the 45-nm node that is targeted for EUVL mask introduction. This paper concentrates on the physical specifications associated with the 45-nm node EUVL mask. Relative to current masks, the defect levels must be lower and the film quality must be higher. Standard cleans may be incompatible with new mask requirements. To understand the development requirements, the cleaning efficiency, film removal, film roughness, defect levels and film reflectivity are quantified on both EUVL mask film monitors and EUVL masks. Target specifications and measured properties of the 45-nm node masks will be compared.